Differences and connections between metallurgy and chemical engineering

Metallurgy is the process and technology of extracting metals or metal compounds from ores, and using various processing methods to produce metal materials with specific properties.

Chemical engineering is short for the field of chemistry engineering; it is a broad category, and metallurgy, being a subset of it, falls under chemical engineering. In the early days, university programs only included chemical engineering; it was not until the rapid development of the national economy and non-ferrous metals, along with an increasing level of specialization, that metallurgy as a field of study emerged.

[Hidden chemical industry catalog] Chemical industry: The chemical industry, chemical engineering, and chemical technology are all referred to as the chemical industry. The chemical industry includes petrochemicals, agrochemicals, pharmaceuticals, polymers, paints, oleochemicals, and more. They emerged in different historical periods, each with its own meaning, yet they are closely related, interpenetrating, and continuous, being endowed with new content throughout their development. Early human life relied more on the direct use of natural materials. Gradually, the inherent properties of these materials became insufficient to meet human needs, leading to the development of various processing techniques aimed at deliberately transforming natural materials into new substances with diverse properties, and these techniques were gradually put into practice on an industrial scale. Broadly speaking, any process that uses chemical methods to alter the composition or structure of substances, or to synthesize new substances, falls under chemical production technology, also known as chemical engineering; the products obtained are referred to as chemicals or chemical products. Initially, chemicals were produced in manual workshops, which later evolved into factories, and gradually a distinct sector of production emerged, namely the chemical industry. With the development of productivity, some production sectors, such as metallurgy, refining, papermaking, and leather processing, have been separated from the chemical industry as independent sectors. With the rapid development of large-scale oil refining industries and petrochemical industries, a new discipline called chemical engineering emerged. Based on chemistry, physics, and mathematics, and incorporating other engineering techniques, it focuses on studying the common principles underlying chemical production processes and addressing the various engineering challenges that arise as production scales up. This discipline enabled the chemical industry to reach a new level of efficiency, moving from an empirical or semi-empirical approach to one based on theory and prediction. 　　In order to survive and thrive, humans have continuously struggled against nature, gradually deepening their understanding of the world around them, and thus acquiring the ability to conquer nature and transform the world. Through long periods of historical practice, humanity has become increasingly adept at making use of natural conditions, thereby creating a rich material world for itself. 　　In ancient times, people’s lives relied more on the direct use of natural materials or on extracting what was needed from them. Since the inherent properties of these substances cannot meet people’s needs, various processing techniques have been developed to transform natural materials into new substances with diverse properties, and these techniques have gradually been put into practice on an industrial scale. Any process that uses chemical methods to alter the composition or structure of substances, or to synthesize new substances, falls under chemical production technology, that is, chemical engineering; the products obtained are known as chemicals or chemical products. In this way, many substances that do not exist in nature are continuously created. Initially, such products were manufactured in handicraft workshops; later, they were produced in factories, and gradually a specific sector of production emerged, namely the chemical industry. With the development of productivity, some production sectors, such as metallurgy, refining, papermaking, and leather processing, have been separated from the chemical industry as independent sectors. As the large-scale petroleum refining industry and petrochemical industry thrived, chemical engineering – a discipline that relies on chemistry, physics, and mathematics along with other engineering techniques to study the common principles underlying chemical production processes and to address the numerous engineering challenges that arise during scale-up – further developed. It raised chemical industry production to a new level, moving from an empirical or semi-empirical stage to a new phase of theory and prediction (see the history of chemical engineering), enabling the chemical industry, with its capacity for large-scale production, to create vast amounts of material wealth for humanity and accelerate the progress of human society. 　　In modern Chinese, the chemical industry, chemical engineering, and chemical technology are all referred to simply as \"chemical engineering.\" They emerged at different historical periods, have distinct meanings, yet are closely related and interpenetrate one another. In people’s minds, the term \"chemical engineering\" has *traditionally come to stand as a synonym for an entire field of knowledge and industry. Its significant importance in the national economy and engineering technology has sparked widespread interest, attracting thousands of people who devote their entire lives to it. Below, the diverse aspects of the chemical industry and its significant contributions are briefly illustrated from various fields of human society. 　　 Fine chemicals The fine chemical industry is the general term for the industry that produces fine chemicals, abbreviated as “fine chemicals”. The meaning of fine chemicals is still under discussion abroad to this day. Currently, chemical products that possess the following characteristics are generally referred to as fine chemicals, namely: 1. A large variety of products, with rapid updates ； 　　2. Low output, with production mostly occurring in intermittent fashion ； 　　3. Functional or for end-use purposes ； 　　4. Many are composite products, and their performance is determined by formulation and other technical factors ； 　　5. High requirements for product quality ； 　　6. High commerciality, with most being sold under brand names ； 　　7. High technology intensity, requiring continuous technical development of new products and research on application technologies, with an emphasis on technical services ； 　　8. Lower equipment investment ； 　　9. High value-added rate, etc. 　　The scope of fine chemicals varies from country to country, but it can generally be categorized into over 40 industries and fields, including pharmaceuticals, pesticides, synthetic dyes, organic pigments, coatings, fragrances and flavors, cosmetics and personal care products, soaps and synthetic detergents, surfactants, printing inks and their additives, adhesives, photosensitive materials, magnetic materials, catalysts, reagents, water treatment agents and polymer flocculants, papermaking additives, leather processing additives, additives for synthetic materials, textile dyes and finishing agents, food additives, feed additives, veterinary drugs, chemicals for oil fields, petroleum additives and refining aids, cement additives, mineral flotation agents, chemicals for casting, metal surface treatment agents, synthetic lubricants and lubricant additives, chemicals for use in automobiles, aromatic deodorants, industrial antimicrobial and antifungal agents, electronic chemicals and materials, functional polymer materials, and biochemical products. [Edit this paragraph] Chemistry and Human Civilization The relationship between humanity and chemistry is very close; in modern life, we rely on chemical products almost at all times. From aspects of material life such as clothing, food, housing, and transportation, to spiritual aspects such as culture, art, and entertainment, chemical products are essential for meeting these needs. Some chemical products have played a groundbreaking and important role in the history of human development. Their production and application even represent a certain historical stage of human civilization. 　　Cooked food that can be ignited represents a remarkable advancement in human history ； By the time chemical processing techniques such as drying herbs, brewing wine and making vinegar, firing pottery to produce bricks, smelting copper and iron, extracting oil to make lacquer, textile weaving and dyeing, and papermaking and printing had emerged one after another, hundreds of thousands of years had already passed in history. The accumulation of these skills created a valuable heritage from ancient times to the Middle Ages, and also laid the foundation for the development of the chemical industry. (See the history of the chemical industry’s development.) An ally of the Industrial Revolution, the chemical industry has, since its inception, provided the essential basic materials for various industrial sectors. As an assistant to the industrial revolutions in various periods, it is precisely this historical mission that it undertakes. During the Industrial Revolution of the 18th and 19th centuries, handicraft production gave way to machine-based production; the steam engine was invented, and large-scale social production began – which was precisely the period when the modern chemical industry took shape. Driven by the urgent needs of the Industrial Revolution, technologies such as the Leblanc process for producing pure soda ash came into being, which also led to the development of the existing lead chamber process for producing sulfuric acid, thereby meeting the demand for acids and alkalis in industries such as textiles, glass, and soap manufacturing. At the same time, with the rise of the iron and coking industries, organic chemistry based on aromatic compounds separated from coal tar and acetylene produced from calcium carbide also developed. Synthetic dyes, chemically synthesized drugs, synthetic fragrances, and the like were successively introduced, while rubber tires, celluloid, and nitrocellulose were also put into production. In this way, the early chemical industry provided the necessary raw materials and auxiliary goods for the textile industry, transportation sector, power industry, and machinery manufacturing industry, contributing to the success of the Industrial Revolution. 　　After two world wars in the 20th century, technologies such as catalytic cracking and catalytic reforming emerged in the oil refining industry, leading to a significant increase in the production of gasoline, coal oil, diesel, and lubricants. In particular, after the industrialization of the hydration of propylene to produce isopropanol, processes for producing ethylene and propylene through hydrocarbon cracking were also developed successfully. This enabled the production of basic organic chemicals to be built on a solid technical foundation provided by the petrochemical industry, thus making it possible to supply various industrial sectors with large quantities of organic raw materials, solvents, additives, and more. From then on, the ability to produce ethylene through hydrocarbon cracking has often been used as a **indicator of the development of petrochemical production capacity. On the other hand, the high-pressure and high-temperature technology for ammonia synthesis using the Haber-Bosch process was put into industrial use, and nitric acid came into production, resulting in the emergence of a large amount of nitrated substances. In particular, this led to the development of explosives from black powder to octogen, with their specific energy increasing by more than ten times. This not only met the urgent needs of war, but more importantly, it was applied in civil blasting projects such as mines, railways, and bridges. Furthermore, the chemical industry has made critical contributions to isotope separation in nuclear engineering and to the use of rocket propellants in the aerospace industry. 　　The pillar of agricultural development: For a long time, humanity has relied on agriculture for its food and clothing. Since its inception in ancient times through slash-and-burn farming, agriculture has relied on a large amount of manual labor and has developed very slowly due to various natural constraints. In the 19th century, the use of agricultural machinery gradually improved working conditions. However, in agricultural production, a real increase in yield per unit area occurs only after the application of chemical fertilizers and pesticides. Practice has shown that among all the measures taken to increase agricultural yields, fertilizers account for 40% to 65% of the impact. Building on the robust development of the petrochemical industry, the large-scale production of synthetic ammonia and urea has resulted in fertilizers accounting for a significant proportion of chemical products. In 1985, the world’s total fertilizer production reached approximately 140 Mt, making it one of the major chemical products. In recent years, the development of nitrogen, phosphorus, and potassium compound fertilizers as well as micronutrient fertilizers has further met the needs of different soil types and crops. 　　In early times, humans used natural plants, animals, and minerals to control pests and diseases in crops. It was not until the end of the 19th century, with the emergence of the modern chemical industry, that new era of chemical control in agriculture began, using Paris green (an arsenic-based substance) to kill the potato beetle and Bordeaux mixture to combat downy mildew in grapes. In the 1940s, insecticides and herbicides such as organochlorines, organophosphates, and phenoxycarboxylic acids were produced and widely used in agriculture, forestry, animal husbandry, and public health. However, some of these pesticides in this generation have caused ecological pollution due to their high residues and toxicity, and have been banned by many countries. In recent years, some new pesticides that are efficient, have low residues, and are low in toxicity have been developed. Pyrethroids (pyrethrum is a plant with insecticidal properties) are a type of bio-inspired pesticide; just a few grams are needed per acre, and they do not pollute the environment. They have already been put into industrial production. Furthermore, biopesticides are currently the most active field in pesticide research. 　　Modern agriculture uses plastic films such as high-pressure polyethylene and linear low-density polyethylene for mulching the soil or for seedling cultivation in greenhouses, which can significantly increase crop yields; their use is being promoted on a large scale. 　　Weapons against diseases: Medicine and pharmacology have always been areas that humanity has strived to explore. In China’s earliest pharmacological work, the \"Shennong Bencao Jing\" (compiled around the 1st century AD), the properties, preparation methods, and combinations of 365 different drugs were recorded. Compendium of Materia Medica, written by Li Shizhen during the Ming Dynasty, lists 1,892 different medicinal herbs. These medicines are derived from natural minerals or plants and animals; most of them need to be processed through soaking before they can be used, in order to enhance their medicinal properties or eliminate any toxicity. From the late 19th century to the early 20th century, chemically synthesized drugs such as the antipyretic and analgesic aspirin, the drug \"606\" (an arsenic-based substance) for treating syphilis, and the antimalarial drug quinine were developed. These drugs had low production costs, high purity, were not affected by natural conditions, and exhibited significant therapeutic effects. In the 1930s, chemical analysis methods were used to determine the structure of vitamins in fruits and rice bran, and synthetic methods were employed to produce vitamins such as vitamin C and vitamin B1, thereby addressing the issues of insufficient yields and unstable quality associated with extracting vitamins from natural sources. After the introduction of sulfonamides in 1935, they saved tens of thousands of patients suffering from puerperal fever. The discovery and production of penicillin had an astonishing effect in treating wounded soldiers during World War II. Streptomycin, along with sodium aminosalicylate and reserpine, succeeded in defeating the tuberculosis bacteria, putting an end to the threat posed by this widespread disease to humanity during that historical period. Diseases such as smallpox, plague, and typhoid were among the scourges that humanity could not control until the 19th century; it was only after antiviral vaccines were put into industrial production that these infectious diseases were essentially eradicated. Vaccines remain a powerful weapon in humanity’s fight against viral diseases. There are also various clinical chemistry reagents and new drug formulations emerging continuously, which have greatly improved healthcare and provided more reliable protection for human health. 　　Ways to improve life: The products offered by the chemical industry are diverse. In addition to producing a large range of materials used to manufacture various goods for people’s use, there are also products that are used in small quantities but have very significant effects, helping to continuously improve people’s lives. For example: various food additives used for food preservation, flavoring, and enhancing nutrition ； Plant growth regulators and preservatives to increase the yield of vegetables and fruits and maintain their freshness ； Feed additives that promote high yields of meat and eggs ； Basic raw materials and additives for the production of cosmetics, as well as fragrances and flavorings ； Paints for houses, furniture, and various tools and equipment used for decoration ； Pigments for various printing inks ； As well as surfactants for cleaning products, and so on – the list is endless. There are also movie film (photo-sensitive material), audio (video) tapes (magnetic recording material), as well as the recently introduced laser TV discs (CDs), and so on. By utilizing these means of transmitting sound and images, communication can be enhanced, historical scenes can be recreated, and exquisite art can be performed. With the help of information recording materials, it is possible to expand people’s horizons to outer space, the depths of the ocean, or even inside the human body, and to examine the structure of atoms as well; this provides the conditions necessary to enhance human spiritual civilization and uncover the mysteries of nature. [Edit this paragraph] Chemicals and Materials The improvement in industrial, agricultural production as well as daily life relies on materials. According to statistics, by 1984, there were approximately 9 million different chemical substances in the world, of which around 430,000 were used as materials in industrially developed countries. Although there are many types of materials, when classified by their chemical composition, they can be summarized into three main categories: metal materials, inorganic non-metallic materials, and polymer materials. There are also those who classify composite materials as the fourth major category, or regard them as a new type of material derived from the three major categories. Generally speaking, except for metals which are products of the metallurgy industry, the rest are materials produced by the chemical industry. 　　Inorganic non-metallic materials are divided into traditional materials and new types of materials. The former are mainly silicate materials ； The latter has a diverse composition and has developed rapidly in recent years. 　　Silicate materials refer to glass, ceramics, cement, and enamel, etc. They are produced using silicate-containing ores as raw materials, and are widely used as building materials, as well as in daily goods and arts and crafts. Although their main drawback is their brittleness and tendency to break, glass and ceramics still exist ； However, due to the easy availability of raw materials, simple production processes, good chemical stability of the product, as well as advantages such as high hardness, heat resistance, and corrosion resistance, it has a wide range of applications, large production volumes, and continues to develop. 　　New inorganic non-metallic materials mainly include special ceramics. With the development of industry and agriculture, **industry, and science and technology, new types of structural ceramics have been developed one after another. They are composed of various oxides, silicides, carbides, nitrides, fluorides, borides, and so on. They mainly include high-temperature resistant materials, electrical insulating materials, ferroelectric materials, piezoelectric materials, semiconductor ceramic materials, etc. They have specific applications, low production volumes, but high values. Recently, a ceramic engine has been developed for use in vehicles, capable of raising the gas temperature to over 1400°C, which is significant for improving efficiency and saving energy. The manufacturing process of these materials is characterized by high requirements for the purity of the raw materials; strict control is needed over their composition, microstructure, as well as the surface and interfaces of the products. Their shapes are also intricate and complex, requiring precision machining. Such new materials have been developed successfully on the basis of advanced science and technology. 　　Polymer materials mainly include three categories: plastics, chemical fibers, and rubber. There are many types of synthetic materials, which are produced by polymerizing monomers derived from the petrochemical industry. Some possess special properties that natural materials cannot achieve, and are widely used in industrial and agricultural production as well as in daily life, which is why they have developed rapidly. In the 1930s, the global production of polymer materials was not more than 100 kt; by the 1980s it had reached around 80 Mt, with plastics accounting for 3/4 of that amount. Since plastic is lighter than metal, its production volume has surpassed that of ferrous metals. 　　The basic material for plastics is synthetic resin. Plastic products are lightweight (usually only 1/9 the weight of steel), resistant to corrosion and heat, have good electrical insulation properties, and are easy to shape. Over the past few decades, they have been widely used as a substitute for metals, glass, paper, wood, and other materials. Plastic film is mainly used as packaging material, and it is also widely used in agriculture. Plastic pipes are widely used as oil and water conduits in cars. Car bodies and parts are also made of plastic. Floors and doors and windows made from PVC are five times more wear-resistant than those made from wood. Plexiglass has a density that is half that of ordinary glass, yet its impact strength is as much as 17 times higher, making it suitable for use as windshields in airplanes. Plastics are also widely used in the electronics and electrical industries to make wires, cables, switches, and instrument casings. Plastic products can be said to have penetrated every aspect of people’s production and daily life. There are also some synthetic resins with special functions, known as functional polymer materials, such as conductive materials, semiconductor materials, photosensitive resins, photoconductive materials, and superconducting materials, which have attracted great interest. 　　Chemical fibers include artificial fibers and synthetic fibers. Man-made fibers are produced through chemical processing of natural fibers; they became popular in the 1920s and 1930s, but their production was limited by the availability of natural fiber sources. Synthetic fiber products appeared in the mid-1940s, with raw materials derived from abundant petrochemical products. There are many types of chemical fibers, including filaments, staple fibers, bristled fibers, elastic fibers, and various shaped fibers. They can be spun pure or in blends, resulting in a great variety of fabrics. Moreover, they offer high production efficiency, are not restricted by natural conditions, and effectively resolve the conflict over land use with crops such as grain and cotton. The production of 10,000 tons of chemical fibers is equivalent to the cotton produced in 300,000 mu of cotton fields over one year (1 mu = 666.6 m2), or to the wool harvested from 2.5 million sheep in one year. By the 1980s, two-thirds of the world’s textiles were made from chemical fibers. Hollow fibers made of certain polymers are used as separation membranes, and they play an important role in areas such as seawater desalination, gas separation, the production of ultra-pure substances, and biotechnology. 　　Rubber is a strategic material. Natural rubber grows only in tropical and subtropical regions; those that do not produce rubber **consider that they would face blockades in times of war, and therefore attach great importance to the development of a synthetic rubber industry based on petrochemicals. There are many types of synthetic rubber, and some of them possess better heat resistance, cold resistance, oil resistance, and other properties compared to natural rubber. The largest consumption of rubber is for tires; it is also used to make hoses, tapes, rubber shoes, and latex products. Rubber is also an essential sealing material for various devices. Since the 1970s, the production of natural rubber has remained relatively stable at 3–3.5 Mt, while synthetic rubber production reached 6 Mt in the 1970s, increased to 8 Mt in the 1980s, and continues to show an upward trend. 　　Composite materials are new types of structural materials. It is characterized by specific strength, specific stiffness, and corrosion resistance that all exceed those of metal materials. It is composed of matrix materials such as synthetic resins, metals, or ceramics, and reinforcing materials such as inorganic or organic synthetic fibers. There are various types of substrates and reinforcing materials, allowing for selective combinations in order to create various composite materials with the desired properties. The emergence of composite materials has opened up broader prospects for chemical materials. [Edit this section] Chemistry and Energy Energy can be divided into primary energy and secondary energy. Primary energy refers to thermal energy or power obtained from nature and that can be used directly; it usually includes fossil fuels such as coal, oil, and natural gas, as well as sources like hydroelectric power and nuclear energy. The world’s energy, which is consumed in enormous quantities, is mainly fossil fuels. In 1985, the world’s consumption of primary energy reached 10,610 Mt of standard coal, of which oil accounted for 39.9%, coal 29.7%, natural gas 21.1%, hydropower 7.7%, and nuclear power 4.9% ； China’s primary energy consumption reached 764 Mt of standard coal, of which coal accounted for 75.9%, oil 17.1%, hydropower 4.8%, and natural gas 2.2%. Secondary energy (other than electricity) generally refers to fuels with higher utility value, which are produced from primary energy sources (mainly fossil fuels) through various chemical processes. For example, liquid fuels such as gasoline, jet fuel, diesel, and heavy oil, which are obtained from petroleum refining, are widely used in cars, airplanes, ships, etc., and are important materials for modern transportation and ** ； There are also important gaseous fuels such as industrial gas and household gas produced from coal processing ； In addition, it also includes synthetic oil produced from coal and oil shale. 　　The relationship between the chemical industry and energy is very close; fossil fuels and their derived products serve not only as a source of energy but also as important raw materials for the chemical industry. Based on petroleum, a modern and powerful petrochemical industry has been developed, producing thousands of petrochemical products. In chemical production, some materials serve both as fuel in a certain processing process (such as syngas production) and as raw materials, with the two roles being combined into one. Therefore, the chemical industry is not only a sector that produces secondary energy but is also often a major energy consumer itself. 　　The processing and use of fossil fuels, particularly coal, often generate wastewater, solid waste, and harmful gases, leading to environmental pollution. The prevention and control of pollution also relies on the application of various chemical engineering technologies. 　　China’s energy production has seen significant development since 1949, but energy (especially oil) remains an important factor restricting the development of the national economy; therefore, increasing energy production and practicing energy conservation are of great significance. Improving chemical production processes and reducing energy consumption can not only lower production costs and enhance economic efficiency but also help alleviate energy shortages. This is also an issue that countries around the world have attached great importance to in recent years. 　　In the long term, on a global scale, fossil fuels are expected to remain the main source of energy throughout the first half of the 21st century. Over time, due to the limitations of fossil fuel resources, the development of several non-conventional energy sources, in addition to the aforementioned conventional energy sources, will receive increasing attention. Non-conventional energy refers to nuclear energy and new energy sources, the latter of which include solar energy, wind energy, geothermal energy, tidal energy, wave energy, ocean energy, and bioenergy (such as biogas). Throughout the long process of research and development, as well as large-scale application of solar and nuclear energy, chemical engineering and chemical production technologies also play a vital role. [Edit this paragraph] Chemistry and other scientific technologies The driving force behind the development of the chemical industry is the demand for chemicals in industrial and agricultural production as well as in people’s daily lives. It relies on chemistry, physics, mathematics, and various engineering techniques. Among them, the relationship with chemistry is particularly close; chemistry is a discipline that is indispensable to the chemical industry. Between them, there were also disciplines such as \"industrial chemistry\" and \"applied chemistry\", which played a certain historical role. Basic chemical engineering construction relies on civil engineering and electrical engineering. The manufacture of chemical engineering machinery relies on mechanical engineering and various metal materials, especially stainless steel, as well as special steels. Chemical processing machinery requires special attention to reliability under high temperature and high pressure, which refers to the probability that a system, equipment, or component will perform its designated functions under specified conditions. As modern chemical plants tend to be larger in scale and operate on a single-production-line basis, research on reliability becomes particularly important. 　　The control of chemical processes relies on electronics, computers, and automation. These theories and instruments can be applied not only in production but also to addressing issues such as development forecasting, decision-making, and business management. In the 1980s, several fields that developed rapidly as part of the new technological revolution – in addition to energy and materials mentioned earlier – such as microelectronics and biotechnology, which are cutting-edge sciences, exerted strong influence on the chemical industry, imposing higher demands on it and thus driving its progress. 　　Microelectronics technology: Electronic computers, microprocessors, and information technology all rely on microelectronics technology. In microelectronics, the use of large-scale and very large-scale integrated circuits has placed new demands on the chemical industry. Such as ultra-pure gases and pure water, reagents for the electronics industry, photoresists, liquid crystals, as well as corrosives, dopants, adhesives, and so on. 　　There are dozens of ultra-pure gases used in microelectronics technology; in addition to common gases such as oxygen, hydrogen, nitrogen, carbon dioxide, and argon, there are also gases that do not exist in nature, such as borane, boron trichloride, dichlorosilane, and carbon tetrafluoride. The purity of the chemical products used has a significant impact on the quality of semiconductor finished products. When industrial gases are used, the yield is only 10%; whereas when gases with impurities below 10 ppm and corresponding high-purity chemical reagents are used, the yield can be increased to 70%–80%. In terms of water usage, an integrated circuit with an integration level of 1 Mb allows particle sizes in the water to be no larger than 0.1 μm. To produce water that is as pure as possible, according to theoretical standards, production methods have evolved from distillation and ion exchange to a combination of membrane separation and ion exchange in the 1970s, pushing water purification technology to a new level. 　　The key to microelectronic device production lies in photoresist. The photoresist used in very large-scale integrated circuits is a photosensitive resin made from aromatic azide compounds, and its advantages include high resolution, easy removal, and clear images. Liquid crystals are essential display materials in microelectronic devices. It is an organic compound; since it is required to display temperatures within the range of -20 to 60°C, a single type of liquid crystal generally cannot meet this requirement, so it is necessary to use a mixture of multiple liquid crystals of the same type or different types. 　　Biotechnology: Microorganisms are living cell catalysts that, under normal pressure and moderate temperatures, convert raw materials into products through a fermentation process. For many years, this traditional biotechnology has been used to produce products such as ethanol, butanol, propanol, and acetic acid. In recent years, research has led to the development of a method using immobilized cells to produce acrylamide from acrylonitrile, with yields reaching 99.8%. Furthermore, enzyme catalysts, especially immobilized enzymes, can also be used to produce organic products. Biotechnology is used in the chemical industry; it requires less investment, saves energy and raw materials, generates less pollution, and enables the production of substances that are difficult to obtain using conventional methods, such as interferons, insulin, monoclonal antibodies, etc. These drugs are produced using recombinant DNA technology, and they are expected to transform the pharmaceutical industry. 　　Biotechnology poses new requirements for chemical engineering, primarily concerning the development of biochemical reactors suitable for the large-scale cultivation of microorganisms, separation technologies to handle complex biochemical reaction processes, and process control. In this regard, a new interdisciplinary field has emerged — biochemical engineering — which applies the theories of chemical engineering to the research and development of biological catalysts, biochemical reaction engineering, and new unit operations, achieving many accomplishments. [Edit this paragraph] Classification of branches: As a field of knowledge, throughout various historical periods and under different objectives, there have been numerous methods for breaking down or combining classifications. It can be classified by the source of raw materials and the properties of the products, or by the patterns of the processes and historical connections. Each partitioning method is difficult to adapt strictly. This volume strives to reduce unnecessary overlaps by adopting a comprehensive classification approach, and has established fuel chemical subfields starting from raw materials ； Branches such as inorganic chemistry based on products, basic organic chemistry, polymer chemistry, and fine chemicals ； There are also branches of chemical engineering that are based on common principles of processes, as well as overviews that take into account historical development and interconnections. The raw materials for the fuel chemicals industry are combustible minerals such as petroleum, natural gas, coal, and oil shale; therefore, it is further divided into the petroleum refining industry, petrochemical industry, natural gas chemical industry, coal chemical industry, and oil shale industry. Among them, the petroleum refining industry is an industrial sector that generates high output values and serves as a vital economic pillar. Natural gas often occurs alongside oil, and natural gas chemistry is also frequently classified under petrochemical industry. At the current stage, petroleum refining and petrochemicals are the main components of the fuel chemicals industry. The products of the fuel chemical industry include fuels and chemical raw materials, the latter being mainly organic chemical raw materials (with syngas also being used to produce inorganic chemical products such as synthetic ammonia). Therefore, petrochemicals are also a major component of basic organic chemicals. Through petrochemical processing, three major synthetic materials can be produced: plastics, synthetic rubber, and synthetic fibers, which are the main products of polymer chemistry. Therefore, fuel chemistry, basic organic chemistry, and polymer chemistry are organically connected. As for the raw materials used in inorganic chemical industry, there are both combustible minerals and inorganic minerals. Its products mainly include fertilizers, acids such as sulfuric acid, nitric acid, and phosphoric acid, alkalis such as soda ash and caustic soda, inorganic salts, industrial gases, and inorganic non-metallic materials. Silicate materials among inorganic non-metallic materials are sometimes classified under the category of traditional building materials. Fine chemical production involves small batches of chemicals with specialized functions, primarily used for consumer purposes. Due to the development of market demand, some products have become mass-produced items, but by convention, they are still often regarded as fine chemical products. They mainly include dyes, pesticides, pharmaceuticals, explosives, information recording materials, coatings, pigments, adhesives, catalysts, various additives, and chemical reagents. The production of pharmaceuticals and fire** is often classified as separate industrial sectors. From the perspective of raw materials, fine chemicals include both inorganic and organic substances as well as polymers; it is an integrated field that focuses on functional applications. In the technological revolution driven by the rapid development of microelectronics, biotechnology, and new materials, fine chemicals have injected new vitality into the chemical industry. 　　Chemical engineering is further divided into chemical engineering thermodynamics, transport processes, unit operations, chemical reaction engineering, and chemical engineering systems engineering. The first two constitute the theoretical foundation of chemical engineering. Unit operations are one of the earliest concepts developed in this field; they involve breaking down the physical processes involved in chemical production into various units, such as fluid transport, distillation, extraction, heat exchange, and drying. Today, these unit operations play an important role not only in chemical production but are also widely used in industries such as metallurgy, light industry, food processing, and the nuclear industry, which share common characteristics with the chemical industry. Unit operations continue to evolve and improve; for example, granulology, which has developed in recent years as a theory in powder engineering, has been applied to catalyst particle size design, dust removal from high-temperature gases, and grain drying and transportation. Chemical reaction engineering focuses on the laws of transport and kinetics in chemical reaction processes on an industrial scale, in order to address the issues related to reactor design and scaling up. As for chemical systems engineering, it is an interdisciplinary field that applies the theories and methods of systems engineering to address optimization problems in chemical processes. 　　The core contents of chemical engineering can basically be classified into the above six branches, and the overall overview is also composed of these six branches. However, this classification method is not entirely reasonable; for example, the catalyst industry is included in the fine chemicals sector. Although in theory, catalysts have the specific function of accelerating reaction rates and are small amounts of substances that do not participate in the reactions themselves, in today’s large-scale production processes, the amount produced and used of catalysts is quite substantial; in 1985, China used 20kt of catalysts for oil refining. Moreover, catalysts are used in all fields such as fuels, inorganic chemicals, organic chemicals, polymers, and fine chemicals. There are still many such issues regarding ownership. 　　Furthermore, environmental protection is both a common issue that various sectors of the chemical industry are constantly working to address, and an area in which the chemical industry can make contributions. The modern chemical industry, which emerged in the 18th century, has a history of over 200 years to date; it has produced countless chemical products, but at the same time it has also released waste gases, liquids, and solids, thereby polluting the environment. Therefore, there is a call on the chemical industry to make full use of raw materials in converting them into products, turning the process into a zero-emission one. The development of other sectors in the national economy also causes pollution to varying degrees. Over time, emissions that exceed the natural environment’s self-purification capacity will inevitably lead to a worsening of human living conditions. Therefore, informed individuals have issued warning alerts about the pollution and degradation affecting the atmosphere, water, soil, and wildlife in the world. To address pollution, protect the environment, and restore ecological balance in nature to a new state of harmony, the chemical industry will play a key role. [Edit this paragraph] Chemicals and the Internet: With the rapid development of the Internet in China, a large number of chemical-related online service platforms have emerged there. Examples include China Chemical Market Seven Days News http://www.qrx.cn, China Chemical Supply and Demand Network http://www.chemshows.com, China Chemical Products Exhibition and Sales Network http://www.chemshows.cn, Fine Chemicals Network http://www.efinechem.com, China Chemical Network http://china.worldchembiz.com, China Chemical Network (NetSheng) http://china.chemnet.com, Chemical Network (HuiCong) http://www.chem.hc360.com, and Chemical Information Download Network http://www.chemdown.cn. These platforms have made significant contributions to the development of China’s chemical industry’s online services, creating great value for chemical enterprises. They represent an indispensable force in China’s chemical sector, bringing substantial convenience to chemical trade and serving as another excellent example of the scientific outlook on development. 　　Looking back on the past and looking forward to the future, the chemical industry will not be confined to traditional boundaries, making immeasurable contributions to transforming the world. 　　The chemical industry is **very important for development, with ethylene serving as a benchmark for industrial progress. Edit this paragraph] History of the Development of Chemical Industry Since history, the chemical industry has been inseparable from the process of developing productivity, ensuring the necessities of life in human society, and coping with wars. In order to meet these needs, it initially simply processed natural substances to produce chemicals, and later carried out in-depth processing and imitation, and even created products that did not exist in nature. It has played an important role in the industrial revolution in history and the new technological revolution in contemporary times, which is enough to show its important position in the national economy. Ancient chemical processing The history of chemical processing before the formation of industry can be traced back to ancient times from the mid-18th century. Since then, humans have been able to use chemical processing methods to make some daily necessities, such as pottery, brewing, dyeing, smelting, lacquer making, paper making, and medicine. * * and soap. There are fragments of pottery in the caves of the Neolithic Age in China. During the Yangshao Culture around the 50th century BC, red pottery, gray pottery, black pottery, painted pottery, etc. appeared (see color picture, " ,,). Among the cultural relics unearthed from Hemudu, Zhejiang, China, there are wooden bowls of the same period, coated with vermilion lacquer. There are fragments of lacquerware in the ruins of the Shang Dynasty (17th to 11th century BC). During the Warring States Period (475 to 221 BC), the craftsmanship of lacquerware was very exquisite. In the 20th century BC, Xia Yu used wine as a drink and for sacrifices. In the 25th century BC, Egypt used dye to wrap mummies. In 2 BC In the 1st century BC, China entered the Bronze Age. In the 5th century BC, it entered the Iron Age. Smelted copper and iron were used to make weapons, farming tools, cooking utensils, tableware, musical instruments, currencies, etc. Salt was already used for food. In the 11th century BC, the Zhou Dynasty had officials in charge of salt administration. In the 7th and 6th centuries BC, the Phoenicians used goat fat and plant ash to make soap. In the 1st century AD, during the Eastern Han Dynasty in China, the papermaking process was quite complete. Around BC, China and Europe entered the period of alchemy and alchemy. China conducted research on medicine due to the refining of elixirs of life. The earliest medicine monograph "Shen Nong's Materia Medica" completed in the Qin and Han Dynasties recorded 365 kinds of animal, plant and mineral medicines. In the 16th century, Li Shizhen's "Compendium of Materia Medica" summarized the culmination of previous medicines and was of high academic level. In addition, there are records of three-component mixing methods in the 7th to 9th centuries, and in the early Song Dynasty * * It has been used for military purposes. Europe has been superstitious about alchemy since the 3rd century, and it was not until the 15th century that alchemy gradually turned into pharmaceuticals. The 15th to 17th centuries are known as the pharmaceutical period. In pharmaceutical research, in order to prepare drugs, some chemicals such as sulfuric acid, nitric acid, hydrochloric acid and organic acids were prepared in the laboratory. Although it did not form an industry, it led to the development of chemical preparation methods and prepared the conditions for the establishment of the chemical industry in the mid-18th century. The early chemical industry was the primary stage of the chemical industry from the mid-18th century to the early 20th century. At this stage, inorganic chemical industry had begun to take shape, organic chemical industry was taking shape, and polymer chemical industry was in its infancy. The first typical chemical plant in the inorganic chemical industry was the sulfuric acid plant established in the United Kingdom in the 1840s. First, sulfur was used as raw material, and then pyrite was used as raw material. The products were mainly used to make nitric acid, hydrochloric acid and drugs. The output was not large at that time. During the industrial revolution, the textile industry developed rapidly. It and Glass, soap and other industries use a large amount of alkali, while plant alkali and trona are in short supply. In 1791, under the bounty of the French Academy of Sciences, he obtained a patent and built a factory using salt as raw material to produce it, which also promoted the development of the sulfuric acid (one of the raw materials) industry; the hydrogen chloride generated in the production was used to make hydrochloric acid , chlorine, bleaching powder and other substances urgently needed by the industry, and soda ash can be causticized to fully utilize raw materials and by-products. This was a pioneering work of chemical companies at that time; filling devices for absorbing hydrogen chloride, rotary furnaces for calcining raw materials and semi-finished products, as well as concentration, crystallization, filtration, etc. The equipment was gradually used in other chemical companies, laying the foundation for chemical unit operations. The Lubrand method was gradually replaced by the Solvay method (see) in the early 20th century. Electrolysis of salt appeared in the late 19th century. In this way, the production of acids and alkali, the basis of the entire chemical industry, has begun to take shape. After the development of the organic chemical textile industry, natural dyes could not meet the needs; with the development of the steel industry and coking industry, the by-product coal tar needed to be utilized. Chemists used the achievements of organic chemistry to separate coal tar into anthracene, phenanthrene, etc. In 1856, the British synthesized aniline violet dye, and then analyzed and determined that natural dyes The structure of alizarin is dihydroxyanthraquinone. It uses anthracene in coal tar as raw material and undergoes oxidation, substitution, hydrolysis, rearrangement and other reactions to imitate products that are exactly the same as natural alizarin. Similarly, the pharmaceutical industry and the perfume industry have also successively synthesized chemicals that are the same as natural products, and the varieties are increasing day by day. In 1867, the Swedes invented Denamat * * (See), which was widely used in mining and military industry. At that time, there was another pillar of organic chemical production, namely acetylene chemical industry. In 1895, the first factory was established to produce calcium carbide (ie) using coal and limestone as raw materials and using electrothermal method. The calcium carbide was then hydrolyzed to produce acetylene, which was used as a starting point to produce a series of basic organic raw materials such as acetaldehyde and acetic acid. After the development in the middle of the 20th century, calcium carbide consumed too much energy, and most of the original acetylene series products were produced as raw materials. Polymer materials become sticky when heated and harden when cooled. In 1839, the United States used sulfur and heated natural rubber to cross-link it into an elastomer, which was used in tires and other rubber products. It has a wide range of uses. This was the budding period of the polymer chemical industry. In 1869 , the United States used camphor-plasticized nitrocellulose to make plastic, which is very valuable. In 1891, the first rayon factory was built in Besançon, France. In 1909, the United States made plastic, commonly known as Bakelite powder, which was the first and widely used in electrical insulation materials. These budding products are far from meeting social requirements in terms of variety, output, quality, etc. Therefore, the production of the above-mentioned basic organic chemicals and the production of polymer materials have achieved great development after the establishment of the petrochemical industry. The great development period of the chemical industry lasted from the early 20th century to the 1960s and 1970s after the war. This was the main stage when the chemical industry truly became large-scale production, and some major fields were formed during this period. The petrochemical industry and petrochemical industry were developed, developed, and gradually emerged. At the beginning of this period, the concepts proposed by people in the United Kingdom and the United States laid the foundation for chemical engineering. It promoted the development of production technology, and both device scale and product output increased rapidly. The synthetic ammonia industry suddenly emerged in the early 20th century. It used the reaction equilibrium theory of physical chemistry to propose a catalytic method for the direct synthesis of ammonia from nitrogen and hydrogen, and the idea of supplementary recycling after the raw material gas was separated from the product, which further solved the equipment problem. This enabled Germany to build the first ammonia production factory during World War I to meet the needs of the war. Synthetic ammonia originally used coke as the raw material, but after the 1940s it was changed to oil or natural gas, which brought the two major sectors of the chemical industry and the petroleum industry closer together and rationally utilized raw materials and energy. Petrochemicals were produced in the United States in 1920, which was the beginning of large-scale development of petrochemicals. In 1939, the American Standard Oil Company developed a hydrogen catalytic reforming process, which became an important source of aromatics. In 1941, the United States built the first set of equipment to produce ethylene from raw materials. In World War II In the future, due to the continuous expansion of the chemical product market, petroleum can provide a large amount of cheap organic chemical raw materials. At the same time, due to the development of chemical production technology, the petrochemical industry has gradually formed. Even areas that do not produce petroleum, such as Western Europe, Japan, etc., also use crude oil as raw materials to develop petrochemical industries. The same raw material or the same product, Each chemical company has different process routes or different catalysts. Since the basic organic raw materials and polymer material monomers are all based on petrochemicals, people use the output of ethylene as a measure of organic chemicals. In the 1980s, more than 90% of organic chemical products came from petrochemicals. For example, In the past, carbide acetylene was used as raw material, but now the oxychlorination method was used to produce vinyl chloride from ethylene, and the propylene ammonia oxidation (see) method was used to produce acrylonitrile. In 1951, natural gas was used as raw material, and steam reforming method was used to obtain carbon monoxide and hydrogen, which attracted attention and is currently used in production. It is used in production in some areas. Polymer chemical polymer materials were used in wartime * * After the war, it was converted to civilian use, achieved great development, and became a new material industry. As a strategic material, natural rubber is produced in the tropics and is blocked by sea transportation. All countries are studying it. In 1937, the German Farben company successfully developed it. After that, various countries have successively developed a variety of synthetic rubbers such as cis-butyl, butyl, chloroprene, nitrile, isopentyl, ethylene-propylene, etc., each with its own characteristics. In terms of characteristics and uses, in 1937, the United States successfully synthesized nylon 66 (see figure) and spun it using the melt method. Because of its good strength, it was used for parachutes and tires. Later, polyester, vinylon, acrylic, etc. were put into production one after another, and because of the petrochemical industry as their raw materials, they gradually occupied most of the market for natural fibers and man-made fibers. Plastics On the other hand, after phenolic resin, thermosetting resins such as alkyd resin were produced. After the 1930s, varieties continued to appear. For example, it was still the largest variety of plastics and was an excellent insulating material at that time. In 1939, high voltage was used for submarine cables and radars. Low-voltage polyethylene and isotactic polypropylene were successfully developed, opening up a wide range of uses for civilian plastics. This is a great contribution made by Ziegler-Natta catalysts to polymer chemical industry. During this period, high-temperature resistant and corrosion-resistant materials also appeared, such as polytetrafluoroethylene, among which polytetrafluoroethylene is known as the king of plastics. After World War II, some of them were also used in the automobile industry, and also as building materials, packaging materials, etc., and gradually became a major variety of plastics. In terms of fine chemicals, reactive dyes were invented to combine dyes with fibers through chemical bonds. Synthetic fibers and their blended fabrics require new dyes, such as those used for polyester, acrylic fibers, and reactive disperse dyes used for polyester-cotton blends. In addition, there are also special dyes used in laser, liquid crystal, microscopy technology, etc. In terms of technology, after Swiss PH Miller invented the first organochlorine pesticide in the 1940s, he developed a series of organochlorines, organophosphorus, The latter has special functions such as gastric killing, contact killing, and systemic absorption. Later, pesticides with high efficiency and low toxicity or no residual toxicity were required, such as bionic synthetic ones. In the 1960s, pesticides developed rapidly, and some varieties with good performance appeared, such as pyridine herbicides, benzimidazole fungicides, etc. In addition, there are antibiotic pesticides (see), such as Jinggangmycin developed by China in 1976 to resist rice sheath blight. In terms of medicine, 6 was made in France in 1910 06 Arsenic preparations (specific drugs for curing mesophylls) were structurally improved to make 914. In the 1930s, quasi-compounds, steroid compounds, etc. were structurally improved and exerted special effects. In 1928, the British discovery opened up a new field of antibiotic drugs. Later, drugs for the successful treatment of physiological diseases were studied, such as drugs for cardiovascular disease, mental illness, etc., as well as contraceptives. In addition, there are some special diagnostic drugs. Come out. Get rid of the tradition of natural paints and use alkyd resins, acrylic resins, etc. to meet the needs of advanced coatings such as the automobile industry. After World War II, styrene-butadiene latex was made into water-based coatings and became a major variety of architectural coatings. New technologies such as high-pressure airless spraying, electrostatic spraying, electrophoretic coating, cathodic electrodeposition coating, and light curing (see) can save labor and materials, and thus corresponding coating varieties have been developed. Since the 1960s and 1970s in the modern chemical industry, competition among enterprises in the chemical industry has been fierce. On the one hand, due to an in-depth understanding of the reaction process, the production equipment of some traditional basic chemical products can be increasingly large-scale to reduce costs. At the same time, due to the rise of the new technological revolution, new requirements have been put forward for the chemical industry, which has promoted the technological progress of the chemical industry and developed fine chemicals, ultrapure substances, new structural materials and functional materials. Large-Scale In 1963, the American Kellogg Company designed and constructed the first single-series ammonia plant with a daily output of 540t (i.e. 600sh.t), which was a symbol of the large-scale chemical production equipment. Since the 1970s, the single-series production capacity of synthetic ammonia has developed to a daily output of 900-1350t, 80 In the 1990s, a design with a daily output of 1800-2700t of synthetic ammonia appeared, and the total energy consumption per ton of ammonia dropped significantly. The single-series production scale of ethylene increased from 50kt in the 1950s to 100-300kt in the 1970s. The maximum production capacity of the newly built ethylene plant in the early 1980s reached an annual output of 680kt. As the metallurgical industry provided resistant High-temperature pipes have been realized in millisecond cracking furnaces, thereby increasing olefin yield and reducing energy consumption. Other chemical production equipment such as sulfuric acid, caustic soda, basic organic raw materials, synthetic materials, etc. are all developing towards large-scale. This reduces environmental pollution, improves long-term operation reliability, and promotes the rapid development of safety and environmental protection prediction and protection technologies. Chemicals for Information Technology Since the 1960s, large-scale integrated circuits and the electronics industry have developed rapidly, and the device materials and information recording materials required for electronic computers have been developed. After the 1960s, the output of polycrystalline silicon and monocrystalline silicon has increased at an annual rate of 20%. The cycle of the 1980s The binary compounds of group V in the table have been used in electronic devices. With the development of semiconductor devices, gaseous sources such as phosphine (PH) are becoming increasingly important. In the preparation process of large-scale integrated circuits, a variety of compounds are used, and their impurity content is less than 1ppm. There are also strict requirements for moisture and dust content. .Another base material for large-scale integrated circuits, its quality and stability directly affect its integration level and yield. In addition, there are also strict requirements for base materials, sealing materials, flux, etc. In 1963, after the Dutch Philips Company successfully developed cassette recording, it became increasingly popular. It not only Used for audio recording, video recording, etc., and more importantly, used in calculators as external memory and internal memory, including tapes, disks, magnetic drums, magnetic bubbles, magnetic cards, etc. It is an important information material, not only used for optical fiber communications, but also used as endoscope materials in industry and medicine. High-performance synthetic materials (commonly known as nylon), polyacetals (such as nylon), and acrylonitrile-butadiene-styrene terpolymer () have been used as structural materials in the 1960s. They have the characteristics of high strength, impact resistance, wear resistance, chemical corrosion resistance, good heat resistance, and excellent electrical properties. They are also light in weight and easy to form. They are widely used in automobiles, electrical appliances, building materials, packaging, etc. After the 1960s, there appeared,,,, etc., especially high temperature resistance, high vacuum resistance, self-lubricating materials, which can be used in spacecraft. Its fibers can be used as space suits to resist radiation. Polybenzothiazole and polybenzimidazole are high temperature resistant resins with high heat resistance and can be used as ablation materials for rockets. Copolymerization, blending and compounding modify structural materials, such as polyol prepolymers and catalyzed reactions. Nylon polyether block copolymer has high impact strength and heat resistance and is used in agricultural and construction machinery. The other is a polymer composite material made of fiber-reinforced resin. The resins used are mainly epoxy resin, unsaturated polyester, polyamide polyimide, etc. glass fiber is used, or (commonly used acrylonitrile-based or asphalt-based). These composite materials have light specific gravity, high specific strength, good toughness, and are particularly suitable for Structural parts used in aerospace, aviation and other transportation vehicles to replace metals and save energy. Fluorine-containing materials are also developing rapidly. Because they have outstanding high and low temperature resistance, excellent electrical properties, aging resistance, and radiation resistance, they are widely used in the electronics and electrical industry, atomic energy industry, and aerospace industry. And because they have physiological compatibility, they can be used as artificial organs and biomedical equipment. Energy materials and energy-saving materials The atomic energy industry began to develop in the 1950s, requiring chemical companies to produce heavy water, neutron absorbing materials and heat transfer materials to meet needs. The aerospace industry requires high energy. Solid propellants are composed of adhesives, plasticizers, and oxidants. It is composed of additives. Liquid high-energy fuels include liquid hydrogen, kerosene, unbiased dimethyl hydrazine, anhydrous hydrazine, etc.; oxidants include liquid oxygen, fuming nitric acid, and dinitrogen tetroxide. These products have strict performance requirements and have formed a specialized production industry. In order to meet the requirements of energy conservation and environmental protection, the United States trial-produced a practical membrane in 1960 to desalinate and treat industrial sewage, and later expanded its use in the pharmaceutical and food industries. However, this membrane is easy to biodegrade and hydrolyze, and has a short service life. In 1970, an aromatic polyamide reverse osmosis membrane was developed, which is resistant to biodegradation but not free chlorine. In 1977, the improved composite membrane was used for seawater desalination, consuming only 23.7 to 28.4 MJ of electricity per cubic meter of fresh water. In addition, polysulfone hollow fiber gas separation membranes have also been developed for use in hydrogen and nitrogen separation of ammonia tail gas and various other gas separations. This technology can save energy than other industrial separation methods. It is known for its hardness and is used as a cutting tool. In 1971, the American Ford Motor Company and Westinghouse Electric Company used β-silicon nitride (β-SiN) as the structural material of the gas turbine. The operating temperature was as high as 1370°C, which improved efficiency, saved fuel, and reduced pollution. , is a good energy-saving material, but after 10 years of testing, there are still many problems and further improvements are needed. Now it is mainly used as ceramic engines, turbine blades, conductive ceramics, artificial bones, etc. The main material systems of ceramics are oxide systems, such as alumina (AlO), zirconia (ZrO), etc., and non-oxide systems, such as carbides (SiC), nitrides (BN), silicon nitride (SiN), etc. In the 1980s, in order to improve the brittleness of ceramics, silicon-carbon fiber reinforced ceramics were developed. Specialty chemicals have been further developed. They use a small amount to enhance or endow another product with specific functions and obtain high use value. For example, food and feed additives, plastic and rubber additives, leather, papermaking, oil field and other special chemicals, as well as adhesives, antioxidants, surfactants, water treatment agents, catalysts, etc. As for catalysts, due to the development of modern instruments such as electron microscopes and electron energy spectrometers, it is helpful to understand the catalytic mechanism, so various special catalysts are prepared, marking the catalyst has entered a new stage.

Chemical engineering refers to the chemical industry. With the development of productivity, some production sectors such as metallurgy, refining, papermaking, and leather processing have been separated from the chemical industry as independent sectors

The explanations on the 2nd and 3rd floors are very good. Floor 5 has been supplemented with relevant knowledge.

Smelting is the process of extracting useful substances from valuable ores

The chemical industry can cover a vast number of sectors, including all traditional chemical industries, as well as textiles, pharmaceuticals, metallurgy, and so on. It is a very broad field.

Metallurgy focuses on the study of metal materials, whereas chemical engineering emphasizes knowledge of chemical reaction principles, which can be applied in the metallurgical industry.

In my opinion, the fundamental difference between metallurgy and chemical engineering lies in the fact that metallurgy is a process of separation, while chemical engineering is a process of combination. During smelting, the metals in the ore are separated, allowing each element to be isolated and purified. Chemical engineering involves synthesizing other chemicals through several chemical units.