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Several fine inorganic fluorides are introduced. China is a country with large reserves of fluorite; its proven reserves account for one-third of the world’s total reserves, which provides very favorable conditions for the development of the organic fluoride industry in the country. Since the 1980s, it has increasingly become a hot topic in research, production, and the market within China’s chemical industry. After nearly 20 years of development, many fluorine-containing compounds such as bulk fluorine intermediates, ODS substitutes, and basic inorganic fluorides have experienced severe overcapacity, while low-grade fluororesins and rubbers are also showing signs of redundant production. Some high-value fine chemicals cannot be industrialized domestically for the time being due to patent protection issues. With the rapid development of industries such as electronics, pharmaceuticals, and chemicals in China, certain fine inorganic fluorides such as sulfur hexafluoride, nitrogen trifluoride, iodine pentafluoride, and tungsten hexafluoride have gradually become focal points for research and production among fluorine-containing compounds. This is due to the steadily increasing market demand for these products, their high added value, and the limited number of domestic manufacturers. The following will mainly discuss the production and market situation of these fine inorganic fluorides with promising market prospects. 1. Sulfur hexafluoride: Sulfur hexafluoride possesses excellent electrical insulation properties and arc-quenching capabilities. Under the same conditions, its insulation performance is 5 times that of air and 2.5 times that of nitrogen. It is thus the most widely used third-generation insulating and cooling medium in the world today. It is applied in various electrical equipment such as circuit breakers, combiners, transformers, large-capacity cables, surge protectors, and ion accelerators. Additionally, it is used as a fluorine source in fiber optic production, in the smelting of colored metals, and as a plasma etching agent. Sulfur hexafluoride is generally produced by reacting fluorine gas, obtained from electrolyzers, with sulfur in the presence of a catalyst to yield crude sulfur hexafluoride. This crude material is then purified through alkaline leaching, and after that it passes through a gas purification system where it is adsorbed and condensed under distillation to produce high-purity sulfur hexafluoride. Currently, the global annual sales volume of sulfur hexafluoride is around 10,000 tons. The main manufacturers are Honeywell in the United States and Solvay; these two companies account for over 50% of the world’s total production. Since 2003, the global supply of sulfur hexafluoride has been tight, resulting in a severe shortage in the domestic market and high profits for production facilities. The main reasons for the shortage in the market are: first, the overall volume of high-voltage electrical equipment produced domestically is increasing rapidly, and export volumes are also rising significantly ； Secondly, in recent years, as the Kyoto Protocol has listed sulfur hexafluoride as one of the six controlled greenhouse gases, its production has been gradually reduced in Western developed countries and regions. Since 2003, there has been strong demand for sulfur hexafluoride on the international market, leading to a sharp rise in prices. This has resulted in an increase in domestic exports of sulfur hexafluoride, further exacerbating the shortage of resources in the domestic market for this substance. In 2005, China’s production capacity for sulfur hexafluoride was approximately 4,000 tons; the main manufacturers were China National Nuclear Corporation Honghua, which had a production capacity of 1,400 tons per year ； Sichuan Tianchen Chemical Company, production capacity of 1,000 t/a ； Dongling Chemical Research Institute, production capacity of 1,000 t/a ； There are also some other small-scale production facilities, with capacities ranging from 50 to 200 t/a, such as Gansu Daming Fluorine Chemical Co., Ltd., Factory 504 of the Nuclear Industry Ministry, Sichuan Yinshan Chemical Co., Ltd., Shanghai Fubang Chemical Co., Ltd., and Foshan Keqi Gas Chemical Co., Ltd., among others. The use of sulfur hexafluoride enhances the safety and reliability of electrical equipment operation, reduces its size and weight, lowers manufacturing costs, and extends its lifespan as well as the interval between maintenance tasks. In China, the number of companies that use sulfur hexafluoride has increased from just over a dozen electrical equipment manufacturers to several hundred today; alone, the five major switchgear manufacturers in Xi’an, Shenyang, Pingdingshan, Beijing, and Shanghai consume 250–300 tons of this substance per year. “During the 11th Five-Year Plan period, **200 million kW of power generation capacity was planned to be established; by 2010, the installed capacity was to reach 650 million kW, and by 2020 it was to reach 1 billion kW. In terms of power grid construction, a development strategy of \"transmitting electricity from the west to the east, enabling mutual supply between the north and south, and establishing a national power grid\" is being implemented. The construction of ultra-high-voltage transmission lines has been included in this strategic plan; investments in this area increased by 50% in 2006, rising from 110 billion to 160–180 billion. At the same time, **a new round of upgrades to both urban and rural networks will be launched. Demand for sulfur hexafluoride is expected to reach its peak in 2006 and 2007. It is anticipated that domestic demand for this substance will amount to 4,000 tons in 2006 and 4,500 tons in 2007; including exports, the figures are expected to be around 5,000 tons and 5,500 tons respectively. Given the booming market for sulfur hexafluoride in recent years and the substantial profits it generates, many domestic companies have planned to build new or expand existing sulfur hexafluoride production facilities. For example, the Liming Chemical Research Institute plans to increase its current production capacity for sulfur hexafluoride to 2,500 tons per year, with commissioning expected in the second half of 2006 ； In 2005, a sulfur hexafluoride production facility with an annual capacity of 1,200 t was built in Xinxiang, Henan Province, in three phases; the first phase, with an annual capacity of 500 t, was completed and put into operation in the first half of 2006 ； Fujian Shaowu Yongfei Chemical Co., Ltd. invested 150 million yuan to introduce advanced foreign technology for the construction of a sulfur hexafluoride production plant with an annual capacity of 1,500 t. The first phase of this project has been largely completed, with an annual production capacity of around 500 t in this phase. 2. Nitrogen trifluoride: Nitrogen trifluoride is an electronic material that has been developed in recent years; it can be used as an etchant for semiconductor materials such as polycrystalline silicon, silicon nitride, and tungsten silicide. In the nuclear industry, it is used for the separation and purification of uranium and plutonium. There are mainly two routes for the industrial production of nitrogen trifluoride: one involves heating ammonium fluoride in a nickel reactor, while fluorine gas, nitrogen gas, and ammonia enter the reactor through a distributor to carry out the fluorination reaction directly. Secondly, at a certain temperature, ammonium hydrogen fluoride in melt is electrolyzed using nickel as the electrode material; during the electrolytic reaction, nitrogen trifluoride is produced at the anode, while hydrogen is produced at the cathode. With the development of the global semiconductor industry, the demand for nitrogen trifluoride has risen sharply. By 2005, the global production capacity of nitrogen trifluoride was expected to reach 4,000 tons. Foreign manufacturers of nitrogen trifluoride are mainly located in the United States, Japan, and other countries; key producers include Air Products and Chemicals in the United States, BOC Edwards, DuPont, Chugai Glass in Japan, Mitsui Chemicals, and Kanto Denka. Among them, Air Products has the largest production capacity, at 1,600 tons per year. As nitrogen trifluoride products gain popularity in the international market, major manufacturers are expanding the capacity of their production facilities; for example, Air Chemicals plans to increase its production capacity to 1,800 t/a by 2006 ； Japanese company Mitsui Chemicals plans to increase its current production capacity of 400 t/a to 1,200 t/a by 2007 ； Kantō Denka plans to increase its production capacity from the current 850 t/a to 1,000 t/a ； Asahi Glass plans to increase the current production capacity of 300 t/a to 600 t/a in 2007 ； Formosa Plastics built a 200 t/a production facility in 2004, with plans to expand capacity to 800 t/a by 2006 ； In 2005, the American company DuPont announced the construction of a 450 t/a nitrogen trifluoride production facility in the Fluorine Chemical Industrial Park in Changshu, Jiangsu, with commissioning expected in 2007. There are few domestic manufacturers; in 2005, China’s production capacity for nitrogen trifluoride was around 200 tons per year. The main manufacturers include China National Nuclear Corporation Honghua Special Gases Co., Ltd., Hubei Shalonda Tianmen Agrochemicals Co., Ltd., and the 718th Research Institute of China State Shipbuilding Corporation. In addition, the Liming Chemical Research Institute has also developed a process for synthesizing nitrogen trifluoride, which has been approved by the relevant authorities. Due to the high demand for this product, the price of nitrogen trifluoride has remained high in recent years, resulting in substantial profits. Nitrogen trifluoride is primarily used as a cleaning agent and etchant in the electronics industry; therefore, its market conditions and development trends depend on the growth of the electronics sector. It is reported that currently 15% to 20% of nitrogen trifluoride is used as a cleaning agent in the LCD market ； About 65% to 70% of nitrogen trifluoride is used for semiconductor cleaning and etching. In recent years, advances in electronic technology have led to a rising demand for various electronic products, and this surge in demand has stimulated the continuous expansion of nitrogen trifluide production capacity. It is estimated that global demand for nitrogen trifluide will exceed 5,500 tons by 2007. Since Taiwan, China is currently the main producer of chips and liquid crystal panels in the world, it is estimated that Taiwan alone will need around 1,300 tons of nitrogen trifluide in 2006. According to the U.S. Semiconductor Industry Association, global sales of silicon wafers increased by 26% year-on-year in 2004 ； In 2005, the year-on-year growth rate for computers was around 12% ； In 2005, mobile phones and digital products saw year-on-year growth of 17% and 15%, respectively. At the same time, the strong demand for liquid crystal displays has contributed to the continued growth of the nitrogen trifluide market. Liquid crystal displays are currently growing at an annual rate of 30%, and China has become the world’s largest producer and exporter of such displays. By 2004, China had produced 44.6 million liquid crystal displays, a 42% increase compared to the previous year, and it is expected that this high growth rate will continue in the coming years. The rapid development of liquid crystal displays will be the main driving force behind the demand for nitrogen trifluide. Therefore, it is estimated that China’s demand for nitrogen trifluide will reach around 700–800 tons by 2007. Based on the development plans in related industries, it is predicted that China’s annual growth rate in nitrogen trifluide demand will remain above 20% from 2007 to 2010. At present, the purity of nitrogen trifluoride produced in China is somewhat lower compared to advanced products manufactured abroad. As a result, when Chinese-made products are exported overseas, they are purchased by some foreign manufacturers of nitrogen trifluoride, who then purify them before reselling them back to the Chinese market. Therefore, in the future, China should focus on improving product quality through a combination of independent development and the introduction of advanced technologies, pay attention to research on purification processes, and increase the added value of its products while expanding production scale. 3. Ultra-pure hydrogen fluoride: Ultra-pure hydrogen fluoride is primarily used as a reagent in the electronics chemicals industry. Currently, there are nearly 10 companies in China capable of producing hydrogen fluoride at the MOS grade (a standard for electronic chemicals used in metal-oxide-semiconductor applications), as well as at higher purity levels; their total production capacity is around 3,050 tons. The main manufacturers include Beijing Research Institute of Chemical Reagents, Suzhou Jingrui Chemical Co., Ltd., Zhejiang Fluorescent Chemical Co., Ltd., Fujian Shaowu Yongfei Chemical Co., Ltd., and Suzhou Sanhe Microelectronics Materials Development Co., Ltd., among others. In recent years, with the rapid development of China’s electronics industry, there has been a demand for specialized ultra-pure reagents that serve as supporting materials for this industry. In 2003, China’s electronics industry consumed 1,610 tons of ultra-pure hydrogen fluoride, of which nearly 800 tons was imported ； In 2004, the consumption of ultra-pure hydrogen fluoride reached 2,180 tons, of which 1,250 tons were imported products ； In 2005, the consumption of ultra-pure hydrogen fluoride was 2,720 tons, of which about 1,550 tons were imported products. Since 1994, China’s integrated circuit industry has maintained rapid growth. During the decade from 1994 to 2003, the annual growth rate of China’s integrated circuit production was as high as 52.2%. The chip manufacturing industry was the main driving force behind the development of China’s integrated circuits, with demand concentrated in four main areas: laptops, mobile phones and program-controlled switches, color televisions, and digital cameras. As China’s national economy continued to grow steadily, the annual growth rate of sales revenue for integrated circuits in China reached 30% from 2004 to 2008. According to forecasts, by 2008, the sales revenue of China’s integrated circuit industry would increase from 43 billion yuan in 2004 to over 100 billion yuan. Based on this, it is estimated that by 2008, the domestic demand for ultra-pure hydrogen fluoride would be around 3,800–4,200 tons. China’s current production capacity is only 3,050 tons per year, and most of this production is at the MOS level; the production of ultra-pure hydrogen fluoride at higher grades is extremely limited, far insufficient to meet domestic demand. Therefore, there is a significant gap in the market, and China still relies heavily on imports. Based on China’s consumption and imports of ultra-pure hydrogen fluoride in 2005, the self-sufficiency rate for domestic products was around 43%. The ultra-pure hydrogen fluoride imported into China mainly came from countries and regions such as Japan, Taiwan Province of China, the United States, South Korea, and Germany, with an average import cost of 2,308 dollars per ton. At present, our country is one of the world’s major producers and exporters of hydrogen fluoride. In 2005, the production capacity for industrial-grade hydrogen fluoride reached 560,000 tons, while exports amounted to around 80,000 tons. There is a significant demand for ultra-pure hydrogen fluoride in the domestic market, and the profits associated with this product are high. Therefore, domestic manufacturers should accelerate technological progress, introduce advanced production processes and equipment, produce ultra-pure hydrogen fluoride, improve the quality of their products, and increase their added value. 4. Tungsten hexafluoride: Tungsten hexafluoride is the only fluoride of tungsten that can be stabilized and produced industrially at present; its main use is as a raw material in the CVD (chemical vapor deposition) process in the electronics industry ； It can also be used as a raw material for semiconductor electrodes, a fluorinating agent, a polymerization catalyst, and a raw material for optical materials, among other things. The industrial production of tungsten hexafluoride is mainly achieved by the direct reaction of metallic tungsten with fluorine or nitrogen trifluoride at high temperatures, followed by purification. When high-purity products are required, high-purity tungsten must be used as the base material. Worldwide, the production of tungsten hexafluoride is concentrated in the United States and Japan. The main manufacturers include Air Products and Chemicals in the United States, Praxair Technologies, and Metheson TriGas ； Japanese companies such as Kanto Denka, Chuo Sangyo, and Mitsui Chemicals. Among them, Kanto Denka is the world’s largest producer of tungsten hexafluoride ； Praxair Technologies is the world’s largest producer of high-purity tungsten hexafluoride, with the purity of its product reaching 99.9999%. The production capacity for this high-purity material is 40 tons per year. In 2005, the total global production capacity for tungsten hexafluoride was around 1,300 tons, with an annual production of approximately 1,000 tons. With the rapid development of the electronics industry worldwide and in China, the demand for tungsten hexafluoride is showing a steady and rapid increase. Since no industrial production facilities exist in China, all domestic demand must be met through imports. It is therefore necessary to intensify efforts in research and development in China in order to achieve industrial production as soon as possible and meet the growing demands of the domestic market. 5. Iodine pentafluoride: As a general-purpose fluorinating agent and strong oxidizing agent, iodine pentafluoride plays an important role in organic synthesis, mainly being used to prepare copolymerization agents for the synthesis of perfluoroiodoalkyl iodides. The most common method for preparing iodine pentafluoride is the combustion of iodine in fluorine gas; depending on the phase state of iodine during the reaction, it can be classified as a gas-solid reaction or a gas-liquid reaction. The gas-solid reaction is intense, and the solid iodine involved in the reaction can easily clog the pipes; however, this reaction process is relatively simple, making it one of the more mature industrial processes available today ； The gas-liquid reaction equipment is severely corroded, but the reaction conditions are relatively mild, and the reaction results are quite satisfactory. The production of iodine pentafluoride requires high standards in terms of corrosion resistance of the reaction equipment as well as operational safety during the reaction process; therefore, it deserves significant attention from development and manufacturing entities. The main foreign manufacturers of iodine pentafluoride include ABCRGMBRCO, Air Products and Chemicals, Solvay Fluorine Chemicals, Honeywell, etc. Due to the rapid growth in demand for downstream fine chemicals, there has been strong market demand for iodine pentafluoride in recent years, keeping prices stable; the current market price is approximately 300,000 yuan per ton. The main use of iodine pentafluoride is as a precursor for the synthesis of perfluoroiodanes, which are used in the production of fluorinated surfactants and fluorinated fabric treatment agents. Fluorinated surfactants possess excellent and unique properties such as high surface activity, high heat stability, high chemical stability, as well as water- and oil-repelling characteristics, making them the most promising products in the field of surfactants. There is great potential for demand in the domestic market; in 2004, the import volume of fluorinated surfactants and fabric treatment agents in China exceeded 6,000 tons, with approximately 600 tons of perfluoroalkyl iodides being consumed. Due to the high profits associated with fluorinated surfactants and fabric treatment agents, foreign companies are reluctant to sell perfluoroiodane directly to China. Currently, Shanghai Zhonglin New Materials Company in China has successfully developed and established small-scale production facilities for perfluoroiodane. At present, there are no production facilities for iodine pentafluoride in China, so the domestic demand for this substance relies entirely on imports. Given the huge demand and rapid development of perfluoroiodanes, fluorinated surfactants, and fabric treatment agents in China, research and development of iodine pentafluoride is of great significance. Currently, companies such as Zhejiang Juhua and Sanai Fu New Materials Co., Ltd. in China show great interest in this area and are actively engaged in related research and development. 6. Sulfur tetrafluoride: Sulfur tetrafluoride is highly toxic, but it also possesses high reactivity; it can replace the oxygen atoms in functional groups such as carbonyl, aldehyde, carboxyl, and alcohol groups in organic compounds with fluorine, resulting in compounds with one, two, or three fluorine atoms substituted. It is an important fluorinating agent for selectively introducing fluorine atoms, and it is widely used in the synthesis of fluorinated pesticides, pharmaceuticals, and their intermediates. The synthesis methods of sulfur tetrafluoride include routes such as the direct reaction of fluorine and sulfur, the reaction of iodine pentafluoride with sulfur, the reaction of sulfur dichloride with calcium fluoride, and the reaction of metal fluorides with sulfur hexafluoride. At present, the main producer of sulfur tetrafluoride in the world is Air Products and Chemicals in the United States, with an annual production volume of several dozen tons. The price of this substance is high; in China, the market price of sulfur tetrafluoride offered by some specialized gas companies is 2,000 yuan per kilogram, while the import price is even higher. Due to these high prices, the production and development of certain pesticides, pharmaceuticals, and their intermediates are hindered. Some domestic end-users hope that Chinese companies will develop and produce sulfur tetrafluoride in order to reduce production costs and meet their industrial needs. Given that sulfur tetrafluoride is highly toxic, difficult to separate and purify, and requires high pressure for transportation and storage, while it is yet essential for the production of downstream fine chemicals, it is recommended that relevant domestic enterprises develop and produce sulfur tetrafluoride, and use it as a raw material to directly create downstream products, thereby promoting the healthy development of sulfur tetrafluoride utilization in China. With the rapid development of industries such as electronics and chemicals in our country, the variety, quantity, and quality of inorganic fluorides will continue to improve. Moreover, the applications of inorganic fluorides are expanding amid technological advancements. Therefore, domestic enterprises can take advantage of China’s abundant fluorspar resources to develop a range of inorganic fluorides, thereby ensuring the rational utilization of these resources and the sustainable development of the fluorine chemical industry. At present, there is a disconnect between research institutions and manufacturers of high-purity inorganic fluorides in China; as a result, many new products and new manufacturing processes cannot be put into industrial use promptly. Compared with advanced foreign levels, these industries suffer from shortcomings such as a limited range of products, relatively backward technical capabilities, poor product quality, and equipment that fails to meet the requirements of the manufacturing processes. In the future, research and development should be closely integrated with production in China. While improving and enhancing the varieties that are already in industrial use, efforts should be accelerated to develop and produce new varieties and high-purity products, so as to maximize the added value of deep processing of fluorite resources and achieve good economic benefits.