Call for proposals on production processes for trace element fertilizers

I have seen the production of boron fertilizers; the manufacturing process involves adding a small amount of borax to the raw materials used in compound fertilizers. There are also fertilizers such as zinc fertilizer, silicon fertilizer, and seaweed fertilizer, all of which involve the addition of trace additives in the process of formulating compound fertilizers. I won’t mention the manufacturer. This post was last edited by 921027abcd on 2008-2-19 16:35.]

Beijing Dabao Shuanglu Green Fertilizer Development Co., Ltd. has 10 branch companies located in Laizhou City, Shandong Province; Hengshui City and Handan City, Hebei Province; Shenyang City, Liaoning Province; Zhuzhou City, Hunan Province; Jiayuguan City, Gansu Province; Xinjiang; Hainan; and Heilongjiang. Products: Bio-fertilizers; green fertilizers; fertilizers containing medium and trace elements. Lanzhou Fuqiang Trace Element Factory produces 3,000 tons of manganese sulfate per year, as well as 10,000 tons of compound fertilizers, fertilizers rich in medium and trace elements, and trace element additives. Products: medium and trace element fertilizers, manganese fertilizers, foliar micronutrient fertilizers ；

Shouguang, Shandong produces and supplies multi-element calcium fertilizers. Baoding, Hebei supplies high-quality boron fertilizers such as disodium octaborate tetrahydrate. Fengtai District, Beijing supplies foliar fertilizers. Nanning, Guangxi supplies Dalihuang foliar fertilizers. Wuhan, Hubei supplies biological fertilizers. Qingyuan, Guangdong supplies calcium carbonate. Nanning, Guangxi supplies trace elements. Daqing, Heilongjiang supplies A’kang triple-element fertilizers. Taiyuan, Shanxi supplies rice yield enhancers. Baoji, Shaanxi supplies multi-element fertilizers as well as mineral fertilizers. Shouguang, Shandong supplies multi-element calcium fertilizers; Hangzhou, Zhejiang supplies boron fertilizers. Wuhan, Hubei supplies biological fertilizers; Qingyuan, Guangdong supplies calcium carbonate. Daqing, Heilongjiang supplies A’kang triple-element fertilizers. Taiyuan, Shanxi supplies rice yield enhancers. Jianghan, Hubei supplies calcium-magnesium-phosphorus fertilizers. Zhengzhou, Henan supplies sulfur-containing urea. Xi’an, Shaanxi supplies potassium chloride. Foshan, Guangdong supplies 31% industrial hydrochloric acid. Changsha, Hunan supplies zinc sulfate monohydrate as well as magnesium sulfate monohydrate fertilizers. Laiwu, Shandong supplies zinc sulfate of fertilizer grade

Hebei, Xingtai supplies sulfuric acid AN; Henan, Zhengzhou supplies sulfur-containing urea; Hubei, Wuhan supplies granular calcium hydrogen phosphate; Beijing, Chaoyang District supplies fertilizers containing trace elements; Yunnan, Kunming supplies compound fertilizers of various concentrations such as 25/30; Jilin supplies microbial fertilizers; Shandong, Linyi supplies fertilizers containing trace elements; Xinjiang, Urumqi supplies high-tower granulated compound fertilizers; Shandong, Heze also supplies high-tower granulated compound fertilizers; Guangdong, Shenzhen supplies biological fertilizers; Hunan, Yueyang supplies high-quality, low-cost green compound fertilizers containing medium and trace elements; Shaanxi, Hanzhong supplies high-quality chemical fertilizers; Beijing, Haidian District supplies microbial fertilizers and organic fertilizers

Chengdu Huahong Ecological Agriculture Technology Co., Ltd. supplies molybdenum fertilizers and iron fertilizers

Glass-based trace element fertilizers are made by using glass as the main raw material, adding one or several common trace elements, mixing them evenly, then heating them to a molten state at high temperatures. After a solid-state reaction occurs, the fertilizer is formed.

Swedish company Rockwell Chemicals has developed a type of long-acting fertilizer in the form of composite micronutrient capsules. This fertilizer contains various micronutrients essential for crops, such as iron, manganese, and zinc, and these are enclosed within microporous capsules. When applied to soil (or to the medium or solution used in hydroponic cultivation), the micronutrients can be released slowly through the pores in the capsules, with this release process lasting up to 10 years, thereby maintaining optimal levels of micronutrients in the soil (or medium/solution).

Silicon fertilizer production process: The use of steel slag as a fertilizer has a long history in Germany. . Currently, the main processes used in Germany to produce silicon fertilizers from blast furnace slag are: applying the slag directly after crushing and grinding it to a certain particle size, or mixing the crushed and ground slag with phosphate compounds before application. Japan uses air quenching to rapidly cool slag. The primary utilization rate of heat recovery reaches 62.6%, the secondary utilization rate can reach 70%, and the vitrification rate is 96%–99%. This not only recovers the waste heat but also increases the vitrification degree and active silicon content of the slag. Slag with a high vitrification index is ground finely, or some additives are added and ball-milled together; once it reaches a certain particle size, it is sold directly as a commercial silicon fertilizer. The effective silicon content in the resulting blast furnace slag silicon fertilizer can reach 20%. The process used by the Korea Yellow Sea Iron and Steel Plant to produce silicon fertilizer from blast furnace slag in iron production is as follows: the high-temperature blast furnace slag is directly poured into a water quenching tank for quenching, after which it is lifted out using a grab machine. 10% fly ash is added to it, along with water, and all these materials are fed into a ball mill for wet grinding until the particle size is reduced to below 0.5 mm; once dried, the resulting material is silicon fertilizer. The resulting silicon fertilizer contains more than 15% soluble silicon, and the total amount of calcium oxide and magnesium oxide is more than 30%. The effective silicon content in the silicon fertilizers produced in these countries is all above 15%, while the total amount of calcium oxide and magnesium oxide is greater than 30%.

Fly ash, slag, glass slag, etc. can be converted into silicon fertilizers and iron fertilizers through high-temperature calcination, with a total content of around 20%~25%

The current types of boron fertilizers mainly include borax, boric acid, boron-containing fertilizers, and boron sludge. 1. Borax has the molecular formula Na2B4O7·10H2O, with 10.8% boron content. Its chemical name is sodium borate or sodium tetraborate. Industrial borax is a colorless, translucent or white monoclinic crystal powder. Odorless, salty in taste, with a relative density of 1.73; soluble in water. It is prone to weathering in dry air; it loses 8 molecules of crystal water at 60°C, and all of its crystal water is lost at 350°C–400°C. Borax is the most widely used boron fertilizer at present, and can be used as a base fertilizer, seed fertilizer, or for foliar spraying. 2. Boric acid has the molecular formula H3BO3, with 16.8% boron. It is actually a hydrate of boron oxide (B2O3·3H2O), appearing as white powdery crystals or shiny flaky crystals; it is tasteless, with a relative density of 1.435 at 15°C. It is soluble in water, alcohol, glycerin, ethers, and essential oils, and its aqueous solution is slightly acidic. Its solubility in water increases as the temperature rises, and it volatilizes with water vapor. Boric acid is also one of the commonly used boron fertilizers, and its application method is the same as that of borax. However, due to its higher cost, it is not used as widely in agriculture as borax; it is generally applied only as an extracellular fertilizer or through foliar spraying. 3. Boron-containing glass fertilizers (boron frits): Boron is melted into moderately soluble glass; its composition is Na2B4·xH2O, with a boron content of 10%-17%. It has low solubility, releasing boron slowly into the soil; it is not easily adsorbed by the soil nor does it leach away easily, and its effects last for many years after a single application. 4. Boron ores: Among the boron-containing minerals found in nature, some can be used directly as boron fertilizers, such as ulexite (2CaO·3B2O3·5H2O), colemanite (4CaO·5B2O3·7H2O), and sodium borocalcite (Na2O·2CaO·5B7O6·10H2O). It is insoluble in water; after being crushed, it forms a white powder. It is suitable only as a base fertilizer, with a steady and long-lasting fertilizing effect. 5. Boron sludge: The waste residue resulting from the production of borax; 4-5 tons of boron sludge can be produced for every ton of borax manufactured. The total boron content (B2O3) in borax sludge is about 2%-3%, with soluble boron at 0.25%. The contents of MgO are 30%-40%, Fe2O3 is 9%-10%, and SiO2 is 19%-20%. There are also small amounts of impurities such as CaO, Al2O3, and Na2CO3. It is alkaline (pH 8-9) and suitable as a base fertilizer for acidic, magnesium-deficient soils in the south; it can also be used as a raw material for producing boron-magnesium fertilizers and boron-calcium-magnesium-phosphorus fertilizers. 6. Macronutrient fertilizers containing boron: These are prepared by adding an appropriate amount of boron to Macronutrient fertilizers and mixing them together. Such as boron-containing superphosphate·H3BO3, containing about 0.6% B and 8% P. In addition, there are also boron-containing gypsum, boron-containing calcium carbonate, boron-containing calcium nitrate, and so on.

Do people really understand the production process of micro-fertilizers? As far as I know, micro-fertilizers are mainly produced by using EDTA as a chelating agent in reaction with sulfates. In this process, disodium EDTA reacts with divalent sulfates, and acids or bases are added appropriately to adjust the pH value, after which evaporation is carried out to complete the production. This method can be used to produce chelated trace elements in their elemental form, as well as poly-chelated trace elements. Well-known companies in this field include AkzoNobel and Covestro. There are also several major producers in China, such as Suzhou Liansheng and Shandong Sanwei Chemical. The quality stability of domestic products is relatively poor, mainly due to the tendency of these products to oxidize easily.

It should be said that there are many types of trace elements. Organic chelated micronutrient fertilizers represent a good option – they are not easily adsorbed by the soil, resulting in high utilization rates. However, due to the high cost of their raw materials, their market price is also high. Inorganic micronutrient fertilizers, on the other hand, are easily adsorbed by the soil but have lower utilization rates; yet their cost is low, so their market price is relatively low. Therefore, the key lies in how users make their choices.............

Lignosulfonic acid complex micro-fertilizers containing Zn and Fe are the most common and widely used types; in addition, there are copper lignosulfonic acid and manganese lignosulfonic acid, but they are not as widely used. Various lignosulfonate micronutrient fertilizers are recommended for use in drip irrigation water or as foliar fertilizers; they are non-toxic to plants, safe to apply, and their efficacy is equivalent to that of 2–3 times that of inorganic sulfate micronutrient fertilizers. Additionally, lignosulfonate can also be concentrated into a powder and mixed into granular fertilizers, or lignosulfonate micronutrients can be sprayed onto the surface of conventional granular fertilizers. The production method involves using the waste liquid from acid pulping processes, which contains a certain amount of lignosulfonic acid, as a chelating agent to react with oxides or inorganic salts of trace elements; after filtration to remove lignocellulose and other harmful impurities, the final product is obtained.

Humic acid is an amorphous polymer compound formed by the decomposition of dead plants and animals through microbial and chemical processes. It is widely found in peat soils and weathered coal. Humic acid contains active functional groups such as aromatic groups, carboxyl groups, carbonyl groups, and methoxy groups, and it possesses properties such as acidity, hydrophilicity, cation exchange capacity, and physiological activity. It exhibits significant fertilizing effects in areas with low fertility, in regions where yields are low, and during the early stages of crop growth. At present, the humic acid-chelated trace element fertilizers produced and used in China include sodium humate boron-magnesium fertilizer, sodium humate boron-phosphorus fertilizer, sodium humate boron-magnesium-nitrogen-phosphorus fertilizer, various humic acid composite fertilizers containing multiple trace elements, and yellow humic acid diamine iron fertilizer. Humic acid chelated micro-fertilizers can be applied as a topdressing or incorporated into the soil, or they can be dissolved in water for spraying ； It can be used as a base fertilizer as well as a top dressing, and it has a significant effect on crops such as rice, sugarcane, tobacco, vegetables, and fruit trees. 1) Sodium humate boron-magnesium fertilizer is prepared by separately crushing peat and boron sludge, mixing them in a 3:1 (by mass) ratio, adding a small amount of water, heating the mixture in a high-temperature environment for 2–3 days, and then allowing it to sit for several days. During this process, sodium in the peat reacts with humic acid to form sodium humate, thereby yielding the sodium humate boron-magnesium fertilizer. This product is neutral in nature and is generally used as a base fertilizer; it can be applied together with organic manure. The application rate is 150–250 kg per 667 m². 2) Sodium humate boron-magnesium-phosphorus fertilizer is prepared by mixing peat, boron sludge, and phosphate rock in a ratio of 100:20:10, then adding 10 kg of water, heating the mixture to 70°C, and allowing it to sit for 5–7 days. The pH of the product is 7–8. This fertilizer can be used as a base fertilizer or top dressing, at a rate of 500 kg per 667 m²; it has a significant effect on sorghum, soybeans, and corn. 3) The sodium humate ammonium-phosphorus-boron-magnesium fertilizer is prepared by evenly mixing 25% peat, 20% ammonium carbonate, 20% phosphate rock powder, and 35% boron sludge. This fertilizer yields a particularly significant increase in corn yield when 25 kg is applied per 667 m². 4) The compound fertilizer containing various trace elements and humic acid is prepared by mixing humic acid-containing peat with several trace elements in the proportions given in Table 5, allowing the mixture to sit for 1–2 months, and then compressing it into tablets to obtain the final product. 5) The production method of diammonium ferrous humate uses humic acid, urea, and ferrous sulfate as raw materials, with a mass ratio of 100:4:0.4 among them. First, urea is dissolved in hot water at a temperature above 90°C, followed by the addition of ferrous sulfate to produce a diamine iron solution. Then, a fulvic acid solution at a temperature above 90°C is added; after thorough mixing, the mixture is cooled to obtain the final product. This product is a new type of chelated iron fertilizer with good efficacy and high stability; it can supply plants with iron nutrients over an extended period of time. Its price is lower than that of EDTA-chelated iron, and it is suitable for use in cases where crops suffer from iron deficiency-induced \"yellow leaf disease\", as well as for fertilizing field crops such as wheat. The typical mass fraction of ferrous diammonium humate applied by spraying on fruit tree leaves is 0.3% ； The seed soaking concentration for winter wheat is 0.02%. It is reported that in the northern regions, the application of diammonium ferrous humate is used to prevent chlorosis and yellowing in apples, poplars, willows, cypresses, plane trees, cedars, and crabapples. Results can be seen within 3–5 days after application, as the yellowed leaves turn green and the new growth also becomes green.

Calcium nitrate and potassium dihydrogen phosphate are the best micro-nutrients for plants, and they are also cost-effective.

I don’t understand. Calcium nitrate can be considered a minor fertilizer; this is because calcium fertilizers are used relatively little in soils. The main reason for calcium deficiency in soils is an excessively high soil pH. Therefore, applying more organic fertilizers or sulfur-based fertilizers to such soils can help meet the soil’s demand for calcium. In other words, the real cause of calcium deficiency in soils isn’t a lack of calcium itself, but rather the inability of the soil to utilize the available calcium. As for potassium dihydrogen phosphate, aside from phosphorus pentoxide and potassium oxide (which indicate the presence of phosphorus and potassium), it seems to contain no other elements, so it’s unclear where the trace elements come from............

Types and properties of iron fertilizers: Commonly used iron fertilizers can be divided into two categories: inorganic iron fertilizers and organic iron fertilizers. Inorganic iron fertilizers include ferrous sulfate (FeSO4), ammonium iron phosphate (FeNH4PO4·H2O), and ammonium ferrous sulfate [(NH4)2SO4·6H2O], among others. Among them, ferrous sulfate is the most commonly used iron fertilizer at present; it contains 19% iron, has a high solubility, is inexpensive, and is suitable for soil fertilization as well as foliar spraying. Organic iron fertilizers include synthetically produced iron chelates such as FeEDTA, FeEDDHA, FeDTPA, etc., as well as organic iron compounds derived from by-products in the papermaking industry, such as ferulic acid iron, iron-substituted polyflavonoid compounds, and iron-substituted methoxyphenylpropane. Organic iron fertilizers are many times more expensive than inorganic iron fertilizers, but their fertilizer efficiency is much better. This post was last edited by yunanshu on 2008-4-30 09:00]

To produce medium and trace element fertilizers from minerals, the methods generally include calcination of slag and solution separation. Calcination and water quenching method: Ore -- Concentration -- Calcination -- Water quenching -- Drying -- Ball milling -- Granulation -- Screening -- Finished product. This process is only suitable for ores that do not contain toxic elements; after calcination, insoluble trace elements can be converted into water-soluble or citrate-soluble compounds. If potash feldspar is heated to a molten state at temperatures of 1100–1350°C and then quenched under high pressure, it breaks down into fine particles; after drying, ball milling, and granulation, it becomes a composite fertilizer containing mainly silicon and potassium, as well as elements such as magnesium and iron. This method features simple process equipment and low production costs, allowing for the simultaneous extraction of multiple trace elements. The dissolution and separation method is suitable for ores containing toxic heavy metal elements. Through roasting, the active components are converted into compounds that are soluble in water and acids; subsequent separation is carried out based on their chemical properties, allowing the heavy metal elements to be removed. This process results in trace elements within the active components being in the form of relatively pure inorganic salts. The advantage of this method is that the resulting fertilizers containing trace elements have high purity and a single composition, but the process is complex and the separation costs are high. In the case of zinc sulfate extraction, zinc ore is roasted first and then treated with dilute sulfuric acid to extract zinc; zinc powder is used to precipitate Fe”, Mn, Fe” and Mn”, and after removing the impurities, the desired product is obtained.

Production of medium and trace element fertilizers from industrial waste: Industrial waste comes from a wide range of sources; waste from the metallurgical and chemical industries contains higher levels of medium and trace elements compared to ores. Some of these components are relatively simple, making separation easier. For example, in the production of hydroquinone, large amounts of waste manganese and manganese slag are generated; meanwhile, the large amount of waste liquid produced in titanium powder manufacturing can be used to produce ferrous sulfate. There is more waste generated in the production of zinc sulfate: zinc oxide waste collected from smelter flue gases, zinc sludge from electroplating plants, and waste residues containing Zn(OH) produced during sodium thiosulfate manufacturing – all of these serve as raw materials for extracting ZnSO4. Generally, these wastes only need to be treated by soaking them in dilute sulfuric acid, followed by sediment removal, filtration, and crystallization, in order to obtain zinc sulfate or ferrous fertilizers. Some industrial waste residues contain two or more useful chemical components; for example, the brass casting slag resulting from copper processing contains Cu, Zn, Si, Ca, etc., and it is necessary to separate these various components one by one ； A considerable amount of industrial waste also contains both the active components of trace element fertilizers and toxic elements; it is therefore necessary to separate and recover these toxic elements in order to prevent secondary pollution and to save resources. For example, zinc smelting plants produce large quantities of copper-cadmium slag each year, which contains many valuable metals such as Zn, Cu, and Cd.

What are trace elements? All objects in the world, whether they are organic living entities such as plants, animals, and humans, or inorganic non-living substances such as minerals, rocks, air, and water, are composed of various chemical elements. According to research, 107 chemical elements have been discovered so far in the world. The concentrations of these elements in nature or in various substances vary greatly; some elements are present in high amounts, while others are present in very low amounts. Among the chemical elements found in nature, they are classified into three categories based on their abundance: major elements (sometimes referred to as essential elements), trace elements, and ultra-trace elements. Macronutrients are a term referring to chemical elements that are present in high concentrations, while micronutrients are a term referring to chemical elements that are present in low concentrations. Elements that lie between major elements and trace elements are collectively referred to as medium elements. Trace elements are a relative concept as opposed to major and medium elements. The so-called trace elements, as the name implies, refer to amounts that are small. \"Shao\" has a dual meaning: it refers to a very low content, and it also means that plants and animals require very little of them. In a broad sense, trace elements refer to chemical elements that are present in very low amounts or are distributed so widely that they are not concentrated in natural environments or various natural objects. The trace elements referred to in soil science can denote all chemical elements present in very low concentrations in the soil, or they can refer to those chemical elements that have biological significance. Research on trace elements in soil not only holds biological significance but also often has specific importance, such as helping to clarify the soil formation process of a particular soil or aiding in environmental quality assessment. Biologically significant trace elements are often components of enzymes or coenzymes. Their specific mechanisms within organisms exhibit high specificity, and they are essential for the normal growth and development of living organisms. We refer to elements in the Earth’s crust whose concentrations range from a few parts per million to a few ten-thousand parts per million, and generally do not exceed a few parts per thousand, as trace elements or elements in trace amounts. Although iron is abundant in the Earth’s crust, its content in plants is very low. It has special functions, which is why it is also classified as a trace element.