Potassium sulfate fertilizer

MgO. Only about 5% of total fertilizer potash is furnished as potassium sulfate and other nonchlotide forms including potassium nitrate. 

Four minerals are the principal commercial sources of potash (Table 2). In all ores, sodium chloride is the principal soluble contaminant. Extraneous water-iasoluble material, eg, clay and siUca, is a significant contaminant ia some of the evaporates being mined from underground deposits. Some European potassium ores contain relatively large amounts of the mineral kieserite, MgS04-H2 0. It is recovered for captive use to produce potassium sulfate compounds or is marketed ia relatively pure form as a water-soluble magnesium fertilizer. 

Potassium sulfate and langbeinite may be screened into three different size ranges to serve all segments of the fertilizer industry. Typical screen analyses of the size products are presented in Table 14. Chemical analyses for the products are shown in Table 15. 

Economic Aspects and Uses. Total world production of potassium products is 29,000,000 tons per year (65). Potassium chloride is removed from brine at Moab, and Wendover, Utah, and at Seades Lake, California. Potassium sulfate is made from Great Salt Lake brine by Great Salt Lake Minerals Corp., which is the largest producer of solar potassium sulfate in the wodd. Combined, these U.S. faciUties stiU produce a relatively small percentage of potash fertilizers in the wodd. Production from the Dead Sea, for example, is 10 times greater than production of potassium from brines in the United States. More than 95% of all the potassium produced is used in fertilizer blends. The remainder is converted to other potassium chemicals for industdal use (see Potassium compounds). 

Nutrient release patterns vary with the amount of coating appHed and the substrate used. Coating weights vary from 10 to 20%. Typically, commercial products are blends of different coating weights. Coated substrates kiclude, but are not limited to, urea, potassium sulfate, and ammonium nitrate-based N—P—K fertilizers. 

Chisso-Asahi Fertilizer Company, Ltd. This company utilizes thermoplastic resins, such as polyolefins, poly(vinyhdene chloride), and copolymers, as their coating materials. The coatings are dissolved in fast-drying chlorinated hydrocarbon solvents and are appHed to a variety of substrates including urea, diammonium phosphate [7783-28-0] potassium sulfate [7778-80-3], potassium chloride [7447-40-7], and ammonium nitrate/potassium sulfate-based N—P—K fertilizers. 

Scotts technology (17) uses fluid-bed (Wurster column) technology to apply polymeric coatings to a number of fertilizer substrates including urea, potassium nitrate, potassium sulfate, and monoammonium phosphate (MAP). The coating material is appHed as a water-borne latex onto the fluidized substrate. As the substrate is fluidized with warm air (40—50°C), water is driven off and the latex coalesces into a continuous film around the fertilizer particle. The particular latex compositions used have selected glass-transition and blocking temperatures, which enable quick removal of the water before the soluble fertilizer core dissolves. This obviates the need to use precoats prior to the latex appHcation. 

A number of products are being marketed under the trade name POLYON. These include coated basic fertilizer materials, ie, urea, potassium nitrate, potassium sulfate, potassium chloride, ammonium sulfate, ammonium phosphate, and iron sulfate, in various particle sizes. Coatings weights on urea vary from 1.5 to 15%, depending on the release duration desired. Table 6 Hsts typical products. 

The catalyst was reformulated by Alwin Mittasch, who synthesized some 2500 different catalysts and performed more than 6500 tests. They arrived at a triply promoted catalyst consisting of a fused iron catalyst, with AI2O3 and CaO as structural promoters and potassium as an electronic promoter. The process was first commercialized by BASF, with the first plant located in Oppau in Germany producing 30 tons per day in 1913. The plant initially produced ammonium sulfate fertilizer, but when the First World War broke out it was redesigned to produce nitrates for ammunition. The plant was expanded and in 1915 it produced the equivalent of 230 tons ammonium per day. 

The industrial term potash can be very misleading. It can refer to potassium carbonate (K2CO3), potassium hydroxide (KOH), potassium chloride (KCl), potassium sulfate (K2SO4), potassium nitrate (KNO3), or collectively to all potassium salts and to the oxide K2O. More correctly KOH is called caustic potash and KCl is called muriate of potash. Production is recorded in weight equivalents of K2O since almost all potash is used as fertilizer and this industry quotes weight percentages of K2O in its trade. 

The major use of potassium sulfates is in agriculture as a fertilizer (97%). The other 3% is used in industry. Potassium sulfate accounts for about 5% of the potash industry. It is twice as expensive as potassium chloride and is only used as potash fertilizer where it performs better than potassium chloride. 

Potassium chloride is the most important salt of potassium from the perspective of its abundant occurrence and apphcations. This salt, along with potassium sulfate, is used heavily in fertilizers as the primary source of potassium, an essential element for crops. Over 90% salt manufactured is consumed as fertilizer. Also, potassium chloride is a raw material for producing potassium metal and several important potassium salts including potassium nitrate, potassium hydroxide, and potassium sulfate. Other applications are in electrode cells photography buffer solutions and measurement of salinity in water. 

Potassium sulfate is used in fertilizers as a source of potassium and sulfur, both of which are essential elements for plant growth. Either in simple form or as a double salt with magnesium sulfate, potassium sulfate is one of the most widely consumed potassium salts in agricultural apphcations. It is preferred over potassium chloride for certain types of crops such as, tobacco, citrus, and other chloride—sensitive crops. Some other applications include making gypsum cements to make potassium alum in the analysis of Kjeldahl nitrogen and in medicine. 

Sulfates. Potassium sulfate. [CAS 7778-80-5], sulfate of potash, K2.SO4, white solid, soluble. Common constituent of potassium salt minerals. Used (l)as an important potassium fertilizer, (2) in the preparation of potassium or potash alums potassium hydrogen sulfate, KHSO4, white solid, soluble potassium pyrosulfate. K2S2O7, white solid, soluble, formed by heating potassium hydrogen sulfate to complete loss ot H2O. See also Fertilizer. 

Ammonium Phosphate and Potassium Sulfate. During the manufacture of 26/16/10 N/P/K fertilizer, the possibility of a thermal explosion exists.8... 

Fertilizers provide the primary nutrients (nitrogen, phosphorus, and potassium) for vegetation and are manufactured by a variety of processes (Fig. 1) and from a variety of raw materials (Fig. 2). The usual sources of nitrogen are ammonia, ammonium nitrate, urea, and ammonium sulfate. Phosphorus is obtained from phosphoric acid or phosphate rock and potassium is available from mined potassium chloride or potassium sulfate or it is obtained from brine. 

Potassium contributes to the formation of sugars, carbohydrates, proteins and to cell division adjusts water balance enhances the flavor, color, and oil content of fruits and is very important for leafy crops. Potassium deficiency produces a spotted, curled, or burned appearance to leaves and lowers crop yields. Potassium fertilizers are applied in the following forms potassium chloride, potassium sulfate, potassium nitrate, and wood ash. 

The sulfur-coating technique may be applied to fertilizers other than urea. Experimental work has included a coating of DAP, potassium chloride, potassium sulfate, and various compound fertilizers, including a pan-granulated urea-potassium chloride product of 32-0-16 grade. 

Fertilizers have potassium, nitrogen, and phosphorus in a form that dissolves easily in water so that plants can absorb them. The potassium in fertilizer is in an ionic compound called potassium carbonate. Two ionic compounds in the fertilizer contain the nitrogen—ammonium nitrate and ammonium sulfate. The phosphorus supplied is in another ionic compound, calcium dihydrogen phosphate. 

Worldwide more than 90% of the potassium-containing fertilizer used is potassium chloride. Potassium sulfate, potassium magnesium sulfate and potassium nitrate are, however, also used as fertilizers, in particular for plants which have a poor tolerance for chloride ions (e.g. tobacco, spinach, cucumbers etc.) or where magnesium-containing fertilizer is also required. 

Economic Importance. The worldwide production of magnesium sulfate products including potassium magnesium sulfate (fertilizer) was 3.4 10 t/a in the mid-1970 s of which 2.3 10 t was kieserite MgS04 H2O (a byproduct of the potash industry). The main producer countries are the USA and the Federal Republic of Germany. The USA consumption in 1996 excluding natural kieserite was 57-10 t. 

Applications Magnesium sulfate is utilized in the potassium chemicals industry for the manufacture of potassium sulfate (from potassium chloride), sodium sulfate and potash magnesia (potassium magnesium sulfate). Magnesium sulfate, particularly as kieserite, is used as a fertilizer (ca. 80% of total consumption). It is also used in the textile industry, in the manufacture of building and refractory materials, in the pulp industry and in the production of animal feedstuffs and motor oil additives. 

Because plants need nitrogen compounds, potassium compounds, and phosphorus compounds to grow, these are often added to the soil as fertilizers. Potassium sulfate, which is used to make fertilizers, is made industrially by reacting potassium chloride with sulfur dioxide gas, oxygen gas, and water. Hydrochloric acid is formed with the potassium sulfate. 

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