Potassium products

Table 2. Potassium Products from Hydrocarbons, Amines, and Alcohols...

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). 

Potassium peroxomonosulfate, 14 67 Potassium peroxydisulfate, 14 292 Potassium peroxymonosulfate, 26 189 Potassium persulfate, 7 856 Potassium phosphates, 18 834-835 20 637 manufacture of, 18 854 Potassium polymetaphosphate, 18 848 Potassium products, 20 5991 Potassium pyrophosphates, 18 843 Potassium residues, 20 603 Potassium salts, 20 609... 

Large deposits of sylvinite (42.7% KCl, 56.6% NaCl) near Carlsbad, New Mexico, account for 85% of the potassium products produced in the U.S. The potassium chloride can be separated by either fractional crystallization or flotation. Potassium chloride is also obtained from the brines of Searles Lake, California. All these sources give potash (97% potassium chloride) with a 60% K2O equivalent for fertilizer use. A chemical-grade product can be obtained to a purity of 99.9% potassium chloride. Almost all potash produced is potassium chloride. Potash is used mainly as fertilizer (88%) with a small amount (12%) used in chemical manufacture. 

In industry, chemical reduction is preferred over electrolytic processes for potassium production. Application of the Down s electrolytic sodium process to produce potassium has not been successful. Potassium—sodium alloy is easily prepared by the reaction of sodium with molten KC1, KOH, or solid KjCC powder (see Sodiumand SODIUMALLOYS). 

Potassium, rubidium, and cesium metals are produced by chemical reduction rather than by electrolysis. Sodium is the reducing agent used in potassium production, and calcium is the reducing agent used for preparing rubidium and cesium. 

Fortunately, as Voshage and co-workers were able to show, the available data do allow the construction algebraically of a mathematical expression that removes the native component and provides a measure of spallogenic potassium production. We begin with the relations below ... 

About 33 million tons (30 million metric tons) of potassium (measured as K20) are produced worldwide annually, mostly in Canada, the United States, and Chile. As an important component of fertilizer and an essential nutrient in the human diet, the demand for potassium products may be expected to continue. 

Justus von Liebig (1842) spread the knowledge that potassium is one of the important plant nutrition elements. In 1861, Adolph frank started the first plant using the process he had developed for producing from carnallite - a potassium salt that could be employed as a fertilizer. When Alsace was returned to franco at the end of World War I, the potash works become French property, so that Germany lost her monopoly in potash. Potash production in Spain began in 1926 in Catalonia. In Sicily (Italy) kainite deposits were used for potassium sulfate production. In Russia, potassium production began 1931 in the northern Urals. In 1939, the Soviet Union took over potassium... 

Important Compounds and Uses Around the turn of the millennium, the total annual output of the world s potash industry including potassium sulfates and potassium products for industrial uses amounted to 30 million tons of K2O. Capital investment in the Soviet Union and Canada and the rapidly increasing use of fertilizers in agriculture in the 1960s and 1970s led to a steep increase in world potash production. Since 1980, the average annual increase in world potash production has been only 0.7%. 

Technically, all signs seemed to point to metallic sodium for the production of potassium from its compounds as a step in the production of potassium superoxide. Sodium is commercially prepared by the electrolysis (I) of molten sodium chloride to which calcium chloride has been added to lower the melting point. The analogous process could not be used for potassium production (7) because the potassium will attack the graphite electrodes and because of the danger of explosion due to potassium carbonyl sometimes formed in the process. Rather than work on alternate electrodes of other material, a thermochemical process was developed, using the reduction of a potassium salt by sodium. Other processes (4) were investigated by Kraus. 

Figure 7-44. Potassium production by direct decomposition of its iodide (KI) in atmospheric-pressure thermal plasma. Composition of products (1) KI (2) I (3)K (4)K+.

Our first assumption was that the formation of 9 and 10 might be due to an intramolecular attack of the Si-K moiety of the monopotassium compound onto the Si(SiMe)3 group. However, this reaction would afford a cyclic structure with four trimethylsilyl groups as in 11, 12 and trimethylsilyl potassium, none of which we were able to observe. Even if the trimethylsilyl potassium reacts immediately with the formed product this does not seem to be very likely, since it would result in the formation of hexamethyldisilane which we also did not observe. In addition we figured out that the new product is formed at the expense of the dipotassium compound and eventually found that the formation was actually caused by partial hydrolysis of the strongly basic dipotassium compound. Once the Si-H bond is formed the now more electrophilic silicon is attacked by the Si-K group and formation of the cyclic product along with trimethylsilane is accomplished. Careful addition of one equivalent of water to a reaction mixture which contained mainly the di-potassium product led to the quantitative formation of the cyclic Si-K species. 

Natural feldspars used for the preparation of ceramics are mineral mixtures. Thus, the commercial potassium products can contain between 2.5 and 3.5% of albite mass, whereas anorthite and a small quantity of orthoclase, between 0.5 and 3.2%, are often present in the available sodium feldspars [MAN 94]. They can also be incorporated into the paste in the form of feldspathic sand. When these natural products are heated, mixed and homogenous feldspar is formed. This compoimd. 

---