Chemical-Grade Potash

About 4%-5% of potash production is used in industrial applications. The industrial potash (chemical grade) has a different purity from fertilizer-grade potash. The composition of chemical-grade potash is given in Table 15.13 [51. 

Potassium chloride [7447-40-7] or muriate of potash (MOP) as it is known in the fertilizer industry (at about 97% purity), is the world s most commonly used potash (5). Chemical-grade potassium chloride (99.9%) is the basis for manufactured production of most potassium salts (10). 

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. 

Potassium chloride as a component in fertilizers is specified in terms of its K2O equivalent. On this basis, 100% pure potassium chloride is equated to 63.18% K2O equivalent. The approximately 96% pure potassium chloride product of the flotation separation is thus equivalent to 60.7% K2O (see Chap. 9). Chemical grades correspond to the once-crystallized, soluble product of about 99.5% KCl, and 99.95% KCl, which is the Refined, twice crystallized material. The price differential, 60-62.4% K2O equivalent at 108-112 US /tonne, and 99.95% KCl at 115-137 US /tonne (1995 prices [30]) is sufficient to cover the cost of the additional processing for Chemical grade potash. 

Chemical-grade potash has the following consumption pattern ... 

Most of the chemical-grade potash is used for production of potassium hydroxide. Potassium hydroxide ... 

The purest grade of europium metal available from the Lindsay Chemical Division of American Potash is 99.9% Eu in terms of rare earth content, but it may contain up to 1% of other metal impurities (mainly tantalum when prepared in tantalum vessels) and typically contains 2.8 mol % oxygen.6... 

Mallinckrodt analytical reagent grade ether, dried over sodium, was used. The methyl borate was the commercial product of American Potash and Chemical Corporation containing 99% ester as received. The phenylmagnesium bromide was purchased as a 3.0M solution in ether from Arapahoe Special Products, Inc., Boulder, Colorado. 

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