Superphosphate of lime

A great many phosphates are used in commercial fertilizers. Perhaps the most important of these is calcium dihydrogen phosphate, Ca(H2P04)2. In relatively pure form, this compound is known as triple superphosphate of lime. A 1 -2 mol mixture of Ca(H2PC>4)2 and gypsum, CaS04 2HzO, is commonly referred to as superphosphate of lime. ... 

The product, Ca(H2P04)2, is more soluble than the phosphate. Sulfuric acid is produced in the largest quantity of any compound, with production that approaches 100 billion pounds annually. Approximately two-thirds of this amount is used in the production of fertilizers. The mixture containing calcium dihydrogen phosphate and calcium sulfate (gypsum) is known as superphosphate of lime, and it contains a higher percent of phosphorus than does calcium phosphate. 

Romans, theirknawiedge of manures, 640 rules for the application of, 553 sewage maxiure 569 eoils, tbflir absorbent power, 658. special men ares, 532. steamed bones, 563. superphosphate of lime, 563,564. theory of, 546. . ... 

Another method of removing ammonia may be noticed it consists lit spreading on the screens superphosphate of lime, consisting of hones decomposed by sulphuric acid the addition of ammonia to this, makeB it a powerful and excellent manure. —Clegg. 

Charles II. Collette proposed to defecate with lime and superphosphate of lime. 

The compound Ca(H2P04)2 contains a higher percentage of phosphorus than does the mixture with calcium sulfate known as superphosphate of lime. Accordingly, it is sometimes called triple superphosphate. 

How much calcium may be obtained from 100 gm. of (a) marble, ( ) gypsum, CaS04.2H20, ( ) fluor spar, CaF2, superphosphate of lime, CaH (POj2 ... 

Enough water is added to convert the calcium sulfate to its dihydrate, gypsum, and the mixture of gypsum and calcium dihydrogen phosphate is sold as superphosphate of lime. Sometimes the phosphate rock is treated with phosphoric acid ... 

A more soluble form of phosphate (Ca(H2P04)2), variously called superphosphate (of lime), monocalcium phosphate, or calcium dihydrogen phosphate, is made by the acidulation of phosphate rock with about 65% sulfuric acid (Eq. 11.61). 

The largest use of phosphorus is in fertilizers. Phosphorus is an essential nutrient, and nature s phosphorus cycle is very slow owing to the low solubility of most natural phosphates. Phosphate fertilizers are therefore essential. To increase the solubility of the natural phosphates, they are treated with H2SO4 to produce superphosphate of lime, a mixture of two salts. This solid is pulverized and applied as a powder. 

Write the formula unit equation for the preparation of superphosphate of lime. ... 

Monocalcic Phosphate—Acid calcium phosphate—Superphosphate of lime—Ca(HaP04)a—234—exists in brain tissue, and in those animal liquids whose reaction is acid It is also formed when CaalPOa) is dissolved in an acid, and is manufactured, for use as a manure, by decomposing bone-ash with HaSOa. It crystallizes in pearly plates very soluble in HaO. Its solutions are acid. 

Acids and bases unite together, and the characteristic properties of both disappear. They are said mutually to neutr ise each other, and the resulting compound is called a salt. If neither the acid nor base be in excess, the salt is a neutral salt if the acid predominate, it is called an acid salt, or a super-salt, and if the base prevail, it is called a basic salt, or a sub-salt. The salt is named from both the ingredients. Thus, when sulphuric acid neutralises soda, the resulting salt is called the sulphate of soda when phosphoric acid unites with lime, the acid being in excess, the salt is called acid phosphate of lime, or superphosphate of lime and when nitric acid unites with oxide of mercury, the latter being in excess, the compound is called basic nitrate of mercury, or subnitrate of mercury. 

Sir John Bennett Lawes (1814-1900), a pupil of Daubeny in Oxford, was a small land-owner. He took out a patent in 1842 for the preparation of superphosphate of lime by the action of sulphuric acid on coprolites, apatite etc., and began manufacture in 1843 he sold the factories etc. in 1872, but continued to be interested in technical chemistry. John Stevens Henslow, professor of botany in Cambridge, found that coprolites contain 56 to 61 p.c. of calcium phosphate. Sir Joseph Henry Gilbert (1817-1901), a pupil of Liebig, after academic work, experimented on dyeing and calico-printing in the Manchester district and then joined Lawes in 1843. ... 

Further applications are the examination of pigments, the detection of CaS04 used as a filler in paper (after ashing), the detection of adulteration of flour with gypsum, and the differentiation of superphosphate of lime (a mixture of monobasic calcium phosphate and calcium sulfate) from phosphate fertilizers containing no CaS04. 

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