Calcium/phosphorus fertilisers - made from superphosphate and lime

摘要

A Ca- and P-contg. fertiliser is produced by mixing x kg of superphosphate (Ca(H2PO4)2) with approx. x kg of H2O in a containers and heated to the b.p.; ca 4 x kg of lime (pref. in the form of sugar-works scum or wastes from the mining building and/or lime inds) are added portionwise to the soln.; the soln. is boiled for =20 mins. at =130 degrees C; and the contents of the container are dried, while retaining their water of crystn., and then ground. The product is resistant to conversion into Fe and Al phosphate or apatite in strongly acid or alkaline soils, thus improving P utilisation.