SOLUBILITY ASSESSMENT FOR FERTILIZER CONTAINING PHOSPHATE ROCK

Various methods have been used worldwide for measuring the solubility of phosphate rock (PR) and fertilizers containing PR. In this review, chemical, mineralogical, and physical factors affecting various measur ements of PR solubility are discussed. The most important factors are (1) PR solubility expression, (2) mineralogical composition of PR, (3) free carbonate (calcite dolomite) effect, (4) effect of apatite cryst allinity and cementing of apatite with silica, and (5) effect of monoc alcium phosphate and gypsum in the mixture of PR and TSP or SSP.