Recovery of phosphate values from phosphate minerals - - by two-stage leaching with acids of different normality

摘要

Process for recovery of calcium phosphate from apatite mineral contg. is not 5% P2O5 comprises (a) dissolving the phosphate content of the mineral in two distinct stages. with two acid solns of different normality (b) combining the spent acids to form a pregnant soln (c) ppting and separating impurities from the pregnant soln and (d) increasing the pH of the pregnant soln to ppte dicalcium phosphate. Pref. the dicalcium phosphate ppte is mixed with a mineral acid having the same normality as the mother liquor and conc H2SO4 is added to this mixt with vigorous stirring, to produce gypsum. The process allows high purity phosphate values to be obtd. from low quality phosphate minerals.