Phosphate Rock - an overview | ScienceDirect .
Phosphate rock of 70 to 75% BPL, or as high as is reasonably obtainable, is finely ground in a ball mill and then mixed with cooled recycled phosphoric acid-gypsum slurry in a digestion tank (Figs. 10.3 and 10.4).At this stage the only reaction which occurs is between acid and any carbonates present in the rock, and between phosphates and low concentrations of sulfuric acid which may be ...
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