Sulfate Ion → Calcium Sulfate, Hemihydrate

Participants

Reaction Steps

adding sulfuric acid to a second reaction vessel in amounts such that the sulfate content of the sulfuric acid plus the sulfate content of the added phosphate rock is equivalent to about 90% to about 99.7% of the stociometric amount of sulfate required to react with the calcium present in the phosphate rock added in part (a) to form calcium sulfate hemihydrate, second reaction vessel containing a second slurry comprising calcium sulfate hemihydrate, monocalcium phosphate, sulfuric acid and phosphoric acid, whereby the sulfuric acid reacts with the monocalcium phosphate to form calcium sulfate hemihydrate and phosphoric acid, said second slurry being maintained at a soluble sulfate concentration of about 0.7% to +4.5%, wherein the slurry has a specific gravity of between about 1.58 to about 1.99 grams/cc and the specific gravity of the liquid portion of the slurry has a specific gravity of from about 1.36 to about 1.72 grams/cc;

Provenance & Evidence