Abstract: A method of recovering uranium from wet-process phosphoric acid wherein the acid is treated with a mixture of an ammonium salt or ammonia, a reducing agent, and then a miscible solvent. Solids are separated from the phosphoric acid liquid phase. The solid consists of a mixture of metal phosphates and uranium. It is washed free of adhering phosphoric acid with fresh miscible solvent. The solid is dried and dissolved in acid whereupon uranium is recovered from the solution. Miscible solvent and water are distilled away from the phosphoric acid. The distillate is rectified and water discarded. All miscible solvent is recovered for recycle.

Abstract: A method of preparing dicalcium phosphate from phosphate rock wherein the rock is treated with a mixture of water, carbonyl, and sulfur dioxide. Solids are separated from the liquid phase. The solid phase consists of a mixture of gangue, and calcium .alpha.-hydroxysulfonate. Carbonyl and part of the sulfur dioxide are recovered from the solid by low temperature thermal decomposition. Dicalcium phosphate is precipitated from the liquid phase by partial distilling of SO.sub.2. All carbonyl is recovered for recycle.

Abstract: dicalcium phosphate is prepared from phosphate rock by a process which comprises reacting phosphate rock with sulfur dioxide and an organic carbonyl compound for 0.5 to 10 hours while maintaining the temperature of the reaction mixture below 50.degree. C. The reaction yields a mixture of gangue, solid calcium .alpha.-hydroxy sulfonate and soluble dicalcium phosphate. The solids are separated from the liquid and P.sub.2 O.sub.5 values adhering to the solid are washed free with a mixture of carbonyl, water, and sulfur dioxide. The wash effluent is recycled to the process and both carbonyl and some sulfur dioxide are recovered from the filter cake by heating it. The offgas from the heated filter cake is recycled to the process and the dry filter cake, now largely calcium sulfite hemihydrate, is discarded.Dicalcium phosphate is precipitated from the reaction mixture filtrate in high yield by partially distilling sulfur dioxide from the filtrate.

Abstract: a method of recovering uranium from wet-process phosphoric acid wherein the acid is treated with a mixture of an ammonium salt or ammonia, a metallic reducing agent such as iron, aluminum or zinc, and then a miscible solvent such as methanol. The precipitated solids, which are separated from the purified phosphoric acid, consist of a mixture of metal phosphates and uranium. This solid is dissolved in acid and the uranium recovered from the solution by liquid-liquid solvent extraction. The miscible solvent and some water are distilled away from the purified phosphoric acid. The distillate is rectified, the water discarded, and the miscible solvent recovered for recycle.When the miscible solvent is methanol, the optimum ranges of ammonia and methanol are 0.05 to 0.20 gram atom nitrogen per gram atom phosphorus and 1.93 to 3.15 pounds methanol per pound of orthophosphoric acid. The amount of reducing agent added should be sufficient to reduce all uraniun to U(IV).