公开(公告)号：DE1567830A1

公开(公告)日：1970-08-20

申请号：DE1567830

申请日：1965-03-18

Applicant: STAMICARBON

Inventor： HERMANUS ROOIJ ABRAHAM ,  ELMENDORP JAN

IPC: C01B25/28 ,  C01B25/40 ,  C01B25/46 ,  C05B1/04 ,  C05B7/00 ,  C05B11/06 ,  C01B25/02

Abstract: Water-soluble calcium phosphate is prepared by decomposing phosphate rock with excess HNO3 of e.g. 45-65% concn., extracting this decomposition liquor with a polar organic solvent which is poorly immiscible with H2O to remove most of the acids and part of the Ca(NO3)2, extracting this extractor soln. with a polar organic solvent poorly immiscible with H2O which preferentially dissolves HNO3, such that Ca(NO3)2 and H3PO4 remaining in the solution are converted to Ca(H2PO4)2 MH2PO4, where M is alkalimetal or NH4, may be prepared by adding M2SO4 to the aqueous extractor solution as above, separating the pptd. gypsum, and extracting the HNO3 as above. The decomposition liquor may be extracted by an ether or ketone but preferably by an aliphatic alcohol having 4-6 carbon atoms in the molecule. The HNO3 may be extracted by an aliphatic ketone or ether. Some Ca(NO3)2 may be removed from the decomposition liquor by partial crystallization before extraction. The process may be carried out in a continuous manner by recycling the organic solvent from the first extraction stage after washing with H2O; crystallizing the phosphate from the aqueous extractor soln. after removal of HNO3 therefrom, and recycling the phosphate mother liquor to the HNO3-extraction stage, and neutralizing the HNO3-containing solvent, e.g. with aq. NH3, and recycling this solvent after removal of the nitrate produced. A flow-diagram for such a continuous process is described.