公开(公告)号：CA1289726C

公开(公告)日：1991-10-01

申请号：CA535637

申请日：1987-04-27

Applicant: STAMICARBON

Inventor： TJIOE TJAY T ,  VAN DUIJN SIMON ,  WEY PAUL

IPC: C01B25/238 ,  C01B25/32 ,  C01G11/00 ,  C22B17/00

Abstract: Cadmium is selectively removed in a single step from an acid, phosphate-containing aqueous medium with the aid of an anion exchanger, in which process, during the removal, iodide or bromide ions are present in a quantity of 100-6000 ppm calculated with respect to the acid phosphatecontaining aqueous medium.

公开(公告)号：CA1320034C

公开(公告)日：1993-07-13

申请号：CA535644

申请日：1987-04-27

Applicant: STAMICARBON

Inventor： SPIJKER RUUD ,  TJIOE TJAY T ,  WITKAMP GEERT J

IPC: C01B25/22 ,  C01B25/223 ,  C01B25/226 ,  C01B25/229 ,  C01B25/238 ,  C01F11/46

Abstract: AE 5400 22772-1093 Virtually cadmium-free calcium sulphate is produced in the preparation of a liquid medium containing phosphoric acid, which comprises digestion with a mineral acid of cadmium-containing phosphate rock and separation from the liquid medium containing phosphoric acid of at least a portion of the calcium in the phosphate rock after precipitation by means of a solution containing sulphate ions in the form of calcium sulphate, in which process halogen ions are present in an amount of 50-20.000 ppm during precipitation of the calcium sulphate to be separated.