Physicochemical modeling of the heterogeneous systems AsCl3-SnCl4-PbCl2-HCl-CaCl2(NaCl)-H2S-H2O

Multicomponent heterogeneous systems containing tin(IV), lead(II), arsenic( III), calcium and sodium chlorides, hydrogen sulfide, and hydrochloric acid were studied by computer-assisted physicochemical modeling. The equilibriu m compositions of liquid, solid, and gaseous phases of the system at 25 deg reesC and the hydrogen sulfide partial pressure from 10 to 100 kPa were cal culated. The concentrational regions of the formation of lead dichlorides a nd tin, lead, and arsenic sulfides were determined. The conditions for the most complete separation of the metals by precipitating their sulfides from hydrochloric and chloride solutions of complex composition were quantified . The results of the calculations are compared with the experimentally deri ved solubilities of tin, lead, and arsenic in hydrochloric solutions at 25 degreesC and the P-H2S pressure of 100 kPa.