MINERALOGICAL CHARACTERIZATION OF ANODE SLIMES .9. THE REACTION OF KIDD CREEK ANODE SLIMES WITH VARIOUS LIXIVIANTS

Kidd Creek raw anode slimes from the bottoms of the refining cells, th at consist principally of PbSO4, Ag2Se, AgCuSe, CuSe, Cu3Se2, Cu2O, Cu SO4 . 5H2O, Sn-Cu arsenate and Sb-Bi As Pb oxide, were leached in vari ous lixiviants. Reaction with aerated H2SO4 solubilizes Cu2O and CuSO4 . 5H2O, and also extracts a significant amount of Cu from the copper s elenides. Some oxidation of selenium to selenite occurs with the resul t that CuSeO3.2H2O is detected. Leaching in 4 M NaCl solution dissolve s some Cu which reprecipitates as an ''oxidate'' phase containing trac es of Cl and SO4. Lead sulphate also dissolves, but reprecipitates as euhedral crystals which have the approximate composition of Pb2Se2O3.P bCl2. Reaction with 30% acetic acid solubilizes part of the Cu, but do es not dissolve PbSO4. Leaching in 30% ammonium acetate solution disso lves Cu2O, CuSO4 . 5H2O and part of the Cu in the copper selenides. Mo st of the PbSO4 is converted to insoluble PbSeO3; the implication is t hat significant selenide oxidation also occurs. Reaction with 2 M Na2C O3 solution converts PbSO4 to NaPb2(CO3)2(OH), but leaves most of the other slime constituents unaffected. Leaching of the Na2CO3-converted slimes in acetic acid solubilizes most of the Pb; this two-step proces s was the only effective deleading technique identified.