RECOVERY OF ELEMENTAL SULPHUR AND METAL FROM PYRITIC ORES - APPLICATION TO ROUEZ (FRANCE)
BRGM and SNEA (P) intend to develop a process to recover the whole sulphur contained in a pyritic ore as elemental sulphur and all the metal values (iron, base metals and precious metals). Three partially original process schemes have been suggested: chlorination; hydrochloric acid leaching after a thermal decomposition; and, pressure leaching also after a thermal decomposition. BRGM studies the first two processes, SNEA(P) the third one and the thermal decomposition in the second one. In chlorination, pyrite is chlorinated in two stages S-2Cl-2 is returned in the first stage. Ferric chloride is condensed separately. After vaporization FeCl-3 is oxidized by air to regenerate chlorine, the non-ferrous metal chlorides are leached with water. Copper is recovered by cementation, zinc by zincex process, lead and silver by precipitation as sulphate. Gold is absorbed on activated carbon. In the second process, pyrite is thermally decomposed to produce pyrrhotite and SO-2. Pyrrhotite is then leached with concentrated hydrochloric acid giving ferrous chloride and H-2S. Spalerite and galena also are leached. Sulphur is obtained by Claus reaction. Two concentrates are produced: a copper concentrate and a zinc - lead concentrate. Hydrochloric acid is recovered by hydrolyzing the pregnant liquor. Gold is in the copper, silver in the zinc - lead concentrate.
Bibliographic Reference: WORKSHOP ON MINERALS LEACHING, BRUXELLES (BELGIUM), NOV. 17, 1983, PP. 99, EUR 9606 EN-FR (1984) FS, 141 P., BFR 450, EUROFFICE, LUXEMBOURG, POB 1003
Record Number: 1989123099500 / Last updated on: 1987-01-01
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