ALKALINE LEACHING OF LOW GRADE OXIDIZED LEAD AND ZINC ORES
The work performed demonstrates that leaching of an oxidized zinc - lead ore with NaOH solutions is possible, however, high temperatures are needed and high concentrations of the leaching reagent. Caustic soda, moreover, is rather costly and somewhat difficult to regenerate. The alkaline ammonia leaching process offers the advantages of selectivity, flexibility and solution recycling. Selectivity: in alkaline solution the silica, silicates and the iron oxides and carbonates, remain in the leaching residue; zinc can be dissolved separately from lead. Flexibility: with the same flow sheet the process can be varied to suit the mineralogical composition of the feed by eliminating unnecessary leaching stages. Designing of the leaching plant to include various stages where it will be possible to use solutions of diverse composition is advisable. Solution recycling: ammoniacal solutions can be recycled after small additions of reagent (NH-3 and CO-2) to make up for the inevitable losses due to valorization. Leaching was performed with stripping, however in-situ leaching is possible; it takes longer, however, extraction rates are lower and there are often pollution problems.
Bibliographic Reference: WORKSHOP ON MINERALS LEACHING, BRUXELLES (BELGIUM), NOV. 17, 1983 PP. 116-131 EUR 9606 EN-FR (1984) FS, 141 P., BFR 450, EUROFFICE, LUXEMBOURG, POB 1003
Record Number: 1989123099800 / Last updated on: 1987-01-01
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