The effect of sodium chloride on the dissolution of chalcopyrite under simulated dump leaching conditions

Multiple Osmotic Stress Responses in Acidihalobacter prosperus Result in Tolerance to Chloride Ions

“…This lack of difference in leaching rates was potentially due to the advantages of chalcopyrite bioleaching in chloride systems as opposed to sulfate systems (reviewed in Watling, 2014). However, not all studies find an advantage with higher chloride ions at temperatures below 50°C (Dutrizac and Macdonald, 1971). …”

Chloride‐promoted leaching of chalcopyrite concentrate by biologically‐produced ferric sulfate

“…In the previous studies no copper leaching enhancement from chalcopyrite was observed for chloride additions at temperatures below 50 °C;9 chloride additions up to 2 g dm −3 significantly increased chalcopyrite leaching at 50 °C, but the leaching enhancement decreased rapidly when the concentration was higher than 2 g dm −3 Cl − 12. The previous studies9, 12 were conducted at temperatures below 60 °C, whereas in this study the effect of chloride on the ferric leaching of chalcopyrite was determined at 50–90 °C. Surface studies showed a precipitate layer consisting of sodium jarosite and sulfur on the chalcopyrite surface.…”

“…Chalcopyrite leaching is slow at 50 °C and below,19 as the chemical reaction rates increase with temperature, and the passive layers formed at higher temperatures are less stable than at lower temperatures 10, 24. In the previous studies no copper leaching enhancement from chalcopyrite was observed for chloride additions at temperatures below 50 °C;9 chloride additions up to 2 g dm −3 significantly increased chalcopyrite leaching at 50 °C, but the leaching enhancement decreased rapidly when the concentration was higher than 2 g dm −3 Cl − 12. The previous studies9, 12 were conducted at temperatures below 60 °C, whereas in this study the effect of chloride on the ferric leaching of chalcopyrite was determined at 50–90 °C.…”

“…Sulfur is, therefore, a desired reaction product, but can form a passivating layer on the chalcopyrite surface, resulting in slow leaching kinetics 1, 4–8. Different catalysts such as chloride9–13 and silver ions14 are known to enhance chalcopyrite leaching. Chloride ions promote the formation of a more porous crystalline sulfur layer instead of crypto‐crystalline or amorphous sulfur and, therefore, disrupt the passivating sulfur layer 11, 15.…”

Peroxodisulfate assisted leaching of chalcopyrite

“…One proposed method substitutes ferric chloride for ferric sulfate as an additive in leach solutions (Cordoba et al, 2008). In laboratory studies, several researches have found that at temperatures between 50 and 100°C, chalcopyrite dissolution was faster in chloride media versus sulfate media (Dutrizac and MacDonald, 1971;Dutrizac et al, 1969;Sullivan, 1933). The improved leaching in the presence of chloride was attributed to an increase in porosity of the passive film (Cordoba et al, 2008).…”