Natural Flotability of Chalcopyrite under Different Redox Conditions.

Microflotation tests carried out in a modified Hallimond tube and rest potential determinations were used to study the collectorless flotability of a sample of natural chalcopyrite. It was found that the natural flotability is strongly dependent on pH, reaching a maximum in the range between 6 and 8, falling steeply in the alkaline range and becoming practically nil at pH 11. The high natural flotability at pH 8 is not suppressed either by the addition of reducing agents nor by moderate amounts of oxidizing agents. Large amounts of oxidizing agents depress the flotation, this effect being irreversible.