Rational Processing of Refractory Copper-Bearing Ores

The results of material composition studies of four samples of refractory copper-bearing ores of the Uzelga deposit are presented along with the results of studies of technological solutions to increase their processing parameters. The refractoriness of ores is associated with a thin dissemination up to micron size and close interbreedings of ore and rock minerals. Iron sulfides are presented by a wide range of minerals: pyrite and marcasite, melnikovite, arsenic pyrite, and arsenopyrite; sooty melnikovite has an increased flotation activity. The grinding of iron sulfides from 89 to 29% is followed by a proportional increase in easily floatable rock minerals to 45% and clay to 9%. These properties make these sulfides difficult to process and retain ore refractoriness to the flotation concentration. The content of copper sulfides in ore samples varies from 3.32 to 7.29%; the relative portion of copper sulfide in a form of tennantite in different samples of deposit varies from 29 to 93%. Copper is also present in a form of chalcopyrite and bornite. The best flotation activity of tennantite can be seen in a neutral and slightly acidic medium, in contrast with the standard flotation regime for chalcopyrite and bornite with butyl xanthate in a high-alkaline calcareous medium. Free grains of copper minerals can be selectively extracted into intercycled concentrates during grinding of no more than 60% of the class–71 μm. The technology of flotation in a low-alkaline medium with M-TF selective sulfhydril collector in the intercycle copper flotation and refinement cycle of the copper concentrate is developed for refractory copper-bearing ores with a variable tennantite content. Aeration is applied to suppress the flotation activity of melnikovite, which makes it possible to attain 80% copper recovery into a conditional copper concentrate. The fine inclusions of bornite, tennantite, chalcopyrite, and sphalerite into pyrite makes it rational to obtain copper–pyrite and copper–zinc–pyrite products with a yield up to 12% for pyro- and hydrometallurgical processing, along with the isolation of enriched copper concentrates.