Designing of engineering solutions to enhance efficiency of high-copper gold-bearing ore processing

Abstract

The modern metals industry is characterised by a downward trend in the quality of ores involved in processing, and conventional methods of extracting useful components are inefficient for raw materials with complex composition. To maintain the growing level of metal production it is required to introduce new efficient technologies for processing of low-grade and refractory ores as well as man-made deposits. The article describes processing methods of refractory raw materials with high cyanide content using copper-gold ores as an example, where gold is the primary commodity, and copper is the accompanying useful component. The most common method of processing copper-gold ores is preconcentration followed by selective leaching of copper and gold. In some cases, technologies involving copper by-products and cyanide recovery from the cyanide leaching solutions offer equally effective options for processing of the copper-gold ores and concentrates. Copper-gold ores are processed at gold mines using the cyanide procedures, supplemented if required by gravity and flotation concentration. In all variations of the cyanide treatment, most of copper minerals actively react with cyanides of alkali metals, binding the CN– ions into the copper complex of [Cu(CN3)]2–. This reaction results in an increased solvent consumption, as well as in number of challenges related to cleaning tailings and slurries from highly toxic cyanide compounds and dissolved copper. In addition to technological complications associated with the need to meet strict requirements for the maximum permissible concentrations, copper accumulated in the cycling solutions also causes a decrease in gold extraction from the processed ores.