Extraction process for metals like gold and platinum including fine grinding, pulping and oxygenating

摘要

This invention relates to a process for obtaining metal values, typically base metals, platinum or gold from a feed material. In a first step of the process of the invention, feed material containing metal values is ground to a particle size d90 of 100 microns or less to form an ultra fine pulp. In a second step of the process of the invention, the ultra fine ground pulp from the first step is oxygenated by pumping it in multiple passes through an in-line high shear static oxygenation device (30), while re-circulating it on a tank (28) or any other vessel. The process of the invention results in a significant reduction in the required leach time, improved recoveries, reduced cyanide consumptions, a steadier gold tail, as well as reduced capital and operational expenditure.