Oxidation agent and oxygen source

Products and solutions for the Mining industry

Hydrogen peroxide is often used as an oxidant in such metallurgical process steps as ore leaching, concentrate preparation or effluent treatment. Production of gold and uranium exemplifies some important hydrogen peroxide applications in the mining industry. Depending on the ore composition as well as the leaching conditions, utilization of hydrogen peroxide results in savings of eluents and acids, simplifies management of chemicals or waste and improves the overall process control.

In nature uranium occurs in the form of tetravalent or hexavalent oxide minerals (uraninite or pitchblende). Tetravalent uranium has, however, a very low solubility in both acidic or alkaline media. Thus, to achieve an economic uranium recovery, oxidation to the much more soluble hexavalent state is of great importance. Trivalent iron compounds are commonly used to increase uranium's oxidation state. Hydrogen peroxide is applied for regeneration of the active Fe(III) ions in the eluent.

For gold production the most common method used nowadays is the cyanidation process, which involves the leaching of gold containing ores by dilute aqueous cyanide solutions. This requires pH adjustment, mostly by lime, and oxygen for the redox reaction to occur. Depending on the leaching conditions, overall concentration of suspended ore as well as concentration of the oxygen consumers in the ore, hydrogen peroxide can be added to increase the oxygen availability and dissolved oxygen in the system and to promote deeper leaching by direct oxidation. On the downstream side hydrogen peroxide is often used for removal of the cyanides from waste streams, such as discharge water or tailing slurries. Cyanide removal from process water may also be required if flotation takes place on site. The cyanide removal occurs via oxidation in a single step, without the formation of toxic intermediates.

For mining applications Evonik recommends the use of its HYPROX® product range.

For further information about our hydrogen peroxide grades or formulations please contact us directly.