Adding small amounts of hydrogen peroxide in the flotation process can boost concentrate yield, according to specialty chemical supplier Evonik.

Evonik Industries AG, an Essen, Germany-based specialty chemical supplier, claims that the use of hydrogen peroxide can solve an old processing problem while significantly increasing the amount of copper extracted from ore. The problem: certain impurities such as iron sulphides (which include pyrite) can be difficult to remove. According to Evonik, a new technology based on hydrogen peroxide now offers a solution.

Using a small copper and gold mine in Australia as an example, Evonik said it has been able to demonstrate that the technology works on an industrial scale and can increase copper yield by roughly 10%.

“Up to now, mine operators have primarily been familiar with hydrogen peroxide as a wastewater treatment agent. Now we’re showing them that this material can also make metal extraction itself notably more efficient,” said Dr. Ingo Hamann, head of production and engineering within Evonik’s Active Oxygen Business Line. “Our process adds significant value for the mine operator—and it does it with very little investment and in an environmentally friendly way.”

When extracting base metals such as copper, the flotation process raises the copper content by 10%–15% over the original concentration in the ore; i.e., 0.5% to 2.5% in the ore compared with 15% to 30% in the concentrate). Hydrogen peroxide is effective, according to Evonik, when added at a specific concentration and at a specific point in the process. Evonik says a very small amount of this highly effective oxidant is all that is required to increase the yield by approximately another 10% and to reduce the problematic pyrite content in the concentrate.

The company said critical steps in its development process included determining the appropriate process window, and adapting the process to various ore compositions.