An important innovation with multiple benefits was successfully tested at Codelco's El Teniente Division, in the copper company's Hydrometallurgy Plant. It involves the use of recycled copper sulphate, an additive used in the process of obtaining copper cathodes, the final product that the mining company sells.

Until last year, the mining company purchased solid cobalt sulphate from foreign suppliers, which had to be dissolved by operators before being used, but the Innovation Department of El Teniente contacted a local supplier, which extracts this additive from used cell phone batteries, in Santiago.

In the copper electrowinning process, cobalt sulphate is a catalyst that prevents corrosion of the anodes and helps ensure the correct transfer of the red metal particles, so that they are deposited on the cathodes and thus reach 99.9% purity.

“In November we carried out tests measuring indicators that ensured operating standards, in addition to the consumption of this element,” explains Javier Valenzuela, an engineer from the Innovation Department.

Thus, after several months of testing, recycled cobalt sulphate obtained even better results than expected, at a lower cost and saving time as it came in liquid form and did not require prior dissolution.

“The liquid worked better, the effect is much faster and it is cheaper. And if we add to that the fact that it is of recycled origin, it also has an environmental value for the process,” says Patricio Navarro, shift manager at the Codelco Hydrometallurgy Plant, El Teniente Division.

Specifically, the cost of recycled cobalt sulphate is 22% lower than imported solid cobalt and, in terms of efficiency, its consumption is 40% lower.

Ensure availability

Another point that this innovation helped to resolve was supporting the continued operation of the Hydrometallurgy Plant, since there was not always sufficient stock of cobalt sulphate from suppliers.

“It was very beneficial to have this alternative, because the stock of cobalt sulphate was depleted, which made the operation of the plant difficult. In addition, it has a lower environmental impact and the cost is also lower,” explains Leticia Martínez, operator of the Hydrometallurgy Plant who closely followed the process and the tests.

Martínez says that the efficiency of the process also improved, since, in addition to saving the dissolution stage and making the calculations to determine the appropriate amount to maintain the required concentrations in the solution, they standardized the addition of liquid cobalt sulfate to just once a day, as opposed to the three times a day they did with the other product.

“With this, we seek to fulfill our commitment as Codelco, to be a benchmark for sustainable mining and development, seeking alternatives that make our processes more efficient, reducing environmental impact, with local suppliers and a circular economy,” says Javier Valenzuela, from the Innovation Directorate of the El Teniente Division.