Metso Outotec ball mill will help recycle slag

A Metso Outotec stirred media detritor (SMD) grinding mill has been sold to be shipped to the Boliden Harjavalta smelter site in Finland to help recover metals from slag.

Metso says Boliden Harjavalta has chosen an SMD grinding mill “to improve the capacity of its slag concentrator.” The purpose of the slag concentrator is to recover copper from the slag produced in the firm’s copper smelter to it can be returned to the copper production cycle.

Boliden Harjavalta produces metals including copper, nickel, gold and silver in its smelting operations. In 2019, the company produced 120,000 metric tons of copper and 26,000 metric tons of nickel.

“At the testing stage, we noticed that slag can be processed very efficiently using SMD technology,” says Timo Sarvijärvi, Metso Outotec’s head of mining in the Nordics market area. “Now the slag concentrator can process larger amounts of material, without compromising the targets set for copper recovery.”

Metso Outotec says its SMD mills are designed for fine grinding applications, and that maintenance for the SMD is safe and cost-effective thanks to the simple mechanical structure of the mill and the smaller number of moving parts compared to many other grinding mills.