One of the world’s largest copper and cobalt producers recently took delivery of a thickener solution that includes six counter current decantation (CCD) thickeners and one pre-leach thickener, each measuring 31 m in diameter.

The mine, located in the Democratic Republic of Congo (DRC), aimed to double its production rates and chose FLSmidth to provide a thickener solution to achieve its objectives.

According to FLSmidth projects and account sales GM Howard Areington, the company’s proposal for the mine’s expanded requirements was based on testwork to confirm the characteristics of the material that would be treated.

The units are said to deliver high solids underflow to optimise the recovery of dissolved metals. In addition to the steeper floor slope, the FLSmidth thickeners were designed with a high torque ring gear drive design, with high tolerances that make for minimal maintenance over long periods of time.

“Our high density thickener design ensures consistently high underflow densities which allows the operator to sustain high production rates and better recoveries,” says Areington.

The CCD thickeners are manufactured from LDX2101 duplex stainless steel, providing mechanical benefits without compromising chemical resistance and allowing the mass of each unit to be reduced. The pre-leach thickener, which was not exposed to corrosive conditions, is constructed from carbon steel.

“We also designed and supplied five impurities removal thickeners, which are high rate thickeners, also in LDX2101 stainless steel,” he says. “The sizes of these units ranged from 20 m to 30 m in diameter.”

Fabrication of the equipment was done in South Africa, with components and platework delivered to site and the welding and construction conducted by the mine with installation assistance from the company and its agent in the region.