Yara Suomi Oy selected Outotec to design and deliver a paste plant for tailings treatment. The contract is valued at more than EUR 40 million.

The contract includes engineering, equipment supply, construction and commissioning of the paste plant as well as spare parts and services. The new plant is expected to become operational in the first half of 2017.

The Siilinjärvi mine produces about 1 million metric tons (mt) of apatite concentrate, which creates approximately 10 million mt/y of tailings.

“Yara is a long-term partner with whom we have developed and pilot tested an optimal thickened tailings solution based on Outotec’s paste thickener technology. Extended lifetime of the existing tailings surface facilities and efficient water circulation are noteworthy from the environmental point of view,” said Kalle Härkki, head of Outotec’s minerals processing business area.

The tailings are currently stored by conventional means in a tailings storage facility. The new high-density tailings disposal system with dewatering will increase the percentage of solids in the slurry, making it possible to deposit as paste and extending the lifetime of the tailings storage facility. Reclaim water is returned to the process water circulation.