Outokumpu Technology has made an agreement with the leading Chinese zinc producer, Hunan Zhuye Torch Metals, a fully owned subsidiary of Zhuzhou Smelter Group, for the design and delivery of a zinc plant expansion with new environmentally sound leaching technology. The plant is located close to the city of Zhuzhou, Hunan province in China. The contract value is nearly €30 million.

Outokumpu’s delivery includes the engineering of a zinc plant with new Atmospheric Direct Leaching Process, iron precipitation and solution purification processes, main equipment supplies as well as supervision of installation and commissioning. The expansion will increase the plant capacity by 100,000 t/y of zinc and the plant is estimated to be operational by July 2008.

Outokumpu has developed a new process for zinc concentrates, called atmospheric direct leaching, which eliminates the conventional roasting phase in zinc processing. The process is already in use in Boliden’s Kokkola zinc plant in Finland and its Odda zinc plant in Norway. Hunan Zhuye Torch Metals selected this process for its expansion because it is an environmentally sound way to produce zinc, it includes recycling of process residues, and it represents the latest technology. A wider selection of zinc concentrates can be used as raw materials in the process, which improves the use of resources.

In order to expand the use of the atmospheric direct leaching process in China, Outokumpu has also signed a collaboration agreement with Zhuzhou Smelter Group.