Chinese smelter uses Rio Tinto's "clean" technology
"Clean" copper smelting technology developed in part by Rio Tinto and being used at the company's Kennecott smelter in Salt Lake City, US, is being applied in a new copper production plant under construction in China.
The smelter and refinery project in China is based on Outokumpu of Finland's flash smelting, and the Rio Tinto-Outokumpu flash converting, technologies. The design of the Yanggu Xiang Guang Copper Company plant is very similar to the Kennecott smelter. This is the first use of flash converting outside Rio Tinto's Kennecott facilities.
The technology is capable of achieving an exceptionally high level of emission control to protect the environment relative to traditional technologies. This was a major factor in selection of Kennecott's technology by the Chinese company Xiang Guang, especially as the new smelter is sited in the heart of an agricultural region in Shangdong province.
Tom Albanese, Rio Tinto's chief executive Copper, said the use of the technology will deliver licence fees to Kennecott, but more importantly, it is an example of Rio Tinto's development of new technologies which further the principles of sustainable development. "This is the leading technology in copper production, embodying cost effectiveness, energy efficiency and environmental soundness."
Yanggu Xiang Guang Copper representatives visited Kennecott in Salt Lake City in October to see the technology in action. Smelters produce sulphur as a by product. Depending on the grade and type of ore, copper smelting actually produces somewhat more sulphur than metal. The sulphur is released in the form of sulphur dioxide, which when captured, is manufactured into sulphuric acid.
If released into the atmosphere, sulphur dioxide causes major environmental pollution. Flash smelting is a closed tightly sealed process which can achieve 99.9 per cent capture of the sulphur rich gases from the smelting furnace. Kennecott's flash converting closely resembles flash smelting.
"Converting" uses oxygen enrished air t remove sulphur and iron impurities left over from the smelting step. Like flash smelting, flash converting is also a closed process and, consequently, off gas emissions can be efficiently controlled. Flash smelting and flash converting reduced the Kennecott smelter's sulphur emissions to 982 tonnes per year from 16,850 tonnes.
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