BEIJING -- China's environmental protection law stipulates that environmental protection taxes of 25 yuan ($3.8) per ton will be imposed on untreated steel slag. Steel plants in China produce around 1 billion tons of crude steel and about 300 million tons of slag annually.
As of this year, there are about 2 billion tons of steel slag in China. Dealing with this waste is thus a pressing problem. In conventional slag treatment, recyclable iron and magnetite are removed and the remaining slag is either ground into fine powder and sold as building material, or used for long-term landfills. Overall less than 30% of this slag is recycled, posing a risk of contamination of soil and groundwater.