Recently, technology for soilless in-situ reclamation of red mud (developed by Chalco Zhengzhou Research Institute of Nonferrous Metals) has undergone testing and demonstration after 2 years of laboratory testing. In the next phase, the technology will be applied in Chalco Group alumina refineries. The technology is based on soil improvement of red mud, which when combined with phytoremediation and microbial reclamation, results in a complete ecosystem in red mud piles, accelerating the process of land reclamation. Compared to conventional methods, which lays fresh soil on top of the red mud, this new technique can reduce land reclamation costs by 30~40%, achieving savings of RMB 120~230 mln per 10,000 mu of land (6.67 square km, 1 mu=0.667 square km).
China’s annual output of red mud exceeds 100 million t, but the comprehensive utilization rate is less than 10%. More than 90% of the red mud is stored in the open air. At present, the cumulative stockpile exceeds 700 million t, covering tens of thousands of mu, mainly in Henan, Shanxi, Shandong, Guangxi, Guizhou, Yunnan and other major agricultural provinces.