Enriching Valuable Elements in Tailings Re-concentration of Bayan Obo Mine by Direct Reduction

摘要

For the re-concentration minerals of RE dressing tailings in Bayan Obo mine, Fe and P compounds were selectively reduced by the methods of coal-based direct reduction in reactionary pot. The metal and slag in sponge iron obtained from reduction was melted and separated. Compared to that in re-concentration minerals, the content of valuable elements oxide in melt-separation slag was enriched to about 2.5 times. Therefore, melt-separation slag can be used as the basic material to extract the valuable elements. This paper is one of fundamental researches on comprehensive utilization of Bayan Obo mine. As the development and practice of utilization of Bayan Obo mine multi-metallic resources has gone on for more than fifty years, the flotation-metallurgy process of the dominant melting of Fe and the subsidiary melting of RE as well as the mass production of Fe and the industrial application of RE have been realized. However, the utilization ratio of RE was only 10%, and the valuable element like Nb has not been fully used. Therefore the comprehensive utilization of Bayan Obo resources has still been a research focus in recent years, including fundamental research[1,2], mineral flotation-metallurgy process[3,4], separation and extraction of valuable elements in tailings[5,6]. Due to the reasons such as complicated composition, close symbiotic relationship, fine dissemination size, little difference of separability between valuable minerals and gangue minerals and difficult dressing of valuable elements, the majority of valuable elements in Bayan Obo minerals entered into tailings minerals, therefore, the tailings become an available secondary resources. In the National Key Technology R&D Program for the 11th five-year plan of Large Scale Mining Base Resources Comprehensive Utilization of Key Technology Research, for the tailings of RE dressing minerals in Bayan Obo mine, re-concentration minerals rich in valuable elements such as Nb etc, were obtained by mixed Flotation-Positive of iron-Positive of Nb Technology. However, due to lower content of valuable elements in re-concentration minerals and main content being Fe compounds, it is very necessary to further enrich the valuable elements in re-concentration minerals. Therefore, the research on this paper was carried out.