Study on recycling and leaching valuable elements from Bayan Obo tailings
Study on recycling and leaching valuable elements from Bayan Obo tailings
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DOI：
10.1051/metal/2018040
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发表时间：
2019-05
影响因子：
1.1
通讯作者：
Bo Zhang;X. Xue;Xiaowei Huang;He Yang;Gongjin Chen
中科院分区：
文献类型：
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作者：
Bo Zhang;X. Xue;Xiaowei Huang;He Yang;Gongjin Chen
研究了从巴彦鄂博尾矿中回收铁、铌、钪的新工艺。采用Ca（OH）2-煤焙烧-硫酸浸出工艺处理巴彦鄂博尾矿。在Ca（OH）2-煤焙烧过程中，含铌矿物转化为可溶于硫酸的CaTiO 3结构Ca（Ti0.8，Fe0.1，Nb0.1）O3和Ca 2Nb 2 O 7。含钪硅酸盐矿物辉石和角闪石主要分解还原为金属铁，经弱磁选可回收利用。硅酸盐中的钪转化为Sc2 O3。在硫酸浸出过程中，Ca（Ti0.8，Fe0.1，Nb0.1）O3和Ca 2Nb 2 O 7在Sc2 O3溶解于热硫酸中时，分解为Nb（OH）4+和OH-，生成易溶于硫酸的Nb（OH）5。以巴彦鄂博尾矿为原料，采用Ca（OH）2-煤高温焙烧、磁选、硫酸浸出的方法，研究了焙烧温度、磁选时间、硫酸浸出时间、焙烧温度、焙烧时间对尾矿浸出率的影响。结果表明：Ca（OH）2：煤尾渣质量比为20：5：100，焙烧温度为1200 °C，焙烧时间为2 h，磁场强度为270 mT，液固比为4：1（ml/g），浸出温度为245 °C，浸出时间为1 h。获得了铁精矿品位88.39%、回收率91.92%的指标。结果表明，铌和钪的浸出率分别可达95.52%和95.75%。
A novel process for recovering iron, niobium and scandium from Bayan Obo tailings has been developed. In this paper, the treatment of Bayan Obo tailings by Ca(OH)2-coal roasting and sulfuric acid leaching process was investigated. In the Ca(OH)2-coal roasting process, niobium-bearing minerals are converted to CaTiO3 structure of Ca(Ti0.8,Fe0.1,Nb0.1)O3 and Ca2Nb2O7 which are soluble in sulfuric acid. The pyroxene and amphibole that are Sc-bearing silicates are mainly decomposed and reduced into metallic iron which can be recycled by weak magnetic separation. Scandium in the silicates is converted to Sc2O3. In the sulfuric acid leaching process, Ca(Ti0.8,Fe0.1,Nb0.1)O3 and Ca2Nb2O7 are converted to Nb(OH)5 that could easily dissolve in sulfuric acid by dissociating into Nb(OH)4+ and OH− when Sc2O3 is dissolved into heat sulfuric acid. Bayan Obo tailings were roasted with Ca(OH)2-coal at elevated temperature, followed by magnetic separation and sulfuric acid leaching. The optimized experimental parameters are proposed as follows: Ca(OH)2-coal-tailings mass ratio of 20: 5: 100; roasting at 1200 °C for 2 h; the magnetic field (magnetic separation) of 270 mT; the liquid-solid ratio of 4:1 (ml/g); leaching at 245 °C for 1 h. Iron concentrate with a grade of 88.39% and a recovery rate of 91.92% is obtained. The leaching results show that the leaching rates of niobium and scandium could achieve 95.52% and 95.75%, respectively.