含钪钒钛磁铁矿尾矿焙烧-浸出提取分离钪

Extraction of scandium from Sc-bearing V-Ti magnetite tailings using roasting and leaching

采用氯化焙烧和碱分解焙烧方法预先处理钪粗精矿(Sc_(2)O_(3)44 g/t),强化载钪矿物晶体结构的转变,为焙烧渣进一步浸出分离钪创造有利条件。结果表明:在Na2CO_(3)和钪粗精矿质量比为0.45、焙烧温度为900℃、焙烧时间为120min、盐酸浸出液固质量比(mliquid:msolid)R=5:1、盐酸浓度为6mol/L的条件下两段浸出240min,钪的浸出率为84.32%,浸出渣中Sc_(2)O_(3)含量为8.67g/t。浸出渣的XRD、SEM-EDS及化学成分分析结果表明:浸出后钪粗精矿中的辉石类、角闪石等硅铝酸盐矿物物相谱峰消失,出现NaCl、Ca TiO_(3)、Fe_(2)O_(3)的谱峰,未见明显金属钪的谱峰,也进一步验证碱分解焙烧能够有效地破坏载矿物的晶体结构;强化矿物层间结构中的钪离子被释放,有助于焙烧渣盐酸浸出生成Sc Cl_(3),显著提高钪的浸出率。

The chlorination roasting and alkali decomposition roasting were used to pre-treat coarse scandium concentrate(Sc_(2)O_(3) content of 44 g/t)to strengthen the transformation of crystal structure of scandium-bearing minerals and create favorable conditions for further leaching scandium from roasting slag.The results show that scandium leaching efficiency of 84.32%is obtained,and the content of Sc_(2)O_(3) in the leaching residue is 8.67 g/t under the compressive conditions of alkali decomposition roasting-leaching process as follows:mass ratio of Na2CO_(3) to coarse of 0.45,roasting temperature of 900℃,roasting time of 120 min,hydrochloric acid mass ratio of leaching liquid to solid ratio(R)5:1,hydrochloric acid concentration of 6 mol/L,two-stage leaching for 240 min.XRD,SEM-EDS and chemical composition analysis results of the leaching residue show that,after leaching,the physical image spectral peaks of pyroxene,hornblende and other aluminate minerals in scandium coarse concentrate disappear,and the spectral peaks of NaCl,CaTiO_(3) and Fe_(2)O_(3) appear,and there is no obvious spectral peak of scandium metal.It is also further verified that the alkali decomposition roasting can effectively destroy the crystal structure of the mineral,and the scandium ion in the enhanced interlayer structure of the mineral is released.It is helpful for hydrochloric acid leaching of roasting slag to produce SCCl_(3) and improve the leaching rate of scandium obviously.