(中南大学 冶金与环境学院，长沙 410083)
摘 要: 辉钼矿经氧化焙烧转化成MoO3的过程中，伴生的铜铅铁等硫化矿亦被氧化，并与MoO3生成难溶钼酸盐。为减少因难溶钼酸盐带来的钼损失，需要对这些钼酸盐进行再浸出处理。针对这些钼酸盐湿法浸出过程进行热力学分析，绘制了25 ℃时Me-Mo-H2O(Me：Cu，Pb，Fe)系组分的浓度对数-pH图。利用热力学平衡图对氢氧化钠分解钼酸盐进行热力学分析。结果表明：整个pH值范围可分为H2MoO4的稳定区、难溶钼酸盐的稳定区、Me(OH)n的稳定区。高pH区钼酸盐中的Me转变为稳定的Me(OH)n物相，即实现了钼酸盐的碱分解。而Fe2(MoO4)3、CuMoO4和PbMoO4的碱浸出难度依次递增，达到一定碱度时这3种难溶盐都能很好地分解，并实现Me与Mo的分离。但过高的碱度又使大量的金属以羟基配合物离子的形式进入溶液，增加了后续除杂难度。
关键字: 钼酸高铁；钼酸铜；热力学；氢氧化钠；浸出
（School of Metallurgy and Environment, Central South University, Changsha 410083, China）
Abstract:When molybdnite was roasted, MoS2 converts to MoO3. Meanwhile, sulfides associated with concentrate are oxidized to copper oxide and lead oxide and iron oxide or partial copper sulfate and lead sulfate and iron sulfate, which will react with MoO3 to form sparingly soluble molybdate. Aiming to decrease the loss of molybdenum in the slag, these sparingly soluble salts have to be handled with. According to the laws of conservation of mass and simultaneous equilibria, the logarithm concentration-pH diagram of Me-Mo-H2O (Me: Cu, Pb, Fe) system was established on the basis of thermodynamic data at 25 ℃. Thermodynamic analysis was carried out to discuss the technology of sodium hydroxide disintegrating sparingly soluble molybdate. The results show that the whole pH value of the system is divided into three areas. The first one is the stable area of H2MoO4, the second area is the stable area of sparingly soluble molybdate, the third one is the stable area of Me(OH)n. In the third area, Me(OH)n is gradually supersaturated in solution with the increase of pH value, so the Me(OH)n is deposited as sediment, and MoO42- goes into solution. As a result, the processing of sparingly soluble molybdate leached by sodium hydroxide is carried out. The incremental difficulty of alkali leaching order is as follows: Fe2(MoO4)3, CuMoO4, PbMoO4. Over a certain alkalinity, copper, lead and iron could be leached out of molybdenum. But these metals will be dissolved numerously as hydroxyl complexes in the case of excessive basicity, which increases the difficulty of subsequent purification.
Key words: ferrimolybdate; copper molybdate; thermodynamics; sodium hydroxide; leaching
