采用硫酸酸沉法从高硫钼酸铵溶液中回收钼的工艺研究

针对钼精矿加压氧化-氨浸-净化工艺所得的高硫钼酸铵溶液,为实现其中钼的高效回收,采用硫酸中和酸沉钼酸铵,考察了酸沉p H值、温度、时间、搅拌速度等因素对钼酸铵酸沉率的影响。结果表明,钼酸铵酸沉率及硫含量主要受酸沉p H值的影响,优化酸沉条件为:p H值2.5、温度35℃、时间0.5 h、搅拌速度220 r/min,在此条件下钼酸铵酸沉率可达93.14%。

钼酸铵溶液净化除杂制备四钼酸铵的试验研究

研究了采用化学沉淀法从杂质含量较高的钼酸铵溶液中深度净化磷、砷、硅的工艺和效果,确定了合适的工艺条件:沉淀剂硫酸镁和硫酸铝加入量均为理论值的2倍、沉淀p H值应控制在9.5~10.0、沉淀温度为40℃、沉淀时间0.5 h,磷、砷、硅的去除率分别达到86.70%、99.37%、91.86%,经过除杂后的钼酸铵溶液可以满足钼产品沉淀的要求。采用硫酸沉淀法从净化液中制备四钼酸铵,考察了酸沉pH值、温度、时间对钼酸铵沉淀率的影响,确定了最佳酸沉条件为:pH值2.0、温度50℃、时间20 min,在此条件下钼酸铵沉淀率可达92.8%。

Initial stages of copper electrodeposition from acidic sulfate solution in the presence of alklpyridinium hydrosulfate ionic liquids

The effect of two alklpyridinium hydrosulfate based ionic liquids(ILs)including N-butylpyridinium hydrogen sulfate(BpyHSO4)and N-hexylpyridinium hydrogen sulfate(HpyHSO4)as additives on the nucleation and growth of copper from acidic sulfate bath was investigated using cyclic voltammetry,chronoamperometric and scanning electron microscopy techniques.Results from cyclic voltammetry indicated that the two studied additives had a blocking effect on copper electrodeposition process and this effect initiated by HpyHSO4was more pronounced in comparison to BpyHSO4.Dimensionless chronoamperometric current-time transients for the electrodeposition of copper from the bath free of additives were in good accord with the theoretical transients for the limiting case of instantaneous three-dimensional nucleation with diffusion-controlled growth of the nuclei.However,the instantaneous nucleation mechanism observed in the additive-free bath was changed to a more progressive one when additives were present in the bath.Surface morphology analysis indicated that alklpyridinium hydrosulfate ILs can induce the formation of leveled and finer grained deposits by the adsorption of additive at the first stages of deposition process,leading to decrease of the nucleation and growth rate of nuclei.