硫氰酸盐光度法测定氨浸渣中的钼

Spectrophotometric Determination of Molybdenum in the Ammonia Leaching Residue Using Thiocyanate

摘要:

将氨浸渣试样用硝酸-硫酸-磷酸混合酸溶解-氢氧化钠分离，2 mol/L的硫酸介质中，在Cu2+催化下，以硫脲将Mo(Ⅵ)还原为Mo(Ⅴ)，与硫氰酸盐生成琥珀色配合物，借此进行光度法直接测定。重点研究样品的分解方法、共存元素的干扰以及干扰消除方法等。并采用重量法、全差式光度法和硫氰酸盐直接光度法（本法）3种分析方法，对同一试样分别独立地进行8次测定，将测定结果进行比较。结果表明：本法操作简便，分析结果有较高的精密度、准确度，对氨浸渣中钼的测定达到满意的效果，优于钼酸铅重量法。

Abstract:

The ammonia leaching residue sample was dissolved by HNO3-H2SO4-H3PO4 mixed acid and separated by NaOH. With Cu2+ and 2 mol/L H2SO4, Mo(VI) was reduced to Mo(V) by thiourea, then reacted with thiocyanate to form amber complexes which was used for the determination of Mo by spectrophotometric method. The sample digestion method, co-existence elements interference and their elimination were studied. The 8-time experimental results of the same samples by the proposed method were compared with that of gravimetric method and full-differential spectrophotometric method. The results indicate that the proposed method is simple, accurate and high-precision, and fit to the determination of Mo in ammonia leaching residue with satisfactory effects, prior to gravimetric method.