过氧化钠熔融-硫氰酸铵差示光度法测定钼精矿和钼焙砂中钼

研究了用过氧化钠在高铝坩埚中700 ℃熔融样品5～10 min，用硫氰酸铵差示光度法测定了钼精矿和钼焙砂中钼含量的方法。对样品的熔融条件、样品溶液的制备条件和测定条件进行了优化。通过加入无水乙醇消除了MnO^2-₄的干扰，采用三氯化铁溶液沉淀吸附和酒石酸钠掩蔽的方式消除了钨(Ⅵ)、铬(Ⅵ)和钒(Ⅴ)等其它共存离子的影响。结果表明，于吸收波长λ=480 nm处，钼质量浓度在14.0～26.0 μg/mL范围内符合比尔定律，检出限为4.2×10^-2 μg/mL。将本法用于钼精矿管理样品GLY-01、钼精矿和钼焙砂生产样品中钼的测定，测定值与参考值或重量法测得结果一致，相对标准偏差(RSD，n=11)为0.10%～0.14%。

Determination of molybdenum in molybdenum concentrate and molybdenum calcine by sodium peroxide fusion-ammonium thiocyanate differential spectrophotometry

In a high-alumina crucible, sample was fused at 700 ℃ with sodium peroxide for 5-10 minutes, then the content of molybdenum in molybdenum concentrate and molybdenum calcine was determined by ammonium thiocyanate differential spectrophotometry. The conditions for sample fusion, sample solution preparation and determination were optimized. The interference of MnO^2-₄ was eliminated by addition of absolute ethyl alcohol, and the impact of tungsten (VI), chromium (Ⅵ), vanadium (Ⅴ) and other coexisting ions was eliminated by precipitation adsorption with ferric trichloride solution and sodium tartrate masking. The results showed that at the absorption wavelength of 480 nm, the mass concentration of molybdenum conformed to Beer's law within the range of 14.0 to 26.0 μg/mL, and the detection limit was 4.2×10^-2 μg/mL. This method has been used for the determination of molybdenum in molybdenum concentrate run samples GKY-01, the production samples of molybdenum concentrate and molybdenum calcine. It was found that the results were in accordance with the reference values or those obtained by gravimetric method, and the relative standard deviations (RSDs, n=11) were 0.10 %-0.14%.