碱性氯化法破氰-碲共沉淀富集-电感耦合等离子体原子发射光谱法测定氰化退镀液中金含量

Determination of Gold by Inductively Coupled Plasma Atomic Emission Spectrometry in Cyaniding Deplating Solution Treated by Alkaline Chlorination and Tellurium Co-Precipitation Method

  • 摘要: 采用碱性氯化法氧化分解样品中氰化物,碲共沉淀法分离富集破氰溶液中的金,建立了电感耦合等离子体原子发射光谱法(ICP-AES)测定退镀液中金的分析方法. 在碱性条件下,使用次氯酸钠氧化分解退镀液中的氰化物,使其转化为二氧化碳和氮气,使用亚硫酸钠溶液中和破氰溶液中的余氯,消除氧化物对氰化物测试包的影响,可以简便快速判断退镀溶液破氰效果. 在3.6 mol/L盐酸介质中,12.5 mL碲溶液(2.5 g/L)和11.0 mL氯化亚锡溶液(1 mol/L)可定量沉淀5~500 μg金,50倍量的杂质元素不干扰测定. 金的质量浓度在0.05~25.00 mg/L范围内与其发射强度呈线性,线性回归方程为y=46.487x+0.343,相关系数r大于0.999 9,检出限为0.004 4 mg/L. 对实际样品进行准确度考察,测定结果的相对标准偏差(RSD, n=7)低于1.0%,加标回收率为96.9%~103.1%,实际样品测定结果与火试金法的对照结果一致性好.

     

    Abstract: The alkaline chlorination method was used to oxidize and decompose cyanide, and the tellurium co-precipitation method was used for the separation and enrichment of gold in the cyanide-breaking solution. The method of determination of gold in cyaniding deplating solution by inductively coupled plasma atomic emission spectrometry (ICP-AES) has been established. Under alkaline conditions, sodium hypochlorite was used to oxidize and decompose the cyanide in the deplating solution and convert it into carbon dioxide and nitrogen: sodium sulfite solution was used to neutralize the residual chlorine in the cyanide-breaking solution and eliminate the effect of oxides on the cyanide test package. The cyanide-breaking effect of deplating solution can be easily and quickly judged. In the acid medium of 3.6 mol/L hydrochloric acid, the 12.5 mL tellurium solution of 2.5 g/L and 11 mL stannous chloride solution of 1mol/L could quantitatively precipitate 5~500 μg Au, and 50 times excess ion/Au(w/w) interfering ions does not interfere determination. The mass concentration of gold was linear with its emission intensity in the range of 0.05~25.00 mg/L. The calibration equation was y=46.487x+0.343, the correlation coefficient (r) was greater than 0.999 9, and the detection limit was 0.004 4 mg/L. The accuracy of the actual sample was investigated, the relative standard deviation (RSD, n=7) was less than 1.0%, and the recoveries were 96.9%~103.1%. The measurement result of experiment method is in good agreement with the comparison of the fire assay method.

     

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