原子吸收光谱法间接测定钼精矿中钼的研究（英文）

发布时间：2018-04-13 04:27

本文选题：钼精矿 + 钼酸铅　；参考：《光谱学与光谱分析》2017年03期

【摘要】：对于钼精矿中钼的测定,标准方法采用钼酸铅重量法,该方法需要将钼酸铅沉淀反复多次洗涤、过滤,以保证沉淀物中夹带的铅离子洗涤完全,再对沉淀物进行灰化、灼烧等多步操作,步骤较繁琐,分析费时,不能快速配合选矿、冶金的科学研究。应用原子吸收光谱法间接测定钼,建立了钼精矿中钼的快速分析方法。钼精矿样品经硝酸、氯酸钾、硫酸加热溶解后,用酚酞和盐酸调节pH值,加入乙酸-乙酸铵缓冲溶液调节pH值至5~7,再加入一定量且过量的铅标准溶液。基于在室温下,钼酸铅为难溶电解质,难溶电解质在一定温度下能否沉淀完全,通常比较离子积Q_c与溶度积常数K_(sp)的相对大小,当Q_cK_(sp),溶液过饱和,沉淀物完全析出,钼精矿中钼的含量为40~60%,铅的加入量为0.125 0~0.150 0 g,取最小值计算出溶液中钼酸铅的离子积,Q_c=[Pb~(2+)][MoO_4~(2-)]=2.51×10~(-5),K_(sp)=1.0×10~(-13),QcK_(sp),因此钼酸铅沉淀可以完全析出,待钼酸铅沉淀完全后干过滤,用原子吸收光谱法测定滤液中过量的铅离子,用差减法计算得出钼精矿中钼的含量。文中分别考察了乙酸-乙酸铵缓冲溶液的加入量及其浓度、铅标准溶液的加入量、钼酸铅沉淀完全的时间、加热时间以及常见共存离子如W~(6+),Sn~(4+)和Cu~(2+)等的最大允许量诸多因素对原子吸收光谱法间接测定钼的影响。与钼酸铅重量法相比,该方法省去了对钼酸铅沉淀反复多次的洗涤、灰化以及灼烧等步骤,操作简便易掌握,分析时间缩短一半,并用钼酸铅重量法与本方法进行对照实验,分析结果进行数理统计,得出结论:本方法具有很好的准确度和精密度,可用于选矿、冶金钼精矿样品中钼的快速分析检测。
[Abstract]:For the determination of molybdenum in molybdenum concentrate, the standard method is lead molybdate gravimetric method, which requires repeated washing and filtration of lead molybdate precipitation to ensure that the lead ion in the sediment is washed completely and the precipitate is then ashes.Multi-step operation, such as burning, is complicated, and the analysis is time-consuming, which can not cooperate with the scientific research of mineral dressing and metallurgy.A rapid method for the determination of molybdenum in molybdenum concentrate by atomic absorption spectrometry (AAS) was established.The molybdenum concentrate was heated and dissolved by nitric acid, potassium chlorate and sulfuric acid, the pH value was adjusted by phenolphthalein and hydrochloric acid, the pH value was adjusted to 5 ~ 7 by adding acetic acid-ammonium acetate buffer solution, and a certain amount of lead standard solution was added.Based on the fact that at room temperature, lead molybdate is difficult to dissolve the electrolyte, and whether the insoluble electrolyte can precipitate completely at a certain temperature, the relative size of the ion product Q _ S _ c and the solubility product constant K _ T _ p _ p is usually compared, and when QcK _ S _ T, the solution is supersaturated and the precipitate is completely precipitated,The excess lead ion in filtrate was determined by atomic absorption spectrometry and the molybdenum content in molybdenum concentrate was calculated by subtraction method.The addition and concentration of acetic acid-ammonium acetate buffer solution, the addition of lead standard solution, the time of the complete precipitation of lead molybdate were investigated.The effects of heating time and the maximum allowable amount of common coexisting ions such as WC6, Sno (4) and Cu~(2) on the indirect determination of molybdenum by atomic absorption spectrometry (AAS) were investigated.Compared with the lead molybdate gravimetric method, the method saves many steps of washing, ashing and burning for the precipitation of lead molybdate, and is easy to operate and easy to grasp, and the analysis time is shortened by half. The comparison experiment is carried out with the method of lead molybdate gravimetric method and this method.It is concluded that this method has good accuracy and precision and can be used for rapid analysis and detection of molybdenum in mineral dressing and metallurgical molybdenum concentrate.
【作者单位】：北京有色金属研究总院生物冶金国家工程实验室;
【基金】：the National Science and Technology Support Program(2012BAB10B08)
【分类号】：TF802.1;O657.31

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