小火试金分离富集火焰原子吸收光谱法测定矿石样品中的金

研究建立了一种有别于传统火试金的分离富集方法--小火试金分离富集矿石中的金，并采用火焰原子吸收光谱仪对金含量进行检测的方法。在小火试金条件的选择中，分别对小火试金熔剂比例、灰吹温度、保护剂用量进行了讨论，确定了这三个参数的最佳值分别为：硼砂-纯碱-黄丹-淀粉比例5∶5∶10∶1，900 ℃，10 mg，将3 g样品经焙烧后，在最佳小火试金条件下分离富集金，铅扣经灰吹得到金、银合金粒，经稀硝酸溶解后，加入盐酸将银与金分离，用火焰原子吸收分光光度计对溶液中的金进行测定，工作中探讨了原子吸收光谱仪测定金的各种影响因素，包括仪器参数优化、线性范围、干扰离子等。干扰实验表明其他共存贵金属元素对金的测量不产生影响，在选定的仪器条件下，对标准样品及某矿送检的金矿石样本中的金进行测定，结果与标准值一致，相对标准偏差（n=11）在0.72%～5.49%之间，方法回收率在98.82%～99.20%之间。此方法稳定可靠，准确度高，对0.X~XX.0 mg·kg-1的矿石中金含量均适用，拓展了火焰原子吸收测量金的含量范围，并且大大降低了传统火试金法对人及环境的伤害和污染，原子吸收光谱法具有响应快、灵敏度高、准确性好等优点，为进一步研究用此法开展其他贵金属的检测奠定了技术基础。

Determination of Gold in Mineral Samples by Flame Atomic Absorption Spectrometry after the Separation and Preconcentration with Small Fire Assay

Study and establish a method of separation and enrichment of different from the traditional fire assay--small fire assay preconcentration of gold in ores, and the detection method for gold content Flame atomic absorption spectrometer. The optimal small fire assay conditions were determined: flux ratio, borax-soda-yellow lead-starch 5∶5∶10∶1, melting temperature 900 ℃, dosage of protectant 10mg. After the separation and enrichment with best small fire assay condition using 3 g sample, the lead button of the mineral samples got the alloy particle of silver, gold by cupellation. After dissolution in dilute nitric acid, gold was separated from silver in hydrochloric acid solution and determined by AAS. In this paper, the factors influencing the detection of gold by AAS were discussed, which include the setting of parameters of the instrument, the liner range and the interfering ions. The interference test indicated that other precious metals had no influence for gold determination. Under the selected instrument conditions, the gold in the standard samples was tested, and the result was in agreement with the standard value. The RSD (n=11) of gold was between 0.72%～5.49%, the recovery was between 98.82%～99.20% by detecting standard and certain mine gold ore sample. This method is stable, reliable and accurate which is suitable for the gold content from 0.X to XX.0 mg·g-1 in ore and extends the analysiscontent range for Au by FAAS. More importantly, it reduces the traditional fire assay on human and environmental damage and pollution. AAS has the advantages of fast response, high sensitivity and good accuracy which provides a technical basis for further research on the detection of other precious metals by this method.