Kolpakova, N.A.; Sabitova, Z.K.; Sachkov, V.I.; Medvedev, R.O.; Nefedov, R.A.; Orlov, V.V. Determination of Au(III) and Ag(I) in Carbonaceous Shales and Pyrites by Stripping Voltammetry. Minerals2019, 9, 78.
Kolpakova, N.A.; Sabitova, Z.K.; Sachkov, V.I.; Medvedev, R.O.; Nefedov, R.A.; Orlov, V.V. Determination of Au(III) and Ag(I) in Carbonaceous Shales and Pyrites by Stripping Voltammetry. Minerals 2019, 9, 78.
Techniques of stripping voltammetry (SV) determination of silver and gold in pyrites and carbonaceous matter were developed. The problem of quantitative transfer of the sample into the solution was solved. For this purpose, the ore matrix of carbonaceous shales was decomposed by mineral acids in autoclaves at high pressures. The element to be determined from the sample matrix was separated by extraction. Ag(I) ions from the solutions were extracted in the form of dithizonate complex in CCl4. Au(III) ions were extracted by diethyl ether. The extracts were decomposed thermally. The dry residue was dissolved in the background electrolyte, and the element was determined by the SV method. The graphite electrode (GE) impregnated with polyethylene was used as a working electrode in SV–determination of silver. SV–determination of gold was carried out using GE modified by bismuth. The limits of detection (LOD) of Ag(I) and Au(III) contents were equal to 0.016 mg L-1 and 0.0086 mg L-1, respectively. The results of SV-determination of gold and silver in standard samples, pyrites and carbonaceous shales were presented. The silver content in the pyrite was 13.6 g t-1, in carbon shale—0.34 g t-1. The concentration of gold in the pyrite ore zone "Kirovsko–Kryklinskaya" was 1.15 g t-1; in carbonaceous shales—2.66 g t-1. The obtained data were consistent with the data of atomic emission spectroscopy (AES) and inductively coupled plasma mass spectrometry (ICP—MS). The error of determination of elements by stripping voltammetry was calculated when determining the silver content of 10...6 g t-1 in pyrite and carbonaceous material, which was less than 12%, and when determining the gold content of 1...3 g t- 1 in pyrite and carbonaceous matter, which was less than 23%.
gold; silver; mineral raw materials; carbonaceous shales; stripping voltammetry; graphite electrode modifiers
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