Techniques of stripping voltammetry (SV) determination of silver and gold in pyrites and carbonaceous matter are developed. The problem of quantitative transfer of the analytes into the solution is 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 a 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 the SV determination of silver. The SV determination of gold was carried out using a 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, and in carbon shale it was 0.34 g t⁻¹. The concentration of gold in the pyrite of the Kirovsko–Kryklinskaya ore zone was 1.15 g t⁻¹, while in carbonaceous shales it was 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 as ranging from 10 to 6 g t⁻¹ (less than 12%) in pyrite and carbonaceous material when determining the silver content, and from 1 to 3 g t⁻¹ (less than 22%) when determining the gold content in pyrite and carbonaceous matter.

The paper considers the possibility of determining platinum metals in mineral raw materials by stripping voltammetry on a graphite electrode modified by metals. Stripping voltammetry method is characterized by low determination limit, wide intervals of determined content and high sensitivity. As a result of the research the conditions for the determination of gold, platinum and palladium by stripping voltammetry have been selected. The comparison of the results of gold, palladium and platinum determination by stripping voltammetry and atomic absorption is presented.

MATEC Web of Conferences, open access proceedings in Materials science, Engineering and Chemistry

The effect of hydrogen on the electrooxidation current of a palladium–hydrogen precipitate is studied. It is shown that the UV irradiation of the solution changes the mechanism of the formation of mol