Institute of Comprehensive Exploitation of Mineral Resources, Russian Academy of Sciences, Moscow, Russia:
T. N. Matveeva, Head of Department, e-mail: tmatveyeva@mail.ru
N. K. Gromova, Researcher
V. A. Minaev, Leading Engineer

An original technique was developed for quantitative evaluation of the adsorption layer of combined diethyldithiocarbamate on the surface of sulfide minerals; this involves the method of analyzing the mineral surface images from scanning laser microscopy using software VK-Analyzer. This program has extensive functions that allow conducting both 2D and 3D measurements. The originality and novelty of the approach in studying the thin reagent films on the surface of mineral samples is to compare the results of numerical measurements of the unevenness of the mineral relief before and after contact with the reagent solutions. Surface analysis of sulphide minerals before and after contact with reagent solutions was carried out on polished sections made in the form of polished plates 10102 mm. The primary evaluation of the homogeneity of the distribution of the reagents over the surface of mineral grains and the localization of their preferential concentration sites was carried out using an optical (Olympus BX 51) and scanning electron microscopy (LEO 1420 VP INCA 350). In this study, the most important type of polished image of the mineral was selected. Measurements were made on the following image parameters: elevation differences of the relief surface, linear dimensions of the contoured newly-formed phases of the reagent, measurement of the areas of the reagent phases on the surface of the section. The areas of the newly-formed phases of the reagent on the polished sections of sulphide minerals treated with combined diethyldithiocarbamate (DEDT) were determined. According to the results of measurements carried out in several areas of the field of view (with an increase of 20) with an area of (0.50–0.64)·10^–6 μm², the degree of coverage of the mineral surface by the DEDT reagent was 21.6% for arsenopyrite, 72.2% for chalcopyrite. At the same time, the fraction of the coating by the molecular form of adsorption of the reagent in the form of drops on arsenopyrite was 2.9% compared to 7.2% for chalcopyrite. The developed technique allows to quantify the adsorption of the reagent-collector on sulfide minerals and to experimentally substantiate the mechanism of action of the main forms of the collector.
The study was carried out with the financial support of the Russian Foundation for Basic Research in the framework of the scientific project No. 16-05-00646a.

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