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Background. During flotation enrichment of Cu-Mo ores at a mining and metallurgy enterprise, flotation reagents are used, including imported frother T-92. Meanwhile, in the republic there is an opportunity for its import substitution, based on local raw materials. Purpose: development of new reagents for depression of flotation-active gangue, without reducing the extraction of molybdenum into an industrial molybdenum product. Methodology. The flotation machine FML-3 manufactured by NPR "Mekhanobr Technika" (RF), flotation reagent T-92 were used. To compare the surface activity of surfactants and the efficiency of rare metal sulfide extraction from flotation pulp, elemental analysis was performed via Agilent 7500 ICP. Originality. Two highly efficient foaming agents have been created from local technogenic raw materials, exhibiting operational properties at a level no worse than the standard flotation reagent T-92. Findings. Foaming capacity, foam stability, depression of flotation-active gangue, without reducing Mo extraction into molybdenum middlings, of new import-substituting foaming agents have been determined. [ABSTRACT FROM AUTHOR]

Background. The kinetics of the oxidation of molybdenite concentrate in sodium hypochlorite solutions was previously studied. It was of interest to compare it with the behavior of pyrite concentrate under the same conditions. Purpose: to study the kinetics of oxidative leaching of gold and silver from pyrite concentrate, in hypochlorite electrolyte, using the rotating disk method. Methodology. Pyrite concentrate of Almalyk MMC JSC was used, pressed into tablet discs18 mm; sodium hypochlorite, controlled Au(I), Ag(I) in solutions (ААС Perkin-Elmer 3030В, ICP-Agilent 7500 IСP MS); solid phase SEM-EDS EVO-MA (Carl Zeiss, Instrum) and JCM-6000 Neoscope II (Jeol, Japan); FTIR Nicolet iS50 (Thermo Scientific, USA), XRD Empyrean (PANalytical). Originality. The parameters of the kinetic equation for the process of oxidative leaching: Au(I), Ag(I) from pyrite concentrate are obtained, the activation energy of the process of diffusion of Au, Ag from the solid into the liquid phase is calculated. Findings. Dependences of the leaching rate of Au, Ag from minerals in a hypochlorite electrolyte on a number of factors are constructed using the rotating disk method. [ABSTRACT FROM AUTHOR]

Background. Almalyk MMC JSC processes molybdenum middling cinder by leaching. The role of metal ion ligands in the leaching of valuable components from Mo-cinder has not been sufficiently studied. Purpose: comparative characteristics of the processes of soda and ammonia leaching of molybdenum middling cinder with depressants of dissolved gold: D1 and zinc. Methodology. The composition of the cinder samples and the solutions and cakes formed during leaching was controlled spectrometrically (ААС Perkin-Elmer 3030В, ICP-Agilent 7500 IСP). The leaching of the cinder was carried out according to soda and ammonia schemes. Originality. According to the analysis of samples of a batch of molybdenite concentrate, a balance of the distribution of metals was compiled in a step-by-step scheme of the processing process. In order to identify losses of Au, Ag, a pilot laboratory test of the process of soda leaching of raw materials was carried out. Findings. The comparative characteristics of PPM cinder leaching in soda and ammonia schemes with D1 depressant and zinc were studied. Leaching products have been studied. [ABSTRACT FROM AUTHOR]

Sm-Nd isochrone, drawn for rock-forming and sulfide minerals from the Ozernoe ore occurrence, indicates albitite age of 1,759 ± 11 Ma. It shows synchronous formation of albitite and sulfide mineralization, and fully corresponds to the earlier defined age of rutile in albitite (1,757 ± 7 Ma U-Pb, n = 3, MSWD = 0.2), and Rb-Sr isochrone age 1,754 ± 39 Ma for biotite, apatite, albite, and WR. Recently published Re-Os ages of molybdenite 1,872 ± 23 Ma and chalcopyrite 1,891 ± 230 Ma indicate more ancient age of sulfide mineralization. These figures are in conflict with the age of rock-forming minerals, defined with Sm-Nd and Rb-Sr methods. The possibility of use of molybdenite from the Salla-Kuolajarvi belt for rock dating has been considered, and low reliability of Re-Os method for it has been shown. The reasons are the following: 1) extremely uneven distribution of Re in molybdenite, where Re content varies 1 wt.% even within one and the same grain, and 2) openness of the Re-Os system after molybdenite crystallization, Re is mobylized and partly removed from the mineral in the zone of hypergenesis. Removal of Re from molybdenite promotes erroneous ancient age of the molybdenite. According to the equations of radioactive decay, the age would be 110–130 Ma bigger if 5–6 % of Re is taken away. The conclusion is that molybdenite must be studied in detail, proved to be homogenous and unaltered, before it is used for Re-Os dating. In the other case the results will be not reliable.

The article is devoted to molybdenum mineralization of the Eastern flank of Au-Mo Serhiivka deposit, located in the Middle Dnipro megablock of the Ukrainian Shield (USh). The generalized description of mineralization is performed on such important questions: discovery and exploration history, structure and composition of the host rocks, metamorphic and metasomatic alteration of rocks, structural position and localization conditions of molybdenum mineralization, ore composition, description of major ore minerals, morphology of mineralization and the most widespread views about its genesis. Molybdenum ores were discovered and named East-Serhiivka occurrence for the first time in 1974, before the discovery of gold mineralization, which occurred in 1985. Serhiivka deposit consists of two Mesoarchaean volcanic-plutonic associations (VPA) of different composition: the early mafic and the late felsic. The Eastern flank of the deposit, where the molybdenum mineralization is concentrated, is a structural knot similar to the lying letter “T”. It is formed by complex joint of the sub-latitudinal Serhiivka and sub-meridional Solone subvolcanic bodies and the East-Serhiivka massif of plagiogranitoids of the late VPA, which intrude basic rocks of early VPA. Molybdenum mineralization is localized in linearly elongated zones with a chaotic network of thin quartz, carbonate-quartz veinlets and poor (2–5 %) sulfide impregnation, including molybdenite. About 20 vein-impregnated ore zones have been recovered with up to 100–150 m thickness and 0,01 to 0,3 %, sometimes more than 1 % average molybdenum grade. The ores are subdivided into two major mineral types: 1) quartz-molybdenite; 2) quartz-sulfide-gold-molybdenite. The main components of ores molybdenite and native gold are associated with pyrite, chalcopyrite, magnetite, occasionally – pyrrhotite, arsenopyrite, scheelite, bismuth telluride, silver and others. Typical non-metallic minerals are quartz, carbonate, feldspar, chlorite, amphibole, biotite, sericite. It is supposed hydrothermal-metamorphogenic genesis of molybdenum (and gold) ores. Molybdenite and gold are rarely detected in the same intersections, which indicates separate genesis of these minerals. According to the accepted classification molybdenum mineralization is systemized as linear stockwork. Molybdenum ores of Serhiivka deposit are mostly considered as independent, separate from gold mineralization, potentially workable mine. It is the most prospective one in the Middle Dnipro region, USh and Ukraine in general. We suggest a comprehensive approach to studying, resource and reserves evaluation of Serhiivka deposit, taking into account the potential of both molybdenum and gold mineralization, as well as concentrations of rhenium and osmium in molybdenite. Geological exploration on the base of this approach will increase investment prospects of Serhiivka gold-molybdenum deposit.

Subject of the study was molybdenite aggregate (0.9 × 0.5 cm) in granite from Cu ± Mo-porphyry mineralisation (Altynai Massif, eastern part of Middle Urals). Microprobe analysis and electron microscopy identified fine alternating microlayers of molybdenite and quartz in all 0.4-5.0 mm flakes of molybdenite. Thickness of normally discontinuous layers of quartz is 0.5-3 μ, distance between layers - 8-100 μ or more. Quartz layers are aligned only with the basal cleavage of molybdenite. In some molybdenite flakes or parts of flakes quartz layers are absent or very few in number. Large flakes of molybdenite are surrounded by fine-grained aggregate of quartz, chamosite and molybdenite. Occasional grains of fluorite and galena have also been found within this aggregate. Molybdenite flakes in such areas contain no quartz layers, have random orientation, and can be seen as fragments cemented by chamosite and quartz. Molybdenite has consistently low rhenium content of 29 ppm (according to ICP-MS). It is suggested that molybdenite-quartz rhythms are likely to correspond to primary oscillatory distribution which was subsequently subjected to deformations and redistribution of silica in crushed areas.