Designing of engineering solutions to enhance efficiency of high-copper gold-bearing ore processing

The modern metals industry is characterised by a downward trend in the quality of ores involved in processing, and conventional methods of extracting useful components are inefficient for raw materials with complex composition. To maintain the growing level of metal production it is required to introduce new efficient technologies for processing of low-grade and refractory ores as well as man-made deposits. The article describes processing methods of refractory raw materials with high cyanide content using copper-gold ores as an example, where gold is the primary commodity, and copper is the accompanying useful component. The most common method of processing copper-gold ores is preconcentration followed by selective leaching of copper and gold. In some cases, technologies involving copper by-products and cyanide recovery from the cyanide leaching solutions offer equally effective options for processing of the copper-gold ores and concentrates. Copper-gold ores are processed at gold mines using the cyanide procedures, supplemented if required by gravity and flotation concentration. In all variations of the cyanide treatment, most of copper minerals actively react with cyanides of alkali metals, binding the CN– ions into the copper complex of [Cu(CN3)]2–. This reaction results in an increased solvent consumption, as well as in number of challenges related to cleaning tailings and slurries from highly toxic cyanide compounds and dissolved copper. In addition to technological complications associated with the need to meet strict requirements for the maximum permissible concentrations, copper accumulated in the cycling solutions also causes a decrease in gold extraction from the processed ores.

An optimal technological scheme for flotation concentration of gold-copper-arsenic ores of the Taror deposit (Republic of Tajikistan)

This article investigates the effect of material size on the efficiency of flotation concentration of gold-copperarsenic ores of the Taror deposit (Republic of Tajikistan) and studies the dependence of gold recovery on the duration of the process with the purpose of developing an alternative technological scheme for processing this ore type. According to X-ray phase analysis, Taror ore samples consist of rock-forming minerals by 92%. Ore mineralization is represented by sulphide minerals, mainly arsenopyrite, chalcopyrite and pyrite, in the total amount of 8%. Ore-forming elements include iron, sulphur, arsenic and copper with the mass fraction of 6.02%, 3.26%, 1.52% and 0.82%, respectively. Gold and silver are contained in the ore in the amount of 7.35 g/t and 20.28 g/t, respectively. The oxidation state of the ore calculated by iron comprises 51.3%. According to this indicator, this ore type can be distinguished as mixed, close to the primary type. According to the conducted chemical phase analysis of gold, this ore type belongs to the category of refractory ores. Flotation concentration experiments showed that grinding the original ore to a size of 95%–71 microns increases the recovery of gold in the concentrate by 10%, compared to grinding to a particle size of 80%–71 microns. The effect of the flotation process duration on gold recovery was also studied. To achieve the maximum gold recovery in the flotation concentrate, the duration of the main flotation and control flotation should be taken equal to 14 and 12 minutes, respectively. As a result of the experiments, a relatively simple technological solution was proposed for flotation concentration of the Taror ore, which includes the main, control and cleaning stages of flotation.

Flotation enrichment of antimony ore using the environmentally friendly reagent-collector KCSb

The problems of extraction and processing of antimony ores are analyzed. The reagent-collector of oxide forms of antimony KCSb is described. It is used to develop operating parameters of the flotation concentration of ore at the Zhipkhosha deposit. The semi-industrial model experiments identified that KCSb is more efficient thatn other known reagents used to enrich antimony oxides. The operating technological conditions of the flotation process were optimized; the use of a collecting reagent indicates the expediency and effectiveness of its use. This fact was confirmed by technical and economic calculations, according to which the profit was up to 30 million rubles per 1 million of processed ore per year. An increase in the resulting product in the form of concentrate was 700–800 tons with 32–36% antimony content, which corresponds to the KSUF-3. This method can be used by antimony deposits containing oxide minerals (10% or more).

Gravity-flotation gold-bearing ore concentration

The paper focuses on the study of the gold-bearing ore dressability. According to technological research, the average gold content is 11.88 g/t. The silver content is insignificant – 2.43 g/t. Main ore minerals in the sample are pyrite and pyrrhotite. According to mineralogical and X-ray structural analysis, the average content of these minerals in the ore is about 6 % (in total). Main rock-forming minerals of the original ore are: quartz (60.1 %), quartz-chlorite-mica aggregates (3.8 %), carbonates (7.1 %). According to the study results, it was found that the gold recovery in the GRG test was 72.75 % with a total concentrate yield of 1.34 % and a content of 664.78 g/t. At the same time, the gold content in tailings was 3.29 g/t. A stage test showed that it is advisable to use a two-stage scheme for ore processing by gravity technology only. The first stage is in the grinding cycle with the 60–70 % ore size, and the second stage is with the final classifier overflow size of 90 % –0.071 mm. Centrifugal separation has high performance as a free gold recovery operation in the grinding cycle. A concentrate with a gold content of 2426 g/t was obtained with a yield of 0.31 % and a recovery of 63.74 %. The beneficiation of first stage tailings ground to 90 % –0.071 mm at the KC-CVD concentrator (modeling) made it possible to extract gold into a total gravity concentrate (KC-MD + KC-CVD) of 87.25 % with a concentrate yield of 22.63 %. The gold content in tailings was 1.97 g/t. The results of gravity and flotation concentration of the original ore indicate the feasibility of using a combined gravity-flotation technological scheme. In a closed experiment of the initial ore beneficiation according to the gravity-flotation scheme at a natural pH of the pulp (without adding acid), the following products were obtained: gravity concentrate with a gold content of 2426 g/t at a yield of 0.31 % and recovery of 64.06 %; flotation concentrate (after the II cleaning) with a gold content of 122 g/t at a yield of 2.90 % and recovery of 33.01 %; the total gold recovery in the gravity-flotation concentrate was 94.07 % with a yield of 3.21 % and an Au content of 345.87 g/t, the gold content in the flotation tailings was 0.72 g/t.

Microextraction flotamicroextraction flotation concentration and determination of chloroacetic acids in watertion concentration and determination of chloroacetic acids in water

The flotation-assisted liquid-liquid microextraction method of mono-, di -, and trichloroacetic acids (CAAs) has been developed. Methyl tert-butyl ether (MTBE) was used as an extractant. The emulsification was performed by the ultrasonic irradiation. The microextraction procedure was carried out in a 27 ml special tube. It was equipped with the capillaries for sampling the extract and an air outlet. A salting-out additive (Na2SO4) was used to reduce the solubility of MTBE in water and to increase the extraction efficiency of CAAs. The air passage through the emulsion of the extractant was carried out using the eight-channel capillary bubbler. The organic matrix replacement was applied for ion chromatographic determination of CAAs with the conductivity detection. Current study showed the advantages of the flotation-assisted demulsification over the centrifugal one. The concentration factors of chlorinated acetic acids were 2-3 times higher. The detection limits of CAAs in water were reduced to (5·10-4 - 4·10-3 mg/l). The extraction time was reduced by more than three times. The trueness of the determination of HUC impurities was confirmed by the addition method. The statistical insignificance of the systematic error in comparison with the random error was shown. The developed method of preconcentration in combination with ion chromatography made it possible to determine the concentrations of CAAs 40-1250 times lower than the normalized SanPiN and WHO. This allowed conducting a highly sensitive determination of CAAs in water long before the onset of the critical ecological state.

Replacement of old flotation cells in the flotation plant of the Lece mine

Russian made FPM-GMO-1.6 flotation machines were previously installed for primary stage flotation concentration of lead and zinc minerals in Lece flotation plant. For cleaning stage FMR-10 flotation machines were in use. Beside low technological characteristic, hard maintenance and worn out are characteristic of this machines. In order to modernize the production and eliminate the above shortcomings primarily in the process of lead minerals flotation, in 2020, the old flotation cells were replaced with new ones. Currently, 8 new RCS-5 cells for coarse and scavengel flotation of lead minerals and 4 RCS-3 cells for cleaning of coarse lead mineral concentrate are working on the lead flotation line in Lece flotation. These cells were produced by Metso Minerals from Finland. Flotation cells, which are installed, have modern technical - technological characteristics, with all the accompanying equipment for automatic control of pulp levels and air consumption. This paper presents comparative characteristics of old and new flotation cells, their appearance and characteristics and technological results achieved in flotation with old and new cells.

Characteristics of zoonotic gastrointestinal parasite infections in owned dogs. Lima-Peru

Urban growth in Peru is accompanied by an increase in dog ownership. Which constitutes a potential risk in the transmission of zoonotic diseases. The objective of the research was to describe the characteristics of the zoonotic gastrointestinal parasite infections in dogs with an owner. For this, 296 stool samples from patients treated in veterinary clinics located in the districts of South Central (Miraflores, Chorrillos) and South (San Juan de Miraflores) Lima were analyzed. Of which 288 were positive for gastrointestinal zoonotic parasites during the period 2015 - 2018. Likewise, the direct examination and the flotation concentration test were carried out to identify zoonotic parasites. Regarding the results, infection caused by Giardia spp (66,3%) was the most frequent, followed by Toxocara canis (18,8%), Ancylostoma caninum (3,5%) and Dypilidium caninum (2,4 %). Likewise, a higher frequency of parasites was observed in the diarrheal feces of male dogs (52,8%) of small breeds (43,8%). Mixed-breed dogs (12,2%), English Bulldog (10%) and Labrador retriever (9,7%) were the most frequently infected. It is concluded that 97,3% of the owned dogs were infected with zoonotic gastrointestinal parasites, which constitutes a problem for public health.

Extraction of Phosphorous from a Phosphorous-Containing Vanadium Titano-Magnetite Tailings by Direct Flotation

In this study, there is 1.42% P2O5 in the P-containing V-Ti magnetite tailings in Miyi Region of China, with the valuable minerals mainly including apatite, and aluminosilicate minerals as the main gangue components. The direction flotation process was used to recover phosphorous from the low-grade phosphorous-bearing V-Ti magnetite tailings. The results showed that an optimized phosphorous concentrate with a P2O5 grade of 31.35% and P2O5 recovery of 88.02% was obtained by flotation process of one roughing, three scavengings, and three cleanings under roughing conditions, which employed pulp pH of 9, grinding fineness of <0.039 mm occupying 90%, flotation concentration of 25%, and dosages of carboxymethylcellulose, oxidized paraffin wax soap, and pine oil of 400 g/t, 300 g/t, and 20 g/t, respectively. Optimized one scavenging, two scavenging, and three scavenging conditions used a pulp pH of 9, and dosages of carboxymethylcellulose, oxidized paraffin wax soap, and pine oil of 200 g/t, 150 g/t, 10 g/t; 100 g/t, 75 g/t, and 5 g/t; and 100 g/t, 75 g/t, and 5 g/t, respectively. Optimized one cleaning, two cleaning, and three cleaning condition dosages of carboxymethylcellulose of 100 g/t, 50 g/t, and 25 g/t, respectively. Study of analysis and characterization of phosphorous concentrate by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) show that most gangue minerals enter the flotation tailings, the main minerals in phosphorous concentrate are apatite, olivine, and feldspar.

INCREASING THE SELECTIVITY OF USEFUL MINERAL DISCLOSURE WHEN PROCESSING DIFFICULT POLYMINERAL RAW MATERIALS WITH PRELIMINARY WEAKENING

Previous studies at a number of research centers in our country, including the Institute of Mining, SB RAS and the Institute of Nuclear Physics, SB RAS, showed the possibility of improving process parameters of flotation concentration of difficult mineral raw materials due to preliminary electron-beam processing, which allows weakening minerals and rocks. Obtaining the data on selective disintegration and disclosure of minerals during ore pretreatment is important for technological application. This study aims at receiving the experimental data confirming an increase in the selectivity of disintegration of mineral raw materials processed by a high-energy electron beam and an improvement in the disclosure of intergrowths of useful minerals. Complex experimental mineralogical and technological studies by the example of rebellious lead-zinc ore with a grain size of -3 mm provided the data on increasing the selectivity of disintegration of mineral raw materials and improving the disclosure of useful minerals. It is found that if in -0.071 mm size class of ground lead-zinc ore without processing, the fraction of free galena and wurtzite grains (sphalerite modification) is 40.7 and 65.7%, then the fraction of free grains of these minerals increases up to 66, 4 and 71.5% in ore pretreatment. It should be noted that ore processing by accelerated electrons allows obtaining the ground material, in which free mineral grains are less overground. For galena, the size of free grains increases from 2.6 to 4.0 μm, and for wurtzite - from 4.5 to 6.6 μm. Scientific novelty includes increasing the selectivity of disintegration and improving the disclosure of useful minerals through the effect of weakening of mineral raw materials in ore pretreatment.