Ore Processing Research Articles

Contribution of Obi Island Reducing the Carbon Footprint in the Transport Sector

Transportation is one of the main sectors contributing to greenhouse gas (GHG) emissions that cause global climate change. One of the decarbonization strategies from the transportation sector that can be implemented is by switching to a sustainable mode of transportation, especially battery electric vehicles (BEV). Since mid-2021, Obi Island has been producing Mixed Hydroxide Precipitate (MHP). It is an intermediate product of limonite nickel ore processed using hydrometallurgical processing techniques through the first refining plant in Indonesia using High Pressure Acid Leaching (HPAL) technology. The MHP will be processed into Nickel Sulfate (NiSO4.6H2O) and Cobalt Sulfate (CoSO4.7H2O), the primary precursor materials for electric vehicles. The potential GHG emissions reduction in the transportation sector from the processing of limonite nickel ore in Obi Island is 2.04 MtCO2 in 2022 to 21.02 MtCO2 in 2040 with a total accumulation until 2040 of 344.56 MtCO2.

Occupational Health Risks for Workers Engaged in Copper-Nickel Ore Processing

Introduction: Despite all preventive measures constantly taken, high incidence of occupational diseases is still registered in workers of copper-nickel enterprises. Objective: To obtain new knowledge about the conditions, timing, structure and frequency of occupational diseases in order to develop methods for their more effective prevention in workers involved in pyrometallurgical copper-nickel ore processing. Materials and methods: We have analyzed incidence rates of occupational diseases in a cohort of 664 workers who processed copper-nickel ore in 2007–2020. Results: Working conditions during pyrometallurgical processing of copper-nickel ore correspond to hazard classes 3.2–3.4 with the chemical exposure being of paramount importance in the development of health disorders (45.6 % of cases). In 2007, 664 workers were examined and 158 occupational diseases were diagnosed in 65 (9.8 %) of them in the years 2008–2020, respiratory and musculoskeletal diseases being the most prevalent categories (50.6 % and 29.1 %, respectively) and chronic bronchitis and sensorineural hearing loss – the most prevalent diseases (27.8 % and 17.1 %, respectively). We established non-occupational disorders (arthralgia, osteochondrosis, early signs of hearing impairment, etc.) contributing to further development of occupational diseases. Smoking history (> 5 packs/year) was found to promote occupational diseases of the respiratory system (RR = 4.84; 95 % CI: 2.51–9.35). Crane operators (17.5 % of the workers) were found to be at highest risk of occupational diseases (366.1 cases per 10,000 workers). Conclusions: Based on data on previously registered occupational diseases, working conditions, length of service, occupation, and clinical conditions, criteria for five risk categories have been developed to predict occupational diseases by time, nosology, and severity of the course in metallurgists involved in copper-nickel ore processing.

Prospects for Return of Valuable Components Lost in Tailings of Light Metals Ore Processing

Prospects for Return of Valuable Components Lost in Tailings of Light Metals Ore Processing

Efficient reduction of Cr(VI) and recovery of Fe from chromite ore processing residue by waste biomass

The traditional chromite ore processing residue (COPR) detoxification process is carried out in strong acid or anoxic high-temperature condition, which not only has a high input cost but leading difficulties for resource utilization of treated COPR. This study first reported the efficient reduction of Cr(VI) and recovery of Fe from COPR by waste molasses-assisted hydrothermal treatment. Under optimal conditions (i.e., the Na2CO3 dosing of 0.5 mol/L, the molasses/COPR mass ratio of 10%, hydrothermal treatment at 140 °C for 150 min), the Cr(VI) reduction efficiency reached 99.96 ± 0.01%, and the leaching toxicity of total Cr met the USEPA regulatory limit of 5 mg/L. Moreover, Fe was recycled in the form of magnetic magnesioferrite with Fe2O3 grade of 52.58 ± 0.90%, which can be used as raw material in steel industry. The Cr(VI) reduction reaction conforms to a pseudo-first-order kinetic model, and the reaction rate constants increase with increasing temperature (120 ∼160 °C). As a potential mechanism of the reaction, the Mg-Al hydrotalcite (LDHs) structure collapses in the presence of Na2CO3 during the hydrothermal treatment, and the embedded Cr(VI) is released, which is then reduced to Cr(OH)3 by reducing substances such as fructose, sucrose, and glucose in waste molasses. From the standpoint of a circular economy, this study may provide a potential strategy for minimizing resource input and waste/emission production by harmless disposal and resource utilization of COPR and waste molasses.

Pre-activation of nepheline before the enrichment

Due to limited reserves of bauxite, nepheline can be used in the industrial production of alumina in Kazakhstan. The most promising deposit is the nepheline syenites of the Kubasadyr deposit. Currently, there is no effective technology for processing nepheline ores. High energy intensity, capital intensity and significant emissions into the atmosphere are the main drawbacks of the conventional technology of nepheline ore processing by sintering method. Efficient hydrochemical processing of nepheline requires pre-enrichment with the separation of a part of silica. According to the existing technology of chemical enrichment in an alkaline solution at a temperature of 280⁰С, the silica extraction degree is no more than 36%. A pre-roasting at 500⁰C is used to increase the extraction rate of silica and this process permits an increase in the extraction rate to 65%. The paper presents the results of the chemical activation of nepheline syenites in a solution of sodium hydrogen carbonate. The optimum conditions of activation are determined. Activation at a temperature of 280 ⁰C resulted in a change in the phase composition of the feedstock and increases the degree of silica extraction up to 65,5%. The results obtained showed the possibility in principle of using hydrochemical enrichment technology for the resulting high-quality nepheline concentrate and replacing the energy-intensive roasting process.

High-efficiency and environment-friendly separation and recovery of manganese from braunite via the ammonium sulfate roasting-water leaching process: Behavior and mechanism

Manganese ore is a key raw resource for the development of new energy, new materials, and other emerging industries, as well as a basic raw material for the steel industry. As resources of the main high-grade pyrolusite are depleting, it is of strategic importance to develop and utilize other manganese oxide ores. This paper proposed the two-stage ammonium sulfate roasting-water leaching process for high-efficiency and environment-friendly separation and recovery of manganese from braunite ((Mn2O3)3MnSiO3). The first-stage was sulfation roasting, which could convert Mn and Fe in braunite into (NH4)2Mn2(SO4)3, (NH4)3Fe(SO4)3, NH4Fe(SO4)2 and Fe2(SO4)3; the second-stage was selective roasting, that could decompose (NH4)2Mn2(SO4)3 into MnSO4, and decompose (NH4)3Fe(SO4)3, NH4Fe(SO4)2 and Fe2(SO4)3 into Fe2O3. Under the optimum leaching conditions, the leaching efficiency of Mn reached 97.79%, while the leaching efficiency of Fe was only 1.52%, and a solution with a concentration of 93.36 g/L for Mn was obtained. The NH3 volatilized during roasting was absorbed by the water solution to get an ammonia solution which was used to precipitate Mn from the leaching solution. The precipitation efficiency of Mn was 99.48% under optimal conditions. Manganese oxide products such as Mn3O4 or Mn2O3 could be obtained by drying and calcining Mn-rich precipitates. The final filtrate was neutralized with H2SO4 and then evaporated and crystallized to give an (NH4)2SO4 product, enabling the recycling of ammonia. The process proposed in this paper is not limited to the treatment of braunite, but can also be applied to the processing of other manganese oxide ores and has a wide application potential. Compared to the traditional reduction roasting-acid leaching process, this process is more efficient and environmentally friendly.

Environmental geotechnology for low-grade ore mining with the creation of conditions for the concurrent disposal of mining waste

Due to the constantly deteriorating environmental situation in the regions with mining enterprises, the article considers the topical issue of disposing the maximum possible volume of waste from the mining and processing of low-grade ferrous ores through the creation of an effective underground environmental geotechnology. Traditional procedure with descending mining of reserves with a caving system does not allow waste to be disposed of in a gob. The idea is to use geotechnology based on the ascending order of mining the ore body, room excavation, leaving truncated pillars, and staggered arrangement of adjacent rooms in height, which makes it possible to form containers for waste disposal in the form of a cementless backfill. The main characteristics of the proposed procedure are investigated and compared with the traditional procedure of low-grade iron ores mining. It was established that from the point of view of the complete extraction of reserves and the unit costs for the preparatory-development operations, the processes are comparable, while in terms of the mining quality, the proposed option is much more efficient. Evaluation of environmental geotechnology by the criterion of waste disposal, performed according to the proposed methodology, showed that the combination of these technical solutions ensures the placement in the formed gob from 80 to 140% of all waste generated during the mining and beneficiation of low-grade iron ores.

Use of clay-containing waste as pozzolanic additives

Growing productivity of mining and processing enterprises entails an increase in the volumes of liquid tailings impoundments and upstream impoundments of ore processing waste. Enterprises face the challenge of minimizing the environmental impact of waste and guaranteeing the sanitary and epidemiological safety of population. The article presents a possibility of recycling one type of such waste (clay-containing concentration tailings of apatite-nepheline and sylvinite ores, coal beneficiation tailings) by using them after preliminary thermochemical treatment as pozzolanic additives to cements and concretes, including concrete mixtures used for soil stabilization, development of territories, reclamation of mine workings, as a component of the insulating layer of landfills for the disposal of municipal solid waste. An analysis of the phase changes of kaolinite, one of the main minerals that make up clay-containing waste, in the temperature range of 200-1,000 °С showed that a change in its mineral form during heat treatment is the main factor in changing its pozzolanic activity. The effect of heat treatment of clay minerals at temperature of 700-800 °C on their pozzolanic activity, estimated by the ability to absorb calcium hydroxide (0.7 g Ca(OH)2 per 1 g of modified kaolinite), is considered. It is shown that the addition of heat-treated samples (20 % by weight) improves the quality of cement increasing its activity by 15 %, in comparison with the use of unmodified clay minerals. It was proved experimentally that partial replacement of Portland cement with thermally modified kaolinite increases the strength of consolidating stowing mixture by up to 15 %. This approach to processing of ores containing layered silicates, which provides for thermochemical modification of run-of-mine ore, intensifies the processes of tailings thickening and filtering.

Формирование экологического ущерба при складировании сульфидсодержащих отходов обогащения полезных ископаемых

The mining industry is one of the most challenging in ensuring environmental safety. During the last century, the Karabash Copper Smelting Plant was processing sulfide ores and depositing the tailings into storage facilities that now occupy an area of more than 50 hectares. To date, abandoned tailings are a significant source of natural water, air, and soil pollution in the Karabash city district. The article comprehensively examines the environmental impact of the Karabashmed copper smelter, one of the oldest metallurgical enterprises in Russia. The effects of seepage from the two Karabashmed tailings facilities on water resources were assessed. We revealed that even outside the area of the direct impact of processing waste, the pH of natural water decreases to values 4-5. Further downstream, the infiltration water from the tailings pond No. 4 reduces the pH of river water to 3.0-3.5. The presented results of environmental engineering surveys are derived from sampling water and bottom sediments of the Ryzhiy Stream and the Sak-Elga River, sample preparation, and quantitative chemical analysis. The study revealed significant exceedances of the maximum permissible concentrations for a number of chemical elements in the impact zone of the copper ore processing tailings.

Silver(I) Recovery by Ion Flotation Process from Aqueous Solutions in Cells with Spargers

Extractive metallurgy has recently turned its attention to waste treatment for the recovery of precious metals through innovative metallurgical processes, such as ion flotation. This work studied the influence of several chemical and physical factors, such as the concentration of xanthate [x], frother agent [e], dithiophosphate [xl], pH, superficial gas velocity Jg, percentage of gas holdup Eg, bubble diameter (Db) calculated with the drift flux model, and the type of sparger, in the efficiency of silver(I) recovery by the ion flotation technique in sub-aerated cells. The results obtained indicate a 90.7% v/v recovery of silver(I) under conditions of 3.77 × 10−4 M [x], 1.25 × 10−4 M [e], Jg 0.5 cm/s, Jl 0.19 cm/s, Eg of 4.1% v/v, and Optimal Db of 0.11 cm, with a rigid bubble generator, achieving an apparent flotation kinetics of 4.16 1/min. The use of combinations [x]–[xl] achieve a silver(I) recovery of 86.9% with a Jg of 1.0 cm/s. The best recovery efficiencies achieved 93% w/w silver(I) are with pH 8.0, [e] of 1.25 × 10−4, Jl of 0.19 (cm/s) and a rigid sparger compared to a flexible one.

Ecological assessment of soil contamination by heavy metals affected in the past by the lead–zinc mining and processing complex in Kentau, Kazakhstan

Polymetallic ore processing plants are serious sources of heavy metal pollution. The present study examined the degree of pollution of surface soils with the metals zinc, cadmium, lead, and copper in the single-industry town of Kentau, Kazakhstan, where an enterprise for the processing of lead-zinc ore has been operating for a long time. This enterprise ceased operations in 1994, and this study may be of interest in terms of assessing the current ecological state of urban soils after a 27-year period of possible soil self-cleaning processes. The study showed that the surface soils of Kentau retain fairly high concentrations of metals. The maximum detected concentrations of zinc, cadmium, lead, and copper were 592mg/kg, 1.651mg/kg, 462mg/kg, and 82.5mg/kg, respectively. According to the classification of the geoaccumulation index, the soils of the town belong to pollution classes II, III, and IV with moderate and strong pollution. The calculated potential ecological risk factor indicates that cadmium poses a considerable potential ecological risk, while lead showed a moderate ecological risk. In general, according to the obtained values of potential ecological risk factors, metals can be arranged in the following order: Cd > Pb > Zn > Cu. In this study, a five-step sequential extraction procedure by the method of A. Tessier was used, and the mobility factors of metals were calculated. Based on the data obtained, it was found that cadmium and lead have the highest mobility and, consequently, availability for biota in modern conditions, which may pose a potential risk to public health in the town.

Mineralogy and Mineral Chemistry of the Au-Ag-Te-(Bi-Se) San Luis Alta Deposit, Mid-South Peru

A mineralogical and mineral chemistry study was carried out in the San Luis Alta telluride-rich gold deposit, mid-south Peru, to contribute towards determining its formation and improving the ore processing. The San Luis mineralization is considered an intrusion-related gold deposit located in the Arequipa segment of the Coastal Batholith. The mineralization occurs in quartz veins hosted in diorites and granodiorites from the Tiabaya Super-Unit. These veins are sulfide-rich in the deep areas and contain abundant iron oxides. Sulfides are mainly pyrite with minor chalcopyrite and galena. Native gold and telluride minerals are abundant. Mineral chemistry was determined using an electron microprobe. The mineralogy of veins was classified into four stages. Gold occurs in the three last stages either in large grains, visible to the naked eye, or, more frequently, in grains of less than 10 µm. Gold appears as grains encapsulated in pyrite, Fe oxides, quartz and filling fractures. The first stage is characterized by the deposition of quartz and massive pyrite, which does not contain gold. During the second stage, hessite, calaverite, petzite and altaite are formed. Additionally, Bi-tellurides, mainly volynskite, rucklidgeite, kochkarite and tellurobusmuthine, are formed. Some of these minerals occur as blebs encapsulated in pyrite, suggesting that a Bi-Te-rich melt was formed from the ore-forming hydrothermal fluid and transported the Au and Ag elements. This stage was followed by a fracturing event and tellurobismuthite, tetradymite and montbrayite precipitated. In the last stage, a supergene replacement formed covellite, bornite and goethite. Te-Bi minerals do not appear in this stage, but selenium minerals occur in minor amounts. Chlorargyrite and iodargyrite occur and are associated with gold.

Ionic Liquids and Deep-Eutectic Solvents in Extractive Metallurgy: Mismatch Between Academic Research and Industrial Applicability

The past 10–20 years have seen numerous academic papers describing the benefits of ionic liquids (ILs) and deep-eutectic solvents (DESs) for leaching, solvent extraction and electrowinning. The scientific community—including the authors of this opinion article—have frequently proclaimed these neoteric solvents as game-changers in extractive metallurgy. Despite this, there have been no commercial breakthroughs. In this paper we reflect on the reasons why ILs and DESs seem to have failed to impact on the metallurgical industry. These include: (1) issues with high viscosity; (2) limited chemical stability under the conditions of metallurgical processes; (3) difficulties with recycling and reuse; (4) a lack of demonstrated unit processes and flowsheets on the pilot scale; (5) insufficient material-property data available for engineering purposes; (6) the administrative burden of obtaining licenses and safety permits; (7) very high costs for large-scale operations; and (8) minimal added value compared to state-of-the-art hydrometallurgical processes. Our belief is that innovations in hydrometallurgy based on ILs or DESs are unlikely. Instead, we should be aiming for a deeper understanding of hydrometallurgical processes at the molecular level. This is because advances are more likely to derive from the refocused efforts of experienced IL/DES researchers investigating the speciation and chemical thermodynamics of hydrometallurgical solutions, which will then hasten the transition from linear to low-energy-input, circular hydrometallurgy.Graphical

Integrated ozonation and mineralization of alkyl xanthate: Influence of operation parameters and structure-activity relationship

Xanthate is widely used in the flotation process of sulfide ores, and large amount of flotation wastewater with xanthate is produced and caused serious wastewater pollution due to its excessive usage. This study intensively studied ozonation and various ozone based advanced oxidation processes (AOPs) for alkyl xanthates (AXs) degradation and mineralization, including catalytic ozonation, peroxone and photocatalytic ozonation. The key operation parameters, such as ozone dosage, ratio of different oxidants and solution were studied. All integrated ozonation processes improved the mineralization efficiency of AXs, among which TiO2 photocatalytic ozonation is the most efficient, and the chemical oxygen demand (COD) removal rate can reach 84.9% in 60 min. A quantitative structure-activity relationship (QSAR) model was also established for ozonation of xanthates for the first time, based on quantum chemical calculation of series of xanthate structures and their degradation rate constants in ozonation. It reveals that the main factor affecting the ozonation rate constant is the molecular volume, which is negatively linearly correlated with the length of carbon chain of alkyl substituent group. The degradation intermediates of potassium amyl xanthate were measured by ultraviolet-visible spectroscopy (UV-Vis) and gas chromatography-mass spectroscopy (GC-MS), based on which a degradation path of xanthate was proposed. This work provides deeper understanding of advanced oxidation and mineralization of AXs, and may guide the development of treating technology for flotation wastewater.

Indium Recovery from Jarosite Pb–Ag Tailings Waste (Part 1)

The processing of zinc ore using hydrometallurgical methods leads to the formation and accumulation of a by-product called jarosite, which contains concentrated precious metals. In this study, we propose the recovery of In and its separation from Cu, Zn, Fe, Pb, and Ag. This study also presents a proposal for a new technological procedure for jarosite treatment. First we roasted the jarosite, and then the calcine collected was leached in water. The leaching extraction values obtained for Cu, Zn, Fe, and In were 91.07%, 91.97%, 9.60%, and 100.0%, respectively. Following the leaching of the roasted material in water, Pb, Ag, and most of the Fe obtained remained in the solid residue. The leaching solution was treated further by a precipitation process using NaOH, where In and Fe were precipitated and consequently separated from Cu and Zn. The In (OH)3 and Fe(OH)3 precipitates were dissolved further in a diluted H2SO4 solution, and then the cementation of In with Al was performed. We used HCl acid to remove Al from the In, after which unwrought In was obtained.

Recovery and preparation of high-grade silica from iron ore tailings by S-HGMS coupling with acid leaching technology: Description of separation mechanism and leaching kinetics

High‑silicon iron ore tailings (IOTs) as mineral solid wastes derived from the processing and utilization of iron ore, which would threaten human health and the ecological environment if handled improperly. Coincidently, it consists of abundant quartz gangue. In this study, we proposed a superconducting high gradient magnetic separation (S-HGMS) coupling with acid leaching technology to prepare high-grade silica from high‑silicon IOTs. S-HGMS was applied to high‑silicon IOTs to pre-concentrate silica into quartz concentrate. Under the optimized conditions, the SiO2 grade in quartz concentrate reached 92.06% with a SiO2 recovery of 43.54%. The results indicate that the S-HGMS effectively achieved a selective separation of silica from high‑silicon IOTs, but entrainment occurred between silica and sub-micron impurities particles, reducing the SiO2 grade and recovery. Quartz concentrate was then subjected to a mixed acid leaching to remove metallic impurities. Under the conditions of the ratio of mixed acid of 5 mol/L HCl + 1 mol/L HF, leaching temperature of 353.15 K, and leaching time of 12 h, the SiO2 purity of high-grade silica reached 99.51%, and the removal efficiency of Fe, Al, Mg, and Ca from quartz concentrate was 95.20%, 85.60%, 97.99%, and 97.19%, respectively. During the leaching process, HF played a vital role and its' nucleophilic attack can provide the effective removal of metallic impurities. The dissolution behaviors of Fe, Al, Mg, and Ca were described as shrinking core models, but their controlled steps were significantly different. Thermodynamic results indicate that Fe, Al, Mg, and Ca leaching processes were dominated by ΔS0 rather than ΔH0, and their ΔG0 from lowest to highest were ΔG0Ca<ΔG0Mg<ΔG0Fe<ΔG0Al<0, indicating that Ca ion may be leached more easily. Ultimately, a prospect was proposed for the high-value application of high‑silicon IOTs resource. This study provides valuable insight to realize the recycling and utilization of tailings for its industrialization.

Hydrochemical Anomalies in the Vicinity of the Abandoned Molybdenum Ores Processing Tailings in a Permafrost Region (Shahtama, Transbaikal Region)

The mobility of chemical elements during the transition from molybdenum ore processing waste to aqueous solutions and the hydrochemical anomalies of a number of elements in surface and underground waters in the vicinity of an abandoned tailings dump were investigated. It is shown that alkaline and alkaline earth metals have high mobility—the main rock-forming components (sodium, lithium, magnesium, strontium), which are released into solution due to leaching from the minerals of the host rocks, as well as metals with zinc, cadmium, manganese, and nickel, which are released into solution due to the dissolution of ore sulfides. Elements with high mobility include Sb, Co, Cu, Be, Se, and Tl. Medium mobility has As, an element of the first hazard class, as well as Mo, Fe, and Pb. Hydrochemical anomalies of cadmium, arsenic, molybdenum, and lead have been determined. The nature of the arsenic and molybdenum anomalies is most likely related to the regional background, while the source of cadmium and lead is most likely the waste studied. The main chemical forms of the presence of elements in the solution of ponds on the surface of tailings ponds are free-ion and sulfate complexes. For example, in the samples of the Shakhtama River and groundwater, we found carbonate, bicarbonate, and hydroxide complexes. The information obtained should be taken into account when planning measures for the purification of surface and groundwater from metals. Additional studies should consider using groundwater in the vicinity of the tailings for drinking water supply.

Literature Review: Comparison of Caron Process and RKEF On The Processing of Nickel Laterite Ore For Battery

Indonesia has abundant resources, especially in natural resources (SDA), one of which is nickel. Nickel is a metal that is loved by many people because of the rapid development of technology in creating electric transportation, in particular, the application of nickel is one of the batteries. Nickel resources in the world are available in the form of Nickel Oxide as much as 60% and the remaining 40% is available in the form of sulfide reserves. Currently, there are 2 extraction methods, namely hydrometallurgy (Caron Process) and pyrometallurgy (Rotary Kiln Electric Furnace). Hydrometallurgy is a process used for nickel ore that has a grade of &lt; 1.5%, while pyrometallurgy is still used for nickel ore that has a Ni content of &lt; 3%. At present, the most common hydrometallurgical process is applied to limonite nickel ore. While the extraction process in pyrometallurgy uses saprolite nickel ore. Nickel metal processing, currently the best and the cheapest in terms of production costs is the hydrometallurgical process followed by the pyrometallurgical process. Using low-grade nickel is more suitable for manufacturing battery manufacture. The reason is that the Limonite Nickel reserves are more and can increase the selling value of the nickel ore. Thus, it is necessary to pay attention to the development in the processing process to increase the purity of the nickel-metal itself.

STUDY OF WATER ABSORPTION OF GEOPOLYMER MATERIALS BASED ON IRON ORE ENRICHMENT TAILINGS

As you know, the problem of environmental safety is important in the process of mining and processing of ore and non-metallic minerals. In the process of primary processing of ore minerals, the so-called enrichment tailings or production wastes are formed. The resulting waste accumulates in huge quantities, contributing to changes in the landscape and worsening the hydrogeological and sanitary conditions of the environment. In addition, rainfall and meltwater contribute to the constant leaching of heavy metals from waste dumps, which eventually leads to the pollution of groundwater, rivers and lakes. Therefore, the important ecological task of rational disposal of mining tailings is very relevant around the world. Research aimed at developing and obtaining new materials on the basis of this waste is of the greatest interest. One of such directions is the utilization (immobilization) of mining tailings when obtaining of geopolymer materials, which eliminates the leaching of heavy metals from the volume of the obtained material. Over the past 60 years, millions of tons of enrichment tailings have accumulated at the Dashkesan iron ore deposit, which are waiting to be disposed of. For this reason, the tailings of Dashkesan iron ore enrichment were used as a mineral filler for producing geopolymer material. Mineralogical and chemical compositions of enrichment tailings were studied using X-ray phase and X-ray fluorescence methods. Water absorption of the obtained specimens of geopolymer material was researched in accordance with the known methodology. It was revealed that with the increase of mineral filler content from 60 to 90%wt. the value of water absorption of geopolymer material specimens in the first five minutes of exposure increased from 1 to 10,2%, respectively. With the increase of mineral filler content from 60 to 90%wt. the maximum value of water absorption increases from 2,6 to 10,2%, respectively. Keywords: geopolymer, water absorption, enrichment tailings, iron ore.

Combined microflotation effects in polymetallic ores beneficiation

Producing of heterogeneous concentrates with good recovery in the processing of polymetallic ores is a challenge. Many factors must be taken into account including ore grinding, reagent mode, water composition, pulp density and the volume of supplied bubbles when producing high-quality selective concentrates. Microbubbles smaller than 50 μm in size were produced based on the frother oxal T-92 at different concentrations using a generator. The most optimal number of microbubbles smaller than 50 µm was produced at a T-92 concentration of 0.5 g/dm3. Polymetallic ore of Kazakhstan deposit was used for flotation studies. The studies were conducted in the copper-lead rough concentrate producing cycle. Flotation active minerals chalcopyrite and galena pass into the foam product, while sphalerite and pyrite remain in the chamber product in this cycle. In this paper, the density of pulp (20, 30 and 50%) as one of the main factors that effects the selectivity of flotation is studied. The kinetics of ore flotation in the base mode and with the use of a microbubble generator has been studied at these densities. Test experiments have been performed at the optimum density. The use of a water–air microemulsion generator makes it possible to maintain the quality of the copper-lead concentrate and increase the extraction of copper into the rough concentrate by 7.41%, lead by 5.98%.