Kompleksnoe Ispolzovanie Mineralnogo Syra = Complex use of mineral resources

Influence of additives and temperature regime on the setting kinetics and strength of foamed concrete

2025-03-20T06:06:12+00:00

The article presents the results of the development of the physico-mechanical characteristics of fast-setting lightweight concrete. Based on the obtained data, it was concluded that the use of metal cassette molds in foam concrete technology is ineffective. Their turnover can be increased by heating the floor in the workshop and insulating the sides and surfaces of the molds. However, the high cost of energy carriers increases the material's production cost and reduces its competitiveness. At ambient temperatures below 16 °C, it is advisable to use insulated wooden molds, which help retain the heat released during cement hydration. The optimal mold dimensions (1.2 × 1.25 × 0.5 m and 1.2 × 1.25 × 0.6 m) were selected based on cutting technology capabilities. The formation of large monolithic masses is associated with the risk of cracks and even structural rupture due to uneven heat distribution. To maintain the initial mix temperature within 22 – 25 °C, the molding mixture should be prepared using water heated to 30 °C. In insulated wooden molds, the formed material retains a temperature of at least 18 – 20 °C before the onset of hydration. Then, due to the exothermic reaction of cement, the temperature remains stable until demolding. Improvements in natural-setting foam concrete technology have demonstrated the feasibility of introducing a chemically active siliceous component into the mixture. This component binds free Ca(OH)₂ released during alite hydration, contributing to long-term strength development. Research objective – The development of effective methods to accelerate the early-stage hardening of foamed concrete by studying the influence of electrolyte additives and surfactants on the setting and hardening processes of cement paste. The novelty of work lies in establishing patterns in the formation of physical and mechanical properties of foamed concrete with accelerated initial hardening, taking into account its porous structure, and the characteristics of the hardening process.

The effect of halite mineral impurities on the technological parameters of the sodium chloride production process

2025-07-30T11:10:38+00:00

This paper shows the findings of a detailed investigation of the natural halite from the Bakhyt-Tany deposit. The mineral’s composition is sodium chloride with the addition of calcium sulfate, magnesium salts, and some other matters, including a residue of less than 2% insoluble residue. Elemental assaying indicates the occurrence of elements like Ca, Mg, Al, Si, Fe, and Pb, which points to the occurrence of clay and some sulfate impurities. To understand how impurities are distributed in different sizes, a sample was classified using a sieve with a mesh of 0.2 mm. It was discovered that less than twenty per cent of the salt mass is a fine fraction (d < 0.2 mm), where up to 3.4% of insoluble impurities are found, and in the coarse fraction (d > 0.2 mm), this value is less than 1.8%. A mathematical model developed showed that the fine fraction and the total amount of the residue insoluble are directly related, which supports its use for estimating contamination and evaluating the effectiveness of the processes of desalination. Moreover, the generated 3D model revealed that temperature and humidity, in addition to raising the concentration of insoluble impurities, also increase the concentration of such impurities in the fine fraction even more. The results obtained also support the need for the pre-purification of halite before its use in food and other technological applications, and support the statement of the fractionation and desalination based purification process for halite.

Development of environmentally sustainable cement compositions based on processed ceramic waste

2025-07-08T05:49:15+00:00

One of the major challenges in the modern construction materials industry is the development of environmentally sustainable, energy-efficient, and economically viable materials. This study investigates the production of composite cement compositions by partially replacing Portland cement clinker with recycled ceramic brick waste (CBW). The primary objective is to reduce carbon dioxide (CO₂) emissions during cement manufacturing by utilising secondary raw materials with pozzolanic and filler properties. The experimental program encompasses a comprehensive analysis of the chemical, mineralogical, and structural characteristics of CBW, as well as its impact on the hydration process and the mechanical properties of cement composites. The clinker was partially replaced with CBW at 15% and 20% by mass in the binder component. Mechanical strength tests (flexural and compressive) were conducted at 2, 7, and 28 days of curing. Additionally, phase composition was analysed by X-ray diffraction (XRD), and microstructural development was evaluated using scanning electron microscopy (SEM). The results show that replacing clinker with CBW improves the microstructural compactness of the hardened matrix and ensures comparable mechanical performance after 28 days. A Life Cycle Assessment (LCA) confirmed that this approach can reduce CO₂ emissions by approximately 15–25% compared to conventional cement. The scientific novelty lies in the combined pozzolanic and micro-filler role of CBW, enabling its use as a supplementary cementitious material in low-carbon binder systems. The findings support the development of sustainable technologies for the cement industry and promote the circular economy through the utilisation of industrial waste.

Main characteristics of quartz-feldspar sands from the Khiva deposit, and the physico-chemical and technological fundamentals of obtaining an enriched concentrate

2025-07-21T10:59:54+00:00

This research presents studies on the beneficiation and application of quartz-feldspar sands from the “Khiva deposit” located in the Khorezm region of the Republic of Uzbekistan for the silicate industry. The composition of raw material samples was analysed using modern X-ray diffraction and IR spectroscopic methods. Based on the results, the quantitative mineralogical composition of the samples was determined using the BGMN/Profex Rietveld software package. According to the obtained data, the average chemical composition of the raw material (in wt.%) was determined as follows: SiO₂ – 86.06; Al₂O₃ – 2.64; Fe₂O₃ – 1.37; CaO – 1.37; MgO – 0.22; K₂O – 1.30; Na₂O – 1.85; TiO₂ – 0.04; SO₃ – 0.4, with a loss on ignition of 4.93. The beneficiation processes of the raw material were studied. Based on the specific characteristics of the composition, it was found appropriate in subsequent studies to apply combinations of beneficiation methods such as washing, gravity separation, classification, attrition scrubbing, electromagnetic separation, and flotation. As a result, it was determined that the SiO₂ content in the beneficiated concentrate increased from 86.06% to 97.07%, while Al₂O₃ decreased from 2.64% to 1.06%, and Fe₂O₃ from 1.37% to 0.05%.

Effect of multicomponent mineral additives on the microstructure and strength of composite cement

2025-08-28T09:40:15+00:00

In the face of growing environmental and energy challenges, the cement industry is shifting towards the use of composite Portland cements containing hybrid mineral additives to reduce clinker consumption and CO₂ emissions. This study investigates the pozzolanic activity and hydration behavior of thermally activated aluminosilicate additives (TAFM), quartz-feldspar sand, apobasalt-orthoshale (APO), and limestone. The chemical composition and calcium oxide binding capacity of each component were examined using the lime saturation method. Results showed that TAFM exhibits the highest pozzolanic reactivity, significantly binding free lime (CaO), followed by APO and limestone. Composite cement mixtures were formulated according to GOST 31108–2020 standards, incorporating 20% hybrid additives. Mechanical tests revealed that such compositions improve long-term compressive and flexural strength, early setting times, and structural density. In particular, the combination of TAFM, APO, and limestone showed synergistic effects in enhancing hydration kinetics and final performance. The findings support the feasibility of using local mineral resources as effective components in sustainable cement production and highlight the benefits of hybrid additives in reducing clinker demand while improving mechanical and durability characteristics of cementitious composites.

To the question of pyrometallurgical technology for processing antimony-gold-bearing ores and concentrates

2025-06-03T05:52:39+00:00

The increasing demand for non-ferrous, precious, and rare metals necessitates more comprehensive and efficient use of mineral raw materials, such as gold-antimony ores and concentrates. A promising approach is the use of pyrometallurgical processing in a fluidized bed, which offers more efficient heat and mass transfer than conventional technologies. This study aims to investigate the evaporation kinetics of antimony sulfide (Sb₂S₃) from gold-antimony ores and concentrates in a fluidized bed under various conditions. The experiments involved varying temperature (923-1223 K), particle size (0.09-2.0 mm), and layer thickness (5-15 mm) to determine the evaporation rate of Sb₂S₃. The experimental setup consisted of a laboratory-scale fluidized bed reactor equipped with a controlled gas flow of nitrogen mixed with sulfur vapor. The evaporation rates were measured using a gravimetric method and confirmed by X-ray diffraction and microscopic analysis of samples. The results show that the evaporation rate of Sb₂S₃ in a fluidized bed is 7-9 times higher than in a fixed bed. This is due to significantly improved heat and mass transfer in the fluidized system. At 1023 K, the overall evaporation rate increased with decreasing grain size. This is associated with an increase in the total surface area of the material, but the specific evaporation rate normalized to unit surface area was independent of particle size. The process was not significantly affected by bed height in the range of 5-15 mm. Antimony recovery into sublimates improved by 2-3% compared to conventional technology. It reached 98-99% due to suppression of Sb₂O₅ formation. These findings confirm the efficiency of supplying an inert gas with sulfur vapors into the fluidized bed. This reduces harmful gas emissions and minimizes dust entrainment. It also allows for effective distillation of volatile components at lower temperatures.

Sorption Concentration of Uranium and Vanadium from Productive Solutions of Black Shale Ores

2025-09-03T06:47:37+00:00

This study examines the sorption and desorption processes of uranium and vanadium from acidic solutions produced during the processing of black shale ores in Southern Kazakhstan. Such ores are considered unconventional sources of strategic metals and are of particular interest under the conditions of limited traditional mineral resources. To evaluate efficiency, several anion-exchange resins (AMP, AV-17, A-140, and Amberlite) were tested, allowing a comparative analysis of their sorption capacity and selectivity. The AMP resin demonstrated the most favorable performance, providing high uranium uptake and satisfactory vanadium recovery in sulfuric acid media. Desorption experiments confirmed the possibility of efficient uranium transfer into the eluate, which is of great importance for subsequent concentration and purification stages. Vanadium recovery was limited due to the coexistence of different ionic forms of the element. The obtained results confirm the potential of sorption technology as a reliable stage for uranium concentration and indicate the need to apply additional methods, such as solvent extraction or selective precipitation, to enhance the completeness of separation and recovery of the target components.

Innovative approaches to the processing of vanadium- and molybdenum-containing technogenic waste

2025-08-15T04:43:11+00:00

This article explores the consumption trends of vanadium and molybdenum across various industrial sectors, highlighting their strategic importance and the growing demand for a sustainable supply of raw materials. It analyses the sources of these elements of both natural and technogenic origin, including metallurgical slags, ashes, spent catalysts, and other industrial waste products. Particular attention is given to the environmental risks associated with the accumulation of vanadium and molybdenum compounds, which can have toxic effects on the environment. The study emphasises the need to incorporate secondary resources into industrial circulation to ensure the rational use of the mineral resource base and improve the efficiency of metal extraction from primary raw materials. A review is provided of existing chemical and hydrometallurgical methods for extracting vanadium and molybdenum, taking into account the composition of the processed material, technological conditions, and the limitations of specific approaches. The article underscores the potential of integrated waste processing, which enables the recovery of multiple valuable components and supports the transition to a circular economy.

Pyrolysis of copper telluride in a water vapour atmosphere

2025-09-22T07:36:41+00:00

This paper presents the results of exploratory studies on the feasibility of extracting tellurium from synthetic copper telluride and industrial tellurium–containing middlings using a vacuum-thermal method conducted in a water vapour atmosphere. It was determined that the thermal behavior of synthetic copper telluride follows an oxidation mechanism involving oxygen in a dry environment. The phase transformations occurring in the tellurium–containing industrial middlings are also comparable to those observed during oxidative-distillation roasting and vacuum-thermal processing in an inert atmosphere. The achieved degrees of extraction of copper telluride and tellurium-containing industrial middlings at a temperature of 1100 °C and a pressure of 1.3-2 kPa were 57.83 % and 94.89 %, respectively. The obtained residues are represented by copper oxide phases. At the same time, tellurium evaporates from the material and deposits on the walls of the condenser in the cold part of the reactor at temperatures below 400 °C. According to X-ray phase analysis, the condensate is represented by tellurium in the form of oxide.

Effect of Complex Alloying on the Phase Composition and Thermal Characteristics of Al–Fe–Si Aluminum Alloys

2025-09-25T10:36:23+00:00

This study presents a comprehensive analysis of phase formation in Al–Fe–Si aluminum alloys with the addition of ten industrially significant alloying elements (Mg, Cu, Ni, Mn, Cr, Zn, Ti, Zr, V, Be), performed using thermodynamic modeling via the Thermo-Calc software package. Phase formation was investigated and compared in a commercial alloy (Al98–Fe1–Si1) and an intermetallic alloy (Al60–Fe33–Si7) under both individual and synergistic alloying conditions. The thermal characteristics (liquidus, solidus, and α- and β-transformations) and phase constituents were analyzed across a broad temperature range (0–1200 °C). It was found that the alloying elements exert diverse effects on phase stability and alloy structure, with intermetallic systems exhibiting greater thermal stability. Particular attention was given to the formation of the matrix phase and the influence of synergistic alloying on phase equilibria and the potential emergence of new stable compounds. The results provide a basis for targeted alloy design, including the use of secondary aluminum, to develop materials with tailored properties for transportation and mechanical engineering applications.

Experimental Study on Dry Magnetic Separation of Kharganat Iron Ore

2025-08-20T10:19:05+00:00

A sample of iron ore from the Kharganat deposit was crushed to under 3 mm and subjected to dry magnetic separation, yielding a concentrate with 60.28% iron content and 98.92% metal recovery. When the sample was further crushed to under 1 mm and reprocessed, a concentrate with 66.7% iron content and 95.88% metal recovery was obtained. Through wet magnetic separation, a concentrate with 67.71% iron content and 96.9% metal recovery was produced. The tests confirmed that the most effective method was wet separation after crushing to under 1 mm and grinding for 40 minutes. In terms of beneficiation technology for the deposit, two process schemes—dry and wet magnetic separation—were developed. It was recommended that dry beneficiation be used in production instead of the water-intensive wet method. The sulfur and phosphorus content in the technological samples met standard requirements. Both previous studies and new exploration results were used in the resource estimation. It was confirmed that using a 10% cutoff grade for resource calculation is economically efficient. The minimum thickness of ore bodies was set at 2.0 meters, and the maximum thickness of waste rock at 4.0 meters. Resources were classified into Measured (B), Indicated (C), and Inferred (P1) categories. The geological structure of the deposit is simple, with a stable ore body distribution. The ore body thickness ranges from 5 to 40 meters, with an average of 23 meters. The deposit is suitable for open-pit mining, and no water drainage issues are expected in the initial years. It is planned to build an open-pit mine with an annual capacity of 500,000 tons of ore, with the cost of mining one ton of ore estimated at 4,312.8 MNT.

A study of the geochemical features of the Nurkazgan copper-porphyry deposit

2025-07-15T10:10:33+00:00

Porphyry copper deposits are the source of most of the world's copper, molybdenum and significant amounts of gold. This makes them a major focus of scientific research due to their economic significance. The article is devoted to the study of the geochemistry of host rocks and copper-porphyry ores at the Nurkazgan deposit. It identifies geochemical criteria for the distribution of gold in copper‑porphyry systems, as well as refines ore formation mechanisms in order to improve predictive criteria. The results were obtained by interpreting analytical data obtained using the ICP-OES (ICP-AES) method and the geostatistical method. Based on this research, key factors have been identified that determine the distribution of element content. As a result of studying the distribution of REEs in the host rocks, conditions for ore formation were established: the deposit has an igneous origin with signs of prolonged fractionation of the magma; a negative Eu anomaly confirms the involvement of plagioclase fractionation typical of medium and acidic magmas; LREE enrichment indicates an evolved magma involving the continental crust, while moderate depletion of HREE indicates a deep source of magmatism with residual garnet involvement. The established strong positive correlation between REES indicates a single geochemical process and reflects the primary magmatic identity. A porphyry system with a deep magmatic source has been revealed, where ore fluids are separated from the residual melt, which is already depleted in Eu but enriched in LREEs and metals.