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.

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.