The possibility of producing cement clinker using low-energy, resource-saving technologies is studied. The composition of industrial waste for low-energy-intensive production of Portland cement clinker at factories in Southern Kazakhstan is analyzed. The possibility of replacing the deficient iron-containing corrective additive with “Waelz clinker for zinc ores” is shown. “Waeltz clinker from zinc ores” as part of the raw material charge performs several tasks: it is a ferrous corrective additive, works as a mineralizer for clinker formation processes, introduces coal into the charge and allows one to reduce the consumption of natural fuel. The processes of burning raw mixtures, wholly or partially consisting of industrial waste, are completed at 1350 °C. This reduces the consumption of main burner fuel for clinker burning and reduces CO₂ emissions into the atmosphere. High-quality cement clinker is obtained based on raw material mixtures with Waeltz clinker from zinc ores from the Achisai Metallurgical Plant, phosphorus slag, coal mining waste from Lenger mines and sodium fluoride. The phase composition and microstructure of low-energy clinkers are revealed. Involving industrial waste in raw material circulation will reduce environmental pollution and improve the environment.

In this article, thermodynamic studies of modeling the formation of the main minerals of cement clinker as a function of the Gibbs energy (ΔG) on temperature were investigated. The temperature range of the studies was 873-1873 K. In the course of modeling studies, the reactions of formation of cement clinker minerals (C2S - belite, C3S - alite, C3A – three calcium aluminates, C4AF – four calcium aluminium ferrite) from standard raw materials and non – standard-technogenic raw materials containing non-ferrous metals were calculated. Equations describing the dependence of the Gibbs energy on temperature with approximation coefficients (R2) equal to 0.99 are found. According to the results of the conducted studies, the beginning (Tb) temperatures of the course of the compared clinker formation reactions were determined, which were 1008 K for the standard reaction, and 1023 K for the non-standard reaction. It was found that the reactions begin to occur in the temperature intervals for the standard (1008 K – 1873 K), for the non - standard (1023 K - 1873 K). At the same time, the values at the initial stage of the course of the standard reaction have a more negative value of the Gibbs energy than the non-standard reaction. With a further increase in temperature, it becomes evident that the Gibbs energy of the non-standard reaction of mineral formation in the temperature range 1173-1873K becomes more negative in comparison with the values of the standard reaction and exceeds its values from 9 to 19.01%.

The main problem of cement production is to reduce energy consumption and reduce the amount of greenhouse gases CO2 emitted into the atmosphere. The prerequisite for solving the problem is: the use of man-made waste and unconventional raw materials in the composition of the charge and the reduction of limestone content from 85% to 70-75% as a source of CO2 gas. The article presents the results of the studied technogenic waste and the suitability of non-traditional raw materials such as tefritobazalt, coal mining waste, and lead slag. The chemical and mineralogical composition of the materials and their suitability for obtaining environmentally friendly clinker have been established. The possibility of obtaining cement clinker using low-energy resource-saving technologies is shown. Clinker formation processes in the developed mixtures are completed at a temperature of 1350 °C, which, with the coal contained in the waste, will reduce the consumption of fuel injectors and reduce CO2 emissions into the atmosphere. In the developed low-energy mixtures, the specific consumption of raw materials for obtaining 1 ton of clinker is reduced to 1516-1525 kg, which is significantly lower than in traditional raw mixtures. Alite crystals are large, reaching 100-140 microns. The content of clinker minerals is C3S-57.88%, C2S-18.82%, C3A-6.46% and C4AF-11.61%. Disposal of large-tonnage waste will reduce environmental pollution and improve the environmental situation in the region.

The potential for creating composite cements by incorporating fly ash is demonstrated. Analysis revealed that the fly ash examined consists of 69.66 wt. % silicon oxide, 21.34 wt. % aluminum oxide, 1.57 wt. % calcium oxide and 2.78 wt. % iron oxide. Fly ash mainly consists of quartz (SiO₂), goethite (FeO(OH)) and mullite (3Al₂O₃·2SiO₂). The properties of the cement composition containing 5 to 25 wt. % fly ash were studied. Incorporating fly ash enhances system dispersion, promotes mixture uniformity, and stimulates the pozzolanic reaction. Compositions of composite cements consisting of 90% CEM I 42.5 and 10% fly ash were developed. The cement stone based on the obtained composite cement had a compacted structure with a density of 2.160 g/cm³, which is 9.4% higher than the control sample. It is shown that when composite cement containing 10% fly ash interacts with water, hydration reactions of cement minerals (C₃S, C₂S, C₃A and C₄AF) begin first. This is accompanied by the formation of hydrate neoplasms, such as calcium hydroxide (Ca(OH)₂) and calcium hydrosilicates (C-S-H). Fly ash particles containing amorphous silica progressively participate in a pozzolanic reaction with Ca(OH)₂, leading to the formation of additional calcium hydrosilicates phases. This process enhances structural densification and reduces the porosity of the cement matrix. After 28 days of curing, the compressive strength of the resulting composite cements ranged from 42.1 to 54.2 MPa, aligning with the strength classes 32.5 and 42.5 as specified by GOST 31108-2020.

The feasibility of producing high-quality zinc phosphate cement based on a frit-sintered mixture of ZnO, SiO₂, MgO, and Bi₂O₃ oxides, with the addition of phosphorous slag and an aqueous solution of orthophosphoric acid as the mixing liquid, was demonstrated. The raw materials used for zinc phosphate cement preparation were investigated using various physicochemical analysis methods. It was found that the phosphorous slag contains silicon oxide (37.6%), aluminum oxide (4.49%), calcium oxide (42.4%), magnesium oxide (2.19%), as well as fluorine (1.94%) and calcium fluoride (4.91%). The slag predominantly consists of an amorphous glassy phase with minor inclusions of crystalline components. During the sintering process, the addition of 1.5–3.0 wt.% phosphorous slag to the frit promotes the formation of low-melting eutectics due to the presence of fluorides, resulting in a 100 °C reduction in the sintering temperature. An optimal zinc phosphate cement powder composition was developed, comprising: ZnO—83.0%, MgO—9.0%, SiO₂—3.5%, Bi₂O₃—3.0%, and phosphorous slag—1.5%. The resulting sintered product exhibited a whiteness of 97.8%, which exceeds that of the reference sample by 2.6%. Upon mixing the powder with the mixing liquid, zinc ions are released first, initiating a chemical reaction that leads to the formation of zinc, magnesium, and aluminum phosphates. The compressive strength of the resulting composite cements ranged from 101.8 to 111.9 MPa, fully complying with the requirements for cement grade as specified in GOST 31578-2012.