Prospects for using waste generated at “Ferganaazot” JSC as a filler in the production of gypsum dry construction mixtures

“Развитие науки и технологий” Научно–технический журнал №2/2025 78 Кимё ва кимёвий технологиялар Various types of waste are generated in various production processes of the economy. These wastes cause a number of ecological harms to the environment. In particular, the main part of solid household waste in the “Ferganaazot” joint-stock company is generated in water softening workshops and in the ammonia production process, in particular, at the stages of alkali recovery. Their volume is about 6 thousand tons per year (Fig.1)[1,2]. Gypsum decorative materials, in addition to providing aesthetic pleasure, must also comply with GOST requirements in terms of composition and quality. Gypsum-based binders are distinguished by a number of properties compared to other binders. These binders have a number of advantages over local fillers produced in the construction industry of the Republic. In particular, they are inexpensive and aimed at solving environmental problems. Mixtures with optimal composition help to increase productivity in the plastering process. The composition of the mixtures is selected depending on the purpose of their use. In addition to binders, fillers (mineral fillers, industrial waste), as well as plasticizers, retarders, accelerators, moisture retainers, air entraining agents, foaming agents, etc. can be included in the mixture. These components are added to the mixture in a certain sequence and tested in accordance with standard requirements [3]. Method. Mixing gypsum with fillers helps to obtain a stable building material. In addition, the addition of plasticizers to the mixture improves the properties of the mixture, which makes it easier to use and has a positive effect on its strength. GOST 31356-2007 - Gypsum mixtures. Technical specifications This standard establishes the requirements for the composition, properties and characteristics of dry mixtures based on gypsum. It establishes the technical specifications that must be met when producing gypsum mixtures and using them in construction. These specifications include: Types of gypsum mixtures. Requirements for the raw materials used. Physical and chemical properties. Safety and environmental issues. GOST 31376-2008 - Gypsum mixtures. Preparation and testing methods.This standard covers the process of preparing gypsum mixtures, including mixing, adjusting and drying. It provides for the following: The production process follows a single technique for consistency. Test methods are standardized to determine the properties of the mixtures during and after preparation. All necessary conditions (such as temperature, humidity and mixing ratio) are controlled during preparation. Fig.1.Waste area generated by “Ferganaazot” JSC “Фан ва технологиялар тараққиёти” Илмий–техникавий журнал №2/2025 79 Химия и химические технологии GOST 23789-2018 - Gypsum mixtures. Physical and mechanical properties. Test methods are given. This standard specifies methods for testing the physical and mechanical properties of gypsum mixtures. It covers: Compressive strength. Flexural strength. Water resistance. Hardening properties and other mechanical properties affecting the performance of gypsum in various construction applications. This standard is essential for assessing the suitability of gypsum mixtures for use in construction. GOST 31376-2008 - Gypsum mixtures. Preparation and inspection methods. This standard addresses the process of preparing gypsum mixtures, including mixing, adjusting and drying processes. It provides for: The production process follows a single technique for consistency. Test methods are standardized to determine the properties of the mixtures during and after preparation. All necessary conditions (such as temperature, humidity and mixing ratio) are controlled during preparation. These GOSTs collectively regulate the entire process, from the creation of gypsum mixtures, to their testing and ensuring compliance with the standards required for use in construction. They are aimed at guaranteeing the reliability, safety and performance of the mixtures in construction applications [4-6]. These standards include all the necessary parameters to ensure the high quality of gypsum mixtures and verify their suitability for long-term use. Results and discussion. It is necessary to study, analyze and determine the chemical composition of microfillers included in the gypsum mixture. Spectral analysis of these wastes was carried out using a high-performance energy dispersive X-ray fluorescence spectrometer (Japan), Rigaku NEX CG EDXRF polarization analyzer - 9022 19 000 0 (Fig. 2). Fig 2. Chemical and spectral analysis table of the waste slurry. “Развитие науки и технологий” Научно–технический журнал №2/2025 80 Кимё ва кимёвий технологиялар Various fillers can be used with gypsum binders. The chemical composition of these fillers must meet the requirements of GOST 8736-2014 and GOST 8735 - 88 and must not affect the quality of the product. The chemical composition of the fillers must not adversely affect the quality of the product. The IR spectrum of technogenic waste was recorded using a Shimadzu IRSpirit Fourier Transform infrared spectrophotometer QATR-S (REFLECTION ATR ACCESSORY) spectrometer (Fig. 3) [7]. Fig 3. Infrared spectral analysis of technogenic Spectra of technogenic waste (1) and CaCO3 (2). The above analyses and conducted chemical tests have shown that the main composition of the waste consists of calcium and magnesium carbonates. This justifies the possibility of using this solid waste as a filler in the preparation of gypsum mixtures for construction materials. The waste is first dried and ground to a constant mass. The degree of dispersion (GOST 8735-88) is determined by passing the material through sieves of various sizes to identify its average dispersion[8]. Fig. 4 below presents data on the size analysis of dispersed particles. 0 10 20 30 40 50 60 Amount, % 1250 630 315 160 71 ≤50 Fig 4. Size of Dispersion Particles of Carbonate Solid Waste Slurry, µm Based on the data in Fig. 4 above, the average dispersion level of the carbonate compound was determined. The dispersion level of the waste can be further improved by special processing, which means that the degree of fineness can be achieved to any desired size. Gypsum (GOST 125-2018) is widely used in the construction industry worldwide. During application, it hardens to its original shape in a short time (3-7 minutes) [9]. This prevents the preparation of large quantities of mixtures and leads to a decrease in work efficiency. Various retarders are used to control the setting time. To extend the setting time of the mixture, citric acid (GOST 908-2004) is mixed in various proportions. The effect of citric acid in various proportions relative to the binder on the initial setting time of the mixture is presented in the table below (Table 1). “Фан ва технологиялар тараққиёти” Илмий–техникавий журнал №2/2025 81 Химия и химические технологии Table 1 Adjusting the Setting Time of the Mixture by Using Plasticizers in Different Proportions Amount of Citric Acid (%) 0 0,1 0,2 0,3 0,5 Initial Setting Time (min) 4-6 15 30 50 480 The analyses show that various additives in the studied carbonate waste do not significantly affect the quality indicators of gypsum mixtures in the preparation of their composition. Thus, the waste generated at the Ferganaazot joint-stock company can be fully used as a filler in the composition of gypsum-based mixtures. Carbonate minerals, in addition, do not significantly affect the physical and mechanical properties of gypsum and help improve the quality of the mixtures within the framework of accepted standards. Conclusion. Overall, this study has revealed the potential for the preparation of effective gypsum mixtures by carefully studying the composition and physical and mechanical properties of waste sludge. Material analysis during the preparation of gypsum-based mixtures is crucial for ensuring material quality and optimizing production processes. The composition of waste sludge, its dispersion level, and production processes are key steps in the production of gypsum-based dry construction mixtures. This scientific research opens up new avenues for material processing and the production of building materials, while expanding the scope of environmentally friendly materials production