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Makhmudova Nadyrakhon Abdukadirovna, Candidate of Technical Sciences, Associate Professor Tashkent Architecture and Construction Institute, Nauryzbaev Azamat Sharipbaevich, Assistant Lecturer, Karakalpak State University named after Berdak Makhmudov Bakhtiyor Mamurovich, Tashkent Architecture and Construction Institute,
Tashkent, Uzbekistan E-mail: shavkat-19912070@umail.uz
TECHNOLOGY OF OBTAINING SILICATE MATERIALS AND PRODUCTS BASED ON MINERAL RAW MATERIALS AND PRODUCTION WASTE
Abstract: Development of technology for obtaining autoclave-silicate materials and products based on mineral raw materials and production wastes in the Republic of Karakalpakstanis considered in the paper.
Keywords: raw mix, ceramic bricks, use of local raw materials, lime-slag, lime-cement, lime-belite.
At the present stage of economic and social development of the Republic of Uzbekistan, the issue of the complex use of local raw materials, the development of environmentally friendly, energy - and resource-saving highly-effective technologies for the production ofbuild-ing materials is of great importance.
Rapidly growing rates of industrial and housing construction require the growth of production of building materials and products, including autoclave-silicate materials, the need for which has increased in recent years. The increase in transportation costs dictates the need to organize the production of building materials (including silicate materials)locally, where there is a demand for them and the availability of relevant raw materials.
Recently, a special attention is paid to the development of research in the field of chemical technology and membrane technology, as well as the creation of new structural materials, the integrated use of natural resources, which excludes harmful effects on the environment.
The production and use of Portland cement, alumina and other types ofbinders is based on the fact that the raw mix is fired at high temperature in order to obtain silicates, aluminates and calcium ferrite. The process of firing is very energy-intensive and the organization of cement production requires very high costs [1].
The building materials industry of the Republic uses only ceramic bricks as wall materials; they are produced by high-temperature firing and clays are used as raw material. Clay minerals are the main and vital components of the soil, necessary for the existence of the flora.
The development of production of these materials requires the expansion of the raw material base through the use of local raw resources. In the production of silicate autoclave materials, various binderssuch as lime, limestone-belite, limestone-slag, lime-cement, etc., are used as a binder.
Technology for obtaining autoclave-silicate materials and products based on mineral raw materials and production wastes is developing in the Republic of Kara-kalpakstan.
Objectives of the study:
- Physical-chemical substantiation and development of highly effective technology for obtaining autoclave silicate materials with increased physical and mechanical properties of special purpose on the basis of local raw materials;
- Analysis of the current state of the matter in the field of structure formation and hydration of binder materials under hydrothermal conditions of setting.
The introduction of autoclave silicate materials on the basis of limestone-belite binders will bring huge
Section 7. Technical sciences
economic benefits, as currently the building materials are mainly producedfrom relatively expensive and not easily accessible Portland cement. The cost of silicate products will be 30-40% lower than the cost of products made of cement concrete.
Accordingly, the development of environmentally friendly, resource-saving, highly efficient technologies for the production of building materials based on barkhan (crescentic dunes)sands and waste products of the Republic is very relevant.
Improvement of the production of lime-and-sand brick is based on the achievements of domestic scientists who conduct research to identify the nature and laws of physical and chemical processes to improve technology and quality of lime-and-sand bricks. This makes it possible to create a theoretical basis for further improvement of the technology of autoclave materials [2].
Study of physical-chemical and physical-mechanical properties of carbonate minerals in the Ustyurt deposit shows that the rockconsists mainly of calcareous and marly minerals based on calcium carbonate CaCO3.
The chemical-mineralogical composition of the Ustyurt carbonate-argillaceous rocks of the explored deposits is a mixture of calcium and magnesium carbonates, silica and alumina compounds (in the form of clay particles), some calcium sulfate in the form of gypsum, a small amount of soluble salts of sulfuric and hydrochloric acids.
Physical and chemical characteristics of the carbonate-clay rocks of the Ustyurt plateau testify to the
Table 1. - Results of physical researc
possibility of their use for the production of various binders for building materials: air lime, construction lime, limestone-belite binder, water lime and Roman cement.
The kinetics of hydration structure formation was judged by the change in plastic strength (Pm) of the system measured on a Geppler consistometer.
The study of HS processeshydration structure formationin concentrated limestone-belite binders pastes makes it possible to reveal the role of the nature of the hydrated phase in the kinetics of strength formation and its creation in originated spatial structure.
The nature ofkinetic changes in plastic strength of the system at B/T = 0.90 differs from the nature of change in strength of the system at B/T = 1.0 and B/T = 1.2; plastic strength first increases, then, after three days of exposureof the system, falls sharply, followed by a second sharp increase after 14 days. At other B/T ratios, a sharp increase in the strength of the system after 14 days has also been observed.
From the data presented, it can be seen that the water demand of the limestone-belite binders, obtained on the basis of studied marls is greater than that of Portland cement or gypsum. This is due to the fact that free calcium oxide CaO (58.24 and 50,30%) is present in large amounts in the composition of the IPMlime-stone-belite binders, together with belite (8 - C2S), which, when hydrated with a high water requirement, passes into calcium oxidehydrate.
;s of limestone-belite binders pastes
№ limestone-belite binderson the basis of marlsdeposit Normal den-sity,% Time of setting, min. Specific surface, cm 2/g
beginning end
1. Porlytau 90 48 131 3200
2. Porlytau 90 46 144 3500
Table 1 shows the dependence of mechanical conditions of moisture-air and thermal-moist setting, strength of the limestone-belite binders samples on the the mechanical strength of the specimens increases with time of setting. As can be seen from the table, both in time; its greatest value takes place after 28 days. Table 2. - Results of the study of mechanical strength under compression of samples of limestone-belite binders in conditions of moisture-air and thermal-moist setting
№ HEB on the basis of marls, deposit B/T Compressive strength, MPa
moisture-air setting thermal-moist setting
3 days 7 days 28 days 3 days 7 days 28 days
1. Porlytau 0.90 0.98 2.83 7.35 4.05 6.40 14.26
2. Porlytau 0.90 1.86 4.77 9.41 4.30 7.81 14.53
Thus, the processeshydration structure formation in the variances of the limestone-belite bindersobtained on the basis of the marls of the Akburly and Porlytau deposits are characterized not only by the formation of different types of structures in the system - coagulation and crystallization ones, with the transition of the first onein-
to the second, but also by different stages of formation of the crystallization structure. On the basis of studies of physical-chemical and physical-mechanical properties of the limestone-belite binders, it can be concluded that they present an effective binding material for obtaining high-strength products of autoclave setting.
References:
1.
Abylova A.Zh., Turemuratov Sh. N., Khamraev S. S. Gypsum binders based on gypsum minerals of the Republic of Karakalpakstan // Chemicallndustry, Russia, - St. Petersburg, - 2015.
2. Abylova A.Zh., Turemuratov Sh. N., Khamraev S. S. Obtaining binders based on gypsum minerals of the Ustyurt deposit // International scientific and technical journal Chemical technology, control and management, - Tashkent, - 2015. - No. 1 (61). - P. 16-20.
