The article shows the prospects of using large-sized ceramic stones for modern housing construction. A review of the raw materials and technologies for their production is given. It is emphasized that the most promising technology for the large-sized ceramic stones’ production is a hard extrusion technology with the possibility of laying raw products on firing buggies and accelerated drying and firing modes. The characteristic of waste piles processing screenings in East Donbass, which are considered to be the by-products of coal mining, as the main raw material for the large-sized ceramic stones’ production is given. Their ceramic properties and results of the raw materials’ selection are given, including: screenings - 60-65%; siliceous clay - 20-30% coal sludge - 10-15%, on the basis of which it is possible to obtain the products with low cost and high strength for the load-bearing wall structures. The features of the ceramic material microstructure based on the obtained raw material mixtures with optimal porosity are noted. It is shown that the waste piles’ involvement in the process of ceramic stones production will make it possible to obtain products with a density of less than 800 kg/m3, less thermal conductivity 0,20 m·°С)/W and the brand strength M150 and above, with a minimum cost. This will create a serious competition for gas silicate products and achieve a level of ceramic stones’ use in the total volume of wall products for the housing construction of 80%, like in Western Europe.
The paper gives a general characteristic of coal refuse processing products: intermediate fractioncoal-free screenings; small fractioncarboniferous sand containing up to 30% coal; fine fractionsilt coal containing up to 50% coal. Green and baked ceramic properties of products of processing waste coal are demonstrated. Compositions of raw mixes for items with compression strength of over 10-15 MPa with a density of below 800 kg/m 3 are substantiated, with considerations for molding with semi-rigid extrusion and requirement of minimizing baking costs. Processing properties of screenings are presented as functions of material grinding and baking temperature. A process diagram has been plotted for a possible production facility using modern equipment. Technical and economic indexes are presented, showing high profitability and promising nature of manufacturing large-size structural clay tiles from the products of processing waste coal thanks to minimal prime cost of the tiles.
General description of coal dumps products processing is described: medium factional materials - screenings that do not contain carbon; kiln fractional - coal sand, coal containing up to 30%; petty factional - coal slurries, coal containing up to 50% are given. Ceramic kilns and technological properties of processing coal dumps products are given. Compositions of raw mixtures for obtaining products with a compressive strength of 10-15 MPa and density less than 800 kg / m3, and considering the fact that the molding process is carried out semi-rigid extrusion and the necessity of minimum costs for firing is defined. Depending on the technological properties of screenings, depending on the degree of grinding and firing temperature is taken into account. Flow production of modern equipment is pointed out. Technical and economic indicators showing high profitability and the prospect of large-scale production of clay tiles on the basis of coal dumps processing products due to minimal manufacturing cost are mentioned. The carried out results of the work allowed to choose the raw materials and to develop the technological scheme of production of high-performance ceramic stones with a minimum cost. Implementation of the results in practice will create a highly profitable production and make the Rostov region a major manufacturer of ceramic wall.
The general characteristic of products of processing of waste heaps is given. Their characteristics by fractional composition are proposed: large-fractional, with grains from 2 to 150 mm in size, medium-fractional with a grain size of 0.5 to 2 mm, and fine-grained with a grain size of 0 to 0.5 mm. The results of work on the study of the chemical-mineralogical composition and physico-mechanical properties of the medium-fractionation products of the waste heaps processing with reference to the production of various wall ceramics products are presented. Their role is shown as a polyfunctional additive when introduced into ceramic masses and affects the properties of finished products. A preliminary classification according to the amount of coal component, mineralogical and petrographic composition, technological properties is proposed. The feasibility of their application in the production of wall ceramics with a reduced cost is given.
The paper presents an effective scheme for studying the direct and inverse problems of identifying the delamination of the elastic layer from the base. The proposed approach is based on the problem’s asymptotic analysis, based on the assumption that the relative size of the defect is small. In the framework of the asymptotic approach, the transcendental equations for reconstructing the bundle parameters are obtained. Identification is carried out using the additional information about the amplitude values of the displacement field measured at the upper boundary of the layer. The numerical results of the restoration are presented.
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