The paper presents the results of a study of the effect of galvanic sludge on the basic performance properties of special-purpose ceramics. The basis of the composition of the charge is low-plastic clay, and the functional additives in its composition are boric acid and cerium oxide. Ceramics are produced by semi-dry pressing at a pressure of 15 MPa and a maximum firing temperature of 1050 ° C. It has been established that galvanic sludge decomposes into calcium and heavy metal oxides, carbon dioxide and water vapor during firing. The oxides formed during liquid-phase sintering are part of the vitreous phase, functionally modifying its characteristics. When the content of galvanic sludge in the charge is more than 5 wt. % a developed porous structure is formed in the material, which reduces its main operational characteristics. It was revealed that liquid-phase sintering provides safe immobilization of heavy metals if the content of galvanic sludge in the charge does not exceed 6 wt. %. Practical application of the charge composition, including galvanic sludge in an amount up to 5 wt. %, will increase the resistance of ceramics to high temperatures, temperature changes, acids and alkalis. The use of galvanic sludge in this area will contribute to solving the environmental problem of its processing.

Keywords: ceramics, heat resistance, chemical resistance, liquid phase sintering, galvanic sludge, low-plastic clay, cerium oxide, boric acid

The paper presents the results of experiments on the production of a composite material using small-lump wood waste based on soft wood varieties and waste products from non-plasticized polyvinyl chloride. An additional component of the raw material mixture was methylene chloride, in which polymer waste was dissolved. The solution was mixed with the filler, and then the solvent was pressed and removed at its boiling point. It is established that an increase in the degree of filling of the studied material contributes to the formation of a developed porous structure. The effect of increased porosity on the main operational properties, primarily thermal conductivity and water resistance, has been revealed. It is determined that the degree of filling, equal to 55 wt. %, makes it possible to obtain a material with the most effective combination of values of basic properties for use as a building thermal insulation. The practical application of the results of the work makes it possible to produce a low-cost thermal insulation material due to the joint disposal of heterogeneous waste.

Keywords: polymer composite material, thermal insulation material, polymer waste, wood waste, polyvinyl chloride, methylene chloride

The paper presents the results of research on the development of the composition of the raw mixture for the production of facing composite material for construction purposes. The composition of the raw material mixture included a brick fight as a filler, waste products from non-plasticized polyvinyl chloride as a binder and methylene chloride for dissolving polymer waste. This composition allows mixing and pressing without heating, which eliminates the possibility of destruction of the polymer component. After pressing, heat treatment is carried out at the solvent evaporation temperature. The paper shows the dependences of the main physical and mechanical characteristics of the resulting material on the degree of filling. The maximum amount of filler has been set, which allows to obtain the material without a lack of binder. With a lack of binder, a decrease in strength and an excess of the proportion of open pores over closed ones were observed. According to the results of the experiments, the polymer : solvent ratio and the degree of filling were selected, allowing to obtain a material with the maximum value of strength characteristics. Practical application of the developed composition of the raw mixture will allow complex utilization of low-demand and large-tonnage polymer and brick waste to obtain composite material for cladding buildings and structures.

Keywords: polymer composite material, facing material, polymer waste, brick fight, polyvinyl chloride, methylene chloride

The paper presents the results of studies of the characteristics of a polymer coating for the protection of steel and concrete surfaces based on low molecular weight dimethylsiloxane rubber SKTN-A. For cold curing of the binder and its modification, the MSN-7-80 hardener was used, an additional functional additive was galvanic sludge calcined at 1000 °C and crushed to a particle size of no more than 40 microns. It was found that polymethylsilazane, which is part of MSN-7-80, increases the strength characteristics of the coating, especially its cohesive strength, while reducing water absorption by increasing the hydrophobicity of the surface. In turn, galvanic sludge increases the mechanical strength upon impact. The ecological safety of the obtained material was confirmed by the method of biotesting on the mortality of Daphnia magna Straus. As a result of comparison with a protective coating similar in composition and purpose, it was revealed that the coating obtained in this work surpasses it in strength and adhesion characteristics. The developed polymer composition can be used to protect steel and concrete surfaces in construction and mechanical engineering from shock and moisture, including in extreme conditions of high or low temperatures and in contact with aggressive media.

Keywords: polymer composition, protective coating, organosilicon binder, electroplating sludge, polymethylsilazane, cold curing

The paper presents the results of a study of the effect of cerium oxide on the sintering process and the basic physico-chemical properties of ceramics based on low-plastic clay with the addition of boric acid. The developed ceramics were obtained by semi-dry pressing at a maximum firing temperature of 1050 ° C. The combined introduction of cerium oxide with boric acid promotes liquid-phase sintering, self-glazing of the ceramic surface and effective filling of pores and voids in it with the vitreous phase. At the same time, cerium oxide increases the refractoriness and chemical resistance of the vitreous phase and equalizes the coefficients of thermal expansion between the crystalline and amorphous phases in the composition of ceramics. The amount of cerium oxide has been determined, which makes it possible to optimally increase the heat resistance, chemical resistance and strength of ceramics. The practical application of the developed composition of the charge makes it possible to use raw materials of low plasticity in the production of high-quality ceramics for lining apparatuses and equipment, lining of industrial buildings and structures, etc. products experiencing mechanical stress with repeated and abrupt temperature changes, as well as in contact with aggressive media.

Keywords: ceramics, heat resistance, chemical resistance, self-glazing, low-plastic clay, cerium oxide, boric acid

The paper presents the results of a study conducted for chemically and thermally resistant ceramics obtained from low-plastic clay using boric acid as a melt, zirconium oxide and galvanic sludge as functional additives. The studied ceramics were obtained by semi-dry pressing technology at a maximum firing temperature of 1050 оC. The dependences of the physical and mechanical properties of ceramics on the content of zirconium oxide and galvanic sludge in the charge are established. Zirconium oxide promotes liquid-phase sintering, compaction and strength enhancement, and galvanic sludge exhibits a pore-forming effect due to calcium carbonate and heavy metal hydroxides in its composition. At the same time, the effect of galvanic sludge on the physical and mechanical properties is lower than that of zirconium oxide. The quantities of the studied additives have been established, which make it possible to obtain high values of operational properties and apply the resulting ceramics in the production of lining and other ceramic products for special purposes.

Keywords: heat-resistant ceramics, acid-resistant ceramics, self-glazing, low-plastic clay, galvanic sludge, zirconium oxide, boric acid

The paper presents the results of studying the dependences of the physico-mechanical properties of facing ceramics on the use of molybdenum trioxide. The additive together with boric acid is introduced into a charge based on low-plastic clay. The studied ceramic material was obtained by semi-dry pressing at a maximum firing temperature of 1050 ° C. Both additives used are fins, contributing to liquid-phase sintering and the effect of self-glazing of the surface of the material. At the same time, molybdenum trioxide also makes it possible to reduce the viscosity of the vitreous phase and increase its degree of crystallinity. The optimal amount of molybdenum trioxide has been established, which allows to effectively increase the strength and frost resistance of ceramics. The practical application of the developed composition of the charge will allow the use of low-quality raw materials for the production of facing construction ceramics with high performance characteristics.

Keywords: facing ceramics, molybdenum trioxide, low-plastic clay, boric acid, melting, liquid-phase sintering, self-glazing

The paper presents the results of evaluating the effectiveness of water softening using sodium-cationite filters with countercurrent modes of operation according to the flow schemes of purified water relative to the direction of supply of regeneration solution and washing water. The research was carried out at a pilot ion exchange facility using a single-stage sodium-cation scheme in laminar operation. It has been found that the flow from bottom to top under the resin layer leads to its compaction due to high hydraulic resistance, which in the case of water supply leads to an increase in softening efficiency, and the flow from top to bottom facilitates its passage through the resin layer due to low hydraulic resistance, which in the case of water supply increases the resin resource, and in the case of the supply of regeneration solution and washing water contributes to a more complete regeneration and washing of the layer from the residual amount of NaCl solution. A comparative characteristic of three grades of resins was carried out during two filter cycles with different countercurrent schemes. According to the results, the resins of the brands Purolite C100E and Tokem-150 are recommended for use in countercurrent circuits of filters for water softening.

Keywords: water purification, water softening, water hardness, hardness salts, ion exchange, sodium-cationite resins, resin regeneration, countercurrent regeneration, resin resource, resin regeneration degree