Artificial Ceramic Binders Research Articles

Карборундовые огнеупорные бетоны на основе искусственного керамического вяжущего

This work considers a method to increase the mechanical strength and corrosion resistance to glass and slag melts of aluminosilicate refractories. For this purpose, artificial ceramic binders (ACB) of mullite-carborundum composition were synthesized using the technology of highly concentrated ceramic binder suspensions (HCCBS). The morphological characteristics and grain size of ACB were analyzed, and the structure and physico-mechanical properties of the sintered products were investigated. It was found that nanodispersed particles are formed as a result of mechanochemical processes occurring during joint grinding. The average particle size was about 30 – 40 nm. Thermally treated samples based on high-alumina chamotte consist of crystalline phases of corundum, mullite, and SiC, which are uniformly distributed in the material. It is shown that with an increase in the annealing temperature, the physico-mechanical properties improve. The introduction of mullite-carborundum binder into the composition of high-alumina chamotte refractories has led to improved physico-mechanical properties and corrosion resistance to glass and slag melts. The results showed that refractories containing 50 % high-alumina chamotte possess the most favorable physico-mechanical properties. Compared to the factory sample, experimental samples demonstrated a significant improvement in corrosion resistance to glass and slag melts by 90 % and 94 %, respectively.

Heat-resistant ceramic concrete based on diatomite. 1. Synthesis and study of artificial ceramic binders based on diatomite

The main aspects of obtaining an artificial ceramic binder (ACB) based on the original (quarry) and heat-treated diatomite are considered. The process of obtaining SCR was studied, its main rheological properties and physico-mechanical characteristics of the samples were analyzed. It has been established that ACB based on quarry diatomite is characterized by a thixotropic rheological behavior, and ACB based on pre-heat-treated diatomite belongs to the thixotropic-dilatant type. The use of this technology for obtaining a binder will reduce the molding moisture in the manufacture of various diatomite products and improve their quality while reducing production costs compared to similar products obtained by traditional technology.

Cement-Free Refractory Concretes. Part 6. Comparative Evaluation of Natural (Clay) and Artificial Ceramic Binders (HCBS)

Comparative assessment of artificial (based on highly concentrated ceramic binders suspensions - HCBS) and natural (based on clay and kaolin) ceramic binders of similar composition is conducted. Analysis of their properties and characteristics shows both their significant similarity and significant difference. As with HCBS, the binding (strength) properties of clay and kaolin are determined by the colloidal particle content and nanoparticles within them. In contrast to HCBS, clay and kaolin have a significant content of chemically bonded water, a high water requirement for molding systems, and clearly different (by an order of magnitude and greater) shrinkage during drying. If binders based on clays are considered from the point of HCBS classification, then according to their chemical composition they may be classified as acid-amphoteric (similar to materials based on chamotte). However, in terms of chemically bonded water and volume concentration of a suspension, they are closer to HCBS of amphoteric and basic compositions. Addition of refractory clay and kaolin is very effective in ceramic concrete production.

Cement free castable. Part 6. Comparative assessment of natural (clay) and artificial ceramic binders (HCBS)

A comparative assessment of artificial (based on highly concentrated ceramic binders suspensions - HCBS) and natural (based on clays and kaolins) ceramic binders of similar composition has been carried out. Analysis of their properties and characteristics shows both their significant similarity and significant difference. As with HCBS, the binding (strength) properties of clays and kaolins are determined by the content of colloidal particles and nanoparticles in them. In contrast to HCBS, clays and kaolins are characterized by a significant content of chemically bound water, a high water requirement of molding systems, and a sharp, different (by an order of magnitude and higher) shrinkage during drying. If binders based on clays are considered from the position of HCBS classification, then according to their chemical composition they can be classified as acid-amphoteric (like materials based on chamotte). However, in terms of chemically bound water, volumetric concentration of the suspension, they are closer to HCBS of amphoteric and basic compositions. The addition of refractory clays and kaolins is very effective in the production of ceramic concrete.

Nitride bonded silicon carbide composites based on artificial ceramic binders

The mass compositions for the production of silicon carbide materials on a nitride bond, in which artificial ceramic binders based on silicon and silicon carbide were used as initial binders, were studied. The influence of the firing regime and the composition of the binder on the main physicomechanical characteristics and microstructure of the samples after nitriding firing is studied.

ИССЛЕДОВАНИЕ ВЛИЯНИЯ ДИСПЕРСНЫХ ДОБАВОК НА СРОКИ СХВАТЫВАНИЯ И МИКРОСТРУКТУРУ ВЫСОКОГЛИНОЗЕМИСТОГО ЦЕМЕНТА

the paper is devoted to a full-scale study of corundum modifying dispersed additives (reactive, tabular, dispersing alumina) and artificial ceramic binder, their impact on high-alumina cement microstructure and setting time. Artificial ceramic binders are characterized by similar chemical, phase and grain composition with modifying corundum additives and characterized by the presence of particles less than 100 nm (up to 0.5%). The studied materials are finely dispersed polyfractional systems from 0.1 to 13 μm with a prevailing grading fraction of 2-10 μm. In this case, dispersing and reactive alumina are more coarse. Using the microscopy method it was established that the corundum additives increase packing density of high-alumina cement samples, especially with artificial ceramic binder addition. Studies of dispersed additives effect on the setting time of cement was conducted. It is established that the adding of artificial ceramic binder or dispersing alumina at 0.5% is speeding up the initial setting, but a further increasing of the additive content does not affect this indicator. The maximum reduction of setting time is caused by the introduction of 5% tabular alumina.

ИССЛЕДОВАНИЕ ИСКУССТВЕННЫХ КЕРАМИЧЕСКИХ ВЯЖУЩИХ НА ОСНОВЕ СИЛИКАТНЫХ МАТЕРИАЛОВ ДЛЯ ПРОИЗВОДСТВА КЕРАМИКИ

this article discusses the possibility of using artificial ceramic binders obtained by the technology of highly concentrated binder suspensions in the production of ceramic materials and products. The results of complex studies of suspensions of artificial ceramic binders based on feldspar and quartz sand, as well as the results of tests of the samples obtained on their basis are presented. A definite advantage of entering the suspensions in the molding compositions of the slurries used in the manufacture of certain varieties of pottery is proved. The solution of the problem of import substitution of raw materials components, caused mainly by the difficult political situation in the country, as well as the lack of its own raw material base of good quality, in connection with which the paper proposes the use of technology of highly concentrated binder suspensions, which allows to optimize the quality of domestic raw materials. The use of technology of highly concentrated binder suspensions, allows not only to expand the assortment and range of products produced by this technology, but also to improve the quality and economic feasibility of individual varieties of ceramics. The emphasis on the introduction of technology of highly concentrated binding suspensions in certain areas of ceramics production is explained by the formation of a completely different structure of materials due to the increased content of nanoparticles in the composition of artificial ceramic binding suspensions, which contributes to a significant increase in mechanical strength while optimizing other basic technological quality indicators for ceramic materials and products. The possibility of reducing the firing temperature by 50-100°C, however, this issue requires additional research.

Nitride-Bonded Silicon-Carbide Composites Based on Artificial Ceramic Binders

Compositions for producing silicon-carbide materials with a nitride binder in which the initial binders were artificial ceramic binders based on silicon and silicon carbide were studied. The influence of the firing regime and binder composition on the main physicomechanical characteristics and microstructure of samples after nitriding firing was studied.

Cement-Free Refractory Concretes. Part 1. General Information. Hcbs and Ceramic Concretes

The general nature of the dependence of engineering and service characteristics of refractory concretes with an average cement content, and also low-cement (LCRC), ultra-low cement (ULCRC) and cement-free (CFRC), on the content of CaO (or HAC) in them is analyzed. Significant advantages of cement-free concretes are the reduced moisture content of the concrete mixture, which determines their increased density, a continuous increase in strength (absence of a softening temperature range typical for LCRC and ULCRC), and improved thermomechanical and operational characteristics. With use of CFRC, the insurmountable complexity of the LCRC and ULCRC connected with their initial heating in the dehydration temperature range of the HAC (up to 450°C) is resolved. The main provisions and stages of creating HCBS or artificial ceramic binders as a matrix system of ceramic concrete, i.e., LCRC with improved characteristics, are described. Classification of HCBS groups proposed by the author based on the chemical nature of their solid phase is considered.

Artificial Ceramic Binders based on Silicon and Silicon Carbide for Silicon-Carbide Refractories in a Nitride Matrix

The main rheological and processing properties of individual and mixed binders based on SiC and Si are studied. Phase and chemical compositions, main physicomechanical characteristics, and microstructures of samples after annealing in N2 are investigated.

Cementless refractory concretes. Part 1. General information. HCBS and ceramic concrete

The general nature of the dependence of the technological and service characteristics of refractory concretes with an average cement content, as well as low-cement (LCRC), ultra-low cement (ULCRC) and cementless (CLRC), on the content of CaO (or НАC) in them is analyzed. Significant advantages of cementless concretes are the reduced moisture content of the concrete mixture, which determines their increased density, a continuous increase in their strength (the absence of a softening temperature range typical for LCRC and ULCRC), and improved thermomechanical and operational characteristics. With the use of BSCH, the insurmountable complexity of the SCB and SSCB associated with their initial heating in the temperature range of the dehydration of the HАC (up to 450 °C) is solved. The main provisions and stages of creating HCBS or artificial ceramic binders as a matrix system of ceramic concrete --- CLRC with improved characteristics are described. The classification of HCBS groups proposed by the author based on the chemical nature of their solid phase is considered. Ill. 6. Ref. 51. Tab. 1.

Silicon and silicon carbide-based artificial ceramic binders for nitride bonded silicon carbide refractories

The basic rheotechnological properties of individual and mixed binders based on SiC and Si were studied. The phase and chemical compositions, the main physicomechanical characteristics, and the microstructure of the samples after firing in nitrogen were studied. Ill. 10. Ref. 13.

Matrices of radiation-protective composites using bismuth oxide

The article presents the results of investigations of radiation-protective composites with two types of matrices based on chamotte and aluminous binders. The synthesis of binders was carried out according to the principles of the production of ceramic concrete based on the artificial ceramic binders (ACB). Bismuth oxide was selected as filler. Basic physical and mechanical, as well as radiation-protective characteristics, of composites with different ratios of ACB and Bi2O3 were shown. It was found out that binder of high-alumina chamotte can be used as an optimal matrix base. Composites on its basis have higher structural and radiation-protective properties.

Corrosive Resistance of Mullite-Silicon Carbide Refractory Composites

Data from a study of the resistance of volume-modified refractory components based on artificial ceramic binders of mullite-silicon carbide composition to the effect of melts of borosilicate glass and metallurgical slag are presented. Laws governing the variation of the wetting angle and degree of impregnation with melts of corrosive media as a function of the molding method compared to the comparable indicators of a factory prototype are established.

Study of Artificial Ceramic Binders of Mullite-Silicon Carbide Composition and Composites Based on Them

Research is conducted for synthesis of artificial ceramic binders of mullite-silicon carbide composition and composites based on them. Binder rheological and physicomechanical properties are studied. Dependences are established for composite compaction in relation to molding conditions and starting raw material type. The possibility is demonstrated of using artificial ceramic binders for preparing highly dense ceramic composites with good operating properties.

Study of Artificial Ceramic Binder Properties in the System Al2O3–SiO2–SiC

Artificial ceramic binders based on silicon carbide and high-alumina chamotte are studied. Rheological and physicomechanical properties of mixed ACB are determined. An optimum content is revealed for silicon carbide and high-alumina chamotte ACB. It is established that a thin film of mullite forms at the surface with a firing temperature of 1300°C for ACB specimens of optimum composition.

Heat-Insulating Properties of Refractory Materials Made with the Use of Artificial Ceramic Binders

It is shown that it possible to produce heat-insulating and heat-insulating/structural refractories based on artificial ceramic binders made from thermally activated refractory clays of different compositions. The slag-alkali binder used in the new materials undergoes strengthening by a unique mechanism. An analysis is made of the granulometric composition of the slag after comminution for different lengths of time and its main granulometric characteristics are determined. The main properties and microstructure of the new heat-insulating materials are studied.

Corundum and Zirconia Composites Based on Artificial Ceramic Binders

Research is carried out on different types of artificial ceramic binders based on single-crystal and polycrystalline zirconia and corundum composition raw material. Features are established for composite compaction in relation to molding conditions and raw material type. The possibility is demonstrated of using these binders for preparing high density ceramic composites with improved operating properties.

The use of artificial ceramic binders based on thermally activated high-alumina raw materials in a semi-dry pressing technology

Results are presented from feasibility studies of the use of artificial ceramic binders based on activated high-alumina raw materials to make refractory materials. It was found that specimens based on heat-treated binders have better indices than HCBS-based specimens and factory prototypes.

Control of the structural and phase characteristics of raw materials in the technology of fine ceramics

Questions related to the preparation and control of the properties of raw materials from the standpoint of structural instability are considered. It is demonstrated that the use of the technology of artificial ceramic binders for the production of fine and technical ceramics and high-alumina refractories is showing promise.