11 research outputs found
Technology of the porous granular material out of thermal power engineering waste
The article presents the results of resource-saving technology development of porous granular material. Research is devoted to the development of scientific ideas about highly porous structures formation. The research objective is to develop a low-energy technology for producing porous granules based on the multiple use of thermal power engineering waste. Research novelty lies in conformity with a principle of combined porous structure’s formation of granules during thermal swelling of molding sand based on technogenic materials. Mixture of liquid sodium glass, fly ash and ash aluminosilicate microsphere has been developed to obtain the granules. Techniques for granulating liquid glass mixture have been developed. The parameters for thermal treatment of granules have been established to ensure formation of a strong, porous, and water-resistant structure. Physicomechanical and thermal properties of porous granules fired at a temperature of 350°С were studied. Microstructure of the fired granules was studied; their porosity is of 78 – 80%, bulk density is 210 – 230 kg/m3, and the thermal conductivity coefficient is 0.084 – 0.085 W/(m·°С). There has been developed a technological scheme for production of a granular material based on finely dispersed thermal power engineering waste. Comparative analysis of characteristics of the developed material and expanded clay was carried out
Service properties of porous liquid glass concrete
The article presents studies’ results of cementless lightweight concretes based on porous granular aggregate. Lightweight concrete components are specially synthesized from mixtures containing liquid sodium glass and thermal energy waste with various fineness. Thermal hardening of a matrix based on liquid glass and technogenic fillers at a temperature of 350ºС provided heat-insulating concrete with 480 kg/m3density and compressive strength of 4.7 MPa. The aim of the work is to study operational stability of lightweight concrete from genetically related components. Durability of lightweight concrete was evaluated in terms of hydro physical properties, resistance to frost and salt aggression, and cyclic heating. Methods of physical and mechanical testing of concrete have been used in the work. X-ray phase analysis and electron microscopy were used to study materials’ composition and structure. The results of complex tests showed stability of the structure of liquid glass concrete based on porous aggregate to the impact of operational factors. The lightweight concretes developed are characterized by a softening coefficient of 0.81; they withstood 50 cycles of alternating freezing and thawing, 20 cycles of cyclic exposure at a temperature of 1050ºС and 20 thermal cycles at a temperature of 250ºС; staying in aggressive sulfate and chloride magnesium solutions
The effect of fillers’ composition on thermal swelling of silicate materials
The article presents the results of studies of the process of thermal pore formation of materials based on sodium alkaline silicates. The aim of the study is to substantiate fillers composition for liquid glass mixtures. Substandard rocks and technogenic materials were used as fillers. There were determined the temperature intervals of intensive formation of the gas phase during heat treatment of fillers. Comparative analysis of swelling characteristics revealed the preference for a combination of several fillers containing substances with different resistance to temperature transformations. The results of studies of the structure and physical and mechanical properties of porous materials confirmed feasibility of using multicomponent fillers. The cellular material developed is characterized by predominantly closed, high porosity, heat-shielding properties and resistance to mechanical stress
Porous formation process of granules from man-triggered raw materials
The results of studies of porous structure formation in a granular glass mixture are presented. Raw mixes were prepared from glass cullet, waste of magnetite ores dressing and liquid glass. The reason for adding of magnetite ores waste to the glass mixture was the information on chemical and mineral composition, results of studies of thermal transformations of waste. The rationale for adding of 20 – 30% of magnetite ores waste into the raw mix is confirmed by lowering the bloating temperature and increasing granules porosity. The effect of pyrite mineral on structural transformations in a glass mixture has been studied for the first time. It was revealed that the presence of pyrite up to 10% in the glass mixture intensifies swelling at lower temperatures. A method for preparing a molding mixture is proposed, which ensures the formation of highly porous granules with equal distribution of cells in the structure. The method involves mechanical activation of mixture of glass cullet and magnetite ores waste by grinding in a vibratory mill and subsequent portion-wise introduction of the activated mixture into liquid glass. A complex of technological methods allows obtaining porous granules with a packed density of 300 kg/m3 at a temperature of 825°C
Foam Glass Crystalline Granular Material from a Polymineral Raw Mix
The article is devoted to the development of resource-saving technology of porous granular materials for energy-efficient construction. The relevance of the work for international research is to emphasize expanding the raw material base of porous lightweight concrete aggregates at the expense of technogenic and substandard materials. The work aims to study the processes of porization of glass crystalline granules from polymineral raw materials mixtures. The novelty of the work lies in the establishment of regularities of thermal foaming of glass crystalline granules when using waste of magnetic separation of skarn-magnetite (WMS) ores and lignite clay. Studies of liquid glass mixtures with various mineral fillers revealed the possibility of the formation of a porous structure with the participation of opoka, WMS and lignite clay. This is due to the presence in the materials of substances that exhibit thermal activity with the release of a gas phase. The foaming efficiency of the investigated materials increases when combined with glass breakage. The addition of WMS and lignite clay to the glass mixture increases the pore size in comparison with foam glass. The influence of the composition of raw mixtures on the molding and stability of granules is determined. The addition of sodium carbonate helps to strengthen the raw granules and reduce the softening temperature of the mass. The composition of the molding mixture of glass breakage, liquid glass and a multicomponent additive is developed, which provides an improvement in the molding properties of the glass mass, foaming of granules at a temperature of 750 °C. Foam glass crystalline granules have polymodal porosity, characterized by a density of 330–350 kg/m3, a compressive strength of 3.2–3.7 MPa, and a thermal conductivity of 0.057–0.061 W/(m·°C). Accordingly, the developed granules have a high potential use in structural and heat-insulating concretes
Effect of additives on hydration and hardening of magnesia compositions
The article is devoted to the investigation of the influence of technological factors on the hydration and hardening of magnesia compositions. The objective – is investigation magnesia compositions with different additives. Factors which impact activity of magnesium oxide in compositions of different structure are investigated. Influence of liquid density on hardening of magnesium bindings is defined. Processes of hydration and hardening of magnesium bindings with participation of minerals – silicates are investigated. It is revealed that the addition of semi-aquatic calcium sulfate contributes to the hardening of magnesia binders. Defined effect of concentration calcium sulfate hemihydrate to the hardening of caustic magnesite. Here are proposed structures of sulphomagnesium compositions containing technogenic components. It revealed a beneficial effect on the hardening of ferrous component of the mixed magnesia binder. Composition of hydration products of magnesium binding with participation of ferriferous minerals is presented. Transformations of phases at hydration of magnesium binding are revealed. Influence of structure of bindings on transformations of hydrates is established. Results of research of magnesia bindings of long hardening are given. It is shown that the durability of stone of bindings is provided with dense structure of hydrates. In researches are used X – Ray and thermal methods, electronic microscopy
Porous aggregate development for lightweight concrete
The article presents the results of studies of a porous aggregate and lightweight concrete obtained using liquid glass and man-made materials (glass cullet, magnetite ore dressing waste, substandard rocks). Feasibility of a multicomponent feed mixture for pyroplastic swelling of granules is substantiated. Optimization of raw mix composition provided the possibility of combining various formation mechanisms of porous granules. A set of technological solutions has been developed aimed at improving the conditions of molding and hardening of raw granules. A method for preparing a raw material mass is proposed that minimizes structural defects of porous granules. Possibility of capacity reaction of a raw mixture due to mechanical activation of solid components and introduction of sodium additives is proved. Technological conditions for low-temperature expansion of a multicomponent mixture and production of porous granules with a density of not more than 300 kg/m3 are determined. The formula of molding mixture for obtaining lightweight concrete using a porous aggregate is proposed. The use of liquid glass as a binder in a concrete mixture is preferred. The temperature of concrete hardening is recommended. The technology of porous concrete developed implements multifunctional properties of liquid glass, provides the use of technogenic materials, saving of energy resources
Porous Fly Ash/Aluminosilicate Microspheres-Based Composites Containing Lightweight Granules Using Liquid Glass as Binder
The modern energy-saving vector of development in building materials science is being implemented in a complex way through the development of new heat-insulating materials with the simultaneous exclusion of low-ecological cement from them. This article presents the results of the development of resource-saving technology for a heat-insulating composite material. The research is devoted to the development of scientific ideas about the technology and properties of effective cementless lightweight concretes. The aim of the work is to create a heat-insulating composite material based on porous granules and a matrix from mixtures of liquid glass and thermal energy waste. The novelty of the work lies in establishing the patterns of formation of a stable structure of a porous material during thermal curing of liquid glass with technogenic fillers. Studies of liquid glass mixtures with different contents of fly ash and aluminosilicate microspheres revealed the possibility of controlling the properties of molding masses in a wide range. To obtain a granular material, liquid glass mixtures of plastic consistency with a predominance of aluminosilicate microspheres are proposed. The matrix of composite materials is formed by a mobile mixture of liquid glass and a combined filler, in which fly ash predominates. The parameters of heat treatment of granular and composite materials are established to ensure the formation of a strong porous waterproof structure. The possibility of regulating the structure of composite materials due to different degrees of filling the liquid glass matrix with porous granules is shown. A heat-insulating concrete based on porous aggregate has been developed, characterized by the genetic commonality of the matrix and the granular component, density of 380–650 kg/m3, thermal conductivity of 0.095–0.100 W/(m °C) and strength of 3.5–9.0 MPa, resistance under conditions of variable values of humidity and temperature. A basic technological scheme for the joint production of granular and composite materials from liquid glass mixtures is proposed
Foam Glass Crystalline Granular Material from a Polymineral Raw Mix
The article is devoted to the development of resource-saving technology of porous granular materials for energy-efficient construction. The relevance of the work for international research is to emphasize expanding the raw material base of porous lightweight concrete aggregates at the expense of technogenic and substandard materials. The work aims to study the processes of porization of glass crystalline granules from polymineral raw materials mixtures. The novelty of the work lies in the establishment of regularities of thermal foaming of glass crystalline granules when using waste of magnetic separation of skarn-magnetite (WMS) ores and lignite clay. Studies of liquid glass mixtures with various mineral fillers revealed the possibility of the formation of a porous structure with the participation of opoka, WMS and lignite clay. This is due to the presence in the materials of substances that exhibit thermal activity with the release of a gas phase. The foaming efficiency of the investigated materials increases when combined with glass breakage. The addition of WMS and lignite clay to the glass mixture increases the pore size in comparison with foam glass. The influence of the composition of raw mixtures on the molding and stability of granules is determined. The addition of sodium carbonate helps to strengthen the raw granules and reduce the softening temperature of the mass. The composition of the molding mixture of glass breakage, liquid glass and a multicomponent additive is developed, which provides an improvement in the molding properties of the glass mass, foaming of granules at a temperature of 750 °C. Foam glass crystalline granules have polymodal porosity, characterized by a density of 330–350 kg/m3, a compressive strength of 3.2–3.7 MPa, and a thermal conductivity of 0.057–0.061 W/(m·°C). Accordingly, the developed granules have a high potential use in structural and heat-insulating concretes