SYSTEM ANALYSIS OF TECHNOLOGICAL PROCESSES

The article discusses ways to solve engineering problems in the study of technological processes using methods of system analysis. The essence of this method is to study the technology as a cybernetic system with an assessment of the" reactions” of this system to external influences formed during an active experiment. At the same time, optimization problems are solved analytically. Analytical optimization is based on two main principles. The regression equations obtained as a result of processing experimental data and testing statistical hypotheses are models that adequately describe real processes. Each of these equations is an algebraic function of several variables, to which methods of mathematical analysis are applicable, including the study of extremums of functions in partial derivatives. The next step is to develop a process algorithm and develop computer programs that allow you to select the composition and predict the properties of the product. As an engineering interpretation, it is possible to construct optimized nomograms that allow solving both direct and inverse problems; that is, predicting the result or selecting technological factors. The research methods described in the article are implemented in the study of technologies of cellular concrete, foam concrete, cement-polymer concrete and products made of mineral wool and foam glass. As an example, the article considers the optimization of the selection of the composition of fine-grained concrete reinforced with chopped glass fiber. The implementation of the developed method allowed us to determine the optimal value of the determining parameters, including the consumption of fiber and plasticizer, as well as to form a method for studying the properties of products.

Waste-to-Reuse Foam Glasses Produced from Soda-Lime-Silicate Glass, Cathode Ray Tube Glass, and Aluminium Dross

Aluminium dross is a hazardous industrial waste generated during aluminium production. It contains metallic oxides of aluminium and magnesium, other phases (aluminum nitride), and residues of fluxes and salts from the melting process of aluminium. Discarding this by-product is considered an environmental and economic challenge due to the high reactivity of dross with water or even air humidity. After removing the hazardous components from the as-received dross, one of the optional approaches is to incorporate the treated dross into construction materials. Dross is applied in several types of research as a secondary raw material source for alumina, clinker, cement or glass-ceramic production, but only a few papers focus on the usage of dross as a foaming agent for foams. Even fewer research are reported where dross was applied as a basic component of foam glasses. In this work, foam glasses were produced completely from waste materials: Aluminium dross, container (SLS) glass, and cathode ray tube (CRT) glass. The research holds several specificities, i.e., combining two industrial waste materials (CRT glass and dross), and adding an increased amount from the wastes. The physical and mechanical characteristics were examined with a special focus on the effect of the foam glass components on the microstructure, density, thermal conductivity, and compressive strength.

Extrusion method for producing microgranular foam-glass ceramic from zeolite rocks

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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.

A Passive Wood-Based Building in Slovakia: Exploring the Life Cycle Impact

The aim of the study is to point out the burden of passive wood-based buildings throughout the life cycle from the environmental point of view to better understand the consequences and importance of building design in Slovakia. The analysis was carried out according to the Life Cycle Assessment methodology. The results were calculated by the CML-IA baseline method. The impacts of the product stage and operational energy use were the highest throughout the considered life cycle. Substances contributing to eleven impact categories were identified. Foundations, especially foam glass, were found to bear the majority of the impact of the overall construction materials. The normalization category showed considerable impact on marine aquatic ecotoxicity mainly due to building energy consumption over the course of 50 years. Loads connected to the replacement stage were the third highest. The study also proved high demand on elements of photovoltaics.

Development of lightweight structural concrete with the use of aggregates based on foam glass

Lightweight concretes are increasingly being used in the construction industry, either for the overall lightweighting of the structure itself, reducing material consumption for construction and thus CO2 emissions, or for specific reasons such as improving the thermal insulation properties of the structure or acoustic properties. Today, lightweight concretes with lightweight expanded aggregates (expanded clay, agloporite) are most commonly used. This paper deals with the production of lightweight concretes lightweighted with foamed glass-based aggregates. Foamed glass is a lightweight material characterised by a very good ratio of thermal insulation and mechanical properties. Foamed glass is made of approximately 90% recycled glass waste (mostly mixed), which cannot be used in any other way, as well as water glass and glycerine. When concrete is lightened with foamed glass, these concretes achieve unique properties while conserving primary aggregate resources, avoiding landfilling of glass waste and efficiently using the waste material to produce lightweight concrete with higher added value. The paper discusses the possibilities of developing lightweight structural concretes using glass foam-based aggregates to achieve higher strength classes while reducing the weight and thermal conductivity of the concrete. As part of the research work, new types of lightweight concrete with a bulk density in the range of 1750–1930 kg/m3 and a thermal conductivity from 0.699 to 0.950 W/(m·K) were developed.

Light autoclaved foam concrete with foam glass-based aggregate

The presented research aims to develop new optimized composition of novel lightweight concrete with a very low bulk density. Low bulk density of developed lightweight concrete is achieved by using a combination of non-traditional lightweight artificial fillers, dispersed fibre reinforcement and pre-generated technical foam. The methodology of lightweight concrete test specimen production, based on technologies commonly applied for the production of lightweight concrete, foam concrete or autoclaved aerated concrete was also designed and verified. Not only the physical and mechanical parameters, but also the thermal insulation properties were verified on the produced test specimens of the developed lightweight concrete.

Improving the shielding efficiency and weight reducing of the radio-absorbing coating by adding a matching layer

The spectra of complex permittivity of the composites consisting of rubber silicone compound and electroconductive fine-dispersed silver-coated copper powder were investigated. To enhance the effectiveness of the composite interaction with microwaves and reduction of its weight and dimensions characteristics two and three-layer constructions were produced. Matching layers were made of foam glass material with addition SiC and Fe3O4.

USE OF MICROWAVE RADIATION FOR SEPARATION OF LIQUID GLASS HEAT INSULATION MATERIALS

The study of the thermal insulation market of Ukraine showed that the market is dominated by aerated concrete and silicates, which are used as thermal insulation materials at an average density of 300-500 kg / m3. Their disadvantages include high values of water absorption and hygroscopicity, as well as very low flexural strength, because this material does not have elasticity and the use of small bending forces leads to its cracking. Foam glass has a set of operational properties that meet the highest regulatory requirements. Foam glass is the strongest of all effective thermal insulation materials, but this material is fragile. It is sensitive to vibration - induced damage. In addition, the technology of production of foam glass is quite complex and requires high energy consumption, as a consequence, the cost of this material is high. Therefore, it was important to develop thermal insulation material with the appropriate level of performance while reducing production costs. This was achieved by using energy-saving microwave technology to swell liquid glass materials. This technology is based on the simultaneous swelling of the liquid glass granulate and the binder under microwave radiation, which, due to the volumetric heating of the liquid glass composition, allows to obtain a strong monolithic material with a rigid, homogeneous and mostly closed-porous structure. The production of thermal insulation materials is proposed to be carried out on the basis of liquid glass granulate, because the introduction of granules reduces the deformability and shrinkage of the material and prevents its cracking, increases its strength, because the granular material has a certain plastic deformation, reduces water hygroscopicity. granules swell to form a compacted shell, which slows down the absorption kinetics of water and its vapor. The monolithic granules are proposed to be carried out with a binder that foams not only due to the release of water, but also with the help of a gasifier, because this technology will allow uniform distribution of the binder in the intergranular space, thus forming a more homogeneous structure of the material, which has a positive effect on its physical and mechanical characteristics.