Browsing by Author "Liutyi, R. V."
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Item Physicochemical Structure Features of Refractory Compositions with Inorganic Binders(Vasyl Stefanyk Precarpathian National University, Ivano-Frankivsk, Ukraine, 2022) Liutyi, R. V.; Solonenko, L. I.; Osipenko, I. O.; Fedorov, M. M.; Moroz, B. I.ENG: The article presents the study results of new inorganic binders and the physicochemical processes of their formation. The main purpose of the created materials is to make molds and cores for foundry production. Creating environmentally-friendly binders with a set of functional properties for foundry production is relevant worldwide. Therefore, scientists from different countries are paying special attention to the study of silicate and phosphate binders. The study analyzes the kinetics of the orthophosphoric acid interaction with several inorganic materials – pulverent pyrophyllite, disthene-sillimanite, a by-product of electrocorundum production, and sodium chloride. The phase and chemical composition of all formed binders have been established. In aluminum-containing compositions, those are represented by aluminum orthophosphates in crystalline and amorphous forms. Sodium metaphosphate is formed in the composition with sodium chloride. Peculiarities of the structuring compositions physical process with liquid glass and granular quartz filler due to steam-microwave treatment are determined. It is shown that structuring occurs due to dehydration, which is completed within 4…12 min, which allows reducing the liquid glass content in the composition to 1.5% while ensuring a high level of strength. The properties of structured compositions with the developed binding components are researched, and it is shown that all of them are competitive. Recommendations for their possible application were created.Item Synthesis of Phosphosulphate Substance and Properties of Its Structured Mixture with Quartz Sand(Dnipro University of Technology, Dnipro, Ukraine, 2022) Liutyi, R. V.; Tyshkovets, M. V.; Yamshinskij, M. M.; Selivorstov, Vadim Yu.; Ivanov, V. G.ENG: Purpose. Creation of binder based on orthophosphoric acid and aluminum sulfate, study on its structure and physicochemical patterns of formation, determination of the properties of structured mixtures for the needs of foundry. Methodology. In the work, X-ray qualitative and quantitative analysis was performed on the Rigaku Ultima IV unit, and differential thermal analysis was performed on the STA 449 C Jupiter synchronous thermal analyzer. Orthophosphoric acid, technical thermal, of 85 % concentration, 18-hydrous sulfate of aluminum Al2(SO4)3 18H 2O and quartz sand of brand 3K5O3025 were used. The strength of core mixtures was determined on the US-700 unit on standard cylindrical samples with a diameter and height of 50 mm. The roughness of the cast surfaces was determined on a profilometer model 107622 with computer processing of the obtained data and construction of profilograms. To determine the propensity of the core mixtures to form caking, a hexagon sample was used according to the method by M. Fedorov. Breakability was determined on standard cylindrical samples with a diameter and height of 50 mm according to the original method described in the text of the article. Findings. For the first time, the mechanism of formation of aluminum phosphates with binding properties during the interaction of aluminum hydrate crystal sulfate Al2(SO4)3 18H2O with orthophosphoric acid in the temperature range of 100–200 °С has been investigated. The formation is proved of an intermediate phase during heating – aluminum hydroxide Al(OH) 3, which, in contrast to its sulfate, according to the results of thermodynamic analysis is able to interact with acid. Formation of aluminum in the system of ortho- and metaphosphates, which features binding properties and ensures high strength of samples based on quartz filler, has been established. The thermal transformations of the obtained binder, which consists of a combination of aluminum phosphates with its residual sulfate, are studied. Stages of gradual disintegration of crystal hydrates, formation of new aluminum phosphates and thermal decomposition of residual sulfate are recorded. The tendency to burn and knockout of the developed core mixtures was determined. Originality. For the first time, a description has been developed of the mechanism of formation of aluminum phosphates with binding properties during the interaction of its sulfate crystal hydrate Al2(SO4)3 18H2O with orthophosphoric acid in the temperature range of 100–200 °С. Practical value. A new inorganic binder from orthophosphoric acid and 18-aqueous aluminum sulfate has been obtained for foundry production. The scheme of its preparation involves preliminary mixing and heating of the specified reagents with the resulting formation of a dry powder material which consists of phosphates and residual aluminum sulfate, and therefore it is called phosphosulfate. The binding has a long shelf life and is introduced into the mixture in a ready-made form while the technology of its production is less energy-intensive and long-lasting compared to the preparation of traditional metal phosphate binding.Item Synthesis of Phosphosulphate Substance and Properties of Its Structured Mixture with Quartz Sand(Dnipro University of Technology, Ukraine, 2022) Liutyi, R. V.; Tyshkovets, M. V.; Yamshinskij, M. M.; Selivorstov, Vadim Yu.; Ivanov, V. G.ENG: Purpose. Creation of binder based on orthophosphoric acid and aluminum sulfate, study on its structure and physicochemical patterns of formation, determination of the properties of structured mixtures for the needs of foundry. Methodology. In the work, X-ray qualitative and quantitative analysis was performed on the Rigaku Ultima IV unit, and differential thermal analysis was performed on the STA 449 C Jupiter synchronous thermal analyzer. Orthophosphoric acid, technical thermal, of 85% concentration, 18-hydrous sulfate of aluminum Al2(SO4)3 18H2O and quartz sand of brand 3K5O3025 were used. The strength of core mixtures was determined on the US-700 unit on standard cylindrical samples with a diameter and height of 50mm. The roughness of the cast surfaces was determined on a profilometer model 107622 with computer processing of the obtained data and construction of profilograms. To determine the propensity of the core mixtures to form caking, a hexagon sample was used according to the method by M. Fedorov. Breakability was determined on standard cylindrical samples with a diameter and height of 50 mm according to the original method described in the text of the article. Findings. For the first time, the mechanism of formation of aluminum phosphates with binding properties during the interaction of aluminum hydrate crystal sulfate Al2(SO4)3 18H2O with orthophosphoric acid in the temperature range of 100200 has been investigated. The formation is proved of an intermediate phase during heating aluminum hydroxide Al(OH)3, which, in contrast to its sulfate, according to the results of thermodynamic analysis is able to interact with acid. Formation of aluminum in the system of ortho- and metaphosphates, which features binding properties and ensures high strength of samples based on quartz filler, has been established. The thermal transformations of the obtained binder, which consists of a combination of aluminum phosphates with its residual sulfate, are studied. Stages of gradual disintegration of crystal hydrates, formation of new aluminum phosphates and thermal decomposition of residual sulfate are recorded. The tendency to burn and knockout of the developed core mixtures was determined. Originality. For the first time, a description has been developed of the mechanism of formation of aluminum phosphates with binding properties during the interaction of its sulfate crystal hydrate Al2(SO4)3 18H2O with orthophosphoric acid in the temperature range of 100200. Practical value. A new inorganic binder from orthophosphoric acid and 18-aqueous aluminum sulfate has been obtained for foundry production. The scheme of its preparation involves preliminary mixing and heating of the specified reagents with the resulting formation of a dry powder material which consists of phosphates and residual aluminum sulfate, and therefore it is called phosphosulfate. The binding has a long shelf life and is introduced into the mixture in a ready-made form while the technology of its production is less energy-intensive and long-lasting compared to the preparation of traditional metal phosphate binding.