Pub Date : 2022-01-01DOI: 10.36807/1998-9849-2022-61-87-92-97
O. Golubyatnikov, E. Akulinin, Alexey A. Kolomoets
The paper presents the results of numerical studies of the aerodynamic structure of the flow in a fixed layer of granular adsorbent in the adsorber of a pressure swing adsorption (PSA) unit for synthesis gas separation and hydrogen purification. Сomputational experiments were conducted in COMSOL Multiphysics software using 1-D and 2-D mathematical models to calculate the velocity field in the bulk layer of the 13X adsorbent for the PSA process of hydrogen purification. When assessing the accuracy of calculating the aerodynamic structure of the gas flow in the adsorbent, it was found that the use of a 2-D mathematical model provides an increase in the accuracy of calculations by an average of ~ 1-2% compared with the 1-D model. It is determined that when using an adsorbent with a particle diameter of more than 2 mm in the PSA unit, the use of 2-D and 3-D mathematical models for calculations is promising at speeds of more than 0.3 m/s, due to an increase in the velocity divergence in the center of the vertical cylindrical adsorber and on its walls
本文对变压吸附(PSA)合成气分离氢气净化装置吸附器内固定层颗粒吸附剂内流动的气动结构进行了数值研究。Сomputational实验在COMSOL Multiphysics软件中使用1-D和2-D数学模型计算了用于PSA制氢过程的13X吸附剂体层的速度场。在对吸附剂内气体流动的气动结构计算精度进行评估时，发现使用二维数学模型比一维模型平均提高了1-2%的计算精度。当在PSA装置中使用粒径大于2mm的吸附剂时，由于垂直圆柱形吸附剂中心及其壁上的速度发散增加，使用二维和三维数学模型进行计算是有希望的，速度超过0.3 m/s
{"title":"CFD MODELING OF FLOW IN A STATIONARY ADSORBENT BED FOR PRESSURE SWING ADSORPTION PROCESS OF HYDROGEN PURIFICATION","authors":"O. Golubyatnikov, E. Akulinin, Alexey A. Kolomoets","doi":"10.36807/1998-9849-2022-61-87-92-97","DOIUrl":"https://doi.org/10.36807/1998-9849-2022-61-87-92-97","url":null,"abstract":"The paper presents the results of numerical studies of the aerodynamic structure of the flow in a fixed layer of granular adsorbent in the adsorber of a pressure swing adsorption (PSA) unit for synthesis gas separation and hydrogen purification. Сomputational experiments were conducted in COMSOL Multiphysics software using 1-D and 2-D mathematical models to calculate the velocity field in the bulk layer of the 13X adsorbent for the PSA process of hydrogen purification. When assessing the accuracy of calculating the aerodynamic structure of the gas flow in the adsorbent, it was found that the use of a 2-D mathematical model provides an increase in the accuracy of calculations by an average of ~ 1-2% compared with the 1-D model. It is determined that when using an adsorbent with a particle diameter of more than 2 mm in the PSA unit, the use of 2-D and 3-D mathematical models for calculations is promising at speeds of more than 0.3 m/s, due to an increase in the velocity divergence in the center of the vertical cylindrical adsorber and on its walls","PeriodicalId":9467,"journal":{"name":"Bulletin of the Saint Petersburg State Institute of Technology (Technical University)","volume":"275 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83189215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.36807/1998-9849-2022-63-89-58-64
D. A. Novikova, O. M. Flisyuk, N. A. Martsulevich, I. G. Likhachev
The features of various types of microstructure of manganese dioxide and the area of its industrial application at present and the prospects for its possible use in the near future were considered. The possible usage of manganese dioxide of active crystalline structure as a sorbent in the purification of exhaust gases from nitrous gases and sulfur dioxide was noted. That usage is of particular importance for solving ecological issues.
{"title":"APPLICATION OF DIFFERENT MODIFICATIONS OF CRYSTALLINE STRUCTURES OF MANGANESE DIOXIDE IN TECHNOLOGICAL PROCESSES","authors":"D. A. Novikova, O. M. Flisyuk, N. A. Martsulevich, I. G. Likhachev","doi":"10.36807/1998-9849-2022-63-89-58-64","DOIUrl":"https://doi.org/10.36807/1998-9849-2022-63-89-58-64","url":null,"abstract":"The features of various types of microstructure of manganese dioxide and the area of its industrial application at present and the prospects for its possible use in the near future were considered. The possible usage of manganese dioxide of active crystalline structure as a sorbent in the purification of exhaust gases from nitrous gases and sulfur dioxide was noted. That usage is of particular importance for solving ecological issues.","PeriodicalId":9467,"journal":{"name":"Bulletin of the Saint Petersburg State Institute of Technology (Technical University)","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87784011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.36807/1998-9849-2022-63-89-3-8
A. Y. Postnov, S. A. Lavrishcheva, O. I. Kopylova, J. V. Alexandrova
The results of the use of silicate wastes (silica gel, sistof, microsilica) as alternative carriers in the technology of vanadium catalysts for the oxidation of sulfur dioxide were presented. The chemical and phase composition of silicate wastes, the parameters of the porous structure and the activity of the synthesized samples were studied. The prospects of microsilica use as carriers of catalysts for the oxidation of sulfur dioxide were shown basing on the analysis of physico-chemical and structural-strength characteristics of synthesized and industrial samples.
{"title":"PROSPECTS OF THE USAGE OF SILICATE WASTE IN VANADIUM CATALYST TECHNOLOGY","authors":"A. Y. Postnov, S. A. Lavrishcheva, O. I. Kopylova, J. V. Alexandrova","doi":"10.36807/1998-9849-2022-63-89-3-8","DOIUrl":"https://doi.org/10.36807/1998-9849-2022-63-89-3-8","url":null,"abstract":"The results of the use of silicate wastes (silica gel, sistof, microsilica) as alternative carriers in the technology of vanadium catalysts for the oxidation of sulfur dioxide were presented. The chemical and phase composition of silicate wastes, the parameters of the porous structure and the activity of the synthesized samples were studied. The prospects of microsilica use as carriers of catalysts for the oxidation of sulfur dioxide were shown basing on the analysis of physico-chemical and structural-strength characteristics of synthesized and industrial samples.","PeriodicalId":9467,"journal":{"name":"Bulletin of the Saint Petersburg State Institute of Technology (Technical University)","volume":"68 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83266676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.36807/1998-9849-2022-63-89-23-27
Igor V. Yesarev, Yu. V. Surovikin, D. Agafonov
The paper considers the possibility of calculating the surface of carbon materials by measuring the capacitance of symmetric supercapacitors. It is shown that this approach allows us to obtain results that are in good agreement with the BET method. Traditional carbon materials for symmetric supercapacitors - activated carbons and carbon composites based on carbon black - are considered and compared. The capacitances of supercapacitors at different charge rates were measured in the work. When using the exponential model for almost all samples, the values of the maximum possible specific area of the sorbed ions are close to the specific surface of the materials calculated by the BET method. The exception is SX1G, for which a twofold difference between the values of specific areas is observed. This difference may be due to the non-equipotential, mostly microporous structure of the material, which is difficult for large solvated cations. Based on the experimental data obtained, it was suggested that it is possible to estimate the specific surface area of carbon materials based on the calculated capacitance. An important conclusion for practice is made - the limit of supercapacitor capacity growth is reached for materials with a specific surface area of 1500 m2/g
{"title":"EVALUATION OF THE CARBON MATERIAL SURFACE BY CAPACITIVE MEASUREMENTS OF A DOUBLE-LAYER SUPERCAPACITOR","authors":"Igor V. Yesarev, Yu. V. Surovikin, D. Agafonov","doi":"10.36807/1998-9849-2022-63-89-23-27","DOIUrl":"https://doi.org/10.36807/1998-9849-2022-63-89-23-27","url":null,"abstract":"The paper considers the possibility of calculating the surface of carbon materials by measuring the capacitance of symmetric supercapacitors. It is shown that this approach allows us to obtain results that are in good agreement with the BET method. Traditional carbon materials for symmetric supercapacitors - activated carbons and carbon composites based on carbon black - are considered and compared. The capacitances of supercapacitors at different charge rates were measured in the work. When using the exponential model for almost all samples, the values of the maximum possible specific area of the sorbed ions are close to the specific surface of the materials calculated by the BET method. The exception is SX1G, for which a twofold difference between the values of specific areas is observed. This difference may be due to the non-equipotential, mostly microporous structure of the material, which is difficult for large solvated cations. Based on the experimental data obtained, it was suggested that it is possible to estimate the specific surface area of carbon materials based on the calculated capacitance. An important conclusion for practice is made - the limit of supercapacitor capacity growth is reached for materials with a specific surface area of 1500 m2/g","PeriodicalId":9467,"journal":{"name":"Bulletin of the Saint Petersburg State Institute of Technology (Technical University)","volume":"73 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80587549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.36807/1998-9849-2022-60-86-18-22
Andrey A. Panferov, G. K. Ivakhnyuk, Nikolay F. Fedorov, Tazhir E. Mametnabiev, A. S. Drinberg
The working hypothesis previously confirmed at Phosphorit JSC (Kingisepp, Leningrad Region) on the significant effect of static electricity on the efficiency of grinding in cement clinker ball mills was successfully tested at the cement production. The method of electrophysical neutralization of static electricity charges has opened up the possibility not only to increase the productivity of grinders (by 12-18% wt.) or save energy for the electric drive (up to 20% rel.), but also made it possible to obtain homogeneous mixtures of dispersed inorganic powders, for example, a clinker encryption preparation, for example, when clinker is charged with sludge incineration ash. The homogeneity of such mixtures experimentally confirms the validity of the proposed mathematical model of the mixing process. The resulting dry mixtures showed the practical invariability of the mechanical strength of the cement stone based on them. The saving of the main binder-clinker was up to 15 wt. %, thus solving the problem of sludge incineration ash utilization
{"title":"ELECTROPHYSICAL INTENSIFICATION AND SIMULATION OF GRINDING AND MIXING OF INORGANIC MATERIALS","authors":"Andrey A. Panferov, G. K. Ivakhnyuk, Nikolay F. Fedorov, Tazhir E. Mametnabiev, A. S. Drinberg","doi":"10.36807/1998-9849-2022-60-86-18-22","DOIUrl":"https://doi.org/10.36807/1998-9849-2022-60-86-18-22","url":null,"abstract":"The working hypothesis previously confirmed at Phosphorit JSC (Kingisepp, Leningrad Region) on the significant effect of static electricity on the efficiency of grinding in cement clinker ball mills was successfully tested at the cement production. The method of electrophysical neutralization of static electricity charges has opened up the possibility not only to increase the productivity of grinders (by 12-18% wt.) or save energy for the electric drive (up to 20% rel.), but also made it possible to obtain homogeneous mixtures of dispersed inorganic powders, for example, a clinker encryption preparation, for example, when clinker is charged with sludge incineration ash. The homogeneity of such mixtures experimentally confirms the validity of the proposed mathematical model of the mixing process. The resulting dry mixtures showed the practical invariability of the mechanical strength of the cement stone based on them. The saving of the main binder-clinker was up to 15 wt. %, thus solving the problem of sludge incineration ash utilization","PeriodicalId":9467,"journal":{"name":"Bulletin of the Saint Petersburg State Institute of Technology (Technical University)","volume":"28 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84855193","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.36807/1998-9849-2022-61-87-39-43
S. Lebedev
Every year, the production volume of electrochromic devices steadily grows; the growth is associated with the spread of energy-saving technologies in many developed countries of the world. These electrochemical products are highly demanded and competitive, but the problems associated with their operation remain unresolved. The aim of the work was to increase the service life of electrochromic devices by determining the optimal ranges of their operation. A new operational evaluation parameter was considered – electrochromic productivity, based on the correlation of optical transmission and consumed electrical energy; the parameter makes it possible to take into account the influence of side uncontrolled processes unrelated to the electrochromic effect. The studies were carried out using the method of multi-stage electrical control actions developed by us. The optimal ranges for the functioning of ECD samples – made using different technologies –were determined; the ranges were from 100% to 40% of light transmission relating to the initial state. The electrochromic productivity for the inorganic technology was 4.8%∙cm2/(mW∙s), and for the organic technology it was 8.0%∙cm2/(mW∙s).
{"title":"DETERMINATION OF THE OPTIMAL MODES OF OPERATION OF ELECTROCHROMIC DEVICES","authors":"S. Lebedev","doi":"10.36807/1998-9849-2022-61-87-39-43","DOIUrl":"https://doi.org/10.36807/1998-9849-2022-61-87-39-43","url":null,"abstract":"Every year, the production volume of electrochromic devices steadily grows; the growth is associated with the spread of energy-saving technologies in many developed countries of the world. These electrochemical products are highly demanded and competitive, but the problems associated with their operation remain unresolved. The aim of the work was to increase the service life of electrochromic devices by determining the optimal ranges of their operation. A new operational evaluation parameter was considered – electrochromic productivity, based on the correlation of optical transmission and consumed electrical energy; the parameter makes it possible to take into account the influence of side uncontrolled processes unrelated to the electrochromic effect. The studies were carried out using the method of multi-stage electrical control actions developed by us. The optimal ranges for the functioning of ECD samples – made using different technologies –were determined; the ranges were from 100% to 40% of light transmission relating to the initial state. The electrochromic productivity for the inorganic technology was 4.8%∙cm2/(mW∙s), and for the organic technology it was 8.0%∙cm2/(mW∙s).","PeriodicalId":9467,"journal":{"name":"Bulletin of the Saint Petersburg State Institute of Technology (Technical University)","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85637631","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.36807/1998-9849-2022-62-88-66-75
V. Loshmanov, A. Kravets
The method of determining the pharmacological properties of a chemical compound based on the prediction of the results of preclinical laboratory tests was presented. The results of preclinical trials are used to obtain information about the safety of the product under development both for the purposes of preclinical studies and throughout the entire drug cycle. The proposed approach makes it possible to determine the presence of specific pharmacological properties of chemicals in the compound intended for preclinical testing. The method includes conducting a factor analysis in order to identify the most significant features that affect the pharmacological activity of the observed synthesized chemical compound. Further, on the basis of the selected factors, a predictive model is built. The model uses data on the quantitative characteristics of the substance and a description of the target involved in the study. The developed approach essentially decreases the period of preclinical studies of new medicines
{"title":"IDENTIFICATION OF THE PHARMACOLOGICAL PROPERTIES OF A CHEMICAL COMPOUND ON THE BASIS OF PREDICTING THE RESULTS OF PRECLINICAL LABORATORY TESTS","authors":"V. Loshmanov, A. Kravets","doi":"10.36807/1998-9849-2022-62-88-66-75","DOIUrl":"https://doi.org/10.36807/1998-9849-2022-62-88-66-75","url":null,"abstract":"The method of determining the pharmacological properties of a chemical compound based on the prediction of the results of preclinical laboratory tests was presented. The results of preclinical trials are used to obtain information about the safety of the product under development both for the purposes of preclinical studies and throughout the entire drug cycle. The proposed approach makes it possible to determine the presence of specific pharmacological properties of chemicals in the compound intended for preclinical testing. The method includes conducting a factor analysis in order to identify the most significant features that affect the pharmacological activity of the observed synthesized chemical compound. Further, on the basis of the selected factors, a predictive model is built. The model uses data on the quantitative characteristics of the substance and a description of the target involved in the study. The developed approach essentially decreases the period of preclinical studies of new medicines","PeriodicalId":9467,"journal":{"name":"Bulletin of the Saint Petersburg State Institute of Technology (Technical University)","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79138680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.36807/1998-9849-2022-61-87-22-26
Alexander F. Alexander F., V. Vinnitskii
The methodological, regulatory and technological aspects of handling radioactive graphite from decommissioned nuclear reactors are discussed. Destructive and decontamination methods of "neutralization" of graphite are considered. An analysis of the feasibility and economic consequences of applying different approaches to the final isolation of graphite waste from industrial and power reactors has been undertaken. Proposals for optimizing the reactor graphite disposal strategy are formulated
{"title":"\"NEUTRALIZATION\" OF REACTOR GRAPHITE: PROBLEMS AND SOLUTIONS","authors":"Alexander F. Alexander F., V. Vinnitskii","doi":"10.36807/1998-9849-2022-61-87-22-26","DOIUrl":"https://doi.org/10.36807/1998-9849-2022-61-87-22-26","url":null,"abstract":"The methodological, regulatory and technological aspects of handling radioactive graphite from decommissioned nuclear reactors are discussed. Destructive and decontamination methods of \"neutralization\" of graphite are considered. An analysis of the feasibility and economic consequences of applying different approaches to the final isolation of graphite waste from industrial and power reactors has been undertaken. Proposals for optimizing the reactor graphite disposal strategy are formulated","PeriodicalId":9467,"journal":{"name":"Bulletin of the Saint Petersburg State Institute of Technology (Technical University)","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74137862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.36807/1998-9849-2022-60-86-23-27
V. Lipin, Teodor G. Milberger, E. Gorbachev, D. M. Shapot, Sergey N. Akhmedov
Phosphogypsum is a waste product in the production of phosphoric acid and can be considered as a raw material for the production of various types of mineral fertilizers. As a result of the conducted research, technical solutions for processing phosphogypsum with the production of granular mineral fertilizers are proposed: type P with a content of assimilable phosphorus of more than 49%; type PKS with a content of phosphorus of 28%, potassium of 28%, sulfur of 10%; type NPKS with a content of nitrogen of 15%, phosphorus of 15%, potassium of 15%, sulfur of 10%; type NS with a nitrogen content of 30%. The resulting fertilizers contain a set of trace elements and have a granule strength above 4 MPa
{"title":"DEVELOPMENT OF TECHNICAL SOLUTIONS FOR THE PRODUCTION OF HYBRID FERTILIZERS FROM PHOSPHOGYPSUM","authors":"V. Lipin, Teodor G. Milberger, E. Gorbachev, D. M. Shapot, Sergey N. Akhmedov","doi":"10.36807/1998-9849-2022-60-86-23-27","DOIUrl":"https://doi.org/10.36807/1998-9849-2022-60-86-23-27","url":null,"abstract":"Phosphogypsum is a waste product in the production of phosphoric acid and can be considered as a raw material for the production of various types of mineral fertilizers. As a result of the conducted research, technical solutions for processing phosphogypsum with the production of granular mineral fertilizers are proposed: type P with a content of assimilable phosphorus of more than 49%; type PKS with a content of phosphorus of 28%, potassium of 28%, sulfur of 10%; type NPKS with a content of nitrogen of 15%, phosphorus of 15%, potassium of 15%, sulfur of 10%; type NS with a nitrogen content of 30%. The resulting fertilizers contain a set of trace elements and have a granule strength above 4 MPa","PeriodicalId":9467,"journal":{"name":"Bulletin of the Saint Petersburg State Institute of Technology (Technical University)","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86135046","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.36807/1998-9849-2022-60-86-3-6
F. al-Saeedi
In this work, glasses were synthesized based on the ternary system Li2O–Al2O3–SiO2 (LAS). The composition was modified by increasing the total concentration of alkali oxides, which made it possible to reduce the synthesis temperature to 1580 ͦС. X-ray phase analysis and dilatometric measurements have shown that the growth of LiAlSi3O8 solid solutions with a negative CTE occurs at temperatures close to the glass transition temperature in a limited time interval, which leads to an insignificant decrease in the CTE of glass ceramics. It has been found that an increase in the time and temperature of heat treatment leads to the growth of LiAlSi2O6 spodumen nanocrystals. Thus, the introduction of high concentrations of alkali oxides does not allow achieving the desired effect of lowering the thermal expansion coefficient
{"title":"EFFECT OF AN INCREASE IN THE SODIUM AND LITHIUM OXIDES CONTENT ON THE PROCESS OF CRYSTALLIZATION OF GLASSES IN THE Li2O–Al2O3–SiO2 SYSTEM","authors":"F. al-Saeedi","doi":"10.36807/1998-9849-2022-60-86-3-6","DOIUrl":"https://doi.org/10.36807/1998-9849-2022-60-86-3-6","url":null,"abstract":"In this work, glasses were synthesized based on the ternary system Li2O–Al2O3–SiO2 (LAS). The composition was modified by increasing the total concentration of alkali oxides, which made it possible to reduce the synthesis temperature to 1580 ͦС. X-ray phase analysis and dilatometric measurements have shown that the growth of LiAlSi3O8 solid solutions with a negative CTE occurs at temperatures close to the glass transition temperature in a limited time interval, which leads to an insignificant decrease in the CTE of glass ceramics. It has been found that an increase in the time and temperature of heat treatment leads to the growth of LiAlSi2O6 spodumen nanocrystals. Thus, the introduction of high concentrations of alkali oxides does not allow achieving the desired effect of lowering the thermal expansion coefficient","PeriodicalId":9467,"journal":{"name":"Bulletin of the Saint Petersburg State Institute of Technology (Technical University)","volume":"417 1-2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77844194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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