Pub Date : 2024-01-03DOI: 10.59957/jctm.v59.i1.2024.21
I. Volokitina, A. Volokitin, Gulnara Ulyeva, Elisey Khlopkov, Oxana Maldina
Combined innovative technology developed in this article makes it possible to produce bimetallic long products in the form of bars and wires with improved mechanical properties, due to the ultrafine grain structure of the material, with less energy and labor costs and implementation of continuity principle in industrial enterprises of metal-working industry. The combination of equal-channel angular pressing with drawing makes it possible not only to harden the composition, but at the same time to preserve important and regulated by a number of GOST plastic properties of the products. This circumstance favorably distinguishes the method under study from other (traditional) types of deformation treatment.
{"title":"DEVELOPMENT OF RECOMMENDATIONS FOR THE IMPLEMENTATION OF COMBINED DEFORMATION TREATMENT “ECAP-DRAWING” INTO PRODUCTION","authors":"I. Volokitina, A. Volokitin, Gulnara Ulyeva, Elisey Khlopkov, Oxana Maldina","doi":"10.59957/jctm.v59.i1.2024.21","DOIUrl":"https://doi.org/10.59957/jctm.v59.i1.2024.21","url":null,"abstract":"Combined innovative technology developed in this article makes it possible to produce bimetallic long products in the form of bars and wires with improved mechanical properties, due to the ultrafine grain structure of the material, with less energy and labor costs and implementation of continuity principle in industrial enterprises of metal-working industry. The combination of equal-channel angular pressing with drawing makes it possible not only to harden the composition, but at the same time to preserve important and regulated by a number of GOST plastic properties of the products. This circumstance favorably distinguishes the method under study from other (traditional) types of deformation treatment.","PeriodicalId":38363,"journal":{"name":"Journal of Chemical Technology and Metallurgy","volume":"4 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139388698","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 : 2024-01-03DOI: 10.59957/jctm.v59.i1.2024.15
M. Najar, Amrita Karn, P. Nageshwar, Pravin Bhukte, Mukesh Chaddha, Anupam Agnihotri
Physico-chemical treatment was adopted for processing alumino-siliceous lithomarg clay known as saprolite. The study explained the potential of utilizing saprolite clay as fast resource for recovering silica mineral phases for value added utilization of unused mining reject. The conversion of saprolite to silica enriched low iron precursor was achieved by chemical activation with 1:1 v/v aqueous hydrochloric acid. Recovery of nano-silicate was achieved from the low iron precursor by dissolution in aqueous sodium hydroxide followed by precipitation in acid medium and centrifugation. Physical characterization of silicate nano particle was accomplished by scanning electron microscopy (SEM) and the range of impurities was determined by inductively coupled plasma (ICP) analysis.
{"title":"PROCESS FOR RECOVERING SILICA FROM LITHOMARG CLAY: VALUE ADDITION OF UNEXPLOITEDMINING REJECT","authors":"M. Najar, Amrita Karn, P. Nageshwar, Pravin Bhukte, Mukesh Chaddha, Anupam Agnihotri","doi":"10.59957/jctm.v59.i1.2024.15","DOIUrl":"https://doi.org/10.59957/jctm.v59.i1.2024.15","url":null,"abstract":"Physico-chemical treatment was adopted for processing alumino-siliceous lithomarg clay known as saprolite. The study explained the potential of utilizing saprolite clay as fast resource for recovering silica mineral phases for value added utilization of unused mining reject. The conversion of saprolite to silica enriched low iron precursor was achieved by chemical activation with 1:1 v/v aqueous hydrochloric acid. Recovery of nano-silicate was achieved from the low iron precursor by dissolution in aqueous sodium hydroxide followed by precipitation in acid medium and centrifugation. Physical characterization of silicate nano particle was accomplished by scanning electron microscopy (SEM) and the range of impurities was determined by inductively coupled plasma (ICP) analysis.","PeriodicalId":38363,"journal":{"name":"Journal of Chemical Technology and Metallurgy","volume":"15 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139388886","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 : 2024-01-03DOI: 10.59957/jctm.v59.i2.2024.7
Margarita Koleva, D. Angelova, D. Zheleva
In recent decades, interest in oxide nanomaterials with multifunctional properties has grown significantly. Titanium dioxide undoubtedly belongs to them, characterized by exceptional photocatalytic activity, non-toxicity, high availability, biocompatibility, antibacterial properties, and low cost. The treatment of textile materials with TiO2 nanoparticles is relatively simple, but the insufficient bonding efficiency between certain fibers and TiO 2 nanoparticles creates a problem regarding the stability and durability of the nanocomposites. In this study, an attempt was made to improve the properties of cotton modified with gelatin hydrogel, which was cross-linked by glutaraldehyde, and incorporated titanium nanoparticles. Three modification methods were applied, varying the mixing regimes of the components and the conditions. The composite materials were investigated via SEM, FTIR, UV-Vis and elemental analysis.For the first time, titanium nanoparticles obtained by the reduction of TiO2 with oxalic acid were used to modify cotton. Cotton samples were modified with gelatin hydrogel cross-linked with glutaraldehyde to increase the active groups of cellulose fibers that bind to Ti ions. Using the hydrogel, the nanoparticles are deposited on the surface of the textile substrate. The elemental analysis shows the presence of TiO2 nanoparticles. Lines for Ti atoms appear, which is evidence that the particles retain their composition after immobilization. Microscopic analyzes showed that TiO2 nanoparticles were distributed unevenly in the cotton matrix. In the UV analysis, the appearance of a new absorption at 890 cm-1 was observed due to the attachment of Ti-NPs. The appearance of the IR peak at 878 cm-1 confirms the formation of chelate complexes of the nanoparticles in the composite material.
{"title":"METHODS FOR THE SYNTHESIS OF TiO2 NANOPARTICLES. PROPERTIES OF TEXTILE MATERIALS TREATED WITH TiO2 NANOPARTICLES","authors":"Margarita Koleva, D. Angelova, D. Zheleva","doi":"10.59957/jctm.v59.i2.2024.7","DOIUrl":"https://doi.org/10.59957/jctm.v59.i2.2024.7","url":null,"abstract":"In recent decades, interest in oxide nanomaterials with multifunctional properties has grown significantly. Titanium dioxide undoubtedly belongs to them, characterized by exceptional photocatalytic activity, non-toxicity, high availability, biocompatibility, antibacterial properties, and low cost. The treatment of textile materials with TiO2 nanoparticles is relatively simple, but the insufficient bonding efficiency between certain fibers and TiO 2 nanoparticles creates a problem regarding the stability and durability of the nanocomposites. In this study, an attempt was made to improve the properties of cotton modified with gelatin hydrogel, which was cross-linked by glutaraldehyde, and incorporated titanium nanoparticles. Three modification methods were applied, varying the mixing regimes of the components and the conditions. The composite materials were investigated via SEM, FTIR, UV-Vis and elemental analysis.For the first time, titanium nanoparticles obtained by the reduction of TiO2 with oxalic acid were used to modify cotton. Cotton samples were modified with gelatin hydrogel cross-linked with glutaraldehyde to increase the active groups of cellulose fibers that bind to Ti ions. Using the hydrogel, the nanoparticles are deposited on the surface of the textile substrate. The elemental analysis shows the presence of TiO2 nanoparticles. Lines for Ti atoms appear, which is evidence that the particles retain their composition after immobilization. Microscopic analyzes showed that TiO2 nanoparticles were distributed unevenly in the cotton matrix. In the UV analysis, the appearance of a new absorption at 890 cm-1 was observed due to the attachment of Ti-NPs. The appearance of the IR peak at 878 cm-1 confirms the formation of chelate complexes of the nanoparticles in the composite material.","PeriodicalId":38363,"journal":{"name":"Journal of Chemical Technology and Metallurgy","volume":"226 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140514505","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 : 2024-01-03DOI: 10.59957/jctm.v59.i2.2024.20
Ekaterina Serafimova, K. Dedelyanova
Mining sector has been the central attention of the business and public policy sustainable development scheme for several years. Reclamation territories are with potential carbon sequestration capacity in degraded mining areas and can be an impeccable option for achieving sustainable development goal-13. This paper made an investigation about the presence of heavy metals in reclaimed area possibilities to improve reclaimed soils with biochar with idea to enhance ecosystem carbon pool and atmospheric CO2 sequestration capacity to offset CO2 emission and soil organic carbon losses. The results show that the carbon content in biochar is 46.6 % and would be classified in class 2 according to the International Biochar Initiative. H/C and O/C atomic ratios could be useful for restoration of degraded poor mine soils through enhanced carbon sequestration. O/C ratio is 0.085 mol mol–1 and half-life of biochar is 2795.65 years, which confirm the biochar stability. For each kilogram of biochar incorporated into the soil, 144 g of carbon were sequestrated 52,8 % CO2 emission reduction. Hence, the biochar developed in this study can be used in carbon-deficient soils with the added benefit of long-term carbon storage.
{"title":"THE POTENTIAL FOR CARBON SEQUESTRATION IN RECLAIMED MINE SOIL","authors":"Ekaterina Serafimova, K. Dedelyanova","doi":"10.59957/jctm.v59.i2.2024.20","DOIUrl":"https://doi.org/10.59957/jctm.v59.i2.2024.20","url":null,"abstract":"Mining sector has been the central attention of the business and public policy sustainable development scheme for several years. Reclamation territories are with potential carbon sequestration capacity in degraded mining areas and can be an impeccable option for achieving sustainable development goal-13. This paper made an investigation about the presence of heavy metals in reclaimed area possibilities to improve reclaimed soils with biochar with idea to enhance ecosystem carbon pool and atmospheric CO2 sequestration capacity to offset CO2 emission and soil organic carbon losses. The results show that the carbon content in biochar is 46.6 % and would be classified in class 2 according to the International Biochar Initiative. H/C and O/C atomic ratios could be useful for restoration of degraded poor mine soils through enhanced carbon sequestration. O/C ratio is 0.085 mol mol–1 and half-life of biochar is 2795.65 years, which confirm the biochar stability. For each kilogram of biochar incorporated into the soil, 144 g of carbon were sequestrated 52,8 % CO2 emission reduction. Hence, the biochar developed in this study can be used in carbon-deficient soils with the added benefit of long-term carbon storage.","PeriodicalId":38363,"journal":{"name":"Journal of Chemical Technology and Metallurgy","volume":"277 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140514378","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 : 2024-01-03DOI: 10.59957/jctm.v59.i1.2024.18
Kenzhebek Rustembekov, A. Toibek, Mitko Stoev, Gulim Mukusheva, Timur Sadykov
The aim of this work was to synthesize and investigate the roentgenographic and electro-physical properties of new phases, namely double tellurites of neodymium. Oxotellurites of the composition NdMeIITeO4.5(MeII - Ca, Ba) were synthesized by the method of ceramic technology with high-temperature interaction of Nd2O3, TeO2 oxides with carbonates of alkaline earth metals in the interval of 800°С - 1200°С. Roentgenograms of the synthesized compounds were obtained using an Empyrean powder diffractometer by PANalytical and indication was determined using the X’Pert HighScore Plus program. It was found that the synthesized tellurites were crystallized in tetragonal syngony. The unit cell parameters, roentgen and pycnometric densities of the compounds were determined. It was revealed that with increasing ionic radii from Ca to Ba, the lattice parameters and unit cell volumes of synthesized tellurites increase. The assumed structure of the synthesized double tellurites of neodymium is a distorted perovskite structure. A study of the temperature dependence of the dielectric permittivity and electrical resistance of tellurites of neodymium-alkaline earth metals established that they can possess semiconducting properties at 293 K - 483 K. Temperature coefficients of resistance and forbidden zone width of tellurites were calculated.
这项工作的目的是合成和研究新阶段（即钕的双碲化物）的射线照相和电物理特性。通过 Nd2O3、TeO2 氧化物与碱土金属碳酸盐在 800°С - 1200°С 高温下相互作用的陶瓷技术方法，合成了成分为 NdMeIITeO4.5(MeII-Ca，Ba) 的氧化碲。使用 PANalytical 公司的 Empyrean 粉末衍射仪获得了合成化合物的伦琴射线图，并使用 X'Pert HighScore Plus 程序确定了指示。结果发现，合成的碲化物呈四方共晶。测定了化合物的单胞参数、伦琴密度和焦耳密度。结果表明，随着离子半径从 Ca 到 Ba 的增加，合成碲化物的晶格参数和单胞体积也随之增加。合成的钕双碲化物的假定结构是一种扭曲的包晶结构。对钕碱土金属碲的介电常数和电阻的温度依赖性的研究表明，它们在 293 K - 483 K 时具有半导体特性。
{"title":"SYNTHESIS AND PROPERTIES OF NdMeIITeO4.5 (MeII – Ca,Ba) TELLURITES","authors":"Kenzhebek Rustembekov, A. Toibek, Mitko Stoev, Gulim Mukusheva, Timur Sadykov","doi":"10.59957/jctm.v59.i1.2024.18","DOIUrl":"https://doi.org/10.59957/jctm.v59.i1.2024.18","url":null,"abstract":"The aim of this work was to synthesize and investigate the roentgenographic and electro-physical properties of new phases, namely double tellurites of neodymium. Oxotellurites of the composition NdMeIITeO4.5(MeII - Ca, Ba) were synthesized by the method of ceramic technology with high-temperature interaction of Nd2O3, TeO2 oxides with carbonates of alkaline earth metals in the interval of 800°С - 1200°С. Roentgenograms of the synthesized compounds were obtained using an Empyrean powder diffractometer by PANalytical and indication was determined using the X’Pert HighScore Plus program. It was found that the synthesized tellurites were crystallized in tetragonal syngony. The unit cell parameters, roentgen and pycnometric densities of the compounds were determined. It was revealed that with increasing ionic radii from Ca to Ba, the lattice parameters and unit cell volumes of synthesized tellurites increase. The assumed structure of the synthesized double tellurites of neodymium is a distorted perovskite structure. A study of the temperature dependence of the dielectric permittivity and electrical resistance of tellurites of neodymium-alkaline earth metals established that they can possess semiconducting properties at 293 K - 483 K. Temperature coefficients of resistance and forbidden zone width of tellurites were calculated.","PeriodicalId":38363,"journal":{"name":"Journal of Chemical Technology and Metallurgy","volume":"13 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139451276","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 : 2024-01-03DOI: 10.59957/jctm.v59.i2.2024.23
Emil Mihailov, Ivanka Petrova, Monika Asenova
The continuous nature of metallurgical technologies and the intensification of production increase the risk of damage to high-temperature equipment during the technological process. The destruction of the structural integrity of the refractory insulation of this equipment leads to the forced interruption of production and significant costs of emergency response and require measures to be taken to reduce the risk of such situations. An opportunity to solve these problems in the metallurgical industry is the introduction into the production process of sustainable systems for making informed decisions and predictive maintenance of equipment, based on continuous or periodic monitoring of the condition of refractory insulation of high-temperature furnaces and auxiliary equipment. Predictive maintenance of technological equipment and aggregates, based on an assessment of their current condition, extends their life, reduces downtime, maintains the optimal level of production, and guarantees compliance with the exact delivery time of production (raw materials, materials, energy). A procedure is presented for assessing the real condition of steel ladles based on periodic monitoring results as part of a decision-making system for predictive and safe use of their maximum resource.
{"title":"CONDITION BASED ASSESSMENT FOR PREDICTIVE MAINTENANCE OF METALLURGICAL EQUIPMENT","authors":"Emil Mihailov, Ivanka Petrova, Monika Asenova","doi":"10.59957/jctm.v59.i2.2024.23","DOIUrl":"https://doi.org/10.59957/jctm.v59.i2.2024.23","url":null,"abstract":"The continuous nature of metallurgical technologies and the intensification of production increase the risk of damage to high-temperature equipment during the technological process. The destruction of the structural integrity of the refractory insulation of this equipment leads to the forced interruption of production and significant costs of emergency response and require measures to be taken to reduce the risk of such situations. An opportunity to solve these problems in the metallurgical industry is the introduction into the production process of sustainable systems for making informed decisions and predictive maintenance of equipment, based on continuous or periodic monitoring of the condition of refractory insulation of high-temperature furnaces and auxiliary equipment. \u0000Predictive maintenance of technological equipment and aggregates, based on an assessment of their current condition, extends their life, reduces downtime, maintains the optimal level of production, and guarantees compliance with the exact delivery time of production (raw materials, materials, energy). A procedure is presented for assessing the real condition of steel ladles based on periodic monitoring results as part of a decision-making system for predictive and safe use of their maximum resource.","PeriodicalId":38363,"journal":{"name":"Journal of Chemical Technology and Metallurgy","volume":"159 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140514632","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 : 2024-01-03DOI: 10.59957/jctm.v59.i2.2024.10
B. Lucheva, P. Iliev, Nadezda Kazakova, Miroslav Iliev
Soda smelting slag is generated during the processing of desulphurized paste from recycling of waste lead acid batteries and other lead containing secondary materials in tilting rotary furnaces, and it represents about 9.5 % of the mass of the charge entering the furnace. This type of slag is very reactive. It contains toxic substances (lead, arsenic and antimony) and because of the presence of alkaline compounds it is corrosive. In addition, it decomposes in contact with air, forming dust. Therefore, such hazardous product cannot be disposed without preliminary stabilization. The aim of the present work is to investigate the possibility for environmentally utilization of this slag. The conducted experiments have shown the possibility of extracting the sodium sulfate from the soda slag only by grinding in an aqueous medium with subsequent filtration. The resulting solution is subjected to sulfide purification from heavy non-ferrous metals and subsequent crystallization for obtaining a commercial product sodium sulfate. These processes could be easily implemented in companies that have applied Engitec’s technology for recycling spent lead-acid batteries and production of sodium sulfate from desulfurization of the lead paste. Implementation of these processes will eliminate the need for slag stabilization and prevent environmental problems.
{"title":"OBTAINING Na2SO4 FROM SODA SMELTING SLAG FROM THE RECYCLING OF LEAD ACID BATTERIES","authors":"B. Lucheva, P. Iliev, Nadezda Kazakova, Miroslav Iliev","doi":"10.59957/jctm.v59.i2.2024.10","DOIUrl":"https://doi.org/10.59957/jctm.v59.i2.2024.10","url":null,"abstract":"Soda smelting slag is generated during the processing of desulphurized paste from recycling of waste lead acid batteries and other lead containing secondary materials in tilting rotary furnaces, and it represents about 9.5 % of the mass of the charge entering the furnace. This type of slag is very reactive. It contains toxic substances (lead, arsenic and antimony) and because of the presence of alkaline compounds it is corrosive. In addition, it decomposes in contact with air, forming dust. Therefore, such hazardous product cannot be disposed without preliminary stabilization. \u0000The aim of the present work is to investigate the possibility for environmentally utilization of this slag. The conducted experiments have shown the possibility of extracting the sodium sulfate from the soda slag only by grinding in an aqueous medium with subsequent filtration. The resulting solution is subjected to sulfide purification from heavy non-ferrous metals and subsequent crystallization for obtaining a commercial product sodium sulfate. These processes could be easily implemented in companies that have applied Engitec’s technology for recycling spent lead-acid batteries and production of sodium sulfate from desulfurization of the lead paste. Implementation of these processes will eliminate the need for slag stabilization and prevent environmental problems.","PeriodicalId":38363,"journal":{"name":"Journal of Chemical Technology and Metallurgy","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140514774","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 : 2024-01-03DOI: 10.59957/jctm.v59.i2.2024.21
Tihomir Petrov, L. Aljihmani
Cobalt, nickel, copper, and tin nanosized particles were synthesized through a borohydride reduction method with a reducing agent of NaBH4. The reductive precipitation was carried out at room temperature and atmospheric pressure. The nanoparticle powders were synthesized from water solutions of sulfate salts. The obtained nanosized particles were investigated by scanning electron microscopy (SEM) and XRD analyses. The SEM micrographs showed the nanoparticles’ morphology and structure. The chemical elements’ distribution was determined by energy dispersive spectroscopy (EDS) analysis. The X-ray diffraction (XRD) analysis determined the phase composition and state (amorphous or crystalline).
{"title":"SYNTHESIS AND PHYSICO-CHEMICAL STUDY OF Co, Ni, Cu, AND Sn NANOPARTICLES","authors":"Tihomir Petrov, L. Aljihmani","doi":"10.59957/jctm.v59.i2.2024.21","DOIUrl":"https://doi.org/10.59957/jctm.v59.i2.2024.21","url":null,"abstract":"Cobalt, nickel, copper, and tin nanosized particles were synthesized through a borohydride reduction method with a reducing agent of NaBH4. The reductive precipitation was carried out at room temperature and atmospheric pressure. The nanoparticle powders were synthesized from water solutions of sulfate salts. The obtained nanosized particles were investigated by scanning electron microscopy (SEM) and XRD analyses. The SEM micrographs showed the nanoparticles’ morphology and structure. The chemical elements’ distribution was determined by energy dispersive spectroscopy (EDS) analysis. The X-ray diffraction (XRD) analysis determined the phase composition and state (amorphous or crystalline).","PeriodicalId":38363,"journal":{"name":"Journal of Chemical Technology and Metallurgy","volume":"65 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140514775","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 : 2024-01-03DOI: 10.59957/jctm.v59.i2.2024.29
Silvia Traykova, L. Radev
Given the complexity of the learning content, in modern engineering education, the need for feedback from the students is also relevant. Not only during an exam when they demonstrate the outcomes of their studying. There is a need to research students’ opinions on effective communication with teachers, teaching methods and assessment. The goal of this publication is to show the results of a study conducted with students in the Fundamentals of Chemical and Metallurgical Technologies (FCME) major at the University of Chemical Technology and Metallurgy (UCTM), Sofia. Students’ opinions are presented regarding the teacher’s requirements for independent work and presentation of results, teaching methods and assessment of knowledge and skills. Respondents were third year full-time and part-time students at the Faculty of Chemical Technologies, major FCME. The outcomes of the study we conducted demonstrate that the use of different methods of teaching and assessment, as part of it, including giving tasks for self-assessment, increase students’ understanding and satisfaction of the learning process. Good communication between teachers and students, clear work requirements and criteria make the course content and assessment more understandable and meaningful for the students. They become active participants in the learning process, which leads to exhibited responsibility and commitment towards it.
{"title":"SIGNIFICANCE OF ASSESSMENT AND COMMUNICATION WITH THE TEACHER IN THE CHEMICAL TECHNOLOGY LEARNING PROCESS","authors":"Silvia Traykova, L. Radev","doi":"10.59957/jctm.v59.i2.2024.29","DOIUrl":"https://doi.org/10.59957/jctm.v59.i2.2024.29","url":null,"abstract":"Given the complexity of the learning content, in modern engineering education, the need for feedback from the students is also relevant. Not only during an exam when they demonstrate the outcomes of their studying. There is a need to research students’ opinions on effective communication with teachers, teaching methods and assessment. The goal of this publication is to show the results of a study conducted with students in the Fundamentals of Chemical and Metallurgical Technologies (FCME) major at the University of Chemical Technology and Metallurgy (UCTM), Sofia. Students’ opinions are presented regarding the teacher’s requirements for independent work and presentation of results, teaching methods and assessment of knowledge and skills. Respondents were third year full-time and part-time students at the Faculty of Chemical Technologies, major FCME. \u0000The outcomes of the study we conducted demonstrate that the use of different methods of teaching and assessment, as part of it, including giving tasks for self-assessment, increase students’ understanding and satisfaction of the learning process. Good communication between teachers and students, clear work requirements and criteria make the course content and assessment more understandable and meaningful for the students. They become active participants in the learning process, which leads to exhibited responsibility and commitment towards it. ","PeriodicalId":38363,"journal":{"name":"Journal of Chemical Technology and Metallurgy","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140514803","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 : 2024-01-03DOI: 10.59957/jctm.v59.i2.2024.18
Ekaterina Serafimova, Asya K. Manoylova, Vilma Stoyanova
The main part of companies in Bulgaria are built, however in the 70s, and upgraded last decade. The countrysupplies around 80 % of its supplies of paper, paperboard and pulp with own production. Integrated treatment ofwastes is a priority for realizing closed life cycle of materials. The aim of the present work is to investigate thecomposition and other important characteristics of biomass wood ash wasted from paper industry. The correlationsand associations among the chemical characteristics are also studied to find some basic trends and importantrelationships between two similar wastes from different enterprises. It was proved that all samples taken containedBa, Cr, Mn, Ni, Co, Al, Fe, Cu and Zn far below the legal limits for such type of products. A product has a certain anti-acidic effect. The other positive result was that the content of iron is between 34 to 60 mg per 1 kg dry waste. The microscopic photos confirmed that the particles are close to the nano-size materials. The content of the elements C, N, H is in good quantities and ratios, which is a prerequisite for their use as a soil improver. By the results of this study, it was confirmed that all samples produced as a result of the thermal treatment and final low water content achieved are free from pathogen microorganisms and different weed seeds, affecting the yield and soil sustainability. That allows determining the optimal ratio between the used components with a view to obtain products with desired thermal stability and physico-chemical properties as soil improvers.
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