A nanometric Mg(OH)2 and MgO particles with high purity were successfully synthesized from Algerian dolomite via a leaching-precipitation-calcination process. The effect of leaching parameters such as H2SO4 acid concentration (C), temperature (T), time (t), solid/liquid ratio (S/L), and precipitation parameters: type of precipitating base (KOH, NaOH, NH4OH), OH-/Mg2+ ratio, and temperature on the obtained product properties were investigated using Taguchi approach. The optimal leaching conditions were selected as: C=5M, T=65?C, t=15 min, and S/L ratio=1:5. Whereas, the potassium hydroxide (KOH) was selected as the optimal precipitating base with OH-/Mg2+ = 10.5. The calcination of the precipitates at 800?C during 2 h made it possible to produce a high purity MgO (~99.45 %) with a crystallite size of approximately 16.5 nm and particles in the form of agglomerated porous plates with a high SSA (70.42 m2/g) which may be of interest for some applications such as catalysts or supports.
{"title":"Synthesis of high purity magnesia MgO from Algerian dolomite ore","authors":"C. Bouchekrit, M. Kolli, M. Altiner, R. Doufnoune","doi":"10.2298/jmmb220406005b","DOIUrl":"https://doi.org/10.2298/jmmb220406005b","url":null,"abstract":"A nanometric Mg(OH)2 and MgO particles with high purity were successfully synthesized from Algerian dolomite via a leaching-precipitation-calcination process. The effect of leaching parameters such as H2SO4 acid concentration (C), temperature (T), time (t), solid/liquid ratio (S/L), and precipitation parameters: type of precipitating base (KOH, NaOH, NH4OH), OH-/Mg2+ ratio, and temperature on the obtained product properties were investigated using Taguchi approach. The optimal leaching conditions were selected as: C=5M, T=65?C, t=15 min, and S/L ratio=1:5. Whereas, the potassium hydroxide (KOH) was selected as the optimal precipitating base with OH-/Mg2+ = 10.5. The calcination of the precipitates at 800?C during 2 h made it possible to produce a high purity MgO (~99.45 %) with a crystallite size of approximately 16.5 nm and particles in the form of agglomerated porous plates with a high SSA (70.42 m2/g) which may be of interest for some applications such as catalysts or supports.","PeriodicalId":51090,"journal":{"name":"Journal of Mining and Metallurgy Section B-Metallurgy","volume":"145 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89064654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The recovery of metals from used lithium-ion battery cathode materials is of both environmental and economic importance. In this study, acid leaching stepwise precipitation was used to separate and recover lithium, iron, and manganese from the mixed cathode material LiFePO4/LiMn2O4. The thermodynamic characteristics of lithium, iron, and manganese metal phases, especially the stability region, were analyzed by Eh-pH diagrams. The sulfuric acid and hydrogen peroxide leaching system released Fe3+, Mn2+, and Li+ ions from the cathode material. Fe3+ in the leaching solution was precipitated as Fe(OH)3 and finally recovered as Fe2O3 after calcination. Mn2+ in the leaching solution was recovered as MnCO3. The remaining Li+-rich solution was evaporated and crystallized into Li2CO3. The purity of the recycled products MnCO3 and Li2CO3 met the standard of cathode materials for lithium-ion batteries. XRD and XPS analysis showed that the main phase in the leaching residue was FePO4. This process can be used to separate and recover metals from mixed waste lithium-ion battery cathode materials, and it also provides raw materials for the preparation of lithium-ion battery cathode materials.
{"title":"Recovery of Li, Mn, and Fe from LiFePO4/LiMn2O4 mixed waste lithium-ion battery cathode materials","authors":"Y.-H. Wang, J. Wu, Guijuan Hu, W. Ma","doi":"10.2298/jmmb220918002w","DOIUrl":"https://doi.org/10.2298/jmmb220918002w","url":null,"abstract":"The recovery of metals from used lithium-ion battery cathode materials is of both environmental and economic importance. In this study, acid leaching stepwise precipitation was used to separate and recover lithium, iron, and manganese from the mixed cathode material LiFePO4/LiMn2O4. The thermodynamic characteristics of lithium, iron, and manganese metal phases, especially the stability region, were analyzed by Eh-pH diagrams. The sulfuric acid and hydrogen peroxide leaching system released Fe3+, Mn2+, and Li+ ions from the cathode material. Fe3+ in the leaching solution was precipitated as Fe(OH)3 and finally recovered as Fe2O3 after calcination. Mn2+ in the leaching solution was recovered as MnCO3. The remaining Li+-rich solution was evaporated and crystallized into Li2CO3. The purity of the recycled products MnCO3 and Li2CO3 met the standard of cathode materials for lithium-ion batteries. XRD and XPS analysis showed that the main phase in the leaching residue was FePO4. This process can be used to separate and recover metals from mixed waste lithium-ion battery cathode materials, and it also provides raw materials for the preparation of lithium-ion battery cathode materials.","PeriodicalId":51090,"journal":{"name":"Journal of Mining and Metallurgy Section B-Metallurgy","volume":"263 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74058267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ü. Başkaya, R. Uzun, K. Davut, Y. Kiliç, O. Gündüz
The relation between microstructure, crystallographic texture and hydrogen diffusion has been studied in an IF-steel. The steel samples were deep drawn until 10%, 20%, 30% and 40% strain levels and then hydrogen diffusion coefficients were determined using Helios II system. Light optical microscope (LOM), scanning electron microscope (SEM) and electron backscatter diffraction (EBSD) were used for microstructural characterization and crystallographic texture studies. The dependence of microstructural parameters was evaluated by Pearson correlation coefficient (PCC) values. Those evaluations showed that local misorientations, crystallographic texture and dislocation density depend on each other. The PCC values show that grain size and dislocation density are the independent microstructure related parameters and those parameters were used to build a model to predict hydrogen diffusion coefficient by multiple linear regression analysis. Using this model sensitivity analysis was also performed to understand which parameter the hydrogen diffusion is most sensitive to. The results of this analysis show that hydrogen diffusion is more sensitive to dislocation density, which indicates that dislocations are more effective trapping sites for hydrogen atoms. On the other hand, grain boundaries are less effective trapping sites since they also provide an additional diffusion mechanism.
{"title":"Influence of microstructure and crystallographic texture on hydrogen diffusion in IF-steel","authors":"Ü. Başkaya, R. Uzun, K. Davut, Y. Kiliç, O. Gündüz","doi":"10.2298/jmmb230201025b","DOIUrl":"https://doi.org/10.2298/jmmb230201025b","url":null,"abstract":"The relation between microstructure, crystallographic texture and hydrogen diffusion has been studied in an IF-steel. The steel samples were deep drawn until 10%, 20%, 30% and 40% strain levels and then hydrogen diffusion coefficients were determined using Helios II system. Light optical microscope (LOM), scanning electron microscope (SEM) and electron backscatter diffraction (EBSD) were used for microstructural characterization and crystallographic texture studies. The dependence of microstructural parameters was evaluated by Pearson correlation coefficient (PCC) values. Those evaluations showed that local misorientations, crystallographic texture and dislocation density depend on each other. The PCC values show that grain size and dislocation density are the independent microstructure related parameters and those parameters were used to build a model to predict hydrogen diffusion coefficient by multiple linear regression analysis. Using this model sensitivity analysis was also performed to understand which parameter the hydrogen diffusion is most sensitive to. The results of this analysis show that hydrogen diffusion is more sensitive to dislocation density, which indicates that dislocations are more effective trapping sites for hydrogen atoms. On the other hand, grain boundaries are less effective trapping sites since they also provide an additional diffusion mechanism.","PeriodicalId":51090,"journal":{"name":"Journal of Mining and Metallurgy Section B-Metallurgy","volume":"189 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81064007","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Yang, Z.L. Wu, K. Ren, P. Dong, D. Zhang, B. Yang, F. Liang
Thermodynamic behavior has been extensively used to evaluate the stability of materials and predict the direction of the chemical reaction at different pH values, temperatures, potentials, and ion concentrations. Although researching efforts on Sn species in an aqueous solution system (Sn/H2O) of acid, alkali, and salt have been reported, scattered data leads to the inefficiency of a thermodynamic method in the practical application. This article provides a brief review on the potential-pH diagram for Sn/H2O system, which reflects the thermodynamic behavior of Sn species in an aqueous solution and extracts thermodynamic data for the practical application of Sn species. Firstly, the relationship of the thermodynamic behavior, potential-pH diagram, and equilibrium relations of Sn species for Sn/H2O system was overviewed. Additionally, the potential-pH diagram of Sn/H2O system at different temperatures (298 K, 373 K, and 550 K), dissolved Sn activities (1, 10?1, 10?3, and 10?6), and the potential-pH diagram of the Sn species in achloridion aqueous solution (Sn/H2O-Cl)was summarized. Finally, the application prospect of the potential-pH diagram for Sn/H2O system is prospected in the intelligent simulation of Sn metallurgy and the practical application of Sn materials.
{"title":"Recent advances of the thermodynamic behavior of tin species in aqueous solution","authors":"D. Yang, Z.L. Wu, K. Ren, P. Dong, D. Zhang, B. Yang, F. Liang","doi":"10.2298/jmmb220617001y","DOIUrl":"https://doi.org/10.2298/jmmb220617001y","url":null,"abstract":"Thermodynamic behavior has been extensively used to evaluate the stability of materials and predict the direction of the chemical reaction at different pH values, temperatures, potentials, and ion concentrations. Although researching efforts on Sn species in an aqueous solution system (Sn/H2O) of acid, alkali, and salt have been reported, scattered data leads to the inefficiency of a thermodynamic method in the practical application. This article provides a brief review on the potential-pH diagram for Sn/H2O system, which reflects the thermodynamic behavior of Sn species in an aqueous solution and extracts thermodynamic data for the practical application of Sn species. Firstly, the relationship of the thermodynamic behavior, potential-pH diagram, and equilibrium relations of Sn species for Sn/H2O system was overviewed. Additionally, the potential-pH diagram of Sn/H2O system at different temperatures (298 K, 373 K, and 550 K), dissolved Sn activities (1, 10?1, 10?3, and 10?6), and the potential-pH diagram of the Sn species in achloridion aqueous solution (Sn/H2O-Cl)was summarized. Finally, the application prospect of the potential-pH diagram for Sn/H2O system is prospected in the intelligent simulation of Sn metallurgy and the practical application of Sn materials.","PeriodicalId":51090,"journal":{"name":"Journal of Mining and Metallurgy Section B-Metallurgy","volume":"112 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81010238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Isa smelting furnace discharges the matte and slag in the same tapping hole. As a result, an electric furnace needs to clean the slag. In the present study, the copper slag cleaning in an electric furnace, particularly the separation of the matte from the slag during the reduction process, was investigated. For Fe3O4 to FeO, the foaming slag in the melt disappeared when the Fe3O4 content was less than 10%. With the formation of the metallic iron, the foaming slag formed again, hindering the sedimentation of the matte. When the anthracite dosage increased to 2.61%, the copper content in the slag increased to 9.46%. The microstructure of the slag and the existence of the metallic iron found in the slag were analyzed in detail. The results obtained in this study provide a theoretical basis for the reasonable control of the transformation of Fe3O4 during the copper slag cleaning.
{"title":"Matte-slag separation behavior as a function of iron phase reduction in copper slag","authors":"Y.-X. Liu, Y. Wei, S.-W. Zhou, B. Li, H. Wang","doi":"10.2298/jmmb220421003l","DOIUrl":"https://doi.org/10.2298/jmmb220421003l","url":null,"abstract":"The Isa smelting furnace discharges the matte and slag in the same tapping hole. As a result, an electric furnace needs to clean the slag. In the present study, the copper slag cleaning in an electric furnace, particularly the separation of the matte from the slag during the reduction process, was investigated. For Fe3O4 to FeO, the foaming slag in the melt disappeared when the Fe3O4 content was less than 10%. With the formation of the metallic iron, the foaming slag formed again, hindering the sedimentation of the matte. When the anthracite dosage increased to 2.61%, the copper content in the slag increased to 9.46%. The microstructure of the slag and the existence of the metallic iron found in the slag were analyzed in detail. The results obtained in this study provide a theoretical basis for the reasonable control of the transformation of Fe3O4 during the copper slag cleaning.","PeriodicalId":51090,"journal":{"name":"Journal of Mining and Metallurgy Section B-Metallurgy","volume":"21 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84482804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
DRI production in tunnel furnaces sometimes encounters an incomplete degree of reduction. A model is required to tackle heterogeneous reaction rates, crucible heat transfer, and oxide morphology. Herein, a three-phase model is proposed based on heat and mass conservation and reaction kinetics, to describe the reduction of hematite to magnetite in the crucibles. The model was implemented via a Fortran program using finite volume discretization, and the results were validated against available experimental data. The model moderated the uncertainties in the reaction rate with a reformulation considering the solid morphology. The results also revealed that the speed and diameter of the crucible have dominant effects on the overall progress of the reduction by changing the heat transfer rate within the crucible. In contrast, the crucible thickness has a minor effect on the reaction and could be regarded as an economical parameter.
{"title":"Modeling of partial reduction of hematite with carbon-monoxide in tunnel furnace","authors":"S. Salimibani, A. Jafari-Ramiani, S. Firoozi","doi":"10.2298/jmmb221129020s","DOIUrl":"https://doi.org/10.2298/jmmb221129020s","url":null,"abstract":"DRI production in tunnel furnaces sometimes encounters an incomplete degree of reduction. A model is required to tackle heterogeneous reaction rates, crucible heat transfer, and oxide morphology. Herein, a three-phase model is proposed based on heat and mass conservation and reaction kinetics, to describe the reduction of hematite to magnetite in the crucibles. The model was implemented via a Fortran program using finite volume discretization, and the results were validated against available experimental data. The model moderated the uncertainties in the reaction rate with a reformulation considering the solid morphology. The results also revealed that the speed and diameter of the crucible have dominant effects on the overall progress of the reduction by changing the heat transfer rate within the crucible. In contrast, the crucible thickness has a minor effect on the reaction and could be regarded as an economical parameter.","PeriodicalId":51090,"journal":{"name":"Journal of Mining and Metallurgy Section B-Metallurgy","volume":"4 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74335304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper investigates the production of alumina from kaolinite by leaching method using hydrochloric acid. Raw kaolin was calcined at 850?C then leached with 6 M hydrochloric acid at 90?C, followed by the addition of 6 M HCl solution to the leachate the aluminum hydroxide was precipitated. Finally, precipitated aluminum hydroxide was heated at 1100?C and turned into aluminum oxide. Materials were identified by XRF, XRD and SEM-EDX techniques. Alumina recovery percentage was determined at different kaolin particle sizes (-200 to -400 standard Tyler screen mesh), different times (1, 2, 3 and 4 h), different leaching temperatures (80, 90, 100 and 104?C) and different concentrations of hydrochloric acid (20, 25, 30 and 37%). Alumina phase changes were also investigated at two calcination temperatures (1100 and 1200?C). The purity of aluminum oxide obtained from this process is about 97% and its recovery percentage is about 98%. It was observed that kaolin granulation with dimensions less than 75 ?m had no significant effect on alumina recovery percentage. It was also found that, the alumina recovery percentage increased with increasing leaching temperature.
研究了以高岭石为原料，用盐酸浸出法制备氧化铝的工艺。生高岭土在850℃下煅烧。然后用6m盐酸在90℃下浸出。C，然后在渗滤液中加入6 M HCl溶液沉淀氢氧化铝。最后，将沉淀的氢氧化铝加热到1100℃。C变成氧化铝。采用XRF、XRD和SEM-EDX技术对材料进行了表征。测定了不同高岭土粒径(-200 ~ -400标准泰勒筛目)、不同浸出时间(1、2、3、4 h)、不同浸出温度(80、90、100、104℃)和不同盐酸浓度(20、25、30、37%)下氧化铝的回收率。在1100℃和1200℃两种煅烧温度下，研究了氧化铝的相变化。该工艺制得的氧化铝纯度约为97%，回收率约为98%。研究发现，粒径小于75 μ m的高岭土造粒对氧化铝回收率无显著影响。氧化铝回收率随浸出温度的升高而增加。
{"title":"Straight synthesis of α and γ alumina from kaolin by HCl acid leaching","authors":"Y. Bagherzadeh, M. H. Golmakani, E. Karimi","doi":"10.2298/jmmb230101017b","DOIUrl":"https://doi.org/10.2298/jmmb230101017b","url":null,"abstract":"This paper investigates the production of alumina from kaolinite by leaching method using hydrochloric acid. Raw kaolin was calcined at 850?C then leached with 6 M hydrochloric acid at 90?C, followed by the addition of 6 M HCl solution to the leachate the aluminum hydroxide was precipitated. Finally, precipitated aluminum hydroxide was heated at 1100?C and turned into aluminum oxide. Materials were identified by XRF, XRD and SEM-EDX techniques. Alumina recovery percentage was determined at different kaolin particle sizes (-200 to -400 standard Tyler screen mesh), different times (1, 2, 3 and 4 h), different leaching temperatures (80, 90, 100 and 104?C) and different concentrations of hydrochloric acid (20, 25, 30 and 37%). Alumina phase changes were also investigated at two calcination temperatures (1100 and 1200?C). The purity of aluminum oxide obtained from this process is about 97% and its recovery percentage is about 98%. It was observed that kaolin granulation with dimensions less than 75 ?m had no significant effect on alumina recovery percentage. It was also found that, the alumina recovery percentage increased with increasing leaching temperature.","PeriodicalId":51090,"journal":{"name":"Journal of Mining and Metallurgy Section B-Metallurgy","volume":"28 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84420896","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pd+Zr and Pd+Hf co-doped aluminide coatings were deposited on the Mar-M247 nickel superalloy by the palladium electroplating followed by zirconizing-aluminizing or hafnizing-aluminizing processes. Both coatings consisted of two zones, the outer and the interdiffusion one build of the ?-(Ni,Pd)Al phase. Hafnium and zirconium formed inclusions that precipitated at the border of the zones and close to the surface (only in the Zr+Pd modified coating). Oxidation resistance of the Pd+Zr co-doped aluminide coating was significantly better than the Pd+Hf co-doped one. Hafnium content in the Pd+Hf co-doped coating could exceed the border value.
{"title":"Microstructure and oxidation resistance of Pd+Zr and Pd+Hf co-doped aluminide coatings deposited on Mar-M247 nickel superalloy","authors":"J. Romanowska, M. Zagula-Yavorska","doi":"10.2298/jmmb221205021r","DOIUrl":"https://doi.org/10.2298/jmmb221205021r","url":null,"abstract":"Pd+Zr and Pd+Hf co-doped aluminide coatings were deposited on the Mar-M247 nickel superalloy by the palladium electroplating followed by zirconizing-aluminizing or hafnizing-aluminizing processes. Both coatings consisted of two zones, the outer and the interdiffusion one build of the ?-(Ni,Pd)Al phase. Hafnium and zirconium formed inclusions that precipitated at the border of the zones and close to the surface (only in the Zr+Pd modified coating). Oxidation resistance of the Pd+Zr co-doped aluminide coating was significantly better than the Pd+Hf co-doped one. Hafnium content in the Pd+Hf co-doped coating could exceed the border value.","PeriodicalId":51090,"journal":{"name":"Journal of Mining and Metallurgy Section B-Metallurgy","volume":"18 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90801301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The tests were carried out for a coal-fired boiler heating a single-family house with a usable area of 220 m2. The tests covered the chimney liner (structure and surface layer - produced oxides/deposits), hard coal (eco-pea coal) and furnace ash. The chimney liner was located in a chimney made of bricks joined with concrete. A chimney liner made of austenitic steel was tested. The chimney liner was operated for 130,000 hours. The chimney insert was studied on the inner and outer side the respective cross-section. Coal with a grain size of 50-210 mm was analyzed. The bottom ash consisted of both loose ash and a mass of glassy sintered ash, the so-called slag. Thorough examinations of the researches materials comprised: microscopic examinations using an digital microscope VHX-7000 and scanning electron microscopes Jeol JSM-6610LV. Analysis of the chemical composition using Energy dispersive X-ray spectroscopy (EDS) in conjunction with the scanning electron microscopy (SEM). The surface topography (roughness) was measured using a VHX microscope using a Gaussian filter. The following parameters were determined on the basis of the tests: arithmetic mean height, maximum height, height of the highest peak, depth of the lowest depression, root mean square height, skewness, kurtosis.
{"title":"Corrosion of a chimney liner operated for 130,000 hours","authors":"M. Gwoździk","doi":"10.2298/jmmb230206023g","DOIUrl":"https://doi.org/10.2298/jmmb230206023g","url":null,"abstract":"The tests were carried out for a coal-fired boiler heating a single-family house with a usable area of 220 m2. The tests covered the chimney liner (structure and surface layer - produced oxides/deposits), hard coal (eco-pea coal) and furnace ash. The chimney liner was located in a chimney made of bricks joined with concrete. A chimney liner made of austenitic steel was tested. The chimney liner was operated for 130,000 hours. The chimney insert was studied on the inner and outer side the respective cross-section. Coal with a grain size of 50-210 mm was analyzed. The bottom ash consisted of both loose ash and a mass of glassy sintered ash, the so-called slag. Thorough examinations of the researches materials comprised: microscopic examinations using an digital microscope VHX-7000 and scanning electron microscopes Jeol JSM-6610LV. Analysis of the chemical composition using Energy dispersive X-ray spectroscopy (EDS) in conjunction with the scanning electron microscopy (SEM). The surface topography (roughness) was measured using a VHX microscope using a Gaussian filter. The following parameters were determined on the basis of the tests: arithmetic mean height, maximum height, height of the highest peak, depth of the lowest depression, root mean square height, skewness, kurtosis.","PeriodicalId":51090,"journal":{"name":"Journal of Mining and Metallurgy Section B-Metallurgy","volume":"17 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81346644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
E. Morales‐Cruz, M. Vargas-Ramírez, A. Lobo-Guerrero, A. Cruz-Ramírez, E. Colin-García, R. Sánchez-Álvarado, V. Gutiérrez-Pérez, J. M. Martínez-Vázquez
The present paper analyzes the effect of low aluminum additions and the hot forging process on the microstructure and non-metallic inclusions of high manganese steels. Four high-manganese steels (HMnS) were obtained by adding low aluminum contents of 1.1 and 1.5 wt. % in four medium carbon austenitic steels (0.3 - 0.4 wt% C) with manganese contents of 17 and 22 wt. Samples of the as-cast steels were hot forged to 1100 ?C to obtain a whole reduction of 70 %. The microstructural evolution was studied by microscopy techniques (OM, and SEM-EDS) and X-Ray diffraction measurements for the as-cast and hot forged steels. A typical grain columnar zone obtained during solidification of an ingot casting was obtained in the as-cast condition where the microstructure was constituted by non-metallic inclusions in a fully austenitic matrix. The non-metallic inclusions were identified as Al2O3 and MnS particles. The thermomechanical treatment allows the formation of an austenitic microstructure characterized by twins in high manganese steels while a duplex austenitic-martensitic microstructure was obtained for HMnS which contained the lowest manganese contents. The highest tensile properties were obtained for the steel 17Mn-1Al which showed the lowest grain size and higher non-metallic inclusions content. The hardness values were similar to those obtained in the as-cast condition.
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