This work contains a systematic study of the diffusion of nitrogen in Ferrite (α Fe, BCC) and Austenite (γ Fe, FCC) from first principles, using a robust multi scale model which combines Density Functional Theory (DFT) and Kinetic Monte Carlo (KMC). Both ferromagnetic BCC and non-magnetic FCC iron are considered using DFT to drive a diffusion model, which shows strong agreement with experimental diffusion data in literature. Further, quantified predictions are calculated for nitrogen diffusion in iron crystals which are vacancy-rich. In particular, it was found that an extended diffusion coefficient of nitrogen can be expressed as a function of nitrogen and vacancy concentration by fitting polynomial coefficients. These are calculated within the 100◦C < T < 1500◦C temperature range, and 0.01 at.% < cN < 10.0 at.% nitrogen concentration range. Such insights in vacancy-rich crystals may be useful to nitriding manufacturers, as enhanced diffusion models are an important factor in improving existing processes and avoiding common manufacturing problems such as the egg-shell-effect.
{"title":"Nitrogen Diffusion in Vacancy-Rich Ferrite and Austenite, from First Principles to Applications","authors":"A. Karimi, M. Auinger","doi":"10.2139/ssrn.3694759","DOIUrl":"https://doi.org/10.2139/ssrn.3694759","url":null,"abstract":"This work contains a systematic study of the diffusion of nitrogen in Ferrite (α Fe, BCC) and Austenite (γ Fe, FCC) from first principles, using a robust multi scale model which combines Density Functional Theory (DFT) and Kinetic Monte Carlo (KMC). Both ferromagnetic BCC and non-magnetic FCC iron are considered using DFT to drive a diffusion model, which shows strong agreement with experimental diffusion data in literature. Further, quantified predictions are calculated for nitrogen diffusion in iron crystals which are vacancy-rich. In particular, it was found that an extended diffusion coefficient of nitrogen can be expressed as a function of nitrogen and vacancy concentration by fitting polynomial coefficients. These are calculated within the 100◦C < T < 1500◦C temperature range, and 0.01 at.% < cN < 10.0 at.% nitrogen concentration range. Such insights in vacancy-rich crystals may be useful to nitriding manufacturers, as enhanced diffusion models are an important factor in improving existing processes and avoiding common manufacturing problems such as the egg-shell-effect.","PeriodicalId":11974,"journal":{"name":"EngRN: Engineering Design Process (Topic)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89006431","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}
Charcoal was investigated as a renewable reducing agent to replace fossil fuel reductants in the metallurgical industry. Since a stepwise transition from fossil fuel-based reductants to renewable charcoal is expected, three charcoal blending ratios (20, 40 and 60%) were analysed. A procedure to determine the mechanical, chemical and electrical properties of carbon blends for submerged arc furnaces (SAF) was developed and evaluated by the stated three blending ratios of charcoal and metallurgical coke. The samples were investigated after heat treatment under pyrolysis and CO2 gasification conditions. The higher reactive carbon material (charcoal) was consumed by the Boudouard reaction, reducing its mechanical stability and affecting the generation of fines in consecutive analyses, e.g. the mechanical strength to withstand abrasion decreased. Chemical analysis showed only minor interaction between the carbon materials under pyrolysis conditions. The electrical resistivity of the carbon bed was mainly affected by the heat-treatment temperature and volume fraction of the carbon materials, in which a linear interpolation resulted in an acceptable accuracy. A volume fraction of at least 40% conductive material (coke) was required to enable an electrical conduction through the packed bed.
{"title":"The Properties of Carbon Blends in Submerged arc Furnaces","authors":"G. Surup, Nicholas Smith-Hanssen, M. Tangstad","doi":"10.2139/ssrn.3926708","DOIUrl":"https://doi.org/10.2139/ssrn.3926708","url":null,"abstract":"Charcoal was investigated as a renewable reducing agent to replace fossil fuel reductants in the metallurgical industry. Since a stepwise transition from fossil fuel-based reductants to renewable charcoal is expected, three charcoal blending ratios (20, 40 and 60%) were analysed. A procedure to determine the mechanical, chemical and electrical properties of carbon blends for submerged arc furnaces (SAF) was developed and evaluated by the stated three blending ratios of charcoal and metallurgical coke. The samples were investigated after heat treatment under pyrolysis and CO2 gasification conditions. The higher reactive carbon material (charcoal) was consumed by the Boudouard reaction, reducing its mechanical stability and affecting the generation of fines in consecutive analyses, e.g. the mechanical strength to withstand abrasion decreased. Chemical analysis showed only minor interaction between the carbon materials under pyrolysis conditions. The electrical resistivity of the carbon bed was mainly affected by the heat-treatment temperature and volume fraction of the carbon materials, in which a linear interpolation resulted in an acceptable accuracy. A volume fraction of at least 40% conductive material (coke) was required to enable an electrical conduction through the packed bed.","PeriodicalId":11974,"journal":{"name":"EngRN: Engineering Design Process (Topic)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80573508","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}
T. Mukono, Jonas E Gjøvik, Heiko Gærtner, M. Wallin, E. Ringdalen, M. Tangstad
Three pilot-scale experiments have been conducted at SINTEF/NTNU in a 440 kVA AC electric furnace to demonstrate the process operation, energy requirements and CO2 emissions in the production of high carbon ferromanganese alloys. Comilog, UMK and Nchwaning (Assmang) ores blended with other materials, such as sinter and flux, thus achieving different charge mixtures have been utilized in the experiments. In the prereduction zone, higher manganese oxides in the ore are reduced to MnO through solid-gas exothermic reactions and at a temperature around 800oC, the unwanted endothermic Boudouard reaction is also active. As such, the total coke and energy consumption is highly dependent on if the prereduction occurs by CO gas or solid C. The pilot furnace has been excavated after each experiment and the extent of prereduction of the ore has been investigated by collecting samples from specific regions in the prereduction zone. In addition, material, and energy balance calculations for the three pilot experiments have been calculated using HSC Chemistry software. The HSC material and energy balance calculations have shown that the slag/alloy ratios, metal analyses, carbon consumption and the overall energy consumption are mainly affected by the composition of the charge mixtures. The relationship between the specific carbon consumption, the off-gas CO2/(CO2+CO) ratio and energy consumption to produce 1 tonne of HCFeMn alloy is discussed for the three different pilot-scale scenarios.
{"title":"Extent of Ore Prereduction in Pilot-scale Production of High Carbon Ferromanganese","authors":"T. Mukono, Jonas E Gjøvik, Heiko Gærtner, M. Wallin, E. Ringdalen, M. Tangstad","doi":"10.2139/ssrn.3926275","DOIUrl":"https://doi.org/10.2139/ssrn.3926275","url":null,"abstract":"Three pilot-scale experiments have been conducted at SINTEF/NTNU in a 440 kVA AC electric furnace to demonstrate the process operation, energy requirements and CO2 emissions in the production of high carbon ferromanganese alloys. Comilog, UMK and Nchwaning (Assmang) ores blended with other materials, such as sinter and flux, thus achieving different charge mixtures have been utilized in the experiments. In the prereduction zone, higher manganese oxides in the ore are reduced to MnO through solid-gas exothermic reactions and at a temperature around 800oC, the unwanted endothermic Boudouard reaction is also active. As such, the total coke and energy consumption is highly dependent on if the prereduction occurs by CO gas or solid C. The pilot furnace has been excavated after each experiment and the extent of prereduction of the ore has been investigated by collecting samples from specific regions in the prereduction zone. In addition, material, and energy balance calculations for the three pilot experiments have been calculated using HSC Chemistry software. The HSC material and energy balance calculations have shown that the slag/alloy ratios, metal analyses, carbon consumption and the overall energy consumption are mainly affected by the composition of the charge mixtures. The relationship between the specific carbon consumption, the off-gas CO2/(CO2+CO) ratio and energy consumption to produce 1 tonne of HCFeMn alloy is discussed for the three different pilot-scale scenarios.","PeriodicalId":11974,"journal":{"name":"EngRN: Engineering Design Process (Topic)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89631818","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}
Yong Wang, A. Karasev, Wangzhong Mu, J. Park, P. Jönsson
Laboratory scale alloying experiments were carried out by the addition of a commercial low carbon ferrochrome (LCFeCr) alloy to 430-grade ferritic stainless steel. The inclusions in FeCr alloys as well as in the steel samples before and after alloy addition were investigated using an electrolytic extraction (EE) technique. The results show that the Ti content decreases after the FeCr alloy addition. MnCr2O4 inclusions from FeCr alloys are transformed into Ti2O3-Cr2O3 based liquid inclusions and Ti2O3-rich solid inclusions. They are formed due to the reactions between MnCr2O4 and either TiN or dissolved Ti, which needs to be further studied. The ratio of Ti/Al in the steel melt has a direct influence on the evolution of the inclusions. The present study aims to contribute for understanding the impurities in FeCr alloys and their effect on the inclusion characteristics for the stainless steel production.
{"title":"Characterization of Impurities and Inclusions in Ferrochrome Alloy and Their Effects on the Inclusion Characteristics in Stainless Steels","authors":"Yong Wang, A. Karasev, Wangzhong Mu, J. Park, P. Jönsson","doi":"10.2139/ssrn.3926688","DOIUrl":"https://doi.org/10.2139/ssrn.3926688","url":null,"abstract":"Laboratory scale alloying experiments were carried out by the addition of a commercial low carbon ferrochrome (LCFeCr) alloy to 430-grade ferritic stainless steel. The inclusions in FeCr alloys as well as in the steel samples before and after alloy addition were investigated using an electrolytic extraction (EE) technique. The results show that the Ti content decreases after the FeCr alloy addition. MnCr2O4 inclusions from FeCr alloys are transformed into Ti2O3-Cr2O3 based liquid inclusions and Ti2O3-rich solid inclusions. They are formed due to the reactions between MnCr2O4 and either TiN or dissolved Ti, which needs to be further studied. The ratio of Ti/Al in the steel melt has a direct influence on the evolution of the inclusions. The present study aims to contribute for understanding the impurities in FeCr alloys and their effect on the inclusion characteristics for the stainless steel production.","PeriodicalId":11974,"journal":{"name":"EngRN: Engineering Design Process (Topic)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77618657","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}
Although the influence of many parameters on the metallic yield of reduction process of Silicomanganese alloy was intensively studied but the magnitude effect of each parameter and their mutual interactions on the metallic yield is still not clear. In the current work, a 23 factorial design was used to investigate the magnitude effect of Mn/Si ratio, charge basicity and coke ratio on the metallic yield of production silicomanganese alloy from manganese rich slag. Regression model was used to deduce a mathematical formulation to predict the effect of Mn/Si ratio (2 -3), charge basicity (1.3 – 2.5) and coke ratio (0.95 – 1.35).The results showed that charge basicity has the highest positive effect while the Mn/Si ratio has highest negative influence on the metallic yield. The interaction combination between Mn/Si ratio with coke ratio has high negative influence while the coke ratio and interaction combination between basicity and coke ratio showed relatively high positive influence on metallic yield. The interaction combination between Mn/Si ratio with basicity and /or coke ratio showed small positive effect on metallic yield. The results of the driven models were found to be in good agreement with the experimental data of reduction process of manganese rich slag. Matlab program was used in calculation and build up the regression model.
{"title":"Factorial Design Analysis of the Metallic Yield of Silicomanganese Alloy from Rich Manganese Slag","authors":"S. Ghali, H. El-Faramawy, M. Eissa, E. Kotb","doi":"10.2139/ssrn.3926094","DOIUrl":"https://doi.org/10.2139/ssrn.3926094","url":null,"abstract":"Although the influence of many parameters on the metallic yield of reduction process of Silicomanganese alloy was intensively studied but the magnitude effect of each parameter and their mutual interactions on the metallic yield is still not clear. In the current work, a 23 factorial design was used to investigate the magnitude effect of Mn/Si ratio, charge basicity and coke ratio on the metallic yield of production silicomanganese alloy from manganese rich slag. Regression model was used to deduce a mathematical formulation to predict the effect of Mn/Si ratio (2 -3), charge basicity (1.3 – 2.5) and coke ratio (0.95 – 1.35).The results showed that charge basicity has the highest positive effect while the Mn/Si ratio has highest negative influence on the metallic yield. The interaction combination between Mn/Si ratio with coke ratio has high negative influence while the coke ratio and interaction combination between basicity and coke ratio showed relatively high positive influence on metallic yield. The interaction combination between Mn/Si ratio with basicity and /or coke ratio showed small positive effect on metallic yield. The results of the driven models were found to be in good agreement with the experimental data of reduction process of manganese rich slag. Matlab program was used in calculation and build up the regression model.","PeriodicalId":11974,"journal":{"name":"EngRN: Engineering Design Process (Topic)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86305231","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}
Harald Philipsson, M. Wallin, K. Einarsrud, G. Tranell
A silicon alloy was produced by reduction of silica in a calcia-silica (CaO-SiO2) slag using aluminium (Al) metal or aluminium dross as reductant. The aluminothermic reduction was conducted in a laboratory scale induction furnace with an argon atmosphere. The reductant and 300 g of 51.3CaO-46.7SiO2 (wt%) pre-fused slag, were heated and held at 1650 °C for 20, 30, 40, 60 and 180 minutes. For the dross material, the metallic Al content was estimated to 75 wt% by melting in salt flux. The kinetics of reduction was investigated by evaluating the Si-alloy and product slag composition against simulated thermodynamic equilibrium obtained from FactSage 7.3. The Al dross was demonstrated to be as effective reductant as pure Al and analysis of the results indicate a rapid aluminothermic reduction as well as good Si-alloy/slag separation for both reductants. The composition of the produced Si-alloys, mainly dependent on the reductant type, were above 70 wt%Si, 8-15 wt%Al, 13-19 wt%Ca and with low (<0.3 wt%) content of other elements such as Fe and P.
{"title":"Kinetics of Silicon Production by Aluminothermic Reduction of Silica Using Aluminum and Aluminum Dross as Reductants","authors":"Harald Philipsson, M. Wallin, K. Einarsrud, G. Tranell","doi":"10.2139/ssrn.3922132","DOIUrl":"https://doi.org/10.2139/ssrn.3922132","url":null,"abstract":"A silicon alloy was produced by reduction of silica in a calcia-silica (CaO-SiO2) slag using aluminium (Al) metal or aluminium dross as reductant. The aluminothermic reduction was conducted in a laboratory scale induction furnace with an argon atmosphere. The reductant and 300 g of 51.3CaO-46.7SiO2 (wt%) pre-fused slag, were heated and held at 1650 °C for 20, 30, 40, 60 and 180 minutes. For the dross material, the metallic Al content was estimated to 75 wt% by melting in salt flux. The kinetics of reduction was investigated by evaluating the Si-alloy and product slag composition against simulated thermodynamic equilibrium obtained from FactSage 7.3. The Al dross was demonstrated to be as effective reductant as pure Al and analysis of the results indicate a rapid aluminothermic reduction as well as good Si-alloy/slag separation for both reductants. The composition of the produced Si-alloys, mainly dependent on the reductant type, were above 70 wt%Si, 8-15 wt%Al, 13-19 wt%Ca and with low (<0.3 wt%) content of other elements such as Fe and P.","PeriodicalId":11974,"journal":{"name":"EngRN: Engineering Design Process (Topic)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80325572","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}
N. Julia, Astrid Hecquet, G. Nussbaum, S. Blancher, A. Amalric
The production of high carbon ferromanganese alloys is traditionally carried out by smelting oxidized ores in electric furnaces using carbonaceous material as reducing agent, generating CO2 emissions which contribute to climate change. The actual carbon consumption is not optimal, there is an overconsumption linked to an incomplete decomposition and prereduction of manganese oxides inside the submerged arc furnace (SAF), where the reactions kinetics can be difficult to control. In the PREMA project, the considered solution consists in optimizing ores heating and pre-reduction before the SAF in a separate unit in order to reduce its electricity consumption as well as its CO2emissions. After preliminary tests in a lab scale rotary kiln have been performed, the pre-heating of raw materials in a continuous pilot scale rotary kiln was studied during a campaign at Eramet Ideas. The objective was to study the kinetics of thermal decompositions of two different Mn ores. The evolution of the ore composition was assessed with chemical analysis and by the study of the phases thanks to the XRD and Qemscan analyses.
{"title":"Pre-Heating Manganese Ore in a Pilot-Scale Rotary Kiln","authors":"N. Julia, Astrid Hecquet, G. Nussbaum, S. Blancher, A. Amalric","doi":"10.2139/ssrn.3926242","DOIUrl":"https://doi.org/10.2139/ssrn.3926242","url":null,"abstract":"The production of high carbon ferromanganese alloys is traditionally carried out by smelting oxidized ores in electric furnaces using carbonaceous material as reducing agent, generating CO2 emissions which contribute to climate change. The actual carbon consumption is not optimal, there is an overconsumption linked to an incomplete decomposition and prereduction of manganese oxides inside the submerged arc furnace (SAF), where the reactions kinetics can be difficult to control. In the PREMA project, the considered solution consists in optimizing ores heating and pre-reduction before the SAF in a separate unit in order to reduce its electricity consumption as well as its CO2emissions. After preliminary tests in a lab scale rotary kiln have been performed, the pre-heating of raw materials in a continuous pilot scale rotary kiln was studied during a campaign at Eramet Ideas. The objective was to study the kinetics of thermal decompositions of two different Mn ores. The evolution of the ore composition was assessed with chemical analysis and by the study of the phases thanks to the XRD and Qemscan analyses.","PeriodicalId":11974,"journal":{"name":"EngRN: Engineering Design Process (Topic)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81398031","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}
Sergey Bublik, S. Gouttebroze, T. Coudert, M. Tangstad, K. Einarsrud
Physical properties of multi-component slag systems are of great importance for metallurgical processes, thereby many studies have shown that properties such as density, surface tension or viscosity can be predicted using previously developed models. However, nowadays there is no such framework integrating published models for calculation of slag properties and allowing for user-friendly post-processing of data. In this study, a web-based application for calculation of slag properties both in solid and liquid state was developed in Python. The web-application predicts density, heat capacity, surface tension and other properties from temperature and slag composition provided by the user and subsequently the user has the possibility to interact with and visualize data, and compare results from various models. The architecture of the web-application was designed to address interoperability and data security concepts. In addition, the modularity of the web-application was based on standardized web architectural styles to facilitate the addition of new models or functions in the future. The current work is aimed at demonstrating the key functionality of the application and initiating discussion and further collaboration for its development.
{"title":"SlagCalculator: A Framework for Slag and Metallurgical Properties","authors":"Sergey Bublik, S. Gouttebroze, T. Coudert, M. Tangstad, K. Einarsrud","doi":"10.2139/ssrn.3926702","DOIUrl":"https://doi.org/10.2139/ssrn.3926702","url":null,"abstract":"Physical properties of multi-component slag systems are of great importance for metallurgical processes, thereby many studies have shown that properties such as density, surface tension or viscosity can be predicted using previously developed models. However, nowadays there is no such framework integrating published models for calculation of slag properties and allowing for user-friendly post-processing of data. In this study, a web-based application for calculation of slag properties both in solid and liquid state was developed in Python. The web-application predicts density, heat capacity, surface tension and other properties from temperature and slag composition provided by the user and subsequently the user has the possibility to interact with and visualize data, and compare results from various models. The architecture of the web-application was designed to address interoperability and data security concepts. In addition, the modularity of the web-application was based on standardized web architectural styles to facilitate the addition of new models or functions in the future. The current work is aimed at demonstrating the key functionality of the application and initiating discussion and further collaboration for its development.","PeriodicalId":11974,"journal":{"name":"EngRN: Engineering Design Process (Topic)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81148385","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}
Chang-Woo Seok, Won-Yeong Son, Ki-Hwan Lee, Jinju Park, Y. Kang
Nickel has been known to be the most important metallic resource, which has been used in various products, such as multi-layer ceramic capacitors, Li-ion batteries, heat-resistance super alloys. Those Ni resources have various types such as metallic nickel, ferronickel alloy, nickel matte, and nickel sulfate depending on the situation. In a production route of high purity nickel matte from ferronickel, which had been implemented many decades ago, a large amount of by-product, as well as relatively high operational cost, have been recently drawing attention. To resolve arisen problems, nickel pig iron can be suggested as a low-cost raw material. The possibility of upgrading nickel pig iron by removal of Fe and enrichment of Ni was investigated by lab-scale oxidation experiments. It was found that major impurities like C and Si should be removed before Fe oxidation initiates. And decarburization and desiliconization of nickel pig iron were enhanced by oxygen injection, compared with other blowing manners. The slag conditions for effective Fe oxidation were discussed using thermodynamic calculation and oxygen blowing tests. Conclusively, the continuous addition of CaO during oxygen blowing enables the formation of liquid slag and further Fe oxidation. In the case of Fe2O3-SiO2 based slag, liquid slag seems to be limited by MgO dissolution from refractory
{"title":"Study on the Refining Conditions of Nickel Pig Iron for High Purity Nickel Matte Production","authors":"Chang-Woo Seok, Won-Yeong Son, Ki-Hwan Lee, Jinju Park, Y. Kang","doi":"10.2139/ssrn.3926649","DOIUrl":"https://doi.org/10.2139/ssrn.3926649","url":null,"abstract":"Nickel has been known to be the most important metallic resource, which has been used in various products, such as multi-layer ceramic capacitors, Li-ion batteries, heat-resistance super alloys. Those Ni resources have various types such as metallic nickel, ferronickel alloy, nickel matte, and nickel sulfate depending on the situation. In a production route of high purity nickel matte from ferronickel, which had been implemented many decades ago, a large amount of by-product, as well as relatively high operational cost, have been recently drawing attention. To resolve arisen problems, nickel pig iron can be suggested as a low-cost raw material. The possibility of upgrading nickel pig iron by removal of Fe and enrichment of Ni was investigated by lab-scale oxidation experiments. It was found that major impurities like C and Si should be removed before Fe oxidation initiates. And decarburization and desiliconization of nickel pig iron were enhanced by oxygen injection, compared with other blowing manners. The slag conditions for effective Fe oxidation were discussed using thermodynamic calculation and oxygen blowing tests. Conclusively, the continuous addition of CaO during oxygen blowing enables the formation of liquid slag and further Fe oxidation. In the case of Fe2O3-SiO2 based slag, liquid slag seems to be limited by MgO dissolution from refractory","PeriodicalId":11974,"journal":{"name":"EngRN: Engineering Design Process (Topic)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85458787","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}
The mechanical properties of the native extracellular matrix play a key role in regulating cell behavior during developmental, healing and homeostatic processes. Since these properties change over time, it may be valuable to have the capacity to dynamically vary the mechanical properties of engineered hydrogels used in tissue engineering strategies to better mimic the dynamic mechanical behavior of native extracellular matrix. However, in situ repeatedly reversible dynamic tuning of hydrogel mechanics is still limited. In this study, we have engineered a hydrogel system with reversible dynamic mechanics using a dual-crosslinkable alginate hydrogel. The effect of reversible mechanical signals on encapsulated stem cells in dynamically tunable hydrogels has been demonstrated. In situ stiffening of hydrogels decreases cell spreading and proliferation, and subsequent softening of hydrogels gives way to an increase in cell spreading and proliferation. The hydrogel stiffening and softening, and resulting cellular responses are repeatedly reversible. This hydrogel system provides a promising platform for investigating the effect of repeatedly reversible changes in extracellular matrix mechanics on cell behaviors. STATEMENT OF SIGNIFICANCE: : Since the mechanical properties of native extracellular matrix (ECM) change over time during development, healing and homeostatic processes, it may be valuable to have the capacity to dynamically control the mechanics of biomaterials used in tissue engineering and regenerative medicine applications to better mimic this behavior. Unlike previously reported biomaterials whose mechanical properties can be changed by the user only a limited number of times, this system provides the capacity to induce unlimited alterations to the mechanical properties of an engineered ECM for 3D cell culture. This study presents a strategy for on-demand dynamic and reversible control of materials' mechanics by single and dual-crosslinking mechanisms using oxidized and methacrylated alginates. By demonstrating direct changes in encapsulated human mesenchymal stem cell morphology, proliferation and chondrogenic differentiation in response to multiple different dynamic changes in hydrogel mechanics, we have established a repeatedly reversible 3D cellular mechanosensing system. This system provides a powerful platform tool with a wide range of stiffness tunability to investigate the role of dynamic mechanics on cellular mechanosensing and behavioral responses.
{"title":"Reversible Dynamic Mechanics of Hydrogels for Regulation of Cellular Behavior","authors":"Oju Jeon, Tae-Hee Kim, E. Alsberg","doi":"10.2139/ssrn.3757900","DOIUrl":"https://doi.org/10.2139/ssrn.3757900","url":null,"abstract":"The mechanical properties of the native extracellular matrix play a key role in regulating cell behavior during developmental, healing and homeostatic processes. Since these properties change over time, it may be valuable to have the capacity to dynamically vary the mechanical properties of engineered hydrogels used in tissue engineering strategies to better mimic the dynamic mechanical behavior of native extracellular matrix. However, in situ repeatedly reversible dynamic tuning of hydrogel mechanics is still limited. In this study, we have engineered a hydrogel system with reversible dynamic mechanics using a dual-crosslinkable alginate hydrogel. The effect of reversible mechanical signals on encapsulated stem cells in dynamically tunable hydrogels has been demonstrated. In situ stiffening of hydrogels decreases cell spreading and proliferation, and subsequent softening of hydrogels gives way to an increase in cell spreading and proliferation. The hydrogel stiffening and softening, and resulting cellular responses are repeatedly reversible. This hydrogel system provides a promising platform for investigating the effect of repeatedly reversible changes in extracellular matrix mechanics on cell behaviors. STATEMENT OF SIGNIFICANCE: : Since the mechanical properties of native extracellular matrix (ECM) change over time during development, healing and homeostatic processes, it may be valuable to have the capacity to dynamically control the mechanics of biomaterials used in tissue engineering and regenerative medicine applications to better mimic this behavior. Unlike previously reported biomaterials whose mechanical properties can be changed by the user only a limited number of times, this system provides the capacity to induce unlimited alterations to the mechanical properties of an engineered ECM for 3D cell culture. This study presents a strategy for on-demand dynamic and reversible control of materials' mechanics by single and dual-crosslinking mechanisms using oxidized and methacrylated alginates. By demonstrating direct changes in encapsulated human mesenchymal stem cell morphology, proliferation and chondrogenic differentiation in response to multiple different dynamic changes in hydrogel mechanics, we have established a repeatedly reversible 3D cellular mechanosensing system. This system provides a powerful platform tool with a wide range of stiffness tunability to investigate the role of dynamic mechanics on cellular mechanosensing and behavioral responses.","PeriodicalId":11974,"journal":{"name":"EngRN: Engineering Design Process (Topic)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77424326","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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