A novel hydrothermal process was developed to extract zinc from pure zinc ferrite(ZnFe2O4) nanopowder and zinc-containing electric arc furnace(EAF) dust using hexahydrated ferric chloride(FeCl3-6H2O) as a decomp...A novel hydrothermal process was developed to extract zinc from pure zinc ferrite(ZnFe2O4) nanopowder and zinc-containing electric arc furnace(EAF) dust using hexahydrated ferric chloride(FeCl3-6H2O) as a decomposing agent.The effects of solid FeCl3-6H2O to ZnFe2O4 ratio by mass(RF/Z),hydrothermal reaction temperature,and time on zinc extraction were systematically investigated.In the results,when the hydrothermal reaction is conducted at 150℃ for 2 h with RF/Z of 15:20,the efficiency of zinc extraction from ZnFe2O4 reaches97.2%,and the concentration of ferric ions(Fe^3+) in the leaching solution is nearly zero,indicating a high selectivity for zinc.In addition,the zinc extraction efficiency from the EAF dust reaches 94.5%in the case of the hydrothermal reaction performed at 200℃ for 10 h with the solid FeCl3-6H2O to EAF dust ratio by mass(RF/EAF dust) of 15:10.Zinc and iron separation is achieved by adjusting the pH value of the leaching solution according to the different precipitation pH values of metal hydroxides.展开更多
The Laser Furnace(LF)method has been applied to directionally solidify NiFe_(2)O_(4)spinel disks from a mixture of Fe and Ni oxides in order to obtain uniform,dense targets for controlled synthesis of spinel nanoparti...The Laser Furnace(LF)method has been applied to directionally solidify NiFe_(2)O_(4)spinel disks from a mixture of Fe and Ni oxides in order to obtain uniform,dense targets for controlled synthesis of spinel nanoparticles via Laser Ablation.Application of a CO2 laser in Line Scan mode onto a sample with the desired stoichiometry,enabled melt processing above 1580C at its outer surface layer.This process was carried out inside a continuous roller furnace at a maximum volume temperature of 1000C.Such combination helps avoid excessive thermal stress,crack formation and catastrophic failure of these magnetic ceramic monoliths.Higher energy incubation values yield increased molten volumes and a thicker resolidified surface layer with a dense microstructure.Despite the high solidification rates imposed,NiFe2O4 spinel is the main phase obtained according to X-Ray Diffraction(XRD)and magnetization studies.LF processed samples exhibit a reduction of the coercive fields and an increase of the saturation magnetization values,evidence for soft ferromagnetism and characteristic of the magnetic behaviour associated with this spinel.This work demonstrates the convenience of the LF method for preparation of uniform,dense targets for Laser Ablation and other evaporation based techniques used in the fabrication of nanoparticles.展开更多
Basic oxygen furnace slag(BOFS) has the potential to remove hexavalent chromium(Cr(VI))from wastewater by a redox process due to the presence of minerals containing Fe2+. The effects of the solution p H, initia...Basic oxygen furnace slag(BOFS) has the potential to remove hexavalent chromium(Cr(VI))from wastewater by a redox process due to the presence of minerals containing Fe2+. The effects of the solution p H, initial Cr(VI) concentration, BOFS dosage, BOFS particle size, and temperature on the removal of Cr(VI) was investigated in detail through batch tests. The chemical and mineral compositions of fresh and reacted BOFS were characterized using scanning electron microscope(SEM) equipped with an energy dispersive spectrometer(EDS)system and X-ray diffractometer(XRD). The results show that Cr(VI) in wastewater can be efficiently removed by Fe2+released from BOFS under appropriate acidic conditions. The removal of Cr(VI) by BOFS significantly depended on the parameters mentioned above. The reaction of Cr(VI) with BOFS followed the pseudo-second-order kinetic model. Fe2+responsible for Cr(VI) removal was primarily derived from the dissolution of Fe O and Fe3O4 in BOFS. When H2SO4 was used to adjust the solution acidity, gypsum(Ca SO4·2H2O)could be formed and become an armoring precipitate layer on the BOFS surface, hindering the release of Fe2+and the removal of Cr(VI). Finally, the main mechanism of Cr(VI) removal by BOFS was described using several consecutive reaction steps.展开更多
Reducing CO_(2)emissions of the iron and steel industry,a typical heavy CO_(2)-emitting sector is the only way that must be passed to achieve the‘dual-carbon’goal,especially in China.In previous studies,however,it i...Reducing CO_(2)emissions of the iron and steel industry,a typical heavy CO_(2)-emitting sector is the only way that must be passed to achieve the‘dual-carbon’goal,especially in China.In previous studies,however,it is still unknown what is the difference between blast furnace basic oxygen furnace(BF-BOF),scrap-electric furnace(scrap-EF)and hydrogen metallurgy process.The quantitative research on the key factors affecting CO_(2)emissions is insufficient There is also a lack of research on the prediction of CO_(2)emissions by adjusting industria structure.Based on material flow analysis,this study establishes carbon flow diagrams o three processes,and then analyze the key factors affecting CO_(2)emissions.CO_(2)emissions of the iron and steel industry in the future is predicted by adjusting industrial structure The results show that:(1)The CO_(2)emissions of BF-BOF,scrap-EF and hydrogen metallurgy process in a site are 1417.26,542.93 and 1166.52 kg,respectively.(2)By increasing pellet ratio in blast furnace,scrap ratio in electric furnace,etc.,can effectively reduce CO_(2)emissions(3)Reducing the crude steel output is the most effective CO_(2)reduction measure.There is still 5.15×10^(8)-6.17×10^(8) tons of CO_(2)that needs to be reduced by additional measures.展开更多
Ti-stabilized 321 stainless steel was prepared using an electric arc furnace, argon oxygen decarburization (AOD) furnace, ladle furnace (LF), and continuous casting processes. In addition, the effect of refining proce...Ti-stabilized 321 stainless steel was prepared using an electric arc furnace, argon oxygen decarburization (AOD) furnace, ladle furnace (LF), and continuous casting processes. In addition, the effect of refining process and utilization of different slags on the evolution of inclusions, titanium yield, and oxygen content was systematically investigated by experimental and thermodynamic analysis. The results reveal that the total oxygen content (TO) and inclusion density decreased during the refining process. The spherical CaO–SiO2–Al2O3–MgO inclusions existed in the 321 stainless steel after the AOD process. Moreover, prior to the Ti addition, the spherical CaO–Al2O3–MgO–SiO2 inclusions were observed during LF refining pro-cess. However, Ti addition resulted in multilayer CaO–Al2O3–MgO–TiOx inclusions. Two different samples were prepared by conventional CaO–Al2O3-based slag (Heat-1) and -TiO2-rich CaO–Al2O3-based slag (Heat-2). The statistical analysis revealed that the density of inclusions and the -TiOx content in CaO–Al2O3–MgO–TiOx inclusions found in Heat-2 sample are much lower than those in the Heat-1 sample. Furthermore, the TO content and Ti yield during the LF refining process were controlled by using -TiO2-rich calcium aluminate synthetic slag. These results were consistent with the ion–molecule coexist-ence theory and FactSage?7.2 software calculations. When -TiO2-rich CaO–Al2O3-based slag was used, the -TiO2 activity of the slag increased, and the equilibrium oxygen content significantly decreased from the AOD to LF processes. Therefore, the higher -TiO2 activity of slag and lower equilibrium oxygen content suppressed the undesirable reactions between Ti and O.展开更多
基金supported by the National Basic Research Priorities Program of China (Nos. 2014CB643401 and 2013AA032003)the National Natural Science Foundation of China (No.51372019)
文摘A novel hydrothermal process was developed to extract zinc from pure zinc ferrite(ZnFe2O4) nanopowder and zinc-containing electric arc furnace(EAF) dust using hexahydrated ferric chloride(FeCl3-6H2O) as a decomposing agent.The effects of solid FeCl3-6H2O to ZnFe2O4 ratio by mass(RF/Z),hydrothermal reaction temperature,and time on zinc extraction were systematically investigated.In the results,when the hydrothermal reaction is conducted at 150℃ for 2 h with RF/Z of 15:20,the efficiency of zinc extraction from ZnFe2O4 reaches97.2%,and the concentration of ferric ions(Fe^3+) in the leaching solution is nearly zero,indicating a high selectivity for zinc.In addition,the zinc extraction efficiency from the EAF dust reaches 94.5%in the case of the hydrothermal reaction performed at 200℃ for 10 h with the solid FeCl3-6H2O to EAF dust ratio by mass(RF/EAF dust) of 15:10.Zinc and iron separation is achieved by adjusting the pH value of the leaching solution according to the different precipitation pH values of metal hydroxides.
基金The authors acknowledge financial support from MINECO-AEIFEDER,EU(projects MAT2016-79866-R and ENE2017-83669-C4-1-R)SPRINT(EU H2020-FET-OPEN/0426)projects and from Gobierno de Aragon“Construyendo Europa desde Aragon”(research group T54_17R).
文摘The Laser Furnace(LF)method has been applied to directionally solidify NiFe_(2)O_(4)spinel disks from a mixture of Fe and Ni oxides in order to obtain uniform,dense targets for controlled synthesis of spinel nanoparticles via Laser Ablation.Application of a CO2 laser in Line Scan mode onto a sample with the desired stoichiometry,enabled melt processing above 1580C at its outer surface layer.This process was carried out inside a continuous roller furnace at a maximum volume temperature of 1000C.Such combination helps avoid excessive thermal stress,crack formation and catastrophic failure of these magnetic ceramic monoliths.Higher energy incubation values yield increased molten volumes and a thicker resolidified surface layer with a dense microstructure.Despite the high solidification rates imposed,NiFe2O4 spinel is the main phase obtained according to X-Ray Diffraction(XRD)and magnetization studies.LF processed samples exhibit a reduction of the coercive fields and an increase of the saturation magnetization values,evidence for soft ferromagnetism and characteristic of the magnetic behaviour associated with this spinel.This work demonstrates the convenience of the LF method for preparation of uniform,dense targets for Laser Ablation and other evaporation based techniques used in the fabrication of nanoparticles.
基金financially supported by the Fundamental Research Fund for the Central Universities(No.N130302004)the National Natural Science Foundation of China(No.21407020)
文摘Basic oxygen furnace slag(BOFS) has the potential to remove hexavalent chromium(Cr(VI))from wastewater by a redox process due to the presence of minerals containing Fe2+. The effects of the solution p H, initial Cr(VI) concentration, BOFS dosage, BOFS particle size, and temperature on the removal of Cr(VI) was investigated in detail through batch tests. The chemical and mineral compositions of fresh and reacted BOFS were characterized using scanning electron microscope(SEM) equipped with an energy dispersive spectrometer(EDS)system and X-ray diffractometer(XRD). The results show that Cr(VI) in wastewater can be efficiently removed by Fe2+released from BOFS under appropriate acidic conditions. The removal of Cr(VI) by BOFS significantly depended on the parameters mentioned above. The reaction of Cr(VI) with BOFS followed the pseudo-second-order kinetic model. Fe2+responsible for Cr(VI) removal was primarily derived from the dissolution of Fe O and Fe3O4 in BOFS. When H2SO4 was used to adjust the solution acidity, gypsum(Ca SO4·2H2O)could be formed and become an armoring precipitate layer on the BOFS surface, hindering the release of Fe2+and the removal of Cr(VI). Finally, the main mechanism of Cr(VI) removal by BOFS was described using several consecutive reaction steps.
基金supported by the National Natural Science Foundation of China(No.52270177)the Young Elite Scientists Sponsorship Program by CAST(No.2022QNRC001)the Key R&D Plan of Liaoning Province(No.2021JH2/10300103)。
文摘Reducing CO_(2)emissions of the iron and steel industry,a typical heavy CO_(2)-emitting sector is the only way that must be passed to achieve the‘dual-carbon’goal,especially in China.In previous studies,however,it is still unknown what is the difference between blast furnace basic oxygen furnace(BF-BOF),scrap-electric furnace(scrap-EF)and hydrogen metallurgy process.The quantitative research on the key factors affecting CO_(2)emissions is insufficient There is also a lack of research on the prediction of CO_(2)emissions by adjusting industria structure.Based on material flow analysis,this study establishes carbon flow diagrams o three processes,and then analyze the key factors affecting CO_(2)emissions.CO_(2)emissions of the iron and steel industry in the future is predicted by adjusting industrial structure The results show that:(1)The CO_(2)emissions of BF-BOF,scrap-EF and hydrogen metallurgy process in a site are 1417.26,542.93 and 1166.52 kg,respectively.(2)By increasing pellet ratio in blast furnace,scrap ratio in electric furnace,etc.,can effectively reduce CO_(2)emissions(3)Reducing the crude steel output is the most effective CO_(2)reduction measure.There is still 5.15×10^(8)-6.17×10^(8) tons of CO_(2)that needs to be reduced by additional measures.
基金The authors gratcfully acknowledge the sup-port of the National Natural Science Foundation of China(Grant No.51374020)the State Key Laboratory of Advanced Metallurgy at theUniversity of Science and Technology Beijing(USTB)the JiuquanIron and Steel Group Corporation.
文摘Ti-stabilized 321 stainless steel was prepared using an electric arc furnace, argon oxygen decarburization (AOD) furnace, ladle furnace (LF), and continuous casting processes. In addition, the effect of refining process and utilization of different slags on the evolution of inclusions, titanium yield, and oxygen content was systematically investigated by experimental and thermodynamic analysis. The results reveal that the total oxygen content (TO) and inclusion density decreased during the refining process. The spherical CaO–SiO2–Al2O3–MgO inclusions existed in the 321 stainless steel after the AOD process. Moreover, prior to the Ti addition, the spherical CaO–Al2O3–MgO–SiO2 inclusions were observed during LF refining pro-cess. However, Ti addition resulted in multilayer CaO–Al2O3–MgO–TiOx inclusions. Two different samples were prepared by conventional CaO–Al2O3-based slag (Heat-1) and -TiO2-rich CaO–Al2O3-based slag (Heat-2). The statistical analysis revealed that the density of inclusions and the -TiOx content in CaO–Al2O3–MgO–TiOx inclusions found in Heat-2 sample are much lower than those in the Heat-1 sample. Furthermore, the TO content and Ti yield during the LF refining process were controlled by using -TiO2-rich calcium aluminate synthetic slag. These results were consistent with the ion–molecule coexist-ence theory and FactSage?7.2 software calculations. When -TiO2-rich CaO–Al2O3-based slag was used, the -TiO2 activity of the slag increased, and the equilibrium oxygen content significantly decreased from the AOD to LF processes. Therefore, the higher -TiO2 activity of slag and lower equilibrium oxygen content suppressed the undesirable reactions between Ti and O.