The production processes for Si and FeSi have traditionally been considered slag-free.However,recent excavations have revealed significant accumulation of CaO–SiO_(2)–Al_(2)O_(3)slag within the furnaces.This accumul...The production processes for Si and FeSi have traditionally been considered slag-free.However,recent excavations have revealed significant accumulation of CaO–SiO_(2)–Al_(2)O_(3)slag within the furnaces.This accumulation can obstruct the flow of materials and gases,resulting in lower metal yield and higher energy consumption.The main objective of the current work is to enhance our understanding of slag formation during Si and FeSi production.We investigate slag formation through the dissolution of limestone and iron oxide in quartz and condensate,focusing on the reactions between these materials at a gram scale.Our findings indicate that most slag reaches equilibrium relatively quickly at temperatures starting from 1673 K.Notably,slag formation starts at lower temperature when the iron source is present (1573 K) compared to when only CaO is involved (1673 K).The minor elements tend to accumulate at quartz grain boundaries prior to slag formation.Furthermore,the slag produced from condensate contains less SiO_(2)than that generated from quartz with limestone.The type of quartz source and SiO_(2)phase appears to have little influence on slag formation.Good wettability is a significant factor in reaction between quartz and slag.FactSage calculations indicates that the viscosity of the slag ranges from 0.02 to 14.4 Pa·s under furnace conditions,comparable to the viscosity of honey or motor oil at room temperature.展开更多
To obtain solid Al2O3 or MgO·Al2O3 inclusions in ladle furnace(LF)refining process and achieve ultra-low total oxygen content in steel through subsequent Ruhrstahl Heraeus degassing,the effects of ferrosilicon al...To obtain solid Al2O3 or MgO·Al2O3 inclusions in ladle furnace(LF)refining process and achieve ultra-low total oxygen content in steel through subsequent Ruhrstahl Heraeus degassing,the effects of ferrosilicon alloy,Si content of steel,and slag basicity on the compositions of inclusions during LF refining were investigated in Al-killed steel.Al2O3 inclusions could be transformed into CaO-Al2O3-MgO-CaS inclusions after adding ferrosilicon alloy in the LF refining process as this alloy contains some CaSi alloy impurities.The addition of all ferrosilicon alloys required for the steel in the tapping process could eliminate the influence of Ca in ferrosilicon alloy on the compositions of inclusions.Si in liquid steel had a significant influence on the compositions of inclusions during LF refining when CaO-Al2O3-SiO2-MgO slag with high basicity of 7.0 was used.This was because[Ca]produced by the reaction of CaO and[Al]could be consumed more readily by SiO2 in Si-free steel than in Si-containing steel,which was confirmed by the difference of total calcium content between Si-free and Si-containing steels.As a result,Al2O3 and MgO·Al2O3 inclusions were retained in Si-free steel,whereas calcium aluminate inclusions were found in Si-containing steel.For CaO-Al2O3-SiO2-MgO slag with low basicity of 2.8,Al2O3 and MgO·Al2O3 inclusions were obtained after LF refining in Si-containing steel when all ferrosilicon alloys required for the steel were added in the tapping process.This was because the reaction of CaO and[Al]was weak,and residual[Ca]in the steel could be rapidly consumed by SiO2 in low-basicity slag owing to the low activity of CaO and high activity of SiO2,leading to a low total calcium content of 0.0003%in Si-containing steel.展开更多
Various nanostructured architectures have been demonstrated to be effective to address the issues of high capacity Si anodes. However, the scale-up of these nano-Si materials is still a critical obstacle for commercia...Various nanostructured architectures have been demonstrated to be effective to address the issues of high capacity Si anodes. However, the scale-up of these nano-Si materials is still a critical obstacle for commercialization. Herein, we use industrial ferrosilicon as low-cost Si source and introduce a facile and scalable method to fabricate a micrometer-sized ferrosilicon/C composite anode, in which ferrosilicon microparticles are wrapped with multi-layered carbon nanosheets. The multi-layered carbon nanosheets could effectively buffer the volume variation of Si as well as create an abundant and reliable conductivity framework, ensuring fast transport of electrons. As a result, the micrometer-sized ferrosilicon/C anode achieves a stable cycling with 805.9 m Ah g-1 over 200 cycles at 500 mA g-1 and a good rate capability of455.6 mAh g-1 at 10 A g-1. Therefore, our approach based on ferrosilicon provides a new opportunity in fabricating cost-effective, pollution-free, and large-scale Si electrode materials for high energy lithium-ion batteries.展开更多
Up to now, the Pedgion magnesium reduction process is the dominating magnesium production process. In 2004, about 98% of raw magnesium is produced by Pedgion magnesium reduction process in China which equals to 60% of...Up to now, the Pedgion magnesium reduction process is the dominating magnesium production process. In 2004, about 98% of raw magnesium is produced by Pedgion magnesium reduction process in China which equals to 60% of the global output. It shows that the dolomite-ferrosilicon thermal reduction process is the most important method to produce magnesium in the world. Limited by the disadvantage of dolomite-ferrosilicon thermal reduction process, the magnesium producing process always followed by relatively severe pollution, while the resource utilizing efficiency keeps very low. With the rapid development of dolomite-ferrosilicon thermal reduction process in China, many research works have been done aiming at the process technology and the reduction theory, and the magnesium producing process has got great evolution. The history of dolomite-ferrosilicon thermal reduction process was introduced; the process character, the merits and which defects were also discussed. Defects in dolomite-ferrosilicon thermal reduction process were expatiated, and feasible method and idea to upgrade the process was put forward. The main problems and the potential troubles hindering the development of magnesium industry were analyzed. Finally, the probability to further improve the thermal reduction process and the effective approaches to develop Chinese magnesium industry were discussed.展开更多
本文针对站场复杂环境中硅铁阳极断缆故障检测难题,提出了基于直流电位梯度测量的“双参比法”检测技术。通过系统分析传统检测方法在站场环境中的失效机理,建立了硅铁阳极地床电流场分布模型,开发了基于双参比电极的直流电压差测量方...本文针对站场复杂环境中硅铁阳极断缆故障检测难题,提出了基于直流电位梯度测量的“双参比法”检测技术。通过系统分析传统检测方法在站场环境中的失效机理,建立了硅铁阳极地床电流场分布模型,开发了基于双参比电极的直流电压差测量方法。现场试验表明:该方法在接地电阻高、杂散电流密度大的强干扰环境下,可实现断缆故障100%检出率,定位精度达±1.5 m。相较于传统交流电位梯度法(alternating current voltage gradient,ACVG)、1/2法,提升了检测效率,降低了设备成本,减少了单次故障排查成本。研究证实,双参比法通过测量阳极地床直流电位梯度(故障特征值0V),有效克服了站场电磁干扰和信号串流问题,为复杂环境下的阴极保护硅铁阳极断缆故障排查提供了创新解决方案。展开更多
基金financially supported by the Norwegian Ferroalloy Producers Research Association (FFF) and the Research Council of Norway through KSP project 326581 Recursive。
文摘The production processes for Si and FeSi have traditionally been considered slag-free.However,recent excavations have revealed significant accumulation of CaO–SiO_(2)–Al_(2)O_(3)slag within the furnaces.This accumulation can obstruct the flow of materials and gases,resulting in lower metal yield and higher energy consumption.The main objective of the current work is to enhance our understanding of slag formation during Si and FeSi production.We investigate slag formation through the dissolution of limestone and iron oxide in quartz and condensate,focusing on the reactions between these materials at a gram scale.Our findings indicate that most slag reaches equilibrium relatively quickly at temperatures starting from 1673 K.Notably,slag formation starts at lower temperature when the iron source is present (1573 K) compared to when only CaO is involved (1673 K).The minor elements tend to accumulate at quartz grain boundaries prior to slag formation.Furthermore,the slag produced from condensate contains less SiO_(2)than that generated from quartz with limestone.The type of quartz source and SiO_(2)phase appears to have little influence on slag formation.Good wettability is a significant factor in reaction between quartz and slag.FactSage calculations indicates that the viscosity of the slag ranges from 0.02 to 14.4 Pa·s under furnace conditions,comparable to the viscosity of honey or motor oil at room temperature.
文摘To obtain solid Al2O3 or MgO·Al2O3 inclusions in ladle furnace(LF)refining process and achieve ultra-low total oxygen content in steel through subsequent Ruhrstahl Heraeus degassing,the effects of ferrosilicon alloy,Si content of steel,and slag basicity on the compositions of inclusions during LF refining were investigated in Al-killed steel.Al2O3 inclusions could be transformed into CaO-Al2O3-MgO-CaS inclusions after adding ferrosilicon alloy in the LF refining process as this alloy contains some CaSi alloy impurities.The addition of all ferrosilicon alloys required for the steel in the tapping process could eliminate the influence of Ca in ferrosilicon alloy on the compositions of inclusions.Si in liquid steel had a significant influence on the compositions of inclusions during LF refining when CaO-Al2O3-SiO2-MgO slag with high basicity of 7.0 was used.This was because[Ca]produced by the reaction of CaO and[Al]could be consumed more readily by SiO2 in Si-free steel than in Si-containing steel,which was confirmed by the difference of total calcium content between Si-free and Si-containing steels.As a result,Al2O3 and MgO·Al2O3 inclusions were retained in Si-free steel,whereas calcium aluminate inclusions were found in Si-containing steel.For CaO-Al2O3-SiO2-MgO slag with low basicity of 2.8,Al2O3 and MgO·Al2O3 inclusions were obtained after LF refining in Si-containing steel when all ferrosilicon alloys required for the steel were added in the tapping process.This was because the reaction of CaO and[Al]was weak,and residual[Ca]in the steel could be rapidly consumed by SiO2 in low-basicity slag owing to the low activity of CaO and high activity of SiO2,leading to a low total calcium content of 0.0003%in Si-containing steel.
基金the National Natural Science Foundation of China(No:21703285)。
文摘Various nanostructured architectures have been demonstrated to be effective to address the issues of high capacity Si anodes. However, the scale-up of these nano-Si materials is still a critical obstacle for commercialization. Herein, we use industrial ferrosilicon as low-cost Si source and introduce a facile and scalable method to fabricate a micrometer-sized ferrosilicon/C composite anode, in which ferrosilicon microparticles are wrapped with multi-layered carbon nanosheets. The multi-layered carbon nanosheets could effectively buffer the volume variation of Si as well as create an abundant and reliable conductivity framework, ensuring fast transport of electrons. As a result, the micrometer-sized ferrosilicon/C anode achieves a stable cycling with 805.9 m Ah g-1 over 200 cycles at 500 mA g-1 and a good rate capability of455.6 mAh g-1 at 10 A g-1. Therefore, our approach based on ferrosilicon provides a new opportunity in fabricating cost-effective, pollution-free, and large-scale Si electrode materials for high energy lithium-ion batteries.
文摘Up to now, the Pedgion magnesium reduction process is the dominating magnesium production process. In 2004, about 98% of raw magnesium is produced by Pedgion magnesium reduction process in China which equals to 60% of the global output. It shows that the dolomite-ferrosilicon thermal reduction process is the most important method to produce magnesium in the world. Limited by the disadvantage of dolomite-ferrosilicon thermal reduction process, the magnesium producing process always followed by relatively severe pollution, while the resource utilizing efficiency keeps very low. With the rapid development of dolomite-ferrosilicon thermal reduction process in China, many research works have been done aiming at the process technology and the reduction theory, and the magnesium producing process has got great evolution. The history of dolomite-ferrosilicon thermal reduction process was introduced; the process character, the merits and which defects were also discussed. Defects in dolomite-ferrosilicon thermal reduction process were expatiated, and feasible method and idea to upgrade the process was put forward. The main problems and the potential troubles hindering the development of magnesium industry were analyzed. Finally, the probability to further improve the thermal reduction process and the effective approaches to develop Chinese magnesium industry were discussed.
文摘本文针对站场复杂环境中硅铁阳极断缆故障检测难题,提出了基于直流电位梯度测量的“双参比法”检测技术。通过系统分析传统检测方法在站场环境中的失效机理,建立了硅铁阳极地床电流场分布模型,开发了基于双参比电极的直流电压差测量方法。现场试验表明:该方法在接地电阻高、杂散电流密度大的强干扰环境下,可实现断缆故障100%检出率,定位精度达±1.5 m。相较于传统交流电位梯度法(alternating current voltage gradient,ACVG)、1/2法,提升了检测效率,降低了设备成本,减少了单次故障排查成本。研究证实,双参比法通过测量阳极地床直流电位梯度(故障特征值0V),有效克服了站场电磁干扰和信号串流问题,为复杂环境下的阴极保护硅铁阳极断缆故障排查提供了创新解决方案。
