Waste-to-Energy treatment is a promising path to environment and energy management in the future.This work detailed a binary molten salt thermal treatment methodology for the detoxification of spent cathode carbon blo...Waste-to-Energy treatment is a promising path to environment and energy management in the future.This work detailed a binary molten salt thermal treatment methodology for the detoxification of spent cathode carbon block(SCCB)waste and the recycling of carbonaceous materials.The thermal behavior of SCCB and SCCB blended with molten salts was investigated.It was found that the NaCl-Na_(2)CO_(3)binary molten salts significantly contributed to reducing pyrolysis onset temperature by 334.3 K compared to that of SCCB itself(i.e.,activation energy of pyrolysis reaction was reduced from 4.24×10^(5)to 2.30×10^(5)J/mol),thus helping to lower thermal treatment energy consumption.With the addition of binary molten salts,the residue after thermal treatment in a horizontal tube furnace experiment was separated into two layers.The bottom-layer residue was mainly composed of molten salts.The fluorine content in the form of NaF and CaF_(2)of top-layer residue was reduced significantly while the carbon content remained unchanged.Specifically,the leaching concentration of fluoride ion was decreased from 4620 mg/L to 856 mg/L.It is noted that the NaF and CaF_(2)can be removed through water-leaching and hydrothermal acid-leaching methods and thus the carbonaceous materials with a calorific value of 17.5 MJ/kg were obtained.展开更多
传统阴极炭块顶部是平坦的,阴极铝液流动时几乎没有阻力。使用表面凸起的阴极炭块进行研究,目的是增加铝电解槽中铝液流动的阻力,起到减波和减少铝液流动速度的作用,以此降低水平电流密度、阴极电压和铝液流速,保障铝电解槽生产安全稳...传统阴极炭块顶部是平坦的,阴极铝液流动时几乎没有阻力。使用表面凸起的阴极炭块进行研究,目的是增加铝电解槽中铝液流动的阻力,起到减波和减少铝液流动速度的作用,以此降低水平电流密度、阴极电压和铝液流速,保障铝电解槽生产安全稳定。通过COMSOL软件进行模拟,发现随着阴极炭块表面凸起块数的增加,阴极压降和水平电流密度均呈下降趋势,其中阴极压降最大降幅为39.8 mV,水平电流密度最大降幅为2087 A m^(2),并对某铝厂400 kA铝电解槽使用异形阴极炭块后进行测试,测试结果与模拟结果一致。展开更多
基金supported by the"CUG Scholar"scientific Research Funds at China University of Geosciences(Wuhan)(Project No.2020088)National Natural Science Foundation of China(No.41920104007)Opening Fund of State Key Laboratory of Fire Science,University of Science and Technology of China(No.HZ2023-KF03)。
文摘Waste-to-Energy treatment is a promising path to environment and energy management in the future.This work detailed a binary molten salt thermal treatment methodology for the detoxification of spent cathode carbon block(SCCB)waste and the recycling of carbonaceous materials.The thermal behavior of SCCB and SCCB blended with molten salts was investigated.It was found that the NaCl-Na_(2)CO_(3)binary molten salts significantly contributed to reducing pyrolysis onset temperature by 334.3 K compared to that of SCCB itself(i.e.,activation energy of pyrolysis reaction was reduced from 4.24×10^(5)to 2.30×10^(5)J/mol),thus helping to lower thermal treatment energy consumption.With the addition of binary molten salts,the residue after thermal treatment in a horizontal tube furnace experiment was separated into two layers.The bottom-layer residue was mainly composed of molten salts.The fluorine content in the form of NaF and CaF_(2)of top-layer residue was reduced significantly while the carbon content remained unchanged.Specifically,the leaching concentration of fluoride ion was decreased from 4620 mg/L to 856 mg/L.It is noted that the NaF and CaF_(2)can be removed through water-leaching and hydrothermal acid-leaching methods and thus the carbonaceous materials with a calorific value of 17.5 MJ/kg were obtained.
文摘传统阴极炭块顶部是平坦的,阴极铝液流动时几乎没有阻力。使用表面凸起的阴极炭块进行研究,目的是增加铝电解槽中铝液流动的阻力,起到减波和减少铝液流动速度的作用,以此降低水平电流密度、阴极电压和铝液流速,保障铝电解槽生产安全稳定。通过COMSOL软件进行模拟,发现随着阴极炭块表面凸起块数的增加,阴极压降和水平电流密度均呈下降趋势,其中阴极压降最大降幅为39.8 mV,水平电流密度最大降幅为2087 A m^(2),并对某铝厂400 kA铝电解槽使用异形阴极炭块后进行测试,测试结果与模拟结果一致。
