梁诚, 赵润民, 彭建平, 狄跃忠, 王耀武. 利用Na2CO3处理铝电解槽炭渣的研究[J]. 工程科学学报, 2021, 43(8): 1055-1063. DOI: 10.13374/j.issn2095-9389.2020.11.30.007
引用本文: 梁诚, 赵润民, 彭建平, 狄跃忠, 王耀武. 利用Na2CO3处理铝电解槽炭渣的研究[J]. 工程科学学报, 2021, 43(8): 1055-1063. DOI: 10.13374/j.issn2095-9389.2020.11.30.007
LIANG Cheng, ZHAO Run-min, PENG Jian-ping, DI Yue-zhong, WANG Yao-wu. Treatment of carbon residue from aluminum electrolysis cell using Na2CO3[J]. Chinese Journal of Engineering, 2021, 43(8): 1055-1063. DOI: 10.13374/j.issn2095-9389.2020.11.30.007
Citation: LIANG Cheng, ZHAO Run-min, PENG Jian-ping, DI Yue-zhong, WANG Yao-wu. Treatment of carbon residue from aluminum electrolysis cell using Na2CO3[J]. Chinese Journal of Engineering, 2021, 43(8): 1055-1063. DOI: 10.13374/j.issn2095-9389.2020.11.30.007

利用Na2CO3处理铝电解槽炭渣的研究

Treatment of carbon residue from aluminum electrolysis cell using Na2CO3

  • 摘要: 铝电解槽炭渣是铝工业冶炼生产过程中产生的一种危险废物。炭渣的大量堆存,在浪费电解质资源的同时,也会造成大气、土壤以及水体的污染。本试验以炭渣为原料,Na2CO3为添加料,对炭渣的焙烧−水浸工艺回收炭粉和冰晶石的可行性与过程进行了研究。试验结果表明,将质量比为2.5∶1的Na2CO3与炭渣混合后置于坩埚电阻炉中,在950 ℃下焙烧2 h,炭渣中氧化铝、冰晶石和亚冰晶石被Na2CO3消耗,焙烧后混合料由C、Na2CO3、NaF、NaAlO2组成。焙烧后混合料在pH为13、浸出温度为25 ℃的条件下浸出1 h,固液分离后的浸出渣经过水洗、烘干后得到炭粉,其纯度可达89%。利用碳酸化法回收浸出液中F,可获得主成分合格的粉状冰晶石。适当地提高焙烧温度和延长保温时间可提高炭和电解质的分离效率。研究经济而有效的炭渣处理方法,不仅可以解决炭渣带来的环境污染问题,还对社会的可持续发展产生深远影响。

     

    Abstract: Carbon residue in aluminum electrolytic cell is a kind of hazardous waste produced during the smelting and production process of the aluminum industry. Approximately 10 kg of carbon residue is produced for every ton of primary aluminum produced. China’s primary aluminum output was as high as 35.04 million tons in 2019, so its carbon residue production was about 350,000 tons. The accumulation of a large amount of carbon residue wastes electrolyte resources, as well as causes air, soil, and water pollution. Additionally, carbon residue was listed on the National Hazardous Waste List in 2016. Therefore, the treatment of carbon residue needs to be solved urgently. In this experiment, the characteristics of carbon residue were introduced, and it was used as the raw material to study the process feasibility of recovering carbon powder and cryolite by the roasting-water leaching process of carbon residue with Na2CO3 as the additive. Na2CO3 with a mass ratio of 2.5∶1 was mixed with carbon residue, placed in a crucible-resistance furnace, and then baked at 950 ℃ for 2 h. Test results show that the alumina, cryolite, and sub-cryolite in the carbon residue are consumed by Na2CO3, and the mixture after roasting consists of C, Na2CO3, NaF, and NaAlO2. After roasting, the mixture is leached for 1 hour with a pH of 14 and at a leaching temperature of 25 ℃. The purity of the recovered carbon powder after solid-liquid separation can reach 89%. The carbonation method is used to recover F in the leachate to obtain powdered cryolite with qualified main components. Properly increasing the roasting temperature and extending the holding time can improve the separation efficiency of carbon and electrolyte. Research on economical and effective carbon residue treatment methods can not only solve the environmental pollution caused by carbon residue, but it can also have a profound impact on the sustainable development of society.

     

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