废炭渣协同二次铁铝渣无害化处理

Harmless treatment of waste carbon slag with secondary iron-aluminum slag

企业通常采用湿法冶金工艺回收退役锂离子电池中的有价金属,在回收过程中产生废炭渣和二次铁铝渣,其中,二次铁铝渣因含有较多镍、铜等重金属,属于重金属固废,需对其进行无害化处理。基于“以废治废”的理念,本研究提出将二次铁铝渣和废炭渣协同处置,经脱硫、还原焙烧和熔融分离回收有价金属。结果表明,随着焙烧温度提高及脱硫时间延长,二次铁铝渣中剩余硫含量均逐渐减少、脱硫率均逐渐提高。当焙烧温度为1300℃、反应时间为2.5 h时,渣中剩余硫含量为0.068%、脱硫率为99.31%;经还原焙烧、熔融分离后,镍、钴、铜、铁的回收率分别为69.43%、74.52%、79.05%、79.29%;对熔渣进行浸出毒性检测,得到浸出液中铜、镍含量分别为0.013、0.984 mg/L,远低于GB 5085.3—2007限定值,实现了对熔渣的无害化处理。

Enterprises usually use hydrometallurgical process to recover valuable metals in retired lithium-ion batteries,and waste carbon slag and secondary iron-aluminum slag are produced in the recycling process.Secondary iron-aluminum slag is heavy metal solid waste due to the high content of nickel,copper and other heavy metals,and needs to be treated of harmlessly.Based on the concept of"treating waste with waste",it is proposed to co-dispose secondary iron-aluminum slag and waste carbon slag,and recover valuable metals through desulfurization,reduction roasting and melt separation.The results show that with the increase of roasting temperature and the extension of desulfurization time,the residual sulfur content in the secondary ironaluminum slag gradually decreases,and the desulfurization rate gradually increases.When the roasting temperature was 1300°C and the reaction time was 2.5 h,the remaining sulfur content in the slag was 0.068%and the desulfurization rate was 99.31%.The recoveries of nickel,cobalt,copper and iron were 69.43%,74.52%,79.05%and 79.29%,respectively.The leaching toxicity of the slag was detected,and the contents of copper and nickel in the leaching solution were 0.013 and 0.984 mg/L,respectively,which were far lower than the GB 5085.3—2007 standard,and the harmless treatment of the slag was realized.