含锌热解漆渣用于湿法冶炼制备电积锌的研究

Study on Electrode-Deposition of Zinc by Hydrometallurgy with Pyrolytic Zinc-Containing Paint Slag

含锌漆渣是富锌防腐涂料涂装后产生的有害废渣,经热解脱除有机组分后可作为湿法冶炼锌的原料。将热解漆渣用于电积锌废液中性浸出-净化除杂-电积回收金属锌板,并对比车间次氧化锌和锌粉为原料的净化后液和功耗参数。结果表明,含锌热解漆渣中-50μm颗粒质量比最大为81.88%,但金属锌含量最低为12.95%,适用于碱洗和废电解液中性浸出;50~125μm热解漆渣金属锌含量较高,适用于置换脱铜和两步除镍钴镉杂质;+125μm热解漆渣中金属锌和金属铁含量均最高,分别为76.01%和68.79%,适合与50~125μm热解漆渣进行两段置换除镉。以上采用热解漆渣的置换除杂效果与采用车间电炉锌粉相当,分别获得镉含量为20.48%和19.68%的两种海绵镉渣。将热解漆渣两段除镉净化液用于生产电积锌,在相同的电积条件下其电流效率和电耗与车间电炉锌粉相当,表明含锌热解漆渣在参数优化后可以生产电积锌,同时为含锌漆渣的资源化利用提供了新方向。

Zinc-containing paint slag is the harmful waste residue from zinc-rich anticorrosive coating,which can be used as the raw material of zinc hydrometallurgy after the organic components are removed by pyrolysis.The pyrolytic zinc-containing paint slag was adopted to neutral leaching with waste electrode-deposition solution,purified and electrode-deposited to produce zinc plate,the purified solution composition and powder consumption of which were compared with that adopting crude zinc oxide and zinc powder as the raw material.The result showed that the pyrolytic paint slag with-50μm size reached the highest ZnO content of 81.88%but the lowest Zn content of 12.95 wt.%,which was suitable for alkaline washing and neutral leaching.The pyrolytic paint slag with 50-125μm size contained higher metal Zn and was suitable for Cu removal and for two-step removal of Ni,Co and Cd.The pyrolytic paint slag with+125μm size had the highest metal Zn and Fe contents of 76.01%and 68.79%,respectively,which was suitable for the second stage of Cd removal with 50-125μm size paint slag.Adopting the above purification process,the solution composition was closed to that purified with the Zn powder,and the sponge Cd products with 20.48 wt.%and 19.68 wt.%content were obtained.Finally,the purified solution was electrode-deposited to produce plate Zn,the current efficiency and power consumption were closed to Zn powder under the same condition,indicating the pyrolytic zinc-containing paint slag was suitable for electrode-deposited Zn production.This research also provided the new direction for the resource utilization of Zn-containg paint slag.