废电池中汞的释放条件研究

Study on mercury release conditions in spent batteries

考虑焙烧温度、焙烧时间和载气流量三因素的影响,采用正交试验研究焙烧过程中废电池中汞的释放情况。结果表明,三个组合因素对其脱Hg率无显著影响,其中温度对Hg释放率影响最大,其次是时间;最佳的汞释放条件为:焙烧温度550℃,焙烧时间120min,载气流量500mL/min。在此条件下,废电池汞释放率可达100%;焙烧后晶态物质增加,Mn等高价态元素绝大部分被还原为低价态,有利于后期金属离子酸解浸出,为废电池无害化和进一步资源化提供依据。

Adopting an orthogonal test design,mercury-releasing rate of spent batteries by roasting was studied,with detailed discussion of the affecting factors including roasting temperature,roasting time and carrier gas flux.The analysis of these data indicated that roasting temperature had the most greatest effect on it,the next was the roasting time.By statistical analysis,comprehensively considering their effects,the optimal condition was 550 ℃ roasting temperature,120 min roasting time,500 mL/min of carrier gas flux.Under these conditions,mercury released by 100%.X-ray and differential thermal analysis of roasted and unroasted powders indicated that the roasted powder had rather complex configuration,the majority of metallic element were reduced by C,especially Mn4＋ or Mn3＋ was reduced into Mn2＋.It would benefit the hazard-free treatment of spent battery and recycling of sources.