吸收脱硫铜渣磁选试验研究

针对铜渣"焙烧—磁选"回收利用工艺的不足,探究了一种"湿法烟气脱硫—磁选"工艺的可行性。通过对比分析铜渣和模拟脱硫渣的磁选效果,主要考察了磁场强度对两种渣中Fe的回收及其他有害元素脱除的影响规律。XRD结果表明脱硫渣中Fe主要以磁铁矿(Fe_3O_4)和铁橄榄石(Fe_2SiO_4)形式存在。磁选对脱硫渣中Fe的富集有显著作用,Si含量较低的磁铁矿进入粗精矿中,Fe品位可达50%以上,满足铁矿石产品标准(GB 32545—2016)中磁精矿五级标准。铜渣直接磁选后可达到与脱硫渣相近的效果,其粗精矿Fe磁选效果(46%)略低于脱硫渣(50%)。粗精矿中Si(5.5%)和Zn(1.1%)超标相比脱硫渣严重。综合考虑,铜渣经烟气脱硫后再进行磁选,其利用价值更高。

Research on magnetic separation of copper slag after absorption desulfurization

The feasibility of "wet flue-gas desulfurization-magnetic separation" process was investigated to address the shortcomings of the "roasting-magnetic separation" process for the recycling of copper slag. The effect of magnetic field strength on iron recovery and harmful elements removal of copper slag and simulated-desulfurization slag was investigated by comparing the magnetic separation effect. The XRD results indicated that the iron in the desulfurization slag mainly existed in the form of magnetite (Fe3O4) and iron olivine (Fe2SiO4). Magnetic separation had a significant effect on the enrichment of iron in the desulfurization slag. Magnetite with low-silicon content entered the rough concentrate and the iron grade reached to more than 50 wt.%. It met the level 5 standard of magnetic concentrate in iron ore product standard (GB 32545-2016). The direct magnetic separation of copper slag achieved a similar effect to that of the desulfurization slag. The magnetic separation effect on iron of the copper slag (>46%) was slightly lower than that of the desulfurization slag (>50%). The excessive degree of silicon (>5.50 wt.%) and zinc (>1.1 wt.%) content in the rough concentrate of copper slag was more serious compared with that of the desulfurization slag. On balance, copper slag was more valuable to be utilized after flue-gas desulfurization and then magnetic separation.