床面倾角对高频气力分选机分选金属影响

Influence of inclination angle of bed of high-frequency vibration separator on metals separation

为研究床面倾角对分选废旧电路板中金属分布规律和金属回收率的影响,采用自制高频气力分选机分选0.75~0.125 mm废旧电路板粉末,通过ICP-AES测定分选产品.结果表明：当床面倾角在操作范围内变化时,铜的分布规律最明显,最高富集比为5.88;密度比铜密度大和与铜密度相近的金属如铅、锌、锡等富集效果明显,分布规律与铜相似;密度比铜密度小很多的金属如铝、镁等富集效果不明显,错配率较高.金属的回收率变化趋势与铜的回收率的变化趋势高度吻合;铅、锌、锡这三种高密度金属的回收率较高,最高回收率都在90%以上;但低密度金属（铝、镁）的回收率很低,物料损失较多,所以若要分离富集该类金属,须对分选后的物料进行二次分选并注意分选过程中物料的损失.

A self-made high-frequency vibration separator was utilized to separate waste printed circuit board（PCB） powder with the particle size ranging from 0.125 mm to 0.75 mm. The effects of the inclination angle of bed on the distributions of different metals in waste PCB were investigated by employing ICP-AES to test the separated products. Results illustrated that the distribution of copper was the most regular providing that the inclination angle of bed changed beyond the operation range, under which the largest concentration ratios were obtained as 5.88. The distributions of the metals with similar density as copper（Pb, Zn, Sn） were as obvious as that of copper. However, the mismatch rates of the metals with much smaller density than copper（Al, Mg） were high and their distributions were not obviously. The variation trend of the recovery rate of overall metal was in good accordance with that of Cu. The recovery rates of metals such as Pb, Zn and Sn were as high as more than 90%. However, the recovery rates of low density metals such as Al and Mg were very low and great losses were observed during the separation process. Therefore, a re-separation was needed for the effective enrichment of metals with low density（Al, Mg） while their weight losses should be avoided.