Research On The Comprehensive Utilization Of Indigenous Zinc Smelting Slag

Non-ferrous mineral resource becoming shortage, enhancing the comprehensive utilization of metallurgical slag is essential for sustainable development. Indigenous zinc smelting has generated a lot of slags, which caused a serious damage to the local ecological environment. Therefore, the rational utilization of the zinc slag is an urgent task, both recovering valuable metals in the zinc slag, and removing the pollution to environment. The indigenous zinc smelting slags have piled for a long time, and species were complex, because of lacking system data of mineralogy and composition, can’t make a rational scheme for comprehensive utilization of the zinc slags. So this paper has analyzed the mineralogy of the zinc slags. The results show that the valuable metals content in the slag were low, and its mineral composition was complex, a variety of minerals intertwined. It is difficult to enrich valuable metals by means of ore dressing or leaching process.Therefore, this article according to the content of Zn the zinc slag, proposed a classification scheme. For the zinc slag with low content of Zn is recovery-worthless, because of its main components were similar to clay, and the contents of MgO, K20+Na20, S were very low (less than3%,4%,2%respectively), which were harmful to cement, consistent with the requirements of the clay raw material for production of cement. So recommend this kind of zinc slag as raw materials for the production of cement and concrete. For another kind of zinc slag which with high content of Zn, have used reduction-oxidation two-stage sintering process to make sintered brick, and have recovered lead and zinc at the same time, made it resources and harmless, achieved full utilization of the IZSS. Carbon contained in the zinc slag have used as a reducing agent to volatilize lead and zinc into dust during the sintering process.The results of experiment have indicated that when the proportion of zinc slag was60%, after reduction process in1050℃for6h, the volatilization rate of Zn and Pb were94.81%and97.61%respectively. Analyzed the dust by XRD, which was byproduct of the production of sintered brick. The main component of the dust is Zn, with little ZnO and Pb, can be recycled as secondary zinc resource. The TCLP test results of sintered bricks have shown that the concentration of heavy metal ions are very low in the leaching solution (Zn<5mg·L-1, Pb<1mg·L-1, Cd <0.1mg·L-1, As, Hg, etc. are not detected), which are much lower than the CNS, can avoid secondary heavy metal pollution in use.