The Study On Recovery Of Zn And Co In Waste Residue From Huludao Zinc Plant

With the development of the national economy,the demand for cobalt resources is increasing dramatically,however,the cobalt resources in China is relatively poor,so it is of great significance to strengthen the comprehensive utilization of the second resource of cobalt.As the cobalt residue is complex and contains a lot of zinc and cobalt,the processing method of acid leaching,impurity removing by zinc,extraction by P204 and settling cobalt is adopted to utilize the cobalt and zinc comprehensively.Besides,a simple technology is designed.The waste residue is leached by acid under the conditions of leaching temperature 60? leaching time 120 min,solid-liquid ration 1:6 and the acid excess rate 1.2.In this reaction,the leaching rate of cobalt,zinc,manganese,copper,cadmium,lead,nickel and iron is 95.9%,91.43%,80.45%,81.44%,90.61%,0.12%,88.58%,77.19%,respectively.In the leaching liquor,the concentration of these metal ion is 6.78g/L,27.12g/L,2.02g/L,4.88g/L,2.12g/L,0.01g/L,0.102g/L,1.12g/L,respectively.The leaching residue is mainly PbSO4.Under the conditions of pH 2,zinc excess rate 3.5,reacting temperature 50 ?and reacting time 20min,the impurity is removed.In this process,the loss of cobalt is less than 3%,but more than 99 percent of copper and cadmium are moved.In the purified liquid,the concentration of Zinc,copper,cadmium,cobalt,manganese,and iron is 48.85g/L,lppm,20ppm,6.67g/L,1.91 g/L,0.34g/L,respectively.The purified liquid is extracted by P204 of 1.5 mol/L to recycle the zinc and cobalt in the condition of pH l.The experiment of cross-current extraction indicates that:when the extraction stage is nine,the concentration of zinc is 10ppm,more than 99 percent of zinc and less than 2.6 percent of cobalt are extracted.The experiment of 6 stage counter-current extraction indicates that:the concentration of zinc,cobalt,manganese,and iron is 0.37g/L,6.56g/L,0.88g/L,0.18g/L,the rate of extraction is 99&,1.6%,53.4%,47.1%,respectively.Under conditions of reacting temperature 60 ?,reacting time 40min,sodium carbonate excess rate 1.5,cobalt concentrate is got by adding sodium carbonate.Through this chemical reaction,the deposition rate of cobalt is more than 99%and amorphous cobalt carbonate is produced.The cobalt carbonate contains 42.27 percent of cobalt,5.6%percent of manganese,2.73 percent of zinc and 1.24 percent of iron,which meets the primary standard.At last,the chemical element balance is calculated and the income is predicted,which shows that this technique is feasible.At the same time,the process is simply designed according to the information of Huludao Zinc Plant.