| Zinc oxide ore which contains zinc less than 10% widely distributes, and the total reserves is large in our country. There are a few million tons in Yunnan province and there is large reserves in other provinces. It is not only a great potential resources, but also a great wealth. It is a very important way that using that deposit to ease shortage of raw materials and maintain long-term and stable development of zinc industry in our country.The paper studies pillar leaching and stirring leaching of low grade oxide zinc deposit. According to granularity, the ore divides into massive ore whose granularity is bigger than 40 meshes and powdery ore whose granularity is smaller than 40 meshes, and contents of zinc respectively are 9.17% and 5.17%.Lump ore whose granularity is bigger than 40 meshes carry on the column to leach, the leaching rate of zinc increases with the concentration and pH value of leaching agent rising. The ore are leached for three times i.e. seventy days with (NH4)2SO4 whose concentration is 2mol/l and PH is 8.5-9.0, leaching rate reaches58.56%, reaction belongs to diffusion control of solid materiel layer, and the dynamic equations respectively are:1-2/3x-(1-x)2/3=4.97862×l0-4t and 1-2/3x-(1-x)2/3 = 5.09345×10-5t.The ore whose granularity is smaller than 40 mesh matches into 5% 325# cement, makes the pellet with the disc and then to leach, the leaching rate of zinc reduces along with solidification time increasing. For guaranteeing the normal circulation of leaching solution, the pellets want concrete at least three days. Solidified three day-long pellets are leached for fifteen days, and the leaching rate of zinc may reach 91.21%. Leaching belongs to diffusion control of solid materiel layer, and the dynamic equation is:1-2x/3-(1-x)2/3 =0.00256t.The ore whose granularity is smaller than 40 mesh are broken separately below 200 meshes and stirring leaching with (NH4)O2SO4. We adjust PH value of leaching solution with ammonia water in the leaching process, and make it to maintain 8.5～9.0. The ore are leached for 15 hours with (NH4)2SO4, the leaching rate reaches 80.79%. Leaching belongs to diffusion control f solid materiel layer, and the dynamic equation is:1-2/3x-(1-x)2/3 =0.01696t. |
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