从废弃镍氢电池负极板中回收稀土金属

Recovery of Rare Earth from Spent MH-Ni Battery Negative Electrode

通过废弃镍氢电池负极板在稀硫酸中的浸出实验,考察了稀硫酸浓度、稀硫酸体积与废弃镍氢电池负极板质量比(液固比)、浸出时间、搅拌转速等因素对稀土金属(RE)浸出率的影响。通过正交实验确定的最佳浸出条件:稀硫酸浓度为2.5 mol/L,液固比为10,浸出时间为60 min,搅拌转速为800 r/min。在此条件下,RE浸出率为92.50%。基于RE的硫酸盐和无水硫酸钠生成RE复盐沉淀的原理,向稀硫酸浸出废弃镍氢电池负极板后得到的硫酸盐溶液中加入无水硫酸钠,得到RE复盐沉淀,通过正交实验确定的最佳沉淀条件为:溶液pH为2.0,无水硫酸钠与浸出液中RE^(3+)的摩尔比为4,反应温度为60℃。在此条件下,RE回收率为94.6%。用X射线衍射仪对RE复盐进行了表征。

Leaching out rare earth from spent MH-Ni battery negative electrode using dilute sulfuric acid was carried out. The factors affecting the leaching rate of rare earth （RE） were studied. The optimum conditions obtained by orthogonal tests are as follows： dilute sulfuric acid concentration 2.5 tool/L, ratio of dilute sulfuric acid volume to negative electrode mass （ratio of liquid to solid） 10, leaching time 60 rain, stirring speed 800 r/min. Under these conditions, the leaching rate of RE is 92.5 %. The precipitate of RE double salt was produced by adding anhydrous sodium sulphate into the sulfate solution obtained in the leaching process. The optimum precipitation conditions determined by orthogonai tests are as follows： solution pH 2.0, mole ratio of anhydrous sodium sulphate to RE^3＋ in leaching solution 4, reaction temperature 60℃. Under these conditions, the recovery of RE is 94.6%. The RE double salt was analyzed by X-ray diffractometer.