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以钠基膨润土(B)为原料,加入两种改性剂,采用湿法制得复合改性膨润土(MB),并用MB固定某锡矿尾矿中的Zn。采用扫描电镜(SEM)和X射线衍射分析仪(XRD)对改性前后的膨润土进行了表征,证实改性剂壳聚糖和乙二胺部分负载到膨润土表面,部分插层到膨润土层间。通过重金属浸出实验对MB固定尾矿中Zn的效果进行了研究,单因素实验结果表明,MB的固定效果要优于B,尾矿中Zn的浸出量降低57%~83%,且在酸度较大时也有良好的固定效果。其最佳固定条件为:MB投加量为1.5 g/50 g,反应温度为35℃,p H可以低至4.0,固定过程在4 h内达到稳定。正交实验结果表明,p H是控制MB固定尾矿中Zn的最重要的影响因素,其最佳的固定条件组合与单因素实验相吻合。
Using sodium bentonite (B) as raw material, two modifiers were added, composite modified bentonite (MB) was prepared by wet method, and Zn in a tin ore tailing was fixed by MB. The bentonite before and after modification was characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). It was confirmed that the modifier chitosan and ethylenediamine partially supported on the surface of bentonite and partially intercalated into the bentonite. The results of single factor experiments showed that the immobilization effect of MB was better than that of B, the leaching amount of Zn in the tailings decreased by 57% -83%, and when the acidity was higher Large also have a good fixed effect. The optimal conditions for immobilization were as follows: MB dosage 1.5 g / 50 g, reaction temperature 35 ℃, p H as low as 4.0, and the immobilization process reached stable within 4 h. Orthogonal experiments show that p H is the most important factor to control Zn in MB fixed tailings, and the best combination of fixed conditions is consistent with single factor experiments.