有机复合改性膨润土固定尾矿浸出液中Zn的研究

Study on Fixing Zinc in Tailings Leachate by Organic Compound Modified Bentonite

关键词:  膨润土  复合改性  Zn  尾矿  尿素  壳聚糖

Key words:  bentonite  compound modification  zinc  tailings  urea  chitosan

摘要:

本研究以钠基膨润土为原土，采用尿素和壳聚糖对其进行复合改性。用扫描电镜、红外光谱和X射线衍射等方法对改性膨润土进行表征，研究不同因素及模拟酸雨对改性膨润土固定尾矿浸出液中Zn的影响。结果表明，改性膨润土对浸出液中Zn的固定率最高可达86%，固定时间可缩短至3 h，pH值可低至4.5，温度的影响较小。正交试验优化的固定条件：改性膨润土投加量为1.5 g/50 g尾矿，pH值为5.0，温度为25℃。模拟酸雨试验表明改性膨润土在酸雨的平均pH值下仍有较好的效果。结构表征结果表明壳聚糖主要结合到膨润土表面，而尿素主要插到膨润土层间。

Abstract:

In this study, as the raw material, sodium bentonite was madified with urea and chitosan. The modified bentonite was characterized by scanning electron microscopy, infrared spectroscopy and X-ray diffraction. The effects of different factors and simulated acid rain on Zn in the leaching solution of modified bentonite fixed tailings were studied. The results showed that the fixation rate of modified bentonite on Zn in the leaching solution could reach up to 86%, the fixation time could be shortened to 3 h, the pH value could be as low as 4.5, and the temperature had a little effect. The optimized fixed conditions of the orthogonal test were as follows:the dosage was 1.5 g/50 g tailings, the pH value was 5.0, and the temperature was 25℃. The experiment of simulated acid rain shows that the modified bentonite was still has a good effect under the average pH value of acid rain. The results of structural characterization showed that chitosan was mainly bound to the surface of bentonite, while urea was mainly intercalated between the bentonite layers.