广东北江铊污染的产生原因与污染控制对策

The reasons and the control technology for thallium pollution in Beijiang,Guangdong Province

铊是稀有分散元素，主要赋存于一些特殊硫化物矿和硅酸盐矿物中，在矿产利用过程中，Tl及其它重金属元素释放进入环境，由此引发的环境污染问题日趋严重．分析2010年广东北江铊污染事件发生的原因，在高温冶炼金属工艺中原子气态铊在水洗或者大气中被氧化成为T1，由于T1的化学活动性，石灰中和过程的沉降作用甚微，使得金属冶炼厂排放口废水铊含量高达600～700μg·L-1以上，导致严重的北江铊污染事件．根据铊在氧化还原条件下不同的环境地球化学特征，采用黄铁矿废渣（主要成分Fe2O3和Fe2O3）作为氧化吸附沉淀剂是理想的废水铊去除剂，以废治废，无二次污染风险．经实验验证可去除工业废水中99％以上微量铊，适用于北江铊污染的源头控制．

Thallium （T1）, as a rare element, mainly dispersed in some particular sulfide ores and silicate min- erals. During the utilization of such mineral resources, T1 and other heavy metals released into the environment, resulting in escalating environmental pollution problems. In this paper the reasons that caused thallium pollution incident of Beijiang, Guangdong Province, occurring in 2010 were analyzed. Smelting at high temperature made T1 transform into gasified atom, which was easily oxidized into T1 ＋ in water or in the atmosphere. Due to the high chemical activity of T1 ＋ , lime neutralization could not effectively precipitate T1, causing the T1 level in the smelter wastewater outfalls higher than 600 -700 lxg ~ L-1. All these lead to serious T1 pollution incident in Beijiang. On the basis of different geochemical characteristics of T1 under different redox conditions, pyrite slag （mainly composed of Fe304 and FezO3 ） may be ideal oxidant and adsorbent for the treatment of Tl-bearing wastewater. This proposed method has the advantage of using waste to treat waste and no secondary pollution risks. The method has been verified by experiments that it can remove more than 99% of trace T1 in industrial waste water. Therefore, this method could be applied to effectively control the source pollution of TI in Beijiang.