基于冷原子吸收分光光度法的热解析-低温等离子体脱汞技术研究

研究含汞土壤的修复问题，采用热解析和低温等离子体综合技术探究新途径，调整温度、添加剂、时间等因素来判断脱汞效果并探究其不同形态，分析工艺过程废料的内部联系，并对废气处理进行分析实验。结论如下：(1)通过改良技术的BCR连续萃取法，得出研究区汞的形态主要为有机结合态(53%)。之后依次是氧化物结合态(33%)、酸可提取态(8%)、残渣态(6%)。(2)温度对热解析程度影响较大。在500℃以上的热解析条件下，土壤中的汞浓度不足1.5 mg·kg-1。(3)当选用400℃的解析温度时，40 min汞去除总体完成。在低于1 700 mg·kg-1的浓度下，汞去除率随着土壤中的含量的增大而减小。(4)氯化钙对于热解析的促进作用最强，柠檬酸、升华硫也有一定作用，硫化钠对于汞去除形成阻滞。(5)低温等离子体的最佳状态是电源设置电压为22 kV，频率为660 Hz。整个系统的汞去除程度可达近90%。

Experimental Study on the Treatment of Mercury Contained Soil by Thermal Analytical Low Temperature Plasma Based on Cold Atomic Absorption Spectrophotometry

In this paper, we selected the Wanshan mercury mine soil as the research object, processed and studied by thermal analysis of low temperature plasma, By study of temperature, time, additives and other process parameters on mercury removal rate and treatment after Mercury, we analysed and compared the process on the mercury containing waste residue , exploring its mechanism of action and summarizing the key factors influencing the process exhaust system. The main results were as follows: (1) The main form of mercury in contaminated soil was organic binding state (52.5%). Secondly, the oxide bound state was (32.5%), acid extractable state was (8.13%) and residual state was (6.25%). (2) Under the condition of 500 ℃ and 40 minute, the residual mercury concentration was only 1.44 mg·kg-1. (3) Under the condition of 400 ℃, with the extension of time, the removal rate of total mercury in soil increased gradually, and the pyrolysis process was basically completed within 40 minute. In the 200~1 600 mg·kg-1 interval, the higher the initial oncentration of mercury, the smaller the removal rate of total mercury in soil. (4) The synergistic effect of calcium chloride on the pyrolysis of mercury containing soil was the best, followed by citric acid and sublimation sulfur, and sodium sulfide had a certain inhibitory effect. (5) The pulse voltage was 21.1 kV, and the discharge frequency was 650 Hz, which was the best parameter to match the high voltage pulse power supply with the low temperature plasma reactor. The total mercury removal rate could reach above 89.73%.