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含镉化合物溶出性能及含镉废渣稳定化处理的工艺研究

发布时间:2019-01-12 12:20  文章来源:笔耕文化传播
【摘要】:为了弄清几种含镉化合物在自然环境条件下的溶出性能,以及降低含镉废渣对环境的污染。本文利用人工制备几种含镉化合物在模拟自然环境的条件下进行溶出反应,对几种化合物在相同条件下的溶出结果进行比较,研究其相对稳定性。在此基础上以广西河池某厂的含镉废渣为研究对象,通过溶出实验探索废渣中镉的溶出性能,研究含镉废渣稳定化的有效方法,选择硫化钠和氢氧化钠为稳定剂,探索含镉废渣稳定化处理的工艺条件,通过浸出毒性对稳定化效果进行表征。其结果如下:(1)反应时间、反应温度和溶液pH对含镉化合物中镉的溶出均有一定的影响,表现为反应时间的延长、反应温度的升高和溶液pH的减小均使镉的溶出率得到提高,其中溶液pH是主要影响因素。(2)通过对三种含镉化合物溶出反应的比较,硫化镉在三种化合物中最为稳定,相同反应条件下镉的溶出率要比碳酸镉和氢氧化镉低得多。(3)在实验范围内,含镉废渣中镉的最佳溶出工艺条件为:搅拌速度300r.min-1,反应时间30min,液固比4:1,溶液pH=1.0,反应温度60℃。在此条件下,镉的溶出率仅为1.183%,因此该废渣中的镉不宜进行回收利用。溶出反应后废渣的浸出毒性为2.351mg.L-1,与未处理废渣浸出毒性2.99mg.L1相比变化不大,未达到将危险废物转化为一般固废的要求。(4)含镉废渣经稳定化处理后,浸出毒性明显降低,且远低于国家标准。在实验范围内最优实验条件为:加入硫化钠:机械搅拌速度300r.min-1、反应时间40min、液固比3:1、硫化钠浓度0.5 mo1.L-1,常温下反应,在此条件下,处理后渣样浸出毒性为0.0275 mg.L-1;加入氢氧化钠:机械搅拌速度300r.min-1、反应时间30min、液固比4:1、氢氧化钠浓度1.0 mo1.L-1,常温下反应,在此条件下,处理后渣样浸出毒性为0.0324 mg.L-1。
[Abstract]:In order to understand the dissolution performance of several cadmium compounds in natural environment and reduce the environmental pollution caused by the waste residue containing cadmium. In this paper, the dissolution reaction of several cadmium compounds was carried out under simulated natural environment. The results of dissolution of several compounds under the same conditions were compared and their relative stability was studied. On this basis, the cadmium containing waste residue of a factory in Hechi, Guangxi, was taken as the research object. The dissolution performance of cadmium in the waste residue was explored through dissolution experiments, and the effective method of stabilizing the waste residue containing cadmium was studied. Sodium sulphide and sodium hydroxide were selected as stabilizers. The stabilization effect of cadmium-containing waste residue was characterized by leaching toxicity. The results are as follows: (1) reaction time, reaction temperature and solution pH have a certain effect on the dissolution of cadmium from cadmium compounds, as shown by the prolongation of reaction time. The dissolution rate of cadmium was increased with the increase of reaction temperature and the decrease of solution pH, among which solution pH was the main influencing factor. (2) cadmium sulfide was the most stable in the three compounds by comparing the dissolution reaction of three kinds of cadmium containing compounds. Under the same reaction conditions, the dissolution rate of cadmium is much lower than that of cadmium carbonate and cadmium hydroxide. (3) in the experimental range, the optimum technological conditions for the dissolution of cadmium in waste residue containing cadmium are as follows: stirring speed 300r.min-1, reaction time 30min, liquid-solid ratio 4: 1, The solution pH=1.0, reaction temperature is 60 鈩,

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