冶金酸性含镉废水的复合硫化法处理研究

Study on the Composite Sulphuration Treatment of Metallurgical Acidic Wastewater Containing Cadmium

针对冶金酸性含镉废水,研究了硫化钠和重金属捕集剂联合处理对镉的去除效果,考察了药剂的加入量、反应时间、p H值和加药方式对废水中Cd^(2+)去除率的影响。结果表明:采用两步处理法,控制反应的初始p H值为4.0,硫化钠的投加量为445 mg/L,捕集剂的投加量为0.2 m L/L,反应时间为60 min时,处理后废水中Cd^(2+)的质量浓度可以由638 mg/L减少至0.1 mg/L,满足国家废水排放标准,滤渣中镉的质量分数大于10%,具有回收价值,且处理过程中无H_2S气体逸出,可以实现冶金酸性含镉废水的无害化和资源化处理。

Aimed at the metallurgical acidic wastewater containing cadmium, the effect of sodium sulfide and heavy metal composite trapping agent on the treatment of cadmium in water is investigated and the effects of chemicals dosage, reaction time, pH value and dosing way on the removal of Cd2 ＋ in wastewater are determined. The results showed that the concentration of the Cd2＋ in water is reduced from 638 mg/L to 0.1 mg/L by the two - step process when the initial pH value is 4.0, dosage of sodium sulfide and heavy metal composite trapping agent is 445 mg/L and 0.2 mL/L respectively and the reaction time is 60 mins and so it can meet the requirements of the national standards on discharge. The cadmium content in the residue is above 10% with a recovery value and no overflow of H2S is detected in the treatment process. Thus, a harmless resource recovery treatment of metallurgical acidic wastewater containing eadmium can be realized.