硫酸亚铁络合-次氯酸钙氧化法联合处理高炉煤气含氰洗涤废水

High Concentration Cyanide-containing Wastewater Treatment by Ferrous Sulfate and Calcium Hypochlorite

研究了硫酸亚铁络合-次氯酸钙氧化两步法静态和联合动态处理高炉煤气高浓度含氰洗涤废水,采用单因素法确定了处理过程的工艺条件。结果表明,硫酸亚铁络合沉淀过程中的优化工艺条件是:硫酸亚铁加药量为理论量的2.5倍,pH值为6,沉淀时间30 min,此时废水中总氰化物和易释放氰化物的去除率分别为95.52%和93.10%;次氯酸钙氧化过程中,次氯酸钙加药量为理论加药量的3.5倍,氧化反应pH值为10,反应时间30 min,此条件下废水中总氰去除率达到93.46%。采用静态和动态两步联合处理后,废水可以稳定达到国家《污水综合排放标准GB8978—1996》一级指标要求。

Through static and continuous dyamic experiment,cyanide containing washing wastewater of blast furnace gas is treated by ferrous sulfate and calcium hypochlorite with a sequent step.The optimum conditions for the treatment are obtained by single factor experiment.The results show that the removal rate of total cyanide and easily liberated cyanide is 95.52% and 93.10% respectively when ferrous sulfate dosage is 2.5 times as the theoretical,the initial pH is 6 and the reaction time is 30 mins in the chelation by ferrous sulfate.In the oxidation of the wastewater by calcium hypochlorite,the optimal conditions are as follows： calcium hypochlorite dosage 3.5 times as the theoretical,pH of 10 and reaction time 30 mins.The removal rate of total cyanide reach 93.46%.After the treatment,the CN-mass concentration in the wastewater can be well controlled,meeting the discharge standard of GB 8978—1996.