钽铌湿法冶炼废水中氨氮去除方法的试验研究

Experimental study on the removal of ammonia-nitrogen from Ta/Nb hydrometallurgy wastewater

为降低钽铌湿法冶炼过程所产生的废水中的氨氮,对分类处理钽铌湿法冶炼产生的各种氨氮废水进行了试验研究。结果表明,对高浓度氨氮(NH4+-N>10000mg/L)废水进行蒸发、冷凝、结晶,制取的氨水可返回钽铌工业使用;对中浓度氨氮(NH4+-N 500～10 000 mg/L)废水进行吹脱,吹脱后出水氨质量浓度<100 mg/L;对低浓度氨氮(NH4+-N<500 mg/L)废水进行离子交换法处理,出水氨氮可满足《城镇污水处理厂综合排放标准》(GB 18918—2002)规定的一级排放标准。这套组合工艺能带来较高的经济效益。

In order to reduce the concentration of NH4＋-N in wastewater brought about in the process of Ta/Nb hydrometallurgy,the sorting operation of various ammonia-nitrogen wastewater brought about in the process of Ta/Nb hydrometallurgy has been studied.Experiments show that the NH3·H2O made from the evaporation,condensation and crystallization of the wastewater with highly concentrated ammonia-nitrogen（NH4＋-N10 000 mg/L）can be recycled in Ta/Nb metallurgy.After the blow-off of ammonia-nitrogen wastewater with medium concentration（NH4＋-N 500～10 000 mg/L）,the ammonia concentration is less than 100 mg/L.After the ion exchange treatment of ammonia-nitrogen wastewater with low concentration（NH4＋-N500 mg/L）,the effluent NH4＋-N can meet the requirements of the First Grade of Comprehensive Discharge Standard of Urban Sewage Treatment（GB 18918—2002）.This combined technology can bring higher economic benefits.