离子型稀土冶炼废水处理工艺研究

Treatment of Smelting Wastewater of Ionic Rare Earths

离子型稀土冶炼企业采用清洁生产工艺后,排放的废水酸度高、含盐量高,磷、重金属离子、CODCr、氨氮等超标。研究了从离子型稀土冶炼废水中去除总磷、重金属离子,提出去除有机相—脱磷—去除重金属离子—分级氧化—石英砂过滤工艺流程。试验结果表明:在用石灰乳调节废水pH为9.5、加入20mg/L聚合氯化铝条件下,废水中总磷质量浓度可降至1mg/L以下,总磷去除率达88.2%;脱磷后的废水中依次投加50mg/L硫化钠、50mg/L有机螯合剂,反应0.5h后絮凝沉降,清液中总铅质量浓度为0.17mg/L,总铅去除率达99%。处理后的出水水质符合《稀土工业污染物排放标准》(GB26451-2011)。

By a clean production process ,the wastewater from smelting ionic rare earths ore is high acidity ,high salt ,and concentration of phosphorus ,heavy metal ions ,CODCr and ammonia nitrogen is over the national standard .This study has carried on removing phosphorus ,heavy metal ions from the wastewater .The technological route of removing organic phase -dephosphorization -removing heavy metal ions - step oxidation -quartz sand filtration is determined .The results show that adjusting wastewater pH to 9 .5 using lime milk and adding 20 mg/L polyaluminium chloride ,total phosphorus in the wastewater can be deduced to lower than 1 mg/L ,total phosphorus removal rate can reach 88 .2% .Adding sodium sulphide of 50 mg/L ,and organic chelating agent of 50 mg/L into the waste water after dephosphorization ,reacting 0 .5 h ,the concentration of total lead ion in the supernatant is 0 .17 mg/L ,total lead removal rate is 99% .The effluent water quality meets the Emission Standards of Pollutants from Rare Earths Industry （GB26451—2011） .