氧化锆基除氟剂协同无定形氢氧化铝除氟实验研究

Experimental Research on Fluoride Removal with Zirconia-Based Reagent Combined with Amorphous Aluminum Hydroxide

对某企业酸性浸出废水进行了一段氧化锆除氟、二段无定形氢氧化铝除氟实验研究。一段氧化锆除氟实验考察了反应温度、反应时间和氧化锆除氟剂加入量对废水除氟效果的影响,结果表明,升高温度、延长反应时间都能促进除氟剂除氟率提高;反应温度75℃、除氟剂加入量50 g/L、反应时间50 min时,除氟率达到96%,废水中氟质量浓度由600 mg/L降至25 mg/L。一段除氟后废水进行二段无定形氢氧化铝除氟,反应温度70℃、反应时间60 min、氢氧化铝加入量5 g/L时,废水氟质量浓度由25 mg/L降至6.5 mg/L;除氟渣晶型良好、衍射峰明显,XRD检测结果显示Na_(3)AlF_(6)是除氟渣中主要成分。

An experimental study was carried out on fluoride removal from the wastewater after acid leaching process in one enterprise.In the experiment,zirconia was used in the 1st-stage reaction and amorphous aluminum hydroxide was adopted in the 2nd-stage reaction for fluoride removal,and effects of reaction temperature,reaction time and adding amount of zirconia-based reagent on the fluoride removal effect were explored.It is found that both higher temperature and longer reaction time can promote fluoride reduction effect of fluoride removing reagent.1st-stage reaction ran for 50 min at 75℃with an addition of 50 g/L zirconia-based reagent,the fluoride reduction rate was up to 96%and fluoride mass concentration in the wastewater was reduced from 600 mg/L to 25 mg/L.After that,2nd-stage reaction at 70℃ran for 60 min,by adding 5 g/L amorphous aluminum hydroxide,the fluoride mass concentration in the wastewater was down from 25 mg/L to 6.5 mg/L.It is shown that the residue left after fluoride removal process has a good crystal structure and obvious diffraction peak.XRD analysis shows that Na_(3)AlF_(6) is the main component in the residue.