摘要
页岩钒工业浸出过程常添加氟化物助浸剂,产生的萃余液为含高浓度氟和铝的强酸性废水。提出直接中和沉淀法同步除氟并回收氟资源,系统考察了反应pH值、反应时间和温度对废水中氟铝去除率及回收率的影响,并将中和所得除氟渣(Residual Fluoride Sludge,RFS)作为氟源返回钒浸出过程。结果表明,在常温(25℃)、反应pH值为7.0、反应时间3 h条件下,氟去除率达98%,滤液氟浓度可降至51.39 mg·L^(-1)。氟以氟钠镁铝石(Na0.5(Al,Mg)_(2)(F,OH)_(6)·H_(2)O)形式沉淀回收(回收率>99%)。将RFS作为部分氟源用于钒页岩浸出,在浸出温度95℃、时间5 h、液固比1.5∶1、硫酸浓度30%、RFS配比(占理论氟用量)20%的条件下,钒浸出率达91.18%,与完全采用CaF_(2)的效果(94.14%)相当。采用20%Ca(OH)_(2)替代NaOH进行中和时,氟回收率仍能达到95.13%,除氟渣作为循环氟源使用时钒浸出率稳定在90%以上。
Fluoride additives are commonly used in the leaching process of vanadium-bearing shale,generating raffinate as highly acidic wastewater containing high concentrations of fluorine and aluminum.This study proposes a direct neutralization-precipitation method to simultaneously remove fluorine and recover fluorine resources.The effects of reaction pH,time,and temperature on the removal and recovery rates of fluorine and aluminum were systematically investigated.The resulting fluoride removal sludge(Residual Fluoride Sludge,RFS)was recycled as a fluorine source back into the vanadium leaching process.The results showed that under ambient temperature(25℃),pH 7.0,and a reaction time of 3 h,the fluorine removal rate reached 98%,with the filtrate fluorine concentration reduced to 51.39 mg·L^(−1).Fluorine was precipitated and recovered as ralstonite(Na0.5(Al,Mg)_(2)(F,OH)_(6)·H_(2)O)with a recovery rate exceeding 99%.When RFS was used as a partial fluorine source for vanadium shale leaching under conditions of 95℃,5 h,liquid-solid ratio of 1.5∶1,sulfuric acid concentration of 30%,and RFS dosage of 20%(of the theoretical fluorine requirement),the vanadium leaching rate reached 91.18%,comparable to the effect of using pure CaF_(2)(94.14%).When 20%Ca(OH)_(2)was substituted for NaOH in neutralization,the fluorine recovery rate remained at 95.13%,and the vanadium leaching rate stabilized above 90%when RFS was reused as a recycled fluorine source.
作者
张驰
邹小平
蒋应平
ZHANG Chi;ZOU Xiaoping;JIANG Yingping(BGRIMM Technology Group,Beijing 100160,China)
出处
《矿冶》
2025年第4期631-636,共6页
Mining And Metallurgy
基金
国家重点研发计划项目(2020YFC1909704)。
关键词
高氟废水
钒页岩
中和沉淀
氟回收利用
除氟
废水处理
high-fluorine wastewater
vanadium-bearing shale
neutralization-precipitation
fluorine recovery
fluoride removal sludge
recycling
