沉淀混凝法处理含氟工业废水的实验研究

Experimental Study on Treatment of Fluorine-containing Industrial Wastewater by Precipitation Coagulation

传统钙盐沉淀法除氟无法满足企业排放标准,且钙盐沉淀法与其他工艺联用时除氟条件的交互作用对除氟结果有决定性影响。为解决某炼钢厂连铸二冷水的除氟问题,使用模拟原水进行实验,采用钙盐沉淀处理后投加高效除氟药剂的工艺路线,并且进行单因素实验分析,以钙盐投加量、沉淀反应时间、复合除氟药剂投加量、复合药剂混凝pH为影响因素,出水剩余氟离子质量浓度为指标,确定了最佳的实验条件。结果表明:沉淀剂使用氢氧化钙与氯化钙复合,双钙摩尔比为1∶1,钙氟摩尔比为1.21∶1,沉淀反应时间为28min,混凝反应pH为6.2,复合药剂投加量为46mg·L^(-1)时为最佳反应条件,使出水氟离子质量浓度稳定在2mg·L^(-1)以下。

The traditional calcium salt precipitation method can not meet the enterprise emission standards,and the interaction of fluoride removal conditions when calcium salt precipitation method is combined with other processes has a decisive influence on the fluoride removal results.In order to solve the problem of fluoride removal in secondary cooling water of continuous casting in a steel plant,the simulated raw water was used for experiments,and the process route of adding efficient fluoride removal agent after calcium salt precipitation treatment was adopted,and the single factor experimental analysis was carried out.Taking the dosage of calcium salt,precipitation reaction time,dosage of composite fluoride removal agent and coagulation pH of composite agent as influencing factors,the optimal experimental conditions were determined with the mass concentration of residual fluoride ions in the effluent as the index.The results showed that when calcium hydroxide and calcium chloride were used as precipitant,the molar ratio of calcium hydroxide to calcium chloride was 1∶1,the molar ratio of calcium to fluorine was 1.21∶1,the precipitation reaction time was 28 min,the coagulation reaction pH was 6.2,and the dosage of composite agent was 46 mg·L^(-1),the fluoride ion mass concentration in the effluent was stabilized below 2 mg·L^(-1).