高镁脱硫废水软化和镁回收实验与机理分析

Experimental study and mechanism analysis of softening and magnesium recovery of high magnesium desulfurization wastewater

随着《节约能源法》、《环境保护法》等一系列用水排水政策和法规的颁布,国内对污水、废水排放标准有了更严格的规定,这无疑使得脱硫废水深度处理研究热情进一步升温,而对废水的软化处理作为废水深度处理的一个必要环节就显得尤为重要。本文根据国内某火力发电厂三联箱前出水的脱硫废水水质特征,介绍了一种脱硫废水的软化方法,在三联箱处理废水的工艺基础上做了适当的改造,通过向脱硫废水加入碱液和碳化的方法介绍了废水软化和镁回收的实验。实验结果表明,去除重金属阶段、回收氢氧化镁阶段和碳化阶段分别将脱硫废水的pH调至8.8、10.2和8.5是比较合理的,处理后的脱硫废水既可以达到后续水处理单元的要求又可以最大程度的回收高品质的氢氧化镁。

With the promulgation of a series of water and wastewater policies and regulations including the Energy Conservation Law and the Environmental Protection Law,domestic pollution and wastewater discharge standards have been more stringent,which undoubtedly makes the desulfurization wastewater deep processing research enthusiastic.Further heating,and softening of wastewater is particularly important as an essential part of the advanced treatment of wastewater.Based on the water quality characteristics of the desulfurization wastewater from the effluent from the triple tank of a thermal power plant in China,a softening method for the desulfurization wastewater is introduced.The process of treating the wastewater in the triple tank is appropriately modified,and the lye is added to the desulfurization wastewater.Experiments with wastewater softening and magnesium recovery were carried out by carbonization.The experimental results show that it is reasonable to adjust the pH value of the desulfurization wastewater to 8.8,10.2 and 8.5 except for the heavy metal stage,the recovery of magnesium hydroxide stage and the carbonization stage.The treated desulfurization wastewater can meet the requirements of the subsequent water treatment unit.Maximum recovery of high quality magnesium hydroxide products.