盐泥中钾镁资源的回收利用研究

Recovery and reutilization of potassium and magnesium resources from salt sludge

以氯碱企业中生产的固体废弃物盐泥为原料,采用旋转液膜反应器强化水洗及CO_(2)碳化方式分别浸取其中的氯化钾和氢氧化镁资源,考察了盐泥浆液的固液比及浆化温度对氯化钾浸出含量的影响以及碳化反应条件对盐泥中氢氧化镁浸取率的影响。实验结果表明,在盐泥与水的固液比为1∶5、浆化温度为35℃时,盐泥中氯化钾的浸出率可达到95.12%。氢氧化镁碳化浸取实验中,当固液比为1∶13、碳化温度为25℃、搅拌转速为900 r/min、CO_(2)通入流量为45 mL/min、通入时间为140 min时,盐泥中氢氧化镁的浸出率可以达到95.43%。水解实验结果表明,在100℃下水解30 min,可得到纳米花状的Mg5(CO_(3))_(4)(OH)_(2)·4H_(2)O产品,水解率达到95.30%。该工艺操作简便,对环境友好,为盐泥的综合利用提供了新的思路。

Salt sludge generated in chlor-alkali enterprises is used as raw material to leach potassium chloride and magnesium hydroxide through the rotating liquid membrane reactor enhanced water washing and carbon dioxide carbonization methods.The influences of the solid-liquid ratio of salt sludge slurry and the slurry-making temperature on the leaching content of potassium chloride are investigated,and the impact of carbonization conditions on the leaching rate of magnesium hydroxide in salt sludge is studied.Experimental results show that the leaching rate of potassium chloride can reach 95.12%when the ratio salt sludge to water in salt slurry is 1∶5 and the slurry-making temperature is 35℃.In the magnesium hydroxide leaching experiment,the leaching rate of magnesium hydroxide in salt sludge can reach 95.43%when the ratio of salt sludge to water is 1∶13,the carbonation temperature is 25℃,the stirring speed is 900 r·min^(-1),carbon dioxide flow rate is 45 mL·min^(-1)and reaction time is 140 min.It is found from hydrolysis experiment that Mg5(CO_(3))_(4)(OH)_(2)·4H_(2)O with nano-flower structure can be obtained through the hydrolysis at 100℃for 30 min,and the hydrolysis rate reaches 95.30%.This recovery process is simple,feasible and environmentally friendly,which provides a new idea for the comprehensive utilization of salt sludge.