氯化铵浸取法回收盐泥中的镁

以盐泥为原料,采用氯化铵浸取回收盐泥中的Mg^2+,以浸取液和回收的氨反应制取氢氧化镁产品。考察了盐泥浆液固含量、浸取时间、物料比(氯化铵与盐泥中氢氧化镁的摩尔比)等工艺条件对Mg^2+浸取率的影响,并以比表面积为考察指标进行正交实验,确定氢氧化镁的最佳制备条件。实验结果表明:在盐泥浆液固含量为248g/L、浸取时间为100min、物料比为2.3的条件下,Mg2+浸取率为75.0%;在n(MgCl2)∶n(NH4Cl)=0.5、氨水浓度3mol/L、氨水滴加速率0.8mL/min、反应温度90℃的最佳条件下,制备的氢氧化镁的比表面积为17.87m2/g,粒径约为3μm。该工艺简单可行,为盐泥的综合利用提供了新的思路。

Recovery of magnesium from salt sludge by leaching with ammonium chloride

Mg²⁺ was recovered from salt sludge by leaching with ammonium chloride,and the leaching solution was reacted with recovered ammonia to prepare magnesium hydroxide. The process conditions on the leaching rate of Mg²⁺ were investigated,such as：solid content of salt sludge,leaching time and material ratio （the molar ratio of ammonium chloride to magnesium hydroxide in salt sludge）. Orthogonal experiments were carried out with specific surface area as the index to determine the optimum preparation conditions of magnesium hydroxide. The results show that：The leaching rate of Mg²⁺ is 75.0% under the conditions of solid content 248 g/L,leaching time 100 min and material ratio 2.3;Under the optimal conditions of n（MgCl₂）:n（NH₄Cl）=0.5,ammonia concentration 3 mol/L,ammonia feed rate 0.8 mL/min and reaction temperature 90 ℃,the specific surface area of the prepared magnesium hydroxide is 17.87 m² /g,and the particle size is about 3 μm. The process is simple and feasible,which provides a new idea for comprehensive utilization of salt sludge.