NH_3-MgCl_2-H_2O体系反应平衡研究  

Study on reaction equilibrium of NH_3-MgCl_2-H_2O system

作　　者：刘露萍[1] 范天博[1] 姜宇[1] 周永红[1] 李雪 刘云义 于昕[1] 

机构地区：[1]沈阳化工大学化学工程学院,辽宁沈阳110142 [2]辽宁精细化工协同创新中心,辽宁沈阳110142

出　　处：《盐科学与化工》2017年第4期14-18,共5页Journal of Salt Science and Chemical Industry

基　　金：国家自然基金(61102041);国家科技支持计划(2013BAB09B01);辽宁省自然基金(201602582);辽宁省高校创新团队支撑计划(LT2013010);辽宁省教育厅项目(L2013169);辽宁省精细化工协同创新中心资助项目

摘　　要：基于以氯化镁为原料,氨气鼓泡法制备Mg(OH)_2的过程,研究了NH_3-MgCl_2-H_2O体系反应平衡。将体系内发生的反应合并表达为统一的反应方程式:cMg^(2+)+aNH_3+a H_2O(a-b)NH_3·H_2O+cMg(OH)_2↓+bNH_4^++(b-2c)OH^-。通过对体系温度45℃~85℃,反应物浓度0.5 mol/L^2.5 mol/L的25组实验结果的研究,对滤液中的Mg^(2+)、NH_4^+离子、游离氨的浓度、Mg(OH)_2收率以及pH值进行检测。讨论了镁离子浓度、反应温度等因素对NH_3-MgCl_2-H_2O体系的反应平衡时各反应计量数情况和产品收率的影响。结果表明,总反应方程式中反应计量数b和c的比值约为2∶1;随着反应物浓度的增大,计量数a的值逐渐减小然后趋于稳定;产品收率却随着a值的变大而增加后趋于稳定;所以镁离子浓度约为1 mol/L^1.5 mol/L,最佳a值约为4,反应体系平衡时,此刻产品收率较大,体系耗能较小。Based on the process of preparing Mg（OH）2 with magnesium chloride as raw material and ammonia bubbling method,study on the reaction equilibrium of NH3-MgCl2-H2O system. The reactions occurring in the system are expressed as a unified reaction equation：cMg^2＋＋ aNH3＋ aH2O（ a-b） NH3·H2O ＋ cMg（ OH）2↓ ＋ bNH4^＋＋（ b-2c）OH^-. The experimental results of 25 groups of 0. 5 mol/L ～ 2. 5 mol/L of the reaction temperature of the system 45 ℃ ～ 85 ℃. The concentrations of Mg^2＋,NH4^＋ ion,free ammonia,Mg（OH）2 yield and pH value in the filtrate were detected. The effects of magnesium ion concentration and reaction temperature on the reaction rate and the yield of NH3-MgCl2-H2O system were discussed. The results show that the ratio of b and c in the total reaction equation is about 2 ∶ 1; With the increase of reactant concentration,the value of the number of a gradually decreases and then becomes stable; The yield increased with the increase of a value and then became stable; Therefore,the concentration of magnesium ion is about 1 mol/L ～ 1. 5 mol/L,the best a value is about 4,when the reaction system is balanced,the product yield is larger,the system energy consumption is small.

关 键 词：氢氧化镁 氨气 收率 反应平衡 

分 类 号：TQ132.2[化学工程—无机化工]