Thermodynamic and kinetic studies of the MgCl2-NH4Cl-NH3-H2O system for the production of high purity MgO from calcined low-grade magnesite
Thermodynamic and kinetic studies of the MgCl2-NH4Cl-NH3-H2O system for the production of high purity MgO from calcined low-grade magnesite
复制标题
低品位煅烧菱镁矿生产高纯氧化镁MgCl2-NH4Cl-NH3-H2O体系的热力学和动力学研究
DOI：
10.1002/aic.14789
复制
发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Petit Camille
中科院分区：
文献类型：
--
作者：
Wang Junfeng;Li Zhibao;Park Ah-Hyung Alissa;Petit Camille
为了提高MgO基耐火材料生产的整体可持续性，开发了一种在氯化铵溶液中从煅烧的低品位菱镁矿生产高纯MgO的新工艺。该工艺是基于使用嵌入OLI软件的混合溶剂电解质模型获得的NH 4Cl-MgCl 2-NH3-H2O体系的相平衡设计的。根据浸出实验中镁和钙的转化率，低品位菱镁矿的最佳煅烧温度确定为650°C。镁浸出的表观活化能为30.98 kJ/mol，略低于钙浸出的表观活化能。还开发了镁提取的经验动力学模型，以描述NH 4Cl浓度、煅烧菱镁矿粒度和固液比对镁提取程度的影响。当浸出时间为10 min时，可得到高Mg/Ca摩尔比的浸出液。再通过中间产物4 MgCO 3·Mg（OH）2·4 H2O的分解，得到纯度为99.09%的MgO。© 2015美国化学工程师学会AIChE J，61：1933-1946，2015
To improve the overall sustainability of MgO‐based refractory production, a novel process to produce high purity MgO from calcined low‐grade magnesite in ammonium chloride solution was developed. The process was designed on the basis of the phase equilibria of the NH4Cl‐MgCl2‐NH3‐H2O system obtained using the Mixed Solvent Electrolyte model embedded in OLI software. The optimum calcination temperature of low‐grade magnesite was determined to be 650°C in terms of the conversion ratio of magnesium and calcium in the leaching experiments. An apparent activation energy of Mg extraction was 30.98 kJ/mol, which is slightly lower than that of Ca leaching. An empirical kinetic model of magnesium extraction was also developed to describe the effects of NH4Cl concentration, particle size of calcined magnesite, and solid‐to‐liquid ratio on the extent of extraction of magnesium. At leaching time of 10 min, the leachate with high Mg/Ca molar ratio was obtained. Then, MgO with a purity of 99.09% was produced through the decomposition of intermediate 4MgCO3·Mg(OH)2·4H2O. © 2015 American Institute of Chemical EngineersAIChE J, 61: 1933–1946, 2015