The orthogonal test was used to optimize the reaction conditions of roasting zinc oxide ore with NaOH aiming to comprehensively utilize zinc oxide ore.The optimized reaction conditions were molar ratio of NaOH to zinc...The orthogonal test was used to optimize the reaction conditions of roasting zinc oxide ore with NaOH aiming to comprehensively utilize zinc oxide ore.The optimized reaction conditions were molar ratio of NaOH to zinc oxide ore 6:1,roasting temperature 450°C,holding time 150 min.The molar ratio of NaOH to zinc oxide ore was the most predominant factor affecting the extraction ratios of zinc oxide and silica.The mineral phase transformations were investigated by testing the phases of specimens obtained at different temperatures.The process was that silica reacted with molten NaOH to form Na_2SiO_3 at first,then transformed into Na_4SiO_4 with temperature rising.ZnCO_3 and its decomposing product ZnO reacted with NaOH to form Na_2ZnO_2.Na_2ZnSiO_4was also obtained.The reaction rate was investigated using unreacted shrinking core model.Two models used were chemical reaction at the particle surface and diffusion through the product layer.The results indicated that the reaction rate was combine-controlled by two models.The activation energy and frequency factor were obtained as 24.12 k J/mol and 0.0682,respectively.展开更多
研究采用硫酸铵焙烧—水浸工艺提高菱镁矿的利用效率,结合XRD和TG-DTA分析以及对比硫酸铵焙烧MgO的物相变化得到焙烧过程中矿相的转化过程。实验结果表明,在菱镁矿粒度为~74μm、硫酸铵与菱镁矿物料摩尔比为1.6:1、焙烧温度为475℃和焙...研究采用硫酸铵焙烧—水浸工艺提高菱镁矿的利用效率,结合XRD和TG-DTA分析以及对比硫酸铵焙烧MgO的物相变化得到焙烧过程中矿相的转化过程。实验结果表明,在菱镁矿粒度为~74μm、硫酸铵与菱镁矿物料摩尔比为1.6:1、焙烧温度为475℃和焙烧时间为2 h的条件下,镁的提取率达到98.7%。反应中物相转化过程可以概括如下:MgCO_(3)先转变为(NH_(4))_(2)Mg_(2)(SO_(4))_(3),再分解得到MgSO_(4)。反应遵循化学反应和扩散混合控制机理,其表观活化能为33.02 k J/mol。展开更多
基金Projects(51774070,51204054)supported by the National Natural Science Foundation of ChinaProject(N150204009)supported by the Ministry of Education Basic Scientific Research Business Expenses,ChinaProject(2007CB613603)supported by the National Basic Research Program of China
文摘The orthogonal test was used to optimize the reaction conditions of roasting zinc oxide ore with NaOH aiming to comprehensively utilize zinc oxide ore.The optimized reaction conditions were molar ratio of NaOH to zinc oxide ore 6:1,roasting temperature 450°C,holding time 150 min.The molar ratio of NaOH to zinc oxide ore was the most predominant factor affecting the extraction ratios of zinc oxide and silica.The mineral phase transformations were investigated by testing the phases of specimens obtained at different temperatures.The process was that silica reacted with molten NaOH to form Na_2SiO_3 at first,then transformed into Na_4SiO_4 with temperature rising.ZnCO_3 and its decomposing product ZnO reacted with NaOH to form Na_2ZnO_2.Na_2ZnSiO_4was also obtained.The reaction rate was investigated using unreacted shrinking core model.Two models used were chemical reaction at the particle surface and diffusion through the product layer.The results indicated that the reaction rate was combine-controlled by two models.The activation energy and frequency factor were obtained as 24.12 k J/mol and 0.0682,respectively.
基金appreciate financial supports from the National Natural Science Foundation of China(Nos.51774070,52004165)the Science and Technology Project of Yunnan Province,China(No.202101AS070029)。
文摘研究采用硫酸铵焙烧—水浸工艺提高菱镁矿的利用效率,结合XRD和TG-DTA分析以及对比硫酸铵焙烧MgO的物相变化得到焙烧过程中矿相的转化过程。实验结果表明,在菱镁矿粒度为~74μm、硫酸铵与菱镁矿物料摩尔比为1.6:1、焙烧温度为475℃和焙烧时间为2 h的条件下,镁的提取率达到98.7%。反应中物相转化过程可以概括如下:MgCO_(3)先转变为(NH_(4))_(2)Mg_(2)(SO_(4))_(3),再分解得到MgSO_(4)。反应遵循化学反应和扩散混合控制机理,其表观活化能为33.02 k J/mol。
