超声辅助隐晶质石墨酸浸动力学及强化机制分析  

Analysis of kinetics and strengthening mechanism of ultrasoundassistedacid leaching of cryptocrystalline graphite

作　　者：卜祥宁 童正[2] 倪梦茜 任玺冰 陈昱冉 王立强 谢广元 BU Xiangning;TONG Zheng;NI Mengqian;REN XiBing;CHEN Yuran;WANG Liqiang;XIE Guangyuan(Key Laboratory of Coal Processing and Efficient Utilization(Ministry of Education),China University of Mining&Technology,Xuzhou 221116,China;School of Chemical Engineering and Technology,China University of Mining&Technology,Xuzhou 221116,China;School of Materials Science and Engineering,Zhengzhou University,Zhengzhou 450001,China)

机构地区：[1]中国矿业大学煤炭加工与高效洁净利用教育部重点实验室,江苏徐州221116 [2]中国矿业大学化工学院,江苏徐州221112 [3]郑州大学材料科学与工程学院,河南郑州450001

出　　处：《中南大学学报（自然科学版）》2023年第11期4228-4237,共10页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(52204296);中国博士后科学基金资助项目(2022M722872);江苏省研究生科研与实践创新计划项目(SJCX23_1299);中国矿业大学研究生创新计划项目(2023WLJCRCZL076)

摘　　要：针对隐晶质石墨酸浸除杂过程中杂质去除率低、浸出时间长等问题,提出酸浸过程中超声波辅助浸出的强化方法。首先,进行常规酸浸除杂试验因素优化,其次,进行常规和超声波酸浸过程动力学参数计算,最后,综合运用激光粒度仪、X射线衍射(XRD)、扫描电镜-能谱(SEM-EDS)、X射线荧光光谱(XRF)、透射电镜-能谱(TEM-EDS)等测试手段分析超声波强化酸浸过程中杂质矿物的赋存状态。研究结果表明:当超声波引入酸浸过程后,在盐酸浓度为8 mol/L、固液比为0.1 g/mL、酸浸温度为343 K、酸浸时间为60 min和超声功率为300 W的条件下,最佳灰分脱除率提高至50%左右。常规和超声条件下的酸浸过程符合Johnson-Mehl-AxTami(JMA)模型,常规浸出过程受扩散控制,超声波浸出过程随着温度的增加由扩散控制向混合控制转变,同时,超声波对酸浸反应速率的强化主要体现在指前因子的显著增大;常规酸浸仅去除一部分含钙、镁、铁的矿物,超声波通过破坏石墨表面形成的惰性层、促进颗粒破碎、产生氧化自由基等方式提高杂质矿物的脱除效率。To solve the problems of low impurity removal rate and long leaching time in the acid-leaching process of cryptocrystalline graphite,an ultrasonic-assisted method was proposed to enhance the acid-leaching process.Firstly,the optimization of the factors for conventional acid leaching tests was carried out.Secondly,the kinetic parameters of conventional and the kinetic parameters of conventional and ultrasonic acid-leaching processes were calculated.Finally,the fugitive state of impurity minerals in an ultrasonic-enhanced acid leaching process was analyzed by laser particle size meter,X-ray diffraction(XRD),scanning electron microscopy-energy spectroscopy(SEM-EDS),X-ray fluorescence spectroscopy(XRF),transmission electron microscopy-energy spectroscopy(TEM-EDS)and other testing means.The results show that the optimal impurity removal rate of acid leaching is increased to approximately 50%with the presence of ultrasound under optimal conditions of 8 mol/L hydrochloric acid concentration,0.1 g/mL solid-liquid ratio,343 K acid leaching temperature,60 min acid leaching time and 300 W ultrasonic power.The acid-leaching processes under conventional and ultrasonic conditions are in accordance with the Johnson-Mehl-AxTami(JMA)model.The conventional leaching process is controlled by diffusion,while the ultrasonic leaching process changes from diffusion control to mixing control with the increase of temperature.The enhancement of the acid-leaching reaction rate by ultrasound is mainly reflected in the significant increase of the finger front factor.The conventional acid leaching method only removes a part of minerals containing calcium,magnesium,and iron,and ultrasound through the destruction of the graphite surface.Ultrasound improves the removal efficiency of impurity minerals by destroying the inert layer formed on the graphite surface,promoting particle fragmentation,and generating oxidation radicals.

关 键 词：隐晶质石墨 超声波 酸浸除杂 浸出动力学 强化机理 

分 类 号：TB321[一般工业技术—材料科学与工程]