摘要
提纯处理是拓宽天然微晶石墨应用领域、提高其产品附加值的重要工艺。已有的天然微晶石墨提纯研究都存在不够系统和深入等不足,未能很好地阐明影响相关工艺提纯效果的根本原因。本文通过XRD、SEM、EDS、FTIR、ICP等表征测试手段,对天然微晶石墨原矿及相关纯化试样的杂质成分进行了深入分析,以期探明影响提纯效果的主要因素。研究结果表明:(1)微晶石墨原矿中有大量尺寸小于1μm的杂质弥散在石墨晶粒边沿及晶粒间的空隙中,无法实现杂质与石墨晶粒的充分解离,是影响浮选提纯效果的主要因素;(2)微晶石墨矿物杂质中的TiO2组分以及石墨晶体中残存的有机官能团物质不能通过氢氟酸去除,是影响氢氟酸法提纯效果的主要因素;(3)碱熔过程中SiO2杂质与NaOH反应可能生成少量难溶的高模数硅酸钠,酸浸过程中可能生成硅酸溶胶或凝胶,是影响碱酸法提纯效果的主要因素;(4)高温法的提纯效果主要受制于加热温度和时间,通入卤素气体可显著降低杂质的沸点,更易实现提纯目的。研究结果对天然微晶石墨工业化提纯工艺方法的选择和优化具有较好的理论指导意义。
Purification is an important prerequisite to broaden the application field and increase the economic value of the natural amorphous graphite.Many studies on purification of amorphous graphite have some shortcomings,and can’t clarify the fundamental reasons that influence the effects of related purification processes.In this paper,the impurity components of natural amorphous graphite raw ore and related purified samples are systematically analyzed by means of XRD,SEM,EDS,FTIR,ICP and other characterization methods,in order to find out the main factors influencing the effects of related purification processes.The results show that:(1)there are a large number of impurities with sizes less than 1μm dispersed in the edges of graphite grains and the gaps between grains in amorphous graphite raw ore,and it is impossible to dissociate the impurities and graphite grains fully,which is the main factor influencing the purification effect of flotation method;(2)impurities such as TiO2and residual organic functional groups in amorphous graphite can’t be effectively removed by hydrofluoric acid,which is the main factor influencing the purification effect of this method;(3)a small amount of insoluble high modulus sodium silicate may be generated by the reaction of SiO2with NaOH in the process of alkali melting,and silicic acid sol or gel may be generated in the process of acid leaching,which influences the purification result of the alkali-acid method;(4)the purification effect of the high-temperature method is mainly subject to the heating temperature and time,and the introduction of halogen gas can significantly reduce the boiling point of impurities,which is easier to achieve the purification purpose.The research results have good theoretical guiding significance for the selection and optimization of industrial purification process of natural amorphous graphite.
作者
李建新
田宁郴
涂莉娟
黄启忠
崔丹
刘伟
Li Jian-xin;Tian Ning-chen;Tu Li-juan;Huang Qi-zhong;Cui Dan;Liu Wei(State Key Laboratory of Powder Metallurgy,Central South University,Hunan Changsha 410083,China;National Quality Inspection and Testing Center of Graphite Products,Hunan Chenzhou 423000,China)
出处
《炭素技术》
CAS
北大核心
2022年第6期40-45,共6页
Carbon Techniques
关键词
微晶石墨
杂质
提纯
Amorphous graphite
impurity
purification
