Development of physicochemical foundations of the technology of extraction of low-ash graphite from high-carbone rocks of the Jiamusi-Hankaiskaya province
The majority of high technologies which are indicators of the level of development of the industrial production in the advanced countries are inconceivable without graphite use. The bulk of graphite is imported into Russia from abroad. Enormous resources of crystal graphite are concentrated in ore deposits of the Jiamusi-Hankaiskaya province with submeridional strike towards the adjacent territories of the South of the Far East of Russia and the northeast of China. There are features of Dalnerechensk group (with Filinskoye being the largest of them), deposits of of Lesozavodsk group (Tamginskoye, Turgenevskoye) and graphite-ore giant of Liumao Mashan group of the Heilongjian province in the Northern, central and Southern sides of this province respectively. A characteristic feature of the graphite ores of these objects is the abundance of inclusions of quartz, native metals, intermetallic compounds. Using the deposits of the Lesozavodsk group as an example, the possibilities of extracting high-purity graphite from them were investigated. The results of the research of the conditions of the purification of the natural graphite with the usage of the processes of the hydrodifluoride technology are given. The interaction of the major impurity elements of the concentrate with NH4HF2 resulting in the formation of the complex fluorine ammonium salts and simple fluorides is established to occur during processing of the graphite concentrate with ammonium hydrodifluoride. Conducting the fluoridization with usage of 20 percents of surplus of NH4HF2 has been found to allow reaching the complete fluoridization of the impurity components which are present in the graphite. The complex fluorine ammonium salts and the fluorides of alkaline metals have appeared to be removed from fluoridated concentrate by means of the water leaching. As a result of the experiments, the foundations for the introduction of promising industrial hydrofluoride technology for the purification of natural graphite from impurities have been created. The application of the developed basic scheme for the production of high-purity graphite opens up wide prospects for the deep processing of graphite ores in the deposits of Primorye