Fluorammonium method of titanium slag processing

Titanium dioxide is the most common titanium-containing product on the world market, and the demand for it is increasing. The global consumption of TiO2 is 7 – 7.5 million tons annually. Titanium dioxide is mainly obtained from ilmenite and rutile concentrates. The largest producers are China, USA, Germany, UK, Mexico, and Saudi Arabia. In addition to the natural resources of titan, there are man-made sources. This type of resource includes titanium-containing slags obtained as a result of pyrometallurgical processing of ores and concentrates containing titanium dioxide. These slags, in addition to titanium dioxide, contain silicon in the form of dioxide, silicates or aluminosilicates, whose chemical processing is difficult due to their high melting point (more than 2000 °C) and the chemical stability of these compounds in mineral acids (sulfuric, nitric, hydrochloric). Processing of such raw materials is carried out by “classical” chlorine and sulfuric acid methods. The use of fluorides in industry is realized in the production of aluminum, zirconium, uranium, beryllium, niobium, etc., which indicates the possibility of using fluoride methods for titanium slags processing. The article discusses a method for producing titanium dioxide based on the use of ammonium hydrodifluoride NH4HF2 , which has a high reactivity to a number of chemically resistant oxides (oxides of silicon, titanium, aluminum, etc.). The fluoroammonium method for processing titanium slag using NH4HF2 involves slag decomposition of in NH4HF2 melt followed by silicon admixture sublimation. Cleaning from iron, aluminum and other impurities is carried out using a solution of NH4HF2. Further precipitation of titanium with treatment of the precipitate by AlCl3 and ZnCl2 solutions followed by calcination allows to obtain a rutile modification of titanium dioxide.

Phase formation processes in natural magnesium silicates of various structures by their ammonium fluoride treatment

The processes of forsterite, enstatite and talc treatment by ammonium fluoride have been studied. The phaseformation processes occurring during firing of fluorinated minerals were studied. It was established that structural silica of minerals reacts with ammonium hydrodifluoride with the formation of ammonium hexafluorosilicate. The sublimation of ammonium hexafluorosilicate leads to remove structural silica from minerals with partial destruction of their structure. The firing of fluorinated minerals leads to their structural transformation with the formation of magnesium nesosilicates and fluoronesosilicates.

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

Complex processing of titanium-rare metal raw material

The paper is devoted to investigation of the complex processing of titanium-rare metal raw materials with ammonium hydrodifluoride. It is stated that fluorination of the main components of the mineral raw materials with ammonium hydrodifluoride proceeds with formation of complex ammonium fluorometallates and simple fluorides. It is showed that in the process of aqueous leaching of the fluorinated mineral raw material niobium and tantalum completely pass into solution together with titanium, iron, and silicon fluoroammonium salts while all the rare-earth elements stay in the insoluble residue as complex fluorosodium salts together with CaF2. The method of separation of the fluoroammonium salts with obtaining marketable products and isolation of the rare-earth elements from the insoluble residue is offered.