Технології та перспективні розробки одержання графіту (огляд)

Abstract

The article is devoted to a review of industrial technologies, promising developments, and research in obtaining graphite, particularly nuclear purity. Due to its unique properties, graphite has become an integral part of products used in nuclear energy, power equipment, mechanical engineering, metallurgy, and other industries. Graphite as a constructional and functional material is applied in high-temperature reactors: AVR (Germany), HTGR-1 (USA), improved gas-cooled reactor AGR (England), and in uranium-graphite high-power channeltype reactor (RBMK) (USSR, Russian Federation, Lithuania). At present time, graphite is a constructive and functional material in nuclear power systems of the IV generation, especially in high-temperature gascooled systems (HTGR, HTR, HTGR, VHTR) and liquid salt reactors (MSR). Due to the development of nuclear power systems of the IV generation and the increase in the popularity of electric transport, there is a dynamic increase in the consumption of graphite, therefore the issue of developing and improving technologies for the production of high-purity graphite (including nuclear) are of great practical importance. The aim of the article was to determine the most promising options for producing graphite, especially for using this material in generation IV nuclear power systems in future. Chemical industrial methods of cleaning natural graphite represent an environmental hazard due to the use of toxic precursors, which makes them prohibited in some countries. The main thermal industrial method of obtaining artificial graphite is the heating of coke or anthracite in special electric furnaces at a temperature of about 3000 °C and high pressure without air access. However, this method has several disadvantages, including high energy and resource costs. Among the considered developments and research in the direction of creating technologies for obtaining high-purity graphite, the biggest problem for thermal methods is the complexity of the hardware design and the low yield of the finished product, and for chemical methods (as well as industrial chemical methods) there is an environmental hazard due to the use of toxic substances. One of the promising possibilities is the high-temperature purification of graphite (including nuclear purity) in devices with an electrothermal fluidized bed. However, due to insufficient research in this direction, the technology has not yet gained industrial implementation. Considering the described factors, developing graphite purification technology in electrothermal fluidized bed reactors is an urgent scientific task.