The effect of SiC additives and the granular composition on porosity, abrasive resistance, and endurance of carbon refractory blocks used in the blast-furnace steel-making technology. The use of microporous refractory blocks makes it possible to extend the blast-furnace production campaign by several years. The high efficiency of low heat-conducting cold-rammed mixes and a carbon-containing concentrate (available from ChEP JSC) is discussed.Since 1997, at the Chelyabinsk Electrode Plant JointStock Co. (ChEP JSC), new types of refractory carbon blocks and cold-rammed mixtures have been developed for the refractory lining of blast furnaces aimed at extending their service life.In an operating blast furnace, the carbon blocks are exposed to high thermal stress, infiltration of molten iron, structural degradation, and abrasive wear. Finally, the carbon blocks undergo cracking and develop brittleness. This results in the reduction of heat conductivity and initiates melting of the hardened layer of metal, the so-called scull, which serves as a protection for the walls and bottom of the blast-furnace hearth.All these factors adversely affect the carbon lining and lead to its degradation.To make the refractory blocks reliable in service, one will have to improve their properties such as density, heat conductivity, microporous structure, and resistance to abrasive wear.A survey of the literature has shown that effective techniques for creating a dense microporous structure of carbon blocks are:
Typical properties (average values) are provided for promising grades of blast furnace blocks. Physical modelling methods are used for the first time and results are presented for a study of thermal shock resistance and resistance to abrasive wear of different grades of carbon blast furnace blocks.Keywords: carbon refractories, blast furnace blocks, blast furnace.The trend in metallurgical development as a whole, and for blast furnaces in particular, is characterized by an increase in furnace unit capacity and constant technical modernization. The main direction of blast furnace production is intensification of the process, construction of new blast furnaces, and reconstruction of existing furnaces using contemporary technology and approaches.Carbon materials exhibit a unique set of physicomechanical properties. Due to the high bonding energy of carbon atoms graphite remains in a solid state up to a temperature of the order of 3500°C; then there is carbon sublimation. Graphite strength increases up to 2500°C, and this combined with low density provides high heat resistance. Carbon is inert with respect to some of the most corrosive reagents. These features give rise to extensive use of carbon materials as elements of a composite lining for the reaction space of various units of metallurgical and chemical production.Conversion of a blast furnace lining from ceramic to carbon is an important step in iron production technology, making it possible to increase the reliability and endurance of furnace units. Serious tasks are also placed in front of the electrode industry. According to the technical specifications of Minchermet a new class of carbon lining materials has been developed and assimilated for blast furnaces. For blast furnaces with a volume of 2200 m 3 output of carbon blast furnace blocks DBU-0 and DBU has been developed and assimilated in accordance with TU 48-12-18-88 "Carbon blocks for lining blast furnaces." Graphite blocks are produced for lining the blast furnace bottom in accordance with TU 48-12-37-91 "Graphite blocks for blast furnaces". In addition carbon lining materials for blast furnaces include mixes and pastes serving for filling the joints between blocks.Contemporary processes for intensifying blast furnace production have increased specifications for blast furnace lining quality, and creation of a new generation of carbon lining materials. Under these conditions research, development of technology and assimilation of new grades of refractories for blast furnaces and revelation of the main features for molding objects with prescribed properties remains important.During operation of blast furnaces the linings are subject to the action of high temperature (1500 -1800°C), corrosive gases, molten iron and slag, the wearing effect of the loaded charge. The degree of action of these factors is governed by the level of physicomechanical properties of the carbon lining, limiting its resistance and service life. Thermoanthracites with addition of artificial graphite are used as a filler for producin...
The need for substantiated formulation of quality requirements for cathode blocks is emphasized. The ratio of the bending strength to elasticity modulus is proposed as a criterion for evaluating the strength properties of blocks. Techniques for improving this ratio in the production of carbon graphite materials are discussed.The operational reliability of cathode blocks is determined by their physicomechanical properties which, in turn, are specified by the corresponding technical documentation. Over the past 5 years, requirements placed on cathodes blocks have time and again been revised, which finally resulted in a poorly substantiated and somewhat relaxed margin of performance. As shown by practice, formal conformance with the specifications placed on cathode blocks is not necessarily a guarantee of their reliable performance. The strength properties of cathode blocks have been and continue to be one of the most debatable and controversial issues.In deciding on which of the strength characteristics is most informative, the reasoning is usually based on the concept of the weakest link.The strength characteristics of carbon graphite materials are typically arranged in ascending order tension -bendingcompression, that is, the weakest link is tensile strength. However, according to reported data [1], viewed technologically, tensile strength is a less sensitive feature than bending strength in the preparation of carbon graphite materials (for example, in regard to the amount of pitch added). The low sensitivity of tensile strength to central technological parameters (such as porosity or specific electric resistance) may be due to imperfectness of the method (diametral compression) used for determining this strength characteristic. Thus, the bending strength has been recognized to be the best informative index for evaluating strength properties of cathode blocks. A similar opinion was also voiced in [2] on the grounds that this parameter gives a measure of the resistance to buckling and shear stress.A still fuller evaluation of the strength properties of blocks is the ratio of the strength to the elasticity modulus considering that this ratio characterizes the maximum permissible strain to failure of the material. Based on the previously reported data [3], it has been decided on taking the ratio of the bending strength to the dynamic modulus of elasticity as the best informative evaluation of maximum permissible strain of graphite materials. The higher the ratio, the higher the ability of a material to sustain loading conditions; the ratio can be made higher either by increasing the bending
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.