No abstract

The production of periclase-carbon refractories based on phenol-formaldehyde resin with modification of different batch components is considered, which ensures a compression strength of 70 -122 MPa. The strength is increased by reinforcing the resite structure by polysiloxane bonds. The synthesis of SiC in the service of refractories contributes to increasing the slag resistance of the refractory by being an additional antioxidant.The refractory industry is currently oriented to increasing the share of high-quality refractories with enhanced service parameters, which lowers the consumption of refractories per ton of product (steel, glass, cement, etc.) [1].Manufacturers currently decrease the production of dinas, semi-acid, chamotte, periclase-chromite and lime-periclase refractories on a binder made of sand and coal-tar pitch and increase the production of carbon-bearing refractories, including nonfired periclase-carbon materials that have high refractoriness and erosion and corrosion resistance to metal and oxide melts and, accordingly, better service durability. Nonfired periclase-carbon refractories are used as lining in steel-casting ladles, electric furnaces, and oxygen converters. One of the main components of periclase-carbon refractories is graphite, whose properties ensure high thermal conductivity and slag resistance of these materials. A disadvantage of periclase-carbon refractories is the capacity of graphite for easy oxidation starting with 600°C. To protect graphite from oxidation, powdered antioxidants are introduced into refractory mixtures. The resistance and service reliability of periclase-carbon refractories largely depend on the quality of the carbonaceous binder. The role of the binder is also essential in the production of refractories; a binder determines the moldability of a product, the convenience of casting the mixture into a mold, and the strength of the preform. The carbonaceous binder in the heat treatment of product and lining and in the service of metallurgical equipment serves as a basis for the emerging refractory matrix, which affects its structural and physicochemical properties [2].Lately phenol-formaldehyde resins have been increasingly used as carbonaceous binders in the production of periclase-carbon refractories. Phenol-formaldehyde resins have a high degree of polymerization and form a three-dimensional resite structure of the carbonaceous skeleton, thus ensuring high heat resistance and a high yield of coke residue [3]. The solidification of pillowcase phenol-formaldehyde resins starts at around 95°C and ends at 180°C. Usually hexamethylenetetramine (urotropin) is used as a catalyst to achieve the deirs4ed degree of solidification [4].The present study investigated the effect of different methods for introducing modifiers and their composition in the properties of nonfired periclase-carbon refractories on phenol-formaldehyde resin. Periclase-carbon samples were prepared from melted periclase of different fractions, graphite, antioxidant, liquid and powdered phenol-form...

No abstract

No abstract

No abstract