Fused-rebonded magnesite-chrome brick with excellent thermal shock resistance and production process

Abstract

The invention provides a fused-rebonded magnesite-chrome brick with excellent thermal shock resistance and a production process. The fused-rebonded magnesite-chrome brick comprises the following raw materials in parts by weight: 5-25 parts of high-purity magnesia, 20-40 parts of large-crystal electro-fused magnesia, 30-40 parts of fused magnesia-chrome sand, 5-16 parts of chromite, 2-8 parts of MgCO3, 2-10 parts of chromium concentrate submicron powder, 0.1-1 part of rare earth agglutinant and 2-3 parts of sulfite pulp waste liquid, wherein the specific gravity delta of the sulfite pulp waste liquid is greater than or equal to 1.28g / cm<3> and smaller than or equal to 1.32g / cm<3>. The production process comprises the steps of: 1) mixing the raw materials, adding high-purity magnesia, large-crystal electro-fused magnesia, fused magnesia-chrome sand, chromite, MgCO3, the chromium concentrate submicron powder and rare earth agglutinant into a mixing pan to uniformly mix according to the weight ratio, adding sulfite pulp waste liquid of which the specific gravity is greater than or equal to 1.28g / cm<3> to mix for 25-30 minutes, and discharging the mixture; 2) molding the mixture by a friction brick press of 800or 1000t, and drying for 48 hours at 110-200 DEG C; 3) sintering the brick blank inside a tunnel kiln, wherein the highest temperature is 168-1700 DEG C, and the heat preservation time is 5 hours; and 4) soaking by salt and baking the brick.

Description

technical field [0001] The invention relates to the technology of high-grade magnesia-chrome bricks for RH refining furnaces in the metallurgical industry, especially a kind of electro-fused rebonded magnesia-chrome bricks with excellent thermal shock stability and its production process. The magnesia-chrome bricks of the invention are mainly used in RH Insert pipes and bottom tanks of vacuum refining equipment. Background technique [0002] RH vacuum refining furnace is an indispensable and important smelting equipment for out-of-furnace refining in the metallurgical industry at present. The service life of its lining refractory material directly affects the rhythm and cost of steelmaking process. The lowest service life of the RH vacuum refining furnace is the insertion tube and the bottom tank. The key factors affecting the service life are the materials and properties of the working lining of the insertion tube and the bottom tank. [0003] The existing refractory mater...

AI Technical Summary

Problems solved by technology

[0003] The existing refractory materials used for the working lining of the RH insertion pipe and the bottom tank are mainly traditional fused rebonded magnesia-chrome bricks, which have poor thermal shock stability and slag resistance, and the firing temperature is higher than 1800°C. Firing increases the process cost of refractory materials, which is not conducive to sustainable development

Images