Method for producing direct-bonded magnesia-chrome brick with high refractorinees under load and high stability of thermal shock resistance

Abstract

The invention discloses a method for producing a direct-bonded magnesia-chrome brick with high refractorinees under load and high stability of thermal shock resistance, which comprises the following steps: (1) selecting 7.5 parts by weight of magnesite, 2.5 parts by weight of chrome ore and 0.5 part by weight of chromium refined powder; (2) mixing the materials evenly, putting into an edge runnermixer, adding a lignin solution with the weight 4-5% of the weight of the total material and putting into a pressing machine with the pressure greater than 630KN for molding after milling wetly to prepare a semi-finished product; and (3) after putting the semi-finished product into a dryer and drying, entering a tunnel kiln, sintering at the temperature of 1750+ / -10 DEG C and keeping the temperature for 10-12 hours under the condition of the temperature of 1750+ / -10 DEG C so as to obtain a finished product of a brick body. The brick body has high refractoriness under load, large volume density, low apparent porosity and high stability of thermal shock resistance, sets up the record of the longest use period of 456 days, replaces imported products in many large-sized cement enterprises successfully and breaks the current situation that fireproof materials used for the burning zone of a large-sized rotary cement kiln with a novel dry method generally depend on import.

Description

Technical field [0001] The invention relates to a magnesia-chrome brick used in the cement production industry, in particular to a method for directly combining high-load softness and high thermal shock resistance with magnesia-chrome bricks. Background technique [0002] Directly combined magnesia-chrome bricks have achieved an irreplaceable position in the use of cement kiln firing zones due to their strong corrosion resistance and good kiln-hanging performance. Due to the technical level of refractory materials in my country, although China is a major exporter of basic refractory raw materials, refractory materials for the firing zone of new dry cement rotary kilns are still generally dependent on imports. Since the beginning of the 21st century, my country’s cement production has grown rapidly, the total production of large and medium-sized precalcining kilns has increased rapidly, the specifications of cement kilns have rapidly expanded, more than 100 5000t / d production line...

AI Technical Summary

Problems solved by technology

Due to the rapid expansion of the production line, coupled with the change of coal quality and the increase of kiln speed, the service conditions of refractory materials, especially basic refractory materials, have seriously deteriorated, which has affected the operation cycle of cement kilns and has become the main factor restricting the operation rate of cement kilns. , under this condition, the service cycle of domestic direct combined magnesia-chrome bricks in the firing zone of large cement kilns has dropped sharply, and the same is true for imported products. The service cycle generally does not exceed about 210 days, and it is difficult to meet the expected requirements of cement enterprises.

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