SU64213A1 - Method of making chromo-magnesite to fire stops - Google Patents

Description

In the cement industry, chromo-magnesite brick is widely used for lining the sintering zone of rotary kilns. A long study of the service of a chrome magnesite brick has shown that its destruction in a furnace goes along two main directions;

1) due to the splitting of bricks at stopping the furnaces for various production reasons;

2) due to the physicochemical effect of calcined Portland cement clinker on brick.

Chipping of brick is significantly reduced by special laying of the lining with the use of iron gaskets that firmly weld individual bricks and prevent the breaking of pieces of brick.

Physico-chemical destruction of chromomagnetite brick cannot be reduced by clinker.

A detailed study of the chemical stability of chromo-magnesite brick with respect to the action of Portland - cement clinker (clinker resistance) showed that the process of destruction of a brick

proceeds approximately as follows. The liquid that is formed during the sintering of the Portland-Cement raw mix impregnates the chrome-magnet bricks to a certain depth. The porosity of the chrome-magnesite brick is quite high (seemingly with - about 22%, true - about 25%), therefore impregnation is quite easy. A dicalcium silicate (2CaO SiOs) penetrating with the melt into the brick body, when the lining is cooled, in the event of stopping the furnace, goes from the | 3-modification to the T-modification. This transition, as is well known, is accompanied by a very significant increase in volume, which leads to an intensive destruction of the chrome-magnesite brick, which manifests itself in the breaking of a brick and loosening its structure.

To increase the clinker-resistant chromo-magnesite brick, the author of the present invention proposes to introduce into the composition of the mixture substances containing boron compounds (boron ore) that would stabilize dicalcium silicate and prevent its transition from: 3-form to T-form. Chrome-magnesite brick, prepared with additive B, its composition of a substance containing boron compounds, showed a very high chemical resistance to portland cement clinker.

Subject invention

A method for the manufacture of chromo-magnesite refractories of the Chl zone of the sintering of cement kilns, which is based on the introduction of boron ore into the components for the production of refractories.