SU498339A1 - The method of blast smelting iron-aluminous ores - Google Patents

Description

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The invention relates to ferrous metallurgy and the building materials industry and can be used in enterprises smelting iron-alumina ores (e.g. bauxite) in blast furnaces to produce pig iron and high-alumina slag, which is used for the production of fast-hardening cement.

The known method of blast smelting with the addition of tourmaline to the mixture, which passes into the slag, improves the chemical properties of the latter and the quality of cast iron.

The disadvantage of this method is the presence of silicon oxides and alkali metals in tourmaline, which have an adverse effect on the blast furnace smelting of iron-alumina ores (increased viscosity of slag, formation of walling).

The aim of the invention is to improve the quality of iron and slag while reducing coke consumption, increasing furnace productivity and reducing the cost per unit of production.

The goal is achieved by the fact that according to the proposed method a small amount of boric oxide is introduced into the furnace as an additive. Boron oxide is introduced into the blast furnace or sintering mixture in the form of natural compounds with calcium oxides or magnesium:

boronalcite, pandermite, colemanite, asharite, etc. Industrial waste, such as slag from the production of ferroboron, can also be used. Boron-rich materials can be blown directly into the furnace furnace together with solid or liquid fuels. The amount of the additive is introduced at the rate of obtaining in the slag the boron oxide content from 0.3 to 3.0% by weight of the slag.

Laboratory experiments have established that the addition of 0.5% DdOz to alumina slag reduces its melting point by 22 ° C. With the introduction of 2.0% B2Oz, the viscosity of the slag at 1500 ° C decreases by 30% (from 0.85 to

0.55 N. sec. / M), melting point - 40 ° C. Smelting boron-containing slag, therefore, requires a lower heating of the hearth furnace. This, in turn, all other things being equal, reduces the specific consumption of coke and increases the productivity of the furnace. Reducing coke consumption, in turn, reduces the silicon oxide content and improves the quality of alumina cement. The studies also showed that the introduction of small additions of boron oxide favorably affects the activity of alumina cement.

The results of the experiments are presented in the table:

Table

Under the conditions of the blast furnace, the boron located in the slag is partially reduced and goes into cast iron. When the content in the slag is 0.3-3.0% B2O3 and the degree of reduction is 20-25%, the boron content in the iron is 0.02-0.25%. Cast iron with such concentrations of boron with a simultaneous content of titanium and chromium is characterized by increased wear resistance.

Thus, the proposed method of blast furnace smelting of alumina ores simultaneously improves the quality of pig iron and slag, reduces the specific consumption of coke, increases the productivity of the furnace, reduces the cost of producing a unit of product.

Claims (1)

Invention Formula The method of blast-furnace smelting of iron-aluminous ores to naturally-doped cast iron and alumina slag, which includes the introduction of boron-containing materials into the mixture, characterized in that, in order to save coke on smelting, reduce costs for redistribution and improve the quality of iron and slag, oxide is introduced into the mixture boron in the main medium in an amount that provides the content of 0.3-3.0% boric oxide in the slag.