SU458580A1 - Silicon-containing additive to the charge of cast iron - Google Patents

Description

one

The invention relates to ferrous metallurgy, in particular to blast furnace production, and is intended for use in blast furnaces in the production of cast iron and silicon alloys.

In the practice of smelting cast iron, silica-containing raw materials, such as quartzite, are introduced into the blast-furnace smelting mixture, which ensures the optimum (reduced) slag basicity and facilitates the conditions for the reduction of silicon. However, in this case, a lot of coke is required to create proper temperature conditions in the furnace.

Silico-coke is also used to produce cast iron and high-silicon alloys. However, the use of silica-coke leads to a decrease in mechanical strength.

The aim of the invention is to intensify the process of silicon recovery and to improve the technical and economic indicators of the blast furnace.

This is achieved by the fact that silicon is containing, and the additive contains carbonaceous material, and the ratio of carbon to silica in addition is 0.5-2.5. The proposed additive ensures that the required silicon content is obtained in the iron at coke consumption at the level characteristic of smelting pig iron.

The essence of the invention is the introduction of silicon containing silicon into the blast furnace smelting mixture, with additives in the form of a mixture of silica and carbonaceous material (chips, pellets, pieces). When heated to 1300-1400 ° C (mine zone) in the bulk of the mixture, silica is reduced to carbide. The formation of silicon carbide is intensified with increasing temperature.

With a sufficiently long exposure time, it can practically proceed until the silica is completely consumed. When silicon carbide comes in contact with iron, they interact, and the reduced silicon forms a melt with iron. The destruction reaction of silicon carbide with iron begins already at 1000 ° C and proceeds very intensively at the temperature of the molten iron (cast iron). Under blast furnace conditions, this reaction is not limited. Thus, the introduction of a mixture of silica with carbon provides thermodynamically more favorable conditions for the reduction of silicon due to the formation of silicon carbide and its subsequent destruction by iron (cast iron). To obtain standard grades of cast iron and silicon-iron alloys, the ratio of carbon and silica in the mixture should be 0.5-2.5.

Example. In a blast furnace with a volume of 1310 m, foundry iron C was smelted With the introduction of a mixture of carbon and silica in the form of lump material (semi-coke) in an amount of 40-100 kg per ton of iron. The ratio of carbon to silica in addition of 1.8. No changes in the technological mode were observed (melting was carried out for a month). The productivity of the furnace increased by 1.5%, the specific consumption of coke decreased by 7%.

4 Subject of the invention

Silicon-containing additive to the cast iron casting mixture in a carbon bond, and, in order to intensify the silicon recovery process and improve the technical and economic indicators of blast furnace pepp, the ratio of carbon to silica in the additive is 0.5- 2.5