RU2308493C2 - Briquette for melting of manganese-containing cast iron - Google Patents

Abstract

FIELD: ferrous metallurgy, in particular, composition of briquette for melting of cast iron.

SUBSTANCE: briquette is produced by pressing of burden containing scale and fines of agglomerate as iron-containing materials, blast-furnace dust and blast furnace gas purification slurry as iron-carbon-containing materials, oxidation phase slag of electric furnace steel-making as fluxing agent, and cement as binder. Components of briquette composition are used in the following ratio, wt%: scale 5-70; agglomerate fines 3-30; blast-furnace dust 15-35; blast furnace gas purification slurry 15-35; oxidation phase slag of electric furnace steel making 5-25; cement 3-7.

EFFECT: increased content of manganese in cast iron without utilization of expensive manganese ore, reduced consumption of coke, reduced cast iron production costs owing to deceased costs of burden materials, and increased efficiency in recovery of production wastes.

Description

The invention relates to ferrous metallurgy, specifically to the composition of the briquette for smelting cast iron.

A known briquette for metallurgical production [1], selected as a prototype, containing oxidized material, a carburizer, a binder, an alloying additive and a plasticizer, characterized in that it additionally contains crushed iron-carbon alloy and fluxing additive in the following ratio, wt.%:

Oxidized Iron Material 5-57 Carburetor 20-30 Binder 10-20 Alloying additive 1-15 Ground Iron Carbon Alloy 1-30 Fluxing additive 1-10

Plasticizer - in excess of 100% in an amount of 0.1-0.5% by weight of the binder.

Significant disadvantages of this briquette are:

- high content of the binder component in the briquette, which leads to the impossibility of using this type of briquettes in blast furnace smelting due to the increased alkali content, as well as insufficient iron content in the briquette;

- the high cost of the briquette due to the need to use scrap or sludge formed during the smelting of ferromanganese.

Also known is a briquette for smelting metal, obtained by pressing a mixture comprising carbon-containing materials, iron-containing materials, fluxing additives and a binder containing carbon, iron, calcium, magnesium, aluminum, silicon oxides, characterized in that in the charge for its production as iron-containing The material used is dust from gas treatment of metallurgical furnaces, and / or sludge from gas treatment from metallurgical furnaces, and / or mill scale, and / or shavings of ferrous metals, and / or metal concentrate for processing steel nyh blast furnace slags and [2].

A significant drawback of this briquette is:

- the need to add manganese ore to the mixture during the smelting of cast iron of various grades of group II and III with a manganese content above 0.5% and the associated increase in the cost of cast iron.

There is also a method of disposing sludge blast furnace gas by clumping sludge in a bowl granulator using a 20% solution of water glass and further firing the granular sludge in a fluidized bed furnace [3].

Significant disadvantages of this method are:

- increased costs for the disposal of this type of material due to the complexity of manufacturing the product in this way;

- significant removal of dust (up to 25%) from fluidized bed furnaces and additional costs for the construction of gas re-purification and utilization of its products.

The desired technical results of the invention are:

- the exception of the introduction into the charge of expensive manganese ore;

- reduction in coke consumption;

- reduction in the cost of cast iron;

- efficient disposal of industrial waste.

For this purpose, we propose a briquette for smelting manganese-containing cast iron obtained by pressing a mixture, including carbon-containing materials, iron-containing materials, fluxing additives and a binder, characterized in that the mixture contains iron oxide and sinter screenings as iron-containing materials, and sludge tops as iron-carbon materials. blast furnace gas treatment, as a fluxing additive - slag of the oxidation period of electric steel production, as a binder - cement p In the following ratio of components, wt.%:

Scale 5-70 Sinter screenings 3-30 Blast furnace dust 15-35 Blast furnace slurry 15-35 Oxidation slag electric steel production 5-25 Cement 3-7

The claimed limits are selected experimentally.

Scale of ferrous metals interacting with soot carbon and graphite formed in the furnace and the lower part of the shaft of the blast furnace is introduced into the briquette to ensure, due to the high content of iron oxide, washing the furnace of the blast furnace and increasing the productivity of the blast furnace, and when using less than 5%, it is impossible to wash the furnace of a blast furnace and, as a result, an increase in its productivity, and at a concentration of more than 70%, it becomes necessary to introduce additional coke I have the heat balance of a blast furnace.

Sinter screenings are added to the briquette to maintain a given amount of iron while reducing the scale of ferrous metals, and when using less than 3% it is not possible to obtain a briquette of a given strength due to particle size distribution, and at a concentration of more than 30%, it is necessary to remove some other components from the briquette, which It will not allow to use their advantages with maximum effect.

The blast furnace dust is introduced into the briquette as an iron-carbon-containing component containing a sufficient amount of iron and carbon for efficiently conducting a blast furnace process without additional costs for the agglomeration of this dust, and when using less than 15%, it is not possible to obtain the required efficiency for reducing coke consumption, and with an increase of more 35% there is a significant decrease in the mechanical strength of the briquette.

The blast furnace gas treatment sludge is also introduced into the briquette as an iron-carbon component of the briquette, and when using less than 15%, this technology for the disposal of industrial waste from blast furnace production is ineffective, and with an increase of more than 35% it is impossible to use the briquette for a long time in blast furnace production due to the increased zinc content in the sludge .

Cement is used as a binder, and when using less than 3%, it is not possible to obtain the required mechanical strength of the briquette, and with an increase of more than 7%, the non-production costs of the production of briquettes increase, the total iron content in the briquette decreases.

The inventive briquettes were made of materials with the following chemical composition.

Dross: 32-38% Fe ₂ O ₃ ; 60-67% FeO; 0.20-0.60% CaO; 0.40-0.80% MgO; 0.70-1.1% SiO ₂ ; 0.07-0.2% S; 0.10-0.20% R.

Screenings of sinter: 50-57% Fe _total ; 10.0-13.0% CaO; 7.5-9.5% SiO ₂ ; 0.05-0.10% S.

Blast furnace dust: 35-45% Fe _total ; 12-25% C; 3.0-7.0% CaO; 1.0-3.0% MgO; 2.0-3.6% Al ₂ O ₃ ; 7.0-9.0% SiO ₂ ; 0.15-0.45% MnO; 0.20-1.5% Zn.

Blast furnace slurry: 10-45% Fe _total ; 10-45% C; 3.0-10.0% CaO; 0.5-3.0% MgO; 2.0-8.0% Al ₂ O ₃ ; 6.2-8.2% SiO ₂ ; 0.50-3.5% Zn.

Oxidation slag of electric steel production:

23-32% FeO; 3-8 MnO; 10-28 MgO; 2-8% Al ₂ O ₃ ; 20-38% CaO; 15-21% SiO ₂ ; up to 0.01% P ₂ O ₅ .

Cement (M - 500): 6.0-6.6% Al ₂ O ₃ ; 3.0-3.08% Fe ₂ O ₃ ; 0.20-0.39% FeO; 56.0-57.8% CaO; 3.0-3.4% MgO; up to 0.05% P ₂ O ₅ .

The above components were mixed, moistened and dried under natural conditions.

Briquettes were used on a blast furnace with a useful volume of 1310 m ³ as a substitute for the iron ore part of the charge in the amount of 10% instead of sinter.

The inventive briquette allowed:

- to obtain cast iron of group II with a manganese content of more than 0.5% (normal manganese content of 0.35-0.40%) without the use of expensive manganese ore;

- reduce coke consumption by 0.2%;

- reduce the cost of pig iron by 0.3%, and group II pig iron (with a manganese content of more than 0.5%) by 0.7%.

- effectively dispose of industrial waste;

Information sources

1. RF patent No. 2183 679 C1.

2. RF patent No. 2244026, cl. C22B 1/24, C21B 5/00.

3. Tolochko A.I., Slavin V.I., Suprun Yu.M., Khayrutdinov P.M. Disposal of dust and sludge in the steel industry. - Chelyabinsk: Metallurgy, 1990 - 152 p.

Claims (1)

A briquette for smelting manganese-containing cast iron obtained by pressing a mixture, including carbon-containing materials, iron-containing materials, fluxing additives and a binder, characterized in that the mixture as iron-containing materials contains scale and sinter screenings, as iron-carbon dust and blacksmith dust and as a fluxing additive, slag of the oxidation period of electric steel production, as a binder, cement in the following ratio and, wt.%: scale 5-70 sinter screenings 3-30 blast furnace dust 15-35 blast furnace slurry 15-35 oxidized period slag electric steel production 5-25 cement 3-7