SU910794A1 - Slag forming mixture - Google Patents

Description

The invention relates to ferrous metallurgy, in particular to the refining of steel. Slag-forming mixture of metal ij refining is known, containing weight: Iron oxides 5 20 Aluminum oxides 2-15 Silica 1-5 Manganese oxide. 0, Magnesium Oxide 0.55 Calcium Oxide Else The disadvantage of the mixture is its low desulfurization ability. The known mixture for casting steel 2, containing weight, is: Lime 26-50 Ferrosilicon5 7 Coxy5 7 7 Alumina Else The disadvantage of the mixture is its refining ability for both sulfur and phosphorus. Closest to the proposed by the components and the effect achieved is a mixture for treating molten steel based on ferromanganese with the addition of aluminum, fluorspar and lime, pressed on a hydrocarbon bond into a briquette with a content of components, wt. Aluminum} -kO Fluor spar -0, Lime 0.5- Ferromanganese 50-98 Briquette has strong deoxidizing properties 3j The disadvantage of this is that it has relatively low desulfurizing and dephosphorizing properties. When treating boiling steel with a briquette consumption of 1 kg / t, the oxygen content decreases from 0.037 ° to 0.021, the sulfur content from 0 to 0, the phosphorus content from O, 029 TO O, 02ii:

The degree of desulfurization is, and the degree of dephosphorization is 1%,

The purpose of the invention is to increase the refining ability of slag-forming mixture.

This goal is achieved by the fact that the slag-forming mixture containing ferrhmanganese, lime, fluorspar, the hydrocarbon-containing material additionally contains iron oxides and graphite in the following ratio of components,% by weight:

Lime69-85

Iron oxides 3-8

Graphite2-5

Fluorspar3 5

Hydrocarbon containing material2-3 Ferromanganese5-10 The content of lime in the mixture in the amount of 69-85 weight is due to the following.

When the lime content in the mixture is less than 69 pts, the basicity of the slags formed in the steelmaking aggregate decreases, which leads to a decrease in the removal of harmful impurities, and when the content of lime in the mixture exceeds 85% by weight, the liquid mobility of the formed slags decreases, which impairs their reactivity.

The content of iron oxides in the amount of 3 - & "EU.% Due to the following

When the content of iron oxides is less than 3 weight. deteriorates the degree of dephosphorization of steel, and when the content of iron oxides is more than 8, the degree of desulfurization of the metal worsens.

The content of graphite in the amount of 2-5 wt. due to the best mixing conditions. When the content of graphite is less than 2% by weight, the rate of mixing of the mixture with the resulting carbon monoxide bubbles is reduced, which reduces the convective component of the rate of dissolution of the mixture. The content of graphite in a mixture of more than 5 weight is not economically feasible.

The amount of fluorspar is due to the fact that when the fluorspar content is less than 3, the melting rate of the mixture decreases, and when the fluorspar content in the mixture is more than 5 weight. pollution of the airspace increases with toxic substances.

Hydrocarbon-containing materials in the amount of 2-3 weight. improve pelletizing mixture. When the content of hydrocarbon materials in

mixtures less than 2 wt. the proportion of the small fraction in it increases, the content of hydrocarbon-containing materials is more than 3 weight. economically; impractical

The content of ferromanganese in the amount of 5-7 weight. due to the following.

When the content of ferromanganese in the mixture is less than 5 wt. The degree of both desulfurization and metal dephosphorization decreases when the content of ferromanganese is more than 10%, the instability of the metal deoxidation process with ferroalloys increases,

0 The mixture can be made as follows.

Dusty waste from the production of lime from kilns, together with a fine fraction of fluorspar, ferromanganese, as well as dross and silvery graphite, is pressed into briquettes with a binder (dehydrated and desulfurised resin) of 5-8 kg. In order to avoid decomposition of the obtained briquettes, they should be used for refining the steel no later than hours after their production. Variants of mixtures and examples of their use for steel processing, not

excluding other options within the scope of the claims are shown in table

Examples Slag-forming mixture No. 1-3 is prepared by mixing raw materials and briquetting IHO

In an induction 50 kg furnace, boiling steel with a content of 0.165 is melted; carbon briquettes are injected under the metal stream in an amount of 0.1% by weight of the metal. Briquettes have a high refining ability with respect to sulfur and phosphorus (see table;)

Thus, the proposed cf-iecb, as compared with the known, possesses higher desulfurizing and dephosphorizing properties. The degree of desulfurization is higher by about 19-27; degree of dephosphorization at 5 20-30:

The expected economic effect of 288 thousand rubles. in year,,

Claims (3)

Claim Slag-forming mixture for metal refining, containing lime, ₄₀ hydrocarbon-containing material, fluorspar, ferromanganese, characterized in that, in order to increase refining ability, it additionally contains ₄₅ graphite and iron oxides in the following ratio of components, weight ,%:. Lime 69-85 Iron oxides 3 ^_ 8 Graphite 2-5 Fluorspar 3-5 Hydrocarbon-containing chewing material 2-3 Ferromanganese . 5th Sources of information, taken into account during the examination. 1, USSR Author's Certificate No. 536232, class C 21 C 7/00, 1976, 2, USSR Author's Certificate No. 415312, class C 21 C 7/00, 1974. 3, UK patent No. 1056974, CL, C 7 D, 1964, \