SU1109444A1 - Flux for thinning slag - Google Patents

Abstract

FLUX FOR DILUTION OF SLAG, calcium fluoride content, magnesium oxide, silica, alumina, sodium oxide, sulfur, calcium carbonate, characterized in that it additionally contains potassium oxide and titanium oxide in order to increase the thinning ability and increase the refining properties of slag. at the next ratio of components, May. %: Calcium fluoride 3-12 Magnesium oxide 2-10 Silica 2-6 Alumina 0.5-6.0 Sodium oxide 0.5-6-6 Potassium oxide 0.05-3.00 Titanium oxide sl 0 , 01-0.20 Sulfur Carbonic Calcium Rest

Description

with

4 1; four;:

The invention relates to ferrous metal metallurgy, in particular, to flux slag additives in steel production.

Known flux (.1 FOR liquefying steelmaking slags, containing, in May.%:

20-40 1-8 2-30

Up to 5

Basis The disadvantage of this flux is the high content of calcium fluoride (at the upper limit of 72 May.%), Which brings it closer to the fluorspar with its inherent toxicity, as well as its high alumina content (at the upper limit of 40 may.%), Which significantly increases the melting point of 1 degree. flux G 21 dl And: wten also containing. slag dilution, May. %: Calcium fluoride Silicon dioxide Alumina 0.5-6.0 mg 0.5-10.0 iron 0.01-1.00 Calcium carbonate Rest The disadvantage of this flux is the high content of silica and sulfur, which makes desulfurization difficult and dephosphorization of steel, especially during the redistribution of phosphorous (, 7%) cast iron. In addition, increasing the amount of silica in the slag causes the lining of the converter to corrode and makes it necessary to use long-lasting lime additives and thinning materials. All this leads to an increase in the amounts of slag in the converter, and therefore to an increase in the loss of iron from the slag and a decrease in the yield of the suitable metal. Closest to the proposed composition and the achieved effect in

C31 flux is used to liquefy slag, containing the following components, May. %:

5-20

2-10 2-8 1-4

and 1-6 0.01-0.20

Else The disadvantage of the known flux is its low dilution capacity, which does not provide the necessary refining properties of slag, and consequently, a high degree of metal refining from harmful impurities. The purpose of the invention is to increase the diluting ability and increase the refining properties of slag. The goal is achieved in that the flux to liquefy slag, containing calcium fluoride, magnesium oxide, silica, alumina, sodium oxide, sulfur, and calcium carbonate, additionally contains potassium oxide and titanium oxide in the following ratio of components, May. %: Calcium fluoride magnesium Silicon Alumina 0.5-6.0 sodium Potassium oxide 0.5-6.0 Titanium oxide 0.05-3.00 0.01-0.20 Calcium carbonate Remaining Some increase compared with the known content calcium fluoride (up to 25 May.% at the upper limit) contributes to an increase in fluidizing properties of the flux. A higher (in excess of 25 wt.%) Amount of thorium calcium (CaF) in the flux provides a very fast, but short-term liquefying effect in the mouth with a rapid removal of gaseous fluorine compounds from the melt.

A large number of which leads to the pollution of the workshop atmosphere with fluoride compounds. Reducing the number of CaFj below 4 May. % Is impractical because the liquid slag is not sufficiently liquid when using such a flux.

The presence of magnesium oxide in the flux in somewhat larger quantities in comparison with the known one is highly desirable, since it contributes to the induction of highly basic slag and favorably affects the increase in the durability of the converter lining. A smaller amount of magnesium oxide almost does not prevent the lining from corroding, and the magnetism does not exceed 12 May. % causes slag thickening ..

 The lower content of silicon dioxide provides low melting of the multicomponent mixture and does not interfere with the guidance of the main slag with high refining properties. An increase in silica above 10 May. The% necessitates the addition of lime additives to preserve the basicity of the slag, and creates the risk of corrosive lining. The lower alumina content ensures a decrease in the melting point of the flux and its earlier participation in the formation of active slag. When the content of alumina above 6 wt.%. The melting point of the flux decreases and the start of its interaction with the slag is slowed down.

 Introduction to the composition of the flux of alkali metal oxides of sodium and potassium in 0.5-6 May. % of each significantly increases the fluidizing properties of the flux, moreover, their content in quantities less than 0.5 May. % almost imperceptible effect on the melting point of the flux and its dilution properties. Increasing their content above 6% is impractical because the addition of a flux of this composition causes technological difficulties associated with abundant foaming of slag.

Additive in the composition of the flux of titanium oxide in the amount of 0.05-3 May. % additionally increases its diluting ability and at the earlier stage of smelting ensures the formation of liquid mobile active slag. The specified limits are optimal.

Increase in titanium oxide content above 3 May. % is undesirable due to the abundant foaming of slag and the increased cost of the flux.

The sulfur content in the flux (0.010.2 May 2%) is due to its relatively low content in the materials used.

Calcium carbonate is the leading component of the fluid and, depending on the content of the other components, its amount is at the lower limit of 31.8 May. %, on the top 87, 94 May. % These limits are optimal and provide the necessary basicity and liquid mobility of the slag and its refining properties. An increase in the amount of potassium carbonate CaCOj above the upper content leads to the formation of thick slags requiring additional addition of thinning materials.

The use of additional potassium and titanium oxides in the flux assists in the assimilation of slag in the lime feed into the filling and in obtaining the required basicity, which makes it possible to reduce the lower limit of carbon dioxide in the flux to 31.8 May. % However, the decrease in the number of caso, less than 31.8 wt. does not provide the necessary basicity of slag, which leads to the need to add additional quantities of lime.

The basis of the proposed flux ow is cheap and non-deficient fluorite ore, to which it can be added in necessary quantities .... pour magnesium oxide in the form of magnesite powder or bo-magnesite refractory bricks, sodium oxide in the form of soda or other sodium oxide-containing materials (broken sodium glass, red mud, etc.) potassium oxide in the form of red mud or potassium oxide containing minerals (nepheline, alunite , leucite, sericite, etc.) and titanium oxide in the form of poor titanium ores or titanium waste

production.

Testing of the proposed flux is carried out in an oxygen converter during the redistribution of phosphorous iron, cast iron, containing, May. %: silicon 0.7-1.0; manganese 0.6-0.9; Foofor 0.7-1.0; sulfur 0,035-0,050.

The compositions of the proposed flux are given in table. one.

T a b

persons 1

For comparison, a flux of known composition is prepared, containing, in May.%; CaFj 15.4%; MgO 6.7; SiOj 4.8; AljO, 3.2; 3.9; S 0,2; CaCO 66,8%.

For comparison, the results of 30 heats carried out in the same period on a parallel converter were used when purging cast iron of similar composition and using fluorspar as a base object to liquefy slag. Known5, 6 0.85 0.038 0.106 0.036 ny 5.6 0.87 0.036 0.064 0.030 0.015

The flux is added immediately after filling in the lime converter during the first period of melting at 7-8 minutes, based on the introduction of 3.3-10 Kg of flux per 1 ton of metal charge, preferably 5-6 kg / t of metal load. Secondary flux additive with insufficient liquid mobility of the slag is produced at the end of the purge.

The results of testing fluxes are given in Table. 2,

Table 2 0.020 0.018 97.6 52.6 0.015 98.3 58.3

Continued table. 2

Claims (1)

FLUID FOR SLAG LIQUIDATION, containing calcium fluoride, magnesium oxide, silica, alumina, sodium oxide, sulfur, calcium carbonate, characterized in that, in order to increase the thinning ability and increase refining properties of slag, it additionally contains potassium oxide and titanium oxide. in the following ratio, May. %: Calcium Fluoride tion 4-25 Magnesium oxide 3-12 Silica 2-10 Alumina 2-6 Sodium oxide 0.5-6.0 Potassium oxide 0.5-6.0 Titanium oxide 0.05-3.00 Sulfur 0.01-0.20 Carbonic calcium Rest