SU1344785A1 - Slag=forming mixture - Google Patents

Abstract

The invention relates to ferrous metallurgy, in particular, to pooled mixtures for secondary treatment of steel. The aim of the invention is to increase the refining capacity of the slag. Slag-forming mixture contains, wt%: volcanic slag 10-20; rewax flux-free remelting of secondary aluminum 20-30; lime the rest. In this case, the volcanic slag contains, in wt.%: The sum of calcium oxide and sodium is 5-8; silicon dioxide 55-60; alumina 18-20; calcium oxide 6-7; iron oxide 7-8; magnesium oxide 4-6. The use of this slag-forming mixture allows to increase the degree of desulfurization of steel by 10-12%, as well as reduce the content of oxygen and non-metallic inclusions in it by 5 0%. 1 hp f-ly, 2 tab. lO CO m1 "4:" -J 00 SP

Description

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The invention relates to ferrous metallurgy, in particular to slag-forming mixtures for secondary treatment of liquid steel.

The purpose of the invention is to develop the refining ability of pshak.

The proposed mixture contains lime, volcanic slag and slag of flux-free melted secondary aluminum in the following ratio of components, May,%:

Volcanic putty 10-20

Slag fluxless

remelting secondary

20-30 aluminum

LimeEverything

Volcanic putty contains, May.

CgO + NajO5-8

SiOj55-60

AljOj18-20

CaO6-7

FejOj7-8

MgO4-6

The main fraction of the volcanic shyak is 10-30 mm, the Kara- tepa field.

Slag flux-free remelting of secondary aluminum contains, wt%:

55-70

2-4 2.8-3.2

MgO 1-1,5

Al er15-20

FeoSu, 4.2-5.7

The flux flux remelt recycled aluminum shpak is formed in the Soyuzvtsvettsvetmet enterprises during the flux-free process of chipping aluminum scrap and is a waste product. The main fraction is 20-50 mm.

Due to the high content of potassium and sodium oxides, as well as the optimal MgO content in a volcanic spat, its temperature does not exceed 1050-1100 C. Under the conditions of after-treatment of steel, the volcanic spack melts in a ladle for 20-40 seconds. The resulting fluid-mobile, active shpak intensively dissolves calcium oxide, lime, and alumina from a flux-free remelted alumina shpak, and liquid slag is formed in the ladle during the first three, four minutes of treatment. The increased aluminum content in the slag of the reflux-free remelting of secondary aluminum provides additional heat input due to oxide

aluminum is dissolved in metal and also reduces the concentration of oxygen in the steel being processed, which creates favorable thermodynamic conditions for the desulfurization process.

Thus, when processing the steel with the proposed slag-forming mixture, favorable thermodynamic and kinetic conditions are established for the desulfurization process.

The thermodynamic conditions are high basicity, the melting point of the sprat formed in the ladle is low, and the temperature is high in the zone of interaction between the slag and the metal. Kinetic conditions - the melting rate of the mixture is high, the viscosity of the bent shpa is low.

When the content of a volcanic slag in the mixture is less than 10 wt.%, The melting rate of the mixture decreases and increases the viscosity of the slag formed in the ladle.

When the content in the volcanic pork mixture is more than 20 wt.%, The silica content is lower and the basicity of the slag formed in the ladle is reduced.

In both cases, the degree of desulfurization of the metal decreases.

When the content of the flux-free remelting of secondary aluminum in the shpa mixture is less than 20 wt.%, The effect of reducing the oxidation of the metal due to aluminum metal is not achieved, and the temperature in the interaction zone of the metal and the shp decreases.

When the content in the mixture is more than 30% by weight of a flux-free remelted pelt, the content in the mixture of lime is reduced. In both cases, the degree of desulfurization of the metal decreases due to a decrease in the refining capacity of the slag.

The physical characteristics of the slags formed during the melting of the proposed emulsion with various ratios of the components included in its composition, in comparison with the characteristics of the known mixture, are presented in Table 1,

From the presented data it follows that the proposed mixture has the best physical parameters with the proposed ratios of the components.

3

Example. Grade 45 tr steel was smelted in a 200-ton open-hearth furnace operating a scrap ore process with oxygen supply to the torch. The steel was subjected to secondary furnace desulfurization with mixtures of the proposed and known composition. To prepare a mixture of known composition, a slag of aluminum flux remelting process containing 5-6% aluminum was used. Sponging mixtures were prepared by thoroughly mixing the pre-dosed components. The mixture was introduced into the bucket from a special container using a pouring tap. Processing began when the bucket was filled with metal at 1/5 of its height and ended when the bucket was filled at 3/4 of its height.

The results of the experimental heats are given in table. 2

From the table. 2 data shows that the proposed slag-forming mixture has a higher refining capacity than is known, which is superior in increasing the degree of desulfurization of the metal and reducing the content of oxygen and non-metallic inclusions in steel.

60 60 60 60 60 60

40

rmula of invention

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five

0

five

1. Slag-forming mixture, including lime and waste from the production of recycled aluminum, characterized in that, in order to increase the refining capacity of the spike, it additionally contains volcanic slag, and as waste from the production of recycled aluminum — spackle of flux-free remelting of secondary aluminum, with the following ratio of components , wt.%:

Volcanic slag 10-20 Slag of flux-free remelting of secondary aluminum 20-30 Lime Else

2. A mixture of POP.1, characterized in that the volcanic slag contains, in wt.%:

Amount of potassium oxide

and rub 5-8

Silicon dioxide 55-60

Aluminum oxide 18-20

Calcium Oxide 6-7

Iron Oxide7-8

Magnesia 4-6

Table 1

Compiled by K.Sorokin Editor N.Kishtulinets Tehred I., Popovich

Order 4888/27 Circulation 549. Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, Projecto st., 4

table 2

Proofreader M. Demchik

Claims (1)

Claim 1. Slag-forming mixture, including lime and waste from the production of secondary aluminum, characterized in that, in order to increase the refining ability of the spar, it additionally contains volcanic slag, and as waste from the production of secondary aluminum, spar flux-free remelting of secondary aluminum, in the following ratio, wt .%: Volcanic slag 10-20 Flux-free slag remelting secondary go aluminum 20-30 Lime Rest 2. The mixture according to claim 1, about t l and h a - u and i with the fact that volcanic slag contains, wt.%: Amount of potassium oxide and sodium 5-8 Silica 55-60 Alumina 18-20 Calcium oxide 6-7 Iron oxide 7-8 Magnesium oxide 4-6 Table 1 The components of the mixture, wt.% Lime Recycled aluminum waste Secondary aluminum flux-free remelting slag Volcanic slag 60 - 31 9 60 - thirty 10 60 - 25 fifteen 60 - 20 20 60 - 19 21 60 40 - - Physical parameters of the spike forming in the bucket Viscous viscosity at 1580 ° С, П Melting point, ° С The melting time of a sample weighing 1% by weight of the metal on the metal surface at 1580 ° C, min 4.2 1380 5.2 3.4 1350 3.8 3.2 1320 3.2 s, s 1340 3.4 4.8 1370 5,4 5.3 1480 8.2 table 2 111l Acoustic Forming Mixture Mixture consumption, kg / t The components of the mixture, wt.% The degree of desulfurization, 7. The oxygen content in the metal after processing, X The content of non-metallic inclusions, X Lime Secondary aluminum flux remelting slag Secondary aluminum flux-free remelting slag Volcanic slag 10 72 - 19 9 55 0.0049 0.0043 10 60 - 19 21 53 0.0052 0.0046 Proposed 10 60 - 20 20 61 0.0023 0.0032 10 70 20 10 62 0.0023 0.0032 10 60 - 25 fifteen 62 0.0022 0.0035 10 60 - thirty 10 61 0.0020 0.0036 10 fifty - thirty 20 60 0.0020 0.0037 10 60 - 31 9 55 0,028 0.0045 10 48 - 31 21 49 0,028 0.0049 Famous 18.2 60 40 fifty 0.0048 0.0061