SU1565913A1 - Charge for melting ferrosilicium - Google Patents

Abstract

The invention relates to ferrous metallurgy and can be used in the production of ferroalloys, in particular in the smelting of ferrosilicon. The aim of the invention is to increase the mechanical strength and deoxidizing ability of the resulting alloy and lower its melting point. The mixture for smelting ferrosilicon contains, wt%: quartzite 20 - 58

coking 10 - 34

iron shavings 5 - 50 and boron-containing briquettes 3 - 20. In this case, boron-containing briquettes contain, wt%: datolite concentrate 63 - 70

coke screenings 25 - 34 and sulphite-alcohol bard 3 - 5. The use of the charge increases the compressive strength, stretching and bending strengths of the alloy by 7.24 and 19%, respectively, increases the deoxidizing ability of the alloy by 1.5 times and reduces the temperature melting the alloy at 70 ° C. 1 hp f-ly, 3 tab.

Description

The invention relates to ferrous metallurgy and can be used in the production of ferroalloys, in particular in the smelting of ferrosilicon. The aim of the invention is to increase the mechanical strength and deoxidizing ability of the resulting alloy and lower its melting point.

The proposed charge for smelting ferrosilicon contains quartzite, coking, iron shavings and boron briquettes in the following ratio of components, mash:

Quartzite20-58

Koksik10-3

Iron chips Boron briquettes 3-20 At the same time, boron briquettes have the following composition, wt. &Amp;

Datolite concentrate KOXIKA25-3

Sulfite-alcohol bard3-5

The ratio of the components of the mixture provides ferrosilicon corresponding to the existing requirements.

Under the conditions of the smelting reduction of siliceous alloys (ferrosilicon), 30–50% of the phosphorus contained in the mixture passes into the gas phase, and the rest of the phosphorus is reduced and converted into the alloy. Phosphide on the surface, located along the grain boundaries of the alloy, during its grinding leads to a decrease in the mechanical strength of the alloy. The reason for the brittle fracture of the alloy is due to the action of phosphorus, which leads to

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ate

with

than the grain boundaries, creating conditions for subsequent destruction.

In the presence of boron-containing briquettes in the mixture from them, it recovers and transforms into an alloy of 0.1–1.0% boron, which contributes to an increase in the mechanical strength and deoxidizing ability of the resulting alloy, as well as a decrease in its melting temperature.

The thief, being a surfactant element, displaces phosphorus from the boundaries into the bulk of the grains and thereby clears the boundaries from the phosphides, which contributes to an increase in the mechanical strength of the resulting alloy. The presence of a surfactant element in the alloy lowers its melting point and increases deoxidizing ability. When the boron-containing briquettes contain less than 3 wt.%, The required amount of boron in the alloy is not provided, which leads to a decrease in the mechanical strength of the alloy and its deoxidizing ability, as well as an increase in the melting temperature.

When the content of boron-containing briquettes in the charge is more than 20 wt.%, More boron passes into the alloy, which forms adsorption layers of different thickness, leading to a strong distortion of the crystal shape, which contributes to a decrease in the mechanical strength of the alloy.

The content of quartzite in the charge (20- 58 wt.%) And iron chips (5 50 wt.%) Provides the required content of silicon and iron in ferrosilicon.

When the content of carbonaceous reductant (coke) in the mixture is less than 10 wt.%, The reduction of boron is difficult, and the reduction of silicon is also reduced. The consumption of a carbonaceous reductant more than 3 masD worsens the electric mode of melting.

Example, In a 100 kVA ore-reduction electric furnace, test melts are carried out to obtain

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five

five

0

ferrosilicon in the known and intended charge. In tab. 1 shows the chemical compositions of the materials used, and table. 2 - compositions of the known and proposed mixtures and indicators of mechanical strength, deoxidizing ability and melting temperature of the resulting alloys.

The results of the experimental melting of ferrosilicon using boron-containing briquettes of variable composition in the proposed mixture are given in Table 3.

From tab. 3, it can be seen that the alloys obtained from the proposed mixture, compared with alloys obtained from the known mixture, have an average of 1.5 times more deoxidizing ability and higher values of mechanical strength. Thus, the limits of compressive strength, tensile strength, and flexural strength are, respectively, 7.2 and 19% higher. At the same time, the melting point of the alloys obtained from the proposed mixture in comparison with the alloys obtained from the known mixture is lower, on average, by 70 ° C.

Claims (2)

1. Charge for smelting ferrosilicon containing quartzite, toxic and iron shavings, so that, in order to increase the mechanical strength and deoxidizing ability of the resulting alloy and lowering its melting point, it additionally contains boron-containing briquettes in the following ratio, wt.%: Quartzite20-58 Koksik10-3 Iron chips Boron briquettes 2. A mixture according to claim 1, characterized in that the boron-containing briquettes have the following composition, in wt.%: Datolite concentrate63 70 Coke screenings25 3 Sulfite-alcohol bard3-5 Table 1  Technical analysis of coke, wt.%: Ash 11.8; volatiles 2.0; sulfur 1, 75 moisture 10.  The oxygen content in steel is 35 minutes after the introduction of the alloy. table 2 Table 3