RU2698161C1 - Charge for producing ferrosilicon - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, particularly to electrothermal production of silicic ferroalloys. Charge for producing ferrosilicon contains, wt. %: quartzite 22.0–46.7; carbonaceous reducing agent 30.3–33.4; steel chips 7.3–7.7; slag for refining of industrial silicon 12.6–40.0.

EFFECT: invention reduces consumption of raw materials for obtaining ferrosilicon.

1 cl

Description

Technical field

The invention relates to the field of metallurgy, in particular to an electrothermal method for producing silicon ferroalloys.

State of the art

Ferrosilicon is obtained by reduction of quartzite using carbonaceous reducing agents in ore-reducing electric furnaces. The reducing agent is metallurgical coke (Ryss MA, Ferroalloy Production, M, Metallurgy, 1985, pp. 33-75). In recent years, to increase the productivity of ferrosilicon furnaces, more active reducing agents have been used as a reducing agent, coal mixed with coconut (Pavlov S.F., Kashlev I.M. “Improving the efficiency of smelting ferrosilicon”, Steel, 2002, p. 35 -38). The disadvantages of such methods is the low degree of extraction of silicon upon receipt of ferrosilicon.

A known mixture for smelting ferrosilicon (RU 2106423, C22C 33/04, publ. 10.03.98) containing quartzite, coke metal waste and pellets of spent contact mass of chemical production in the following ratio of components, wt. %: coke 10.0 - 40.0, metal waste 6.0 - 30.0, pellets 0.3 - 20.0, quartzite - the rest. The disadvantage of this method is the need for the manufacture of pellets, which requires additional equipment.

A known mixture for producing ferrosilicon (SU 998558, C22C 33/04, publ. 23.02.83), including carbon reducing agent, metal additive, quartzite, additionally contains silicate slag and quartzitobarite in the following ratio of components, wt. %: carbon reducing agent 20-35, metal additive 1-40, silicate slag 1-10, quartzitobarite 0.5-10, quartzite - the rest. The disadvantage of this method of involving in the production of additional components of the charge is the use of quartzitobarite, which will increase the amount of impurities in the final product.

The closest analogue of the present invention is a mixture for producing ferrosilicon (RU 2109836, C22C 33/04, publ. 04/27/98), including quartzite, carbon reducing agent and steel shavings, additionally contains a mixture of fluxed iron ore pellets and iron oxide in the ratio 1: (1 -3) in the ratio of components, wt. %: quartzite 35-55, carbon reducing agent 20-30, a mixture of fluxed iron ore pellets and iron oxide in a ratio of 1- (1-3), steel shavings - the rest. The disadvantage of this method is the need for the manufacture of pellets, which leads to the need to use additional equipment.

Disclosure of invention

The task of the invention is to reduce the cost of obtaining ferrosilicon.

The technical result is to reduce the consumption of raw materials for producing ferrosilicon.

The claimed technical result is achieved due to the fact that the mixture for producing ferrosilicon, including quartzite and carbon reducing agents, steel shavings, in addition to the silica-containing material, contains slag formed during oxidative refining of industrial silicon from impurities, in the following ratio of components, wt. %: quartzite 22.0 - 46.7; carbon reducing agent 30.3 - 33.4; steel shavings 7.3 - 7.7; silicon refining slag 12.6 - 40.0.

Silicon is obtained by reducing silica with carbon in electric furnaces. The resulting silicon, as a rule, contains impurities of aluminum and calcium, which are transferred to silicon from mineral raw materials and from reducing ash. Refining, purification of silicon from unwanted impurities, is carried out in a ladle during the release of the melt from the furnace using oxidizing gases of oxygen and / or compressed air. Oxides of oxidized metals pass into slag. Together with them passes into the slag and part of the oxidized silicon, which significantly reduces the viscosity of the slag. During the cleaning of the bucket from the slag along with thick slags, part of the liquid silicon is also removed, which increases the loss of silicon with waste slag. This slag has the following composition, wt. %: SiO ₂ 64.4-81.2 (average 72.3); SiC 4.5-11.1 (average 8.1); Al ₂ O ₃ 0.5-1.5 (average 0.9); CaO 1.5-4.5 (average 2.7); Fe ₂ O ₃ 0.05-0.15 (average 0.1); Si metal 10.3-20.4 (average 15.9). Due to the presence of free silicon in the slag, it can be used in the production of silicon ferroalloys.

The implementation of the invention

At an industrial furnace, high-percentage ferrosilicon was smelted using slag of refining of industrial silicon containing free metallic silicon as a silica-containing material, which, during reduction smelting, ferrosilicon goes into finished products and reduces the required amount of raw materials.

Example 1. Smelting ferrosilicon using typical charge materials showed the following consumption of raw materials, wt. %:

quartzite 56.1 carbon reducing agent 37,4 steel shavings 6.5

Example 2. When smelting ferrosilicon in an ore-thermal electric furnace, the slag was refined with technical silicon in the amount of 200 kg per ton of smelted silicon. The consumption of raw materials during the experimental melting amounted to:

по массе, кг/т

by weight, kg / t

Example 3. In further experiments, the amount of slag refining silicon was increased to 400 kg per ton of smelted ferrosilicon. Raw material consumption amounted to:

Example 4. During the next test stage, 600 kg of slag per ton of ferrosilicon was introduced into the mixture. Raw material consumption amounted to:

Example 5. With an increase in the amount of slag refining silicon in the charge to 1000 kg per ton of smelted ferrosilicon, the consumption of raw materials amounted to:

Example 6. With a further increase in the amount of slag refining silicon in the mixture to 1200 kg per ton of ferrosilicon, the consumption of raw materials amounted to:

Example 7. With a further increase in the amount of slag refining silicon in the mixture to 1400 kg per ton of ferrosilicon, the consumption of raw materials amounted to:

When slag refining of technical silicon is introduced into the charge, less than 200 kg / t does not significantly reduce the consumption of mineral raw materials, quartzite. With an increase in the amount of silicon refining slag in the charge, more than 1200 kg / t, the furnace top is compacted by reducing the top surface porosity, which negatively affected the reduction of quartzite consumption. The optimal amount of silicon refining slag introduced additionally into the charge is the amount of 400-1200 kg per ton of ferrosilicon, which corresponds to the ratio of components in the charge, wt. %:

quartzite 22.0 - 46.7 carbon reducing agent 30.3 - 33.4 steel shavings 7.3 - 7.7 silicon refining slag 12.6 - 40.0

Claims (2)

The mixture for producing ferrosilicon containing quartzite, a carbon reducing agent and steel shavings, characterized in that it additionally contains a silica-containing material in the form of slag formed during oxidative refining of industrial silicon from impurities, in the following ratio, wt.%: quartzite                                     22.0-46.7 carbon reducing agent 30.3-33.4 steel shavings                           7.3-7.7             refining slag             technical silicon                     12.6-40.0