SU1315507A1 - Carbon mixture for smelting ferrosilicium - Google Patents

Abstract

The invention relates to the field of metallurgy, namely to the smelting of ferrous jelly alloys produced in electric arc furnaces by the carbon thermal method. The aim of the invention is to increase the recovery of silicon and reduce the specific consumption of electricity, quartzite and coke. The carbonaceous mixture for the smelting of ferrosilicon contains, in wt.%: Odubin 16-47.8, carbon waste from the production of ferrosilicon 4.3-14.3 and coke 47.8- 79.5. At the same time, carbonaceous waste from the production of ferrosilicon contains, in wt.%: Silicon carbide, 5.9-33.3, carbon, 0.7-5.01, metallic king, 28-76.2, slag, the rest. The use of carbonaceous mixture allowed to increase the extraction of silicon by 1.1-3.5%, to reduce the specific consumption of basic materials and electricity. 1 3.p. f-ly, 4 tab. i (L

Description

The invention relates to metallurgy, namely, to the smelting of iron-silicon alloys produced in an electric arc furnace using the carbon thermal method.

The aim of the invention is to increase the recovery of silicon and reduce the specific energy consumption of quartzite and coke.

The proposed carbonaceous mixture for smelting ferrosilicon contains dubin, carbonaceous waste from the production of ferrosilicon and coke in the following ratio of components, in May.% Odubin 16-47,8

Carbon waste production of ferrosilicon 4, 3-14,3 Coke. 47.8-79.5 In this case, carbonaceous waste from the production of ferrosilicon has the following composition, wt%: silicon carbide 5.9-3353-, carbon 0.7-5.01, metal cores 28-76.2; slag else.

The proposed composition of the carbonaceous mixture for the smelting of ferrosilicon is based on the features of the technological process, the operation of electric furnace equipment, as well as the physicochemical properties of odubins and carbonaceous waste of ferrosilicon. The use of these materials significantly improves the condition of the furnace top and the operation of the electric furnace equipment.

In terms of its physicochemical properties, odubine differs from known reducing agents, including wood chips, from which it is obtained.

It has been established that after high-temperature cooking under pressure, the source of wood chips significantly changes its physicochemical characteristics — density, porosity, grain size distribution, electrical conductivity. For example, the original wood - birch has a bulk weight of 0.418 g / cm, strength along the fiber 469 kg / cm and strength across the fiber 33 kg / cm. After cooking, birch has a bulk weight of 0.281– 0.240 g / cm, strength along the fiber is 55–110 kg / cm, and strength across the fiber is 6–15 kg / cm, i.e. after high-temperature cooking under pressure reduces its bulk weight

by 32-43%, increases by the same amount its porosity and at the same time loses its structural strength along the fiber by 38-77% and across the fiber

by 54-76%. Odubina, which is a product of high-temperature cooking of larch wood, differs sharply from the original wood chips. Coal derived from dubins,

15.2 times less electrical conductivity (3.5-10 cm) compared to beech charcoal (2.3-10). The use of Dubin in the composition of the proposed mixture in

3, 0-3.17 times increases the electrical resistance of the ferrosilicon mixture in comparison with the usual charge with coke. Unlike other carbonaceous materials, odubin has a very

small volumetric weight (0.1 t / m) and small particle size distribution.

The electrical resistivity of the ferrosilicium mixture using known and proposed carbonaceous

mixtures are given in table. one.

The consumption of single-bluards within the specified limits in the composition of the carbonaceous mixture leads to an increase in its volume (by

compared with the known mixture) 1.16-2.78 times, 1.14-2.73 times the ratio of the volume of the carbonaceous mixture to silica-containing material increases and 1.13-3.21 times the surface of carbonaceous materials involved in holding sublimated Sic into gas, which reduces silicon loss.

These physical properties are odubins

with an increase in its consumption in the composition of the mixture, it is possible to increase the consumption of carbon waste from the production of ferrosilicon without substantially disrupting the properties of the carbon mixture,

the task of complete utilization of production wastes with a simultaneous increase in the extraction of silicon.

When entering the dubin in the amount of less than 16 wt.%, There is an uneven descent of the charge, its suspension and collapses. In case of large falls, hot bursts are emitted to the electric furnace equipment, and sometimes a short network, which leads to the shutdown of the electric furnace and an increase in its hot idle time. At the same time, the operating conditions of the furnace personnel deteriorate. In addition, when the charge is discharged, large losses of heat, charge materials and electricity occur and a large amount of dust and gas enriched with silicon monoxide gas is emitted into the atmosphere of the workshop. This increases the specific consumption of raw materials and electricity and worsens the environmental conditions of the process.

When the content in the proposed mixture of odubiny in the amount of 16-47,8 wt. comparative characteristics izvest20

25

The process of ferrosilicon melting is characterized by a uniform charge flow and good gas permeability of the top. Due to the higher electrical resistance of the charge -5 with the proposed carbon mixture, the smelting of ferrosilicon takes place with a deep and stable landing of the electrodes. The furnace works without collapses and emissions of the charge, which improves the main technical and economic indicators of the process and reduces the dust content of the shop.

With a greater than 47.8 wt.% Content of dubins in the proposed carbon mixture, significant changes occur in the composition of the resulting alloy, which gives the mixture a different purpose.

The amount of carbon waste from the production of ferrosilicon in the proposed carbon mixture is technologically interrelated with the amount of dubins.

The use of carbonaceous waste from the production of ferrosilicon allows us to solve the problem of the complete utilization of our own production waste with a simultaneous increase in the extraction of silicon. However, due to the high content of the refractory and electrically conductive donkey (33.88-36.33%), which negatively affects the operation of the electric furnace, the upper limit for the input of coal-based spider-waste in the mixture is limited by the technological features of the electric smelting of ferrosilicon. It has been established that at greater than 14.3 wt.% Of waste in the composition of the mixture, because of the high content of refractory and electrically conductive slag in them, the slag multiplicity increases, its output from the furnace deteriorates, and with it the metal

which dramatically worsens the operation of the furnace and its main technical and economic indicators. For these reasons, the use of carbon waste from the production of ferrosilicon in the amount of

more than 14.3 wt.% in the proposed mixture is impractical.

When the content in the proposed carbonaceous mixture of waste in the amount of 4.3-14.3 wt.%, The smelting of ferrosilicon is characterized by a normal furnace course and a good yield of metal and slag.

In tab. 2 shows some

0

five

-five

0

0 5 0

five

and proposed carbonaceous mixtures, in table. 3 - the composition of carbon waste production of ferrosilitsr.

The proposed carbonaceous mixture has a lower electrical conductivity, is better distributed between | Quartzite, prevents sintering of the charge in the upper horizon of the furnace. This improves the convergence of the charge and its gas permeability, the operation of the electric furnace and its main indicators.

The proposed carbonaceous mixture is tested under industrial conditions in the smelting of 75-90% ferrosilicon in a 22.5 MVD ore-thermal furnace.

The carbonaceous mixture in the mixture is continuously loaded into the furnace and melted, periodically carrying out the release of metal and slag.

The results of the furnace when using the known and proposed carbonaceous mixtures are presented in table. four.

The use of the proposed carbonaceous mixture allows an increase of silicon extraction by 1.1-3.5%, a reduction in the specific consumption of basic materials and electricity and, in addition, the utilization of waste from the production of ferrosilicon and wood processing, which significantly reduces the consumption of expensive and scarce coke. , to improve the ecology and working conditions, to increase the reliability of work and the service life of the equipment.

Claims (1)

1. A carbonaceous mixture for smelting ferrosilicon containing dubuina and coke, characterized in that, in order to increase the extraction of silicon and reduce the specific consumption of electricity, quartzite and coke, it additionally contains carbonaceous waste from the production of ferrosilicon in the following ratio, wt.%: Odubina16-47j8 Carbonaceous from the Application, The denominator indicates the average value. the production of ferrosilicon contain, wt.%: Work time, days Specific consumption for 1 bt, alloy, kg (%): quartzite 2.6 23 3.6 7.3 15.2 3.0 1891 1819 1794 1761 1795 1883 Editor N. Gunko Compiled by K. Sorokin Tehred M. Khodanich Proofreader S. Shekmar Order 2319/27 Circulation 604 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4 Table. four 3.6 7.3 15.2 3.0 2.3 1875