RU2449038C1 - Charge for smelting ferrosilicomanganese - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to ferrous metallurgy and particularly to processing manganese material for smelting ferrosilicomanganese in arc furnaces containing less than 0.35% phosphorus. The charge contains the following, wt %: carbonaceous reducing agent 3-10, fluxing agent 7-20, ferrosilicon 1-7, and slag from production of manganese ferrous alloys being the balance.

EFFECT: invention increases the degree of extraction of manganese into metal, reduces specific consumption of electric powder and enables recycling of manganese-containing industrial wastes.

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Description

The invention relates to the field of ferrous metallurgy, in particular to the processing of manganese raw materials by melting in electric arc furnaces, and can be used for smelting ferrosilicon manganese with a low phosphorus content.

At present, Russian enterprises producing manganese-containing ferroalloys operate in difficult conditions associated with the lack of high-quality domestic manganese raw materials. Most of the manganese ores in Russia have a relatively low manganese content (19-35% Mn) and a high P / Mn ratio = 0.0052-0.042, which makes it impossible to obtain alloys with a phosphorus content of less than 0.35%.

High-quality manganese ores from Gabon, South Africa, India, Australia and some other countries are characterized by a high manganese content (~ 50%) and P / Mn≤0.0021 ratio. They are suitable for the production of low phosphorus alloys in demand on the market. At the same time, imported materials have a rather high cost and require additional shipping costs.

Known mixture for smelting ferrosilicon manganese, consisting of a carbon reducing agent, flux and manganese raw materials [Handbook of electrothermal processes / B.I. Emlin, M.I. Gasik. M .: Metallurgy, 1978, 288 pp.], Used at the Nikopol Ferroalloy Plant. Below is a typical composition of the mixture, kg (wt.%):

Carbon Reducing Agent (Coke) 486 (15.7) Flux (dolomite) 171 (5.5) Flux (quartzite) 470 (15.2) Manganese ore raw materials (agglomerate and concentrate) 1971 (63.6)

The disadvantage of this mixture is the production of ferrosilicon manganese with a high phosphorus content (> 0.35% P).

A known mixture for smelting ferrosilicon manganese of low phosphorus groups using an additional redistribution and obtaining at the first stage malophosphorous slag, the amount of which in the charge of the second stage is determined by the required phosphorus content in the final metal. The mixture consists of a carbon reducing agent, flux, manganese-containing waste, iron ore pellets, low-phosphorous manganese slag and low-phosphorous manganese ore raw materials [Technology of manganese ferroalloys. Part 2. Low carbon alloys. Zhuchkov V.I., Smirnov L.A., Zayko V.P. Yekaterinburg: Ural Branch of the Russian Academy of Sciences, 2008, 442 p.]. The following is the composition of the mixture for smelting ferrosilicon manganese with a content of 0.15% phosphorus, kg (wt.%):

Carbon Reducing Agent (Coke) 310 (12.6) Flux (limestone) 60 (2.4) Flux (quartzite) 250 (10.2) Manganese-containing waste and secondary raw materials 200 (8.2) Pellets 55 (2.2) Malophosphorous Manganese Slag 900 (36.7) Manganese ore raw materials (low phosphorus Manganese Ore (Australia) 680 (27.7)

The advantages of this composition of the charge include the possibility of obtaining low-phosphorous ferrosilicon manganese with a content of 0.15% phosphorus in the metal.

The disadvantage of this mixture is the need to use low-phosphorous manganese slag to ensure a given phosphorus content in the alloy, which requires an additional technological stage in the production environment and can only be implemented at enterprises with the corresponding free additional capacities. At the same time, productivity decreases, specific energy consumption increases, manganese extraction decreases, and the cost of raw materials increases.

The mixture was selected as a prototype [RF Patent No. 2047664, IPC6 C22C 33/04, publ. 10.11.1995], which allows to obtain ferrosilicon manganese with a low phosphorus content (<0.35% P), including: carbon reducing agent; flux; production waste and manganese sinter with a ratio of phosphorus to manganese equal to 0.0035-0.005, with the following ratio of components, wt.%:

Carbon Reducer 12-18 Flux (quartzite) 11-14 Waste production 0.1-5.0 Manganese sinter with ratio phosphorus to manganese equal to 0.0035-0.005 63.0-75.9

The advantages of this composition of the charge include the possibility of obtaining low-phosphorous ferrosilicon manganese and the use of manganese-containing waste.

A disadvantage of the known mixture is the use of manganese sinter with a low phosphorus content. There are very few such raw materials in the Russian Federation, its cost is high and its use in production is limited.

The technical result of the invention is the production of ferrosilicon manganese with a low phosphorus content (less than 0.35% P), increasing the degree of extraction of manganese in the metal, reducing the specific energy consumption and involving manganese-containing man-made waste in the processing.

The specified technical result is achieved by the fact that the proposed mixture for smelting ferrosilicon manganese in electric arc furnaces contains manganese-containing raw materials, a carbon reducing agent and flux, according to the invention, as a manganese-containing raw material, the mixture contains slag from the production of manganese ferroalloys and additionally ferrosilicon in the following ratio of components, wt.%:

Carbon Reducer 3-10 Flux 7-20 Ferrosilicon 1-7 Manganese Ferroalloy Production Slag rest

The proposed composition and ratio of charge materials allows us to provide favorable physicochemical conditions in the bath of the electric furnace, which increase the degree of reduction and transition of manganese from the oxide state to the metal phase and reduce the specific energy consumption.

The introduction of manganese ferroalloy production slag into the charge allows us to involve technogenic waste from metallurgical production into processing and produce ferrosilicon manganese without using low-phosphorus slag and high-grade manganese ores.

The choice of the boundary values of the components of the charge is determined experimentally and is due to the requirements for the composition of ferrosilicon manganese according to GOST 4756-91, as well as the difference in the chemical composition of the starting charge materials.

The content of the carbonaceous reducing agent in the charge in an amount of 3-10 wt.% Is determined from its stoichiometrically necessary amount for the reduction of charge manganese oxides taking into account deviations for process control. The lack of a reducing agent (less than 3 wt.%) Leads to a decrease in the degree of extraction of manganese, the loss of part of the manganese in the oxide state with slags, and the excessive consumption of silicon ferrosilicon for the reduction of manganese, which entails various kinds of process disruptions. With an excess of reducing agent of more than 10 wt.%, An unjustified overconsumption of the reducing agent and loss of the unreacted part of the reducing agent with slags during casting occur, which is accompanied by a deterioration in technical and economic indicators.

Flux limits are due to the carbothermic process of producing ferrosilicon manganese. It was experimentally established that when smelting ferrosilicon manganese, the addition of flux in an amount of 7-20 wt.% Is optimal. With a decrease in the amount of flux less than 7 wt.%, So-called “acidic” slags with a high content of SiO ₂ are obtained, which leads to a complication of the reactions of manganese reduction and a decrease in the degree of transition of manganese into the metal phase. When introducing a flux of more than 20 wt.% There is an unjustified overspending of the flux, the slag multiplicity increases and the specific energy consumption increases.

The introduction of less than 1 wt.% Ferrosilicon into the charge leads to the smelting of ferrosilicon manganese with a low silicon content and does not allow to obtain a silicon standard ferroalloy (according to the requirements of GOST 4756-91), and when the content of ferrosilicon is more than 7 wt.%, An alloy with an excess silicon content is obtained, unreasonable overspending of ferrosilicon occurs, which entails an increase in the cost of production.

The invention is illustrated by experimental swimming trunks carried out in a Tamman furnace.

The following materials were used as charge materials: slag from the production of manganese ferroalloys (chemical composition is presented in Table 1), coke (carbon reducing agent) with a content of 84 wt.% C, lime (flux) with a content of 90 wt.% CaO and ferrosilicon with a content of 65 wt. .% Si.

Table 2 shows the compositions of the blends and the results of the experimental melts. The experiments showed that the proposed composition of the charge provides a standard ferrosilicon manganese with a low phosphorus content (less than 0.35 wt.%). The content of all components in the smelted ferrosilicon manganese is within the requirements of GOST 4756-91.

The economic effect of using the proposed invention is achieved mainly through the use of relatively cheap manganese raw materials and the production of widely demanded high-quality ferrosilicon manganese.

Table 1 The chemical composition of the slag from the production of manganese ferroalloys, wt.% Mn _total Si _total Cao Al ₂ O ₃ MgO 47.5 18.7 5.15 4.96 1.22

table 2 The composition of the charges and the results of experimental laboratory swimming trunks No. p / p Materials, wt.% The content in the alloy, wt.% The degree of extraction of manganese in the alloy,% Note Slag from the production of manganese ferroalloys Ferrosilicon Coke Lime Mn Si P one 86.5 0.5 3 10 67.0 14.5 0.20 81.5 Beyond the Formula 2 91.0 1,0 3 5 63.0 14.7 0.20 77.0 Beyond the Formula 3 86.0 1,0 3 10 67.0 15.1 0.20 81.6 four 78.0 7.0 5 10 66,2 19.8 0.20 82.0 5 74.0 6.0 10 10 66,4 19.2 0.20 82.5 6 70.0 6.0 5 19 66,2 18.7 0.19 82.1 7 77.0 8.0 5 10 65.5 20,2 0.20 82.0 Beyond the Formula 8 72.0 6.0 12 10 66,4 19.2 0.19 82.5 Beyond the Formula 9 64.0 6.0 5 25 66,2 18.7 0.19 81.7 Beyond the Formula

Claims (1)

The mixture for smelting ferrosilicon manganese in electric arc furnaces containing manganese raw materials, a carbon reducing agent and flux, characterized in that it contains slag for the production of manganese manganese ferroalloys and additional ferrosilicon in the following ratio of components, wt.%:
Carbon Reducer 3-10 Flux 7-20 Ferrosilicon 1-7 Manganese Ferroalloy Production Slag Rest