RU2283352C1 - Burden for production of iron-free low-phosphorous manganese slag - Google Patents

Abstract

FIELD: metallurgy; burdens for production of low-phosphorous manganese slag suitable for melting manganese ferro-alloys.

SUBSTANCE: proposed burden contains the following components, % of burden mass: lumpy carbonate iron-manganese ore (fractions 10-100 mm), 54.0-68.0; sieve residues of oxide manganese ore (fractions 0-20 mm), 12.0-26.0; carbon (fractions 0-40 mm), 9.0-11.0; the remainder being materials containing silicon oxide. Provision is made for use of lumpy carbonate manganese ore mixed with fine fractions of oxide manganese ore including silicon oxides and possessing lower melting point, thus making it possible to accelerate fusion of silicate melt and manganese reduction process; as a result, process of reduction of phosphorus pentoxide by manganese is developed, thus compensating for losses of heat for dissociation.

EFFECT: reduced losses of heat for dissociation and reduced power requirements.

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Description

The invention relates to metallurgy, and in particular to blends for producing iron-free low-phosphorous manganese slag, suitable for smelting manganese ferroalloys.

Known mixture (1) for producing iron-free low-phosphorous manganese slag, including alkaline-earth metal oxide and carbon-containing material. The ratio of the amount of alkaline earth metal oxide to the amount of silicon dioxide is 0.5-1.5, and the mass of carbon in the carbon-containing material is 4-10% by weight of the ore. The disadvantage of this charge is that it does not allow direct processing of carbonate ore, but requires complex technology, including heat treatment at 850-1300 ° C and processing the obtained cake with a solution of nitric acid, which is associated with significant costs for additional hardware design, high energy costs and deterioration environmental indicators of the process, as work with acids is associated with the organization of a system of sedimentation tanks, sludge storages, etc.

The prototype of the invention is (2) the mixture to obtain a deferrized low-phosphorus manganese slag, including, kg:

manganese oxide ore or calcined carbonate 8100 coke breeze 950 quartzite fines 650 silicomanganese slag 850

The disadvantage of this charge is that it can be applied only to oxide ores, and carbonate ores must undergo preliminary firing, which complicates the process flow diagram and increases energy consumption.

The problem to which this invention is directed, is the involvement of carbonate manganese ores in the process of obtaining iron-free low-phosphorus manganese slag, simplifying the technology and reducing energy costs.

The problem is solved in that the mixture to obtain iron-free low-phosphorus manganese slag as manganese ore contains a mixture of carbonate lump (fraction 10-100 mm) ore with screenings of oxide manganese ore fraction 0-20 mm with the following components,% by weight of the mixture:

manganese carbonate ore (piece of 10-100 mm) 54.0-68.0 screenings of oxide manganese ore (fraction 0-20 mm) 12.0-26.0 coal (fraction 0-40 mm) 9.0-11.0 silica materials rest

The essence of obtaining iron-free low-phosphorus slag from high-phosphorous iron ore is carbothermic reduction of iron and phosphorus, dissolution of phosphorus in iron with the formation of iron phosphides and slagging of manganese in the form of silicates. In the case of purely lumpy carbonate ores, decarbonization occurs first in the first stage, and only then dissociation of higher manganese oxides into lower ones with subsequent carbothermic reduction. Therefore, the use of lumpy carbonate ore in a mixture in a mixture with small fractions of manganese oxide containing an increased amount of silicon oxide and having a lower melting point allows the latter to accelerate the appearance (essentially exothermic in nature) of a silicate melt, in which not only processes of manganese recovery, but also a secondary active process of reduction of phosphorus pentoxide by this manganese is being developed, which allows not only to compensate for the loss and heat for dissociation, but in general to achieve significant savings in electric energy (even at the melting stage from 900 to 1100 kWh / t), in addition to the fact that there is no need for an additional energy-intensive burning stage of the process. Thus, this mixture allows to process carbonate ore into a low-phosphorus iron-free manganese concentrate using a simplified technology (in one stage, without preliminary roasting of the ore) with a reduction in energy consumption.

The ranges of the contents given in the mixture are explained as follows: when introduced, wt.%:

manganese ore carbonate lump in the amount of: over 68 and screenings of oxide manganese ore in the amount of: less than 12

- sharply increases energy consumption; carbonate ore processing becomes unprofitable

lump of manganese ore in the amount of: less than 54 and screenings of manganese ore in the amount of: more than 26

- the processability is reduced due to a decrease in the gas permeability of the mixture, strong melting in the region of the electrodes, accompanied by collapses; carbonate ore processing becomes unprofitable

Coal in quantity more than 11

- unwanted silicon and manganese reduction processes will develop;

in quantity less than 9

- the degree of reduction of iron and phosphorus will decrease.

As materials containing silicon oxides, which contribute to the formation of a slag composition that is optimal in terms of melting temperature and selective reduction, quartz fines, slags from smelting of silicomanganese and ferrosilicon can be used.

Examples of implementation

Used:

Manganese carbonate ore containing, wt.%: Mn total. - 28.8; MnO 11.2; Fe - 11.0; SiO ₂ 35.2; Al ₂ O ₃ - 1.85; CaO 4.9; MgO - 1.5; P - 0.36; S 0.32; C 1.45; nnn - 12.1; moisture - 8.2.

Screenings of oxide manganese ore containing, wt.%: Mn total. - 29.8; MnO 30.2; Fe - 12.0; SiO ₂ 35.2; Al ₂ O ₃ - 4.85; CaO - 3.9; MgO - 0.5; P - 0.26; S 0.35; C - 0.45; nnn - 9.1; moisture - 6.2.

Coal CSPC, containing, wt.%: SiO ₂ - 0.3, Al ₂ O ₃ - 0.85; CaO - 0.5; MgO - 0.2; P - 0.035; S is 0.13; C - 80.0, nnn - 18.2.

Slag from smelting of silicomanganese, containing, wt.%: MnO - 14.5; SiO ₂ - 44.0; FeO - 2.5; Al ₂ O ₃ - 13.85; CaO - 16.2; MgO 8.5; P - 0.065.

Ferrosilicon smelting slag, containing, wt.%: SiO ₂ - 42.3; Al ₂ O ₃ - 36.3; FeO 2.2; oxides of calcium and magnesium the rest.

Example 1. The mixture to obtain iron-free low-phosphorus manganese slag contained, wt.%:

manganese carbonate ore (piece of 10-100 mm) 54.0 screenings of oxide manganese ore (fraction 0-20 mm) 26.0 SSPK coal (fraction 5-40 mm) 11.0 quartz fines 9.0

The mixture was mixed and heated in a magnesite crucible. The slag obtained by melting was separated from the alloy. Electric power consumption was 900 kWh / t.

63.4% Fe, 1.5% Mn and 68% R were converted to the resulting alloy.

The composition of the phosphorus-free slag obtained, wt.%:

MnO SiO ₂ Al ₂ About ₃ Cao MgO FeO R 45.1 28.3 6.8 10.5 6.5 2,4 0.14

The Mn / Fe ratio of 18.75 and the low phosphorus content make it possible to consider slag suitable for smelting both bulk and refined ferromanganese grades. Thus, it has been proved that it is possible to obtain a deferred low-phosphorous manganese concentrate from carbonate ore on the proposed charge according to the simplified technology and with a reduced consumption of electric energy.

Example 2. The mixture to obtain iron-free low-phosphorus manganese slag contained, wt.%:

manganese carbonate ore (piece of 10-100 mm) 68.0 screenings of oxide manganese ore (fraction 5-10 mm) 12.0 SSPK coal (fraction 5-40 mm) 10.0 silicomanganese smelting slags (piece 10-100 mm) 10.0

The mixture was mixed and wound in a magnesite crucible. The slag obtained by melting was separated from the alloy. Electric power consumption amounted to 1100 kWh / t.

67.0% Fe, 1.2% Mn and 65.3% R were converted to the resulting alloy.

The composition of the phosphorus-free slag obtained, wt.%:

MnO SiO ₂ Al ₂ About ₃ Cao MgO FeO R 48.0 26.2 8.1 8.0 7.3 2.2 0.13

A Mn / Fe ratio of 21.8 and a low phosphorus content make it possible to use the resulting slag for the smelting of all major grades of ferromanganese. Thus, it has been proved that it is possible to obtain iron-free low-phosphorous manganese slag from carbonate ore on the proposed charge using a simplified technology with a reduced consumption of electric energy.

Example 3. Used ore containing, wt.%: Mn total. - 30.8; MnO - 12.7; Fe - 9.56; SiO ₂ - 16.2; Al ₂ O ₃ - 2.3; CaO - 2.3; MgO - 1.7; P - 0.34; S is 0.15; C 1.45; nnn - 14.6.

The mixture for obtaining iron-free low-phosphorus manganese slag contained, wt.%:

manganese carbonate ore (piece of 10-100 mm) 62.0 screenings of oxide manganese ore (fraction 0-10 mm) 18.0 SSPK coal (fraction 5-40 mm) 9.0 ferrosilicon smelting slag 11.0

The mixture was mixed and heated in a magnesite crucible. The slag obtained by melting was separated from the alloy. Electric power consumption amounted to 1050 kWh / t.

71.0% Fe, 1.0% Mn, and 65.0% P went into the resulting alloy.

The composition of the low phosphorus slag, wt.%:

MnO SiO ₂ Al ₂ About ₃ Cao MgO FeO R 50.1 24.0 8.5 7.5 7.4 1.9 0.13

The Mn / Fe ratio of 26.3 and the low phosphorus content make it possible to use the resulting slag for the smelting of all major grades of ferromanganese. Thus, it has been proved that it is possible to obtain iron-free low-phosphorous manganese slag from carbonate ore on the proposed charge using a simplified technology with a reduced consumption of electric energy.

Bibliography

1. RF patent No. 2153019, class C 22 V 47/00. "A method of producing manganese concentrates", Vozzhenikov SG, Vasiliev V.G., applicant CJSC "Aegis", publ. 2000.07.20, application No. 2000101145/02, s. 01.01.19.

2. M.A. Ryss, Ya.N. Khodorovsky, "Production of Ferroalloys," - M.: Metallurgizdat, 1960, pp. 157-158.

Claims (1)

The mixture for obtaining iron-free low-phosphorus manganese slag, including manganese-containing material, carbon-containing reducing agent and materials containing silicon oxide, characterized in that as the manganese-containing material, it contains a mixture of carbonate lumpy ferromanganese ore fraction of 10-100 mm with screenings of manganese oxide fraction 0-20 mm, and as a carbon-containing reducing agent - coal fraction 0-40 mm, with the following components, wt.%: Carbonate lump ferromanganese ore 54.0-68.0 Screenings of Manganese Oxide Ore 12.0-26.0 Coal fraction 0-40 mm 9.0-11.0 Silica Materials Rest