RU2361940C2 - Processing method of ilmenite concentrates - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: charge consisting of ilmenite concentrate and carbonaceous reducing agent in ratio 1:(0.09-0.15) respectively are grinned up to size particle size 40-73 micron, it is mixed with binding agent and with addition of water in amount 6-7.3% of mass, there are manufactured pellets and they are dried at temperature 200-400°C. Pellets metallisation is implemented in pipe furnace at temperature 1100-1300°C. Hot pellets are molten in electric furnace at temperature 1830-1870°C and melt is isolated in electric furnace before poring during 3-5% of total duration of melting. In the capacity of ilmenite concentrate there are used iron-titanic concentrates with low content of admixtures, containing 50-55% % TiO₂, 32-36% FeO, 10-15% Fe₂O₃, up to 0.5% AL₂O₃, up to 0.8% SiO₂, up to 0.1% Cr₂O₃, up to 0.6% MnO, up to 0.05% P₂O₅, up to 0.3% V₂O₅, up to 0.1% CaO and up to 0.7% MgO. Used during reduction processes carbonaceous reducing agent - blast-furnace coke, pitch coke, petroleum coke, coal contains active carbon not less than 80% and sulphur not more 1%.

EFFECT: receiving of titanic slag with high content of TiO₂.

5 cl, 1 tbl, 1 ex

Description

The invention relates to the field of metallurgy, in particular to the production of titanium slag, which is the raw material for the production of pigment titanium dioxide and metallic titanium, and naturally-alloyed pig iron.

A known method of producing titanium slag and a metal intermediate from ilmenite concentrates, which consists in the fact that boron compounds are introduced into briquettes or pellets with a moisturizing solution (ed. USSR USSR No. 188011, C22B 34/12, 4/00, 1966) . The introduction of boron compounds by the specified method will lead to contamination of titanium slag and a decrease in its quality.

There is a method of smelting titanium slag and metal intermediate from ilmenite concentrates in an ore-thermal electric furnace, which allows, with the aim of simplifying technological schemes, to purge initial iron-titanium concentrates heated to 1400-1500 ° C with natural gas (ed. USSR USSR No. 191817, С22В 4/00 , 1967). The specified method provides for gas-thermal reduction of iron-titanium concentrates, which leads to a significant increase in the cost of the process.

A known method of producing ferrosilicotitanium ligature and titanium slag, allowing the use of silicon-titanium and titanomagnetite concentrates and carbon reducing agent in a ratio of 1: (0.05-0.15) :( 0.25-0.55), respectively, and the melting of the charge in an ore-thermal electric furnace at a temperature of 1750-1850 ° C (RF patent No. 2177049, C22C 33/00, 33/04, 35/00, 2000). By the specified method, it is impossible to obtain titanium slag with a SiO ₂ content below 9.0%.

The closest known method to the claimed one is a method of processing iron-titanium (ilmenite) concentrates by a carbon thermal process in an ore-thermal electric furnace described under the rubric of two-stage smelting of titanium concentrates (V.A. Garmata, A.N. Petrunko, N.V. Galitsky and others. Titanium. - M.: Metallurgy, 1983, pp. 215-219). As smelting materials, smelting is carried out using Lemnensky and Samotkan ilmenite concentrates containing 50.5-64.0% TiO ₂ , 0.2-4.3% FeO and 26.5-28.7% Fe ₂ O ₃ ; Sokolov-Sarbaisky magnetite concentrate containing 77.48% Fe ₂ O ₃ and 8.17% FeO; and Montenegrin coal containing carbon of the total 55.7% and sulfur 0.3%. The mixture before the production of pellets is crushed to a particle size of 74 μm (0.074 mm), moistened with a 5% solution of a surfactant, humidity before pelletizing 4-5%, binder (sulfite liquor) consumption 4-5%, pellet drying temperature in zones , ° С: the first one is 80, the second one is 120, the third one is 150. Pellets are metallized in a tubular furnace at a temperature of 1050-1100 ° С, while the metallization degree is 44.7-90.5%, and melting is carried out in 10 t steelmaking electric furnace with the loading of the hot charge on the slopes of the furnace. Melting is carried out at a temperature of 1650-1700 ° C. The content of TiO ₂ in titanium slags is 78.8-87.5%.

The main disadvantage of this method is that this method cannot produce titanium slag with a TiO ₂ content _of more than 90%.

The objective of the present invention is to develop a technology for the production of titanium slag with a content of at least 90% TiO ₂ .

The problem is solved in that the mixture consisting of ilmenite concentrate and a carbon reducing agent in a ratio of 1: (0.09-0.15), respectively, is crushed to a particle size of 40-73 microns, mixed with a binder and with the addition of water in an amount of 6-7 , 3% by weight, raw pellets are made and dried at a temperature of 200-400 ° С, pellets are metallized in a tube furnace at a temperature of 1100-1300 ° С, then hot pellets are melted in an electric furnace at a temperature of 1830-1870 ° С and the melt is held in an electric furnace before casting. The melt is kept in the furnace before casting for 3-5% of the total melting time.

To improve the technical and economic indicators, the mixture is pelletized by the method of making pellets; organic, for example, lignosulfonate or synthetic, for example, Floform 1049 reagents, are used as a binder in the amount of 0.46-3.9% of the mass of the charge for melting.

To achieve the main goal - to obtain titanium slag with a content of at least 90% TiO ₂ , iron-titanium concentrates with a low impurity content of 50-55% TiO ₂ , 32-36% FeO, 10-15% Fe ₂ O ₃ are used as ilmenite concentrate; up to 0.5% Al ₂ O ₃ ; up to 0.8% SiO ₂ ; up to 0.1% Cr ₂ O ₃ ; up to 0.6% MnO; up to 0.05% P ₂ O ₅ ; up to 0.3% V ₂ O ₅ ; up to 0.1% CaO and up to 0.7% Mg0. The carbon reducing agent used in the reduction processes is metallurgical coke, pitch coke, petroleum coke, coal contains at least 80% active carbon and no more than 1% sulfur.

A distinctive feature of the proposed method is that the use of ilmenite concentrate iron titanium concentrates with a content of 50-55% TiO ₂ , 32-36% FeO, 10-15% Fe ₂ O ₃ and impurities ∑ (AL ₂ O ₃ + SiO ₂ + Cr ₂ O ₃ + MnO + P ₂ O ₅ + V ₂ O ₅ + CaO + MgO) not more than 3.15% in a given ratio with a carbon reducing agent and the indicated technological methods allows to obtain titanium slag with a content of at least 90% TiO ₂ and along with it, converted iron for one metallurgical redistribution. Titanium slag is used as a raw material for pigments and metallic titanium, and pig iron in iron and steel for steelmaking.

Known methods for the processing of ilmenite concentrates do not allow to obtain titanium slag with a content of at least 90% TiO ₂ .

A smaller change in the ratio of the components of the charge will lead to the unreduction of iron oxides from iron-titanium concentrates and an increased content of FeO in titanium slag.

A change in the ratio of the components of the charge in a larger direction will lead to the reduction of titanium oxides from iron-titanium concentrates, the formation of titanium carbides, which will lead to overgrowing of the electric furnace bath and the furnace’s exit from the lines.

A decrease in the melting temperature of the mixture below 1830 ° C will lead to a decrease in the output of titanium slag from the furnace during casting, and a temperature increase of more than 1870 ° C will result in additional energy consumption for smelting.

Grinding a mixture with a particle size of less than 40 microns will lead to additional energy consumption and a significant loss of charge particles in the manufacture of pellets, grinding more than 73 microns to the strength of raw pellets.

Reducing water below 6% of the mass of the charge in the manufacture of pellets will lead to poor lumpiness and low strength of raw pellets, the addition of water more than 7.3% will lead to the formation of large pellets with low strength.

Drying the pellets at a temperature below 200 ° C will lead to a lengthening of the drying process and increased moisture in the pellets, which can lead to the destruction of the pellets during metallization. Drying at temperatures above 400 ° C will lead to additional energy consumption.

A decrease in temperature during the metallization of pellets below 1100 ° C will lead to a decrease in the degree of metallization and, as a result, to an increase in energy consumption during the smelting of titanium slag. An increase in temperature of more than 1300 ° C will lead to the formation of a liquid phase in the tube furnace and the formation of deposits.

Reducing the amount of binder in the manufacture of raw pellets to less than 0.46% of the mass of the charge for melting will lead to partial destruction of the pellets - their strength decreases, and an increase of more than 3.9% will lead to increased consumption of binder and a decrease in the strength of raw pellets.

Reducing the exposure time of the melt before casting less than 3% of the total duration of the smelting will lead to losses of metal with slag (small particles of the metal “crown” do not have time to sink into the ingot), and increasing the exposure time of more than 5% will increase the specific energy consumption.

Example

The testing of a method for processing ilmenite concentrates was carried out at the Klyuchevsk ferroalloy plant in an experimental workshop. The mixture was crushed in a ball mill, pellets were produced on a plate granulator with a plate diameter of 1000 mm and a plate side height of 140 mm. The pellets were dried in a drying chamber with electric heating. Pellet metallization was carried out in a tubular furnace of cylindrical, inclined, counter-current, inside lined with fireclay brick. Fuel is natural gas. Titanium slag and cast iron were smelted in a three-electrode electric furnace with a transformer power of 600 kVA and coal lining. The test results are shown in the table.

Analyzing the results of processing ilmenite concentrates by the proposed method, we can conclude that the method allows to obtain titanium slag with a content of at least 90% TiO ₂ and pig iron for one metallurgical processing. Moreover, titanium slag satisfies the requirements of TU 1715-452-05785388-99 for the manufacture of pigments and metallic titanium, and cast iron GOST 805-80 "Converted cast iron" grade PVKZ.

Claims (5)

1. The method of processing ilmenite concentrates for the production of titanium slag, including the preparation of a mixture consisting of ilmenite concentrate and a carbon reducing agent, its grinding, the manufacture of raw pellets using a binder, their drying, metallization, melting in an electric furnace and casting of molten titanium slag, characterized in that the preparation of the charge is carried out from ilmenite concentrate and carbon reducing agent in a ratio of 1: (0.09-0.15), respectively, grinding is carried out to a particle size of 70-73 microns, Raw pellets are developed using a binder by mixing with water in an amount of 6-7.3% of the mass of the charge, they are dried at a temperature of 200-400 ° С, pellets are metallized in a tube furnace at a temperature of 1100-1300 ° С, hot pellets are melted carried out at a temperature of 1830-1870 ° C with the exposure of the melt in an electric furnace before casting. 2. The method according to claim 1, characterized in that iron-titanium concentrates with a content of 50-55% TiO ₂ , 32-36% FeO, 10-15% Fe ₂ O ₃ , up to 0.5% Al ₂ are used as ilmenite concentrate O ₃ , up to 0.8% SiO ₂ , up to 0.1% Cr ₂ O ₃ , up to 0.6% MnO, up to 0.05% P ₂ O ₅ , up to 0.3% V ₂ O ₅ , up to 0 , 1% CaO and up to 0.7% MgO. 3. The method according to claim 1, characterized in that metallurgical coke, pitch coke, petroleum coke, coal with an active carbon content of at least 80% and sulfur no more than 1% are used as the carbon reducing agent. 4. The method according to claim 1, characterized in that as a binder in the manufacture of raw pellets using organic, for example, lignosulfonate or synthetic, for example, Floform 1049, reagents in the amount of 0.46-3.9% by weight of the mixture. 5. The method according to claim 1, characterized in that the exposure time of the melt in an electric furnace before casting is 3-5% of the total melting time.