RU2258760C1 - Method for concentration of titanium-silica concentrates - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: method includes melting in water-cooled crystallizer, into which at bottom a layer of non-electric-conductive source material is placed and in the center of it a channel is formed with diameter approximately equal to two electrode diameters, which is filled by current-conductive material. After that crystallizer Is connected to minus, and electrode with plus of direct current power block and electrode is lowered until touching current-conductive material until appearance of stable arc, and after start of crystallization of titanium slurry main working period is begun - accumulation of slurry block, during whole period of which periodically before end of melting portion loading of material of given compound is performed. Current-conductive material is formed by adding to source material not less than 33% of breeze coke from mass o source material.

EFFECT: lower costs, higher efficiency, broader functional capabilities.

3 cl, 7 tbl, 1 dwg

Description

The invention relates to metallurgy and can be used to obtain artificial rutile from titanium-containing raw materials, in particular from leukoxene concentrates obtained by the beneficiation of titanium-siliceous ores.

There is a method of enrichment of titanium-siliceous concentrates, which consists in creating a liquid metal bath in the furnace, onto the surface of which a charge containing leucoxene concentrate is loaded, in raising the temperature in the furnace above the melting temperature of the metal bath and holding the melt until its density is divided into silicon-titanium and titanium-siliceous melts, which are then drained separately. (See, for example, patent RU 2220222 C1 with priority of September 16, 2002 on "Method for the enrichment of titanium-silicon concentrates").

This invention is a prototype for the claimed solution.

One of the main disadvantages of the known invention is its inertia and significant heat loss associated with heating a metal bath to the melting point of a titanium-siliceous concentrate.

The proposed invention is free from the above disadvantages.

A method of enriching titanium-siliceous concentrates, including loading and melting the charge, characterized in that the melting is carried out in a water-cooled crystallizer, into which a layer of a non-conductive initial charge is loaded to the bottom and a channel is created in the center with a diameter of approximately two diameters of the electrode, which is filled with a conductive charge, then connect the mold with a minus, and the electrode with the plus of the DC power supply and lower the electrode until it contacts the conductive charge until Nia stable arc, and after the beginning of crystallization of titanium slag melting is carried out on the primary working period - slag fusing unit to perform predetermined charge Batch formulations for the entire period which periodically until the end of melting. The conductive charge is created by adding at least 33% of the coke content of the charge to the initial charge. The layer of non-conductive initial charge loaded on the bottom of the mold is 1.5-2 diameter of the electrode.

All of these signs can eliminate the above disadvantages of the prototype. In addition, in the smelting process, an additional enrichment of the mixture occurs due to the directed crystallization of slag during the deposition of the ingot. In this case, more refractory crystals of titanium oxides crystallize first and push the lighter silicate melt up.

The invention is illustrated by the drawing, which schematically shows a device for implementing the method of enrichment of titanium-silica concentrates.

The designations in the drawing are as follows.

The furnace, which is made in the form of a crystallizer 1, made of copper and cooled by water, at the bottom of which there is an initial charge 2 with a conductive channel 3 in the center. The conductive channel 3 consists of an initial charge with a coke content of at least 33% of the mass of the charge and is made with a diameter corresponding to two diameters of the electrode 4, which is coaxially mounted in the mold 1. The electrode 4 is graphitized and connected to the plus, and the mold 1 to the minus of the power supply 5 DC.

The method is as follows.

At the bottom of the mold 1 serves the mixture 2, forming a layer with a height corresponding to a value of 1.5-2 diameter of the electrode. The initial charge 2 consists of a titanium-siliceous concentrate and 5-6% coke from the mass of the concentrate fraction of 0.1 mm, which is non-conductive at room temperature. This layer can also be formed from the initial concentrate with the material of the skull layer; possibly from pure starting concentrate or only from skull material. In the center of this layer, a conductive channel 3 is created, the diameter of which is proportional to the inner diameter of the furnace and approximately equal to the two diameters of the electrode 4. It follows that with the diameter of the mold 1 equal to 1.6 m and the diameter of the electrode 300 cm, the initial layer at the bottom of the mold will be look like this. With a bulk density of the concentrate equal to 1420 kg / m ³ , and with a bulk density of coke powder of 863 kg / m ^{3, the} calculated density of the mixture of 67% concentrate and 33% of coke will be 1240 kg / m ³ . Accordingly, the mass of the conductive charge in the conductive channel 4 will be equal to 346 kg, of which 232 kg of pure concentrate and 114 kg of coke. The mass of the "filler" around the conductive channel 3 will be 1600 kg. After creating the conductive channel 3, the electrode 4 is lowered into the mold 1 until it contacts the charge of the conductive channel 3 and a stable arc appears.

The total mass of the concentrate at the bottom of the mold of the initial layer is 1832 kg. With a starting capacity of the furnace of 3000 kW / h, the melting time of this amount of charge will be 1.2-1.5 hours, which will result in 1212 kg of titanium slag and 426 kg of silicate slag, which form a liquid slag layer 25 cm thick. At the same time crystallization of titanium slag begins, which means the furnace goes to the main working period of melting - the deposition of slag block.

After reaching the main working period of the smelting, the power is reduced to 2535 kW / h and the charge 2 of a given formulation is loaded into the furnace during the entire period of fusion of the slag block. Carbon introduced into the charge in the form of coke, promotes better separation of the liquid phases, vigorously mixing the supplied bulk charge 2 into the melt and transfers the combustion of the electric arc to a layer of foamy slag, shielding the arc and reducing heat loss due to arc radiation into the empty space of the furnace. During the smelting process, due to carbon, the higher titanium oxides are also reduced to lower ones. The enrichment of titanium slag proceeds due to the effect of separation in the liquid state of a titanium-siliceous concentrate into two immiscible liquids - titanium-target slag and siliceous by-product slag, and further separation of the melts by density. Additional enrichment of the titanic slag with titanium oxides is achieved due to the directed crystallization of the titanic slag during deposition of the ingot onto a water-cooled crystallizer. In this case, more refractory crystals of titanium oxides crystallize first and push the lighter silicate melt up. When melting at a direct current of polarity: “-” on the bath, “+” on the electrode, additional removal of iron oxides from the slag to the metal, reduction of the content of silicon oxide in the slag due to the release of silicon monoxide, and acceleration of the deposition of droplets of electrically conductive titanium slag from silicate slag are provided with predominantly ionic conductivity.

The furnace loading is carried out periodically, in portions of 50-150 kg, according to the charge supply with the energy consumption and visual monitoring of the charge penetration, not allowing the “opening” of the top, i.e. the surface of the melt must be covered by a layer of unmelted charge 2, and during melting, the electrode is uniformly moved up. The duration of this melting period is 11-12 hours.

To remove the shrinkage shell of the titanic part of the block and create a smooth interface between the titanium and silicate parts of the slag block at the end of the smelting, a gradual decrease in the removed power is carried out for 1.5-2 hours. Upon completion of the smelting, the charge to the furnace is stopped and the furnace top is melted to more fully precipitate drops of titanium slag from silicate slag and, accordingly, to maximize the separation of titanium and silicon slag. After melting, the furnace is de-energized and the mold 1 is rolled out without shutting off water cooling.

When using 100 kg of titanium-siliceous concentrate and coke composition shown in Table 1:

Per 1000 kg of titanium slag:

The phase structure of titanium slag consists of vertically elongated crystals of sesquioxide titanium oxide TiO ₃ separated by interlayers of silicate glass with rare metallic inclusions of carbon iron.

The phase structure of silicate slag consists of silicate glass. Sometimes there are no time to settle globules of titanic slag.

The main production waste is silicate slag with 75% SiO ₂ and 20% Ti ₂ O ₃ , which is formed when using 67.5% of the initial concentrate in an amount of 350 kg per 1 ton of titanium slag with 82% Ti ₂ O ₃ (92% TiO ₂ in terms of). This slag can be used for the production of slag-metal casting with subsequent dilution of silicate slag with lime-containing materials to SiO ₂ / CaO = 1.5.

In the process of separation melting, up to 38 kg of dust per 1000 kg of titanium slag is formed.

Dust is not abrasive. The electrical resistivity of dust is unfavorable for trapping it in electrostatic precipitators, the dust has a high angle of natural suction and is poorly removed from the bunkers, well wetted by water. Dust with such properties is well captured in fabric filters.

Considering that such dust will be enriched with silicon oxide due to the selective evaporation of silicon monoxide during smelting, it is advisable not to use it for new remelting in the furnace, and, together with silicate slag, to use for the production of slag-metal casting. The dust captured during the crushing of titanium slag is subsequently recycled to an electric furnace.

The composition of the exhaust gases during melting in closed mode, vol.%: WITH - up to 41%; CO ₂ -11.606%; H ₂ O - 1.675%; N ₂ - 44.676%; CH ₄ - 0.778% (possibly the presence of hydrogen H ₂ - up to 2%). The amount of exhaust gases - 370 m ^3/1000 kg of titaniferous slag.

Exhaust gases, in addition to dust removal, must be cleaned of carbon monoxide and other combustible gases. It is advisable to use blast furnace gases as an auxiliary process fuel in other technological processes.

This method allows to carry out enrichment of titanium slag with titanium oxides without additional large-scale recovery processes due to directed crystallization of titanium slag during deposition of the ingot in a water-cooled crystallizer.

Claims (3)

1. The method of enrichment of titanium-siliceous concentrates, including loading and melting the mixture, characterized in that the melting is carried out in a water-cooled crystallizer, into which a layer of non-conductive initial mixture is loaded to the bottom and a channel is created in the center with a diameter approximately equal to two diameters of the electrode, which is filled with conductive charge, then connect the mold to the minus, and the electrode with the plus of the DC power supply and lower the electrode until it contacts the conductive charge until eniya stable arc, and after the beginning of crystallization of titanium slag melting is carried out on the primary working period - slag fusing unit to perform predetermined charge Batch formulations for the entire period which periodically until the end of melting. 2. The method according to claim 1, characterized in that the conductive charge is created by adding at least 33% of the coke content of the charge to the initial charge. 3. The method according to claim 1, characterized in that the layer of non-conductive source charge loaded onto the bottom of the mold is 1.5-2 diameter of the electrode.