Method for preparing ferrotitanium from vanadium-titanium DRI electric furnace melt separation slag

Abstract

The invention discloses a method for preparing ferrotitanium from vanadium-titanium DRI electric furnace melt separation slag. The method comprises the following steps that (1) the melt separation slag, titanium concentrate, iron powder and a slag former are dried; (2) uniformly mixing the dried melt separation slag, titanium concentrate, iron powder and slag former with aluminum powder and potassium chlorate; (3) transferring the uniformly mixed material into a reactor, paving a proper amount of magnesium rods on the surface layer of the material, and igniting to start the reaction; after the self-propagating reaction is completed, an electric arc furnace is used for electrifying and heating for 20 And (4) after the reaction is finished, the alloy is separated from slag, and the ferrotitanium alloy is obtained. By means of the method, the production cost of the ferrotitanium alloy is reduced, the problem that a large amount of melt separation slag generated in the electric furnace smelting process of the vanadium titano-magnetite is piled up is solved, and the method has positive significance on comprehensive utilization of secondary resources.

Description

Technical Field

[0001] The invention belongs to the technical field of secondary metal resource recycling and relates to a method for preparing ferrotitanium alloy by smelting and separating slag in a vanadium-titanium DRI electric furnace. Background Art

[0002] Titanium-iron alloy is an alloy of titanium and iron. There are three main types according to the titanium content: FeTi 30 (containing Ti25.0%~35.0%, Al<8.5%, Si<5.0%), FeTi 40 (containing Ti 35.0% to 45.0%, Al <9.5%, Si <4.0%) and FeTi 70 (Contains Ti 65% to 75%, Al 0.5% to 5%, Si <0.5%). The main uses of titanium-iron alloys are: (1) Used as a deoxidizer, degasser and carbon-sulfur stabilizer in steelmaking. Titanium deoxidation in the production of calm steel can reduce segregation on the upper part of the ingot, improve the quality of the steel and increase the yield rate of the ingot. Titanium and nitrogen dissolved in molten steel can combine to form stable titanium nitride, which can eliminate the adverse effects of nitrogen on steel properties. Titanium and sulfur in molten steel form titanium sulfide, which can eliminate the formation of iron sulfide that causes hot brittleness. Titanium and carbon form extremely stable titanium carbide. Titanium carbide particles can prevent steel grain growth, refine the steel structure, and increase the strength of the steel. The chemical affinity between titanium and carbon is greater than that between chromium and carbon. Adding titanium-iron to stainless steel to fix carbon can eliminate the depletion of chromium at the grain boundary of stainless steel and improve the corrosion resistance of stainless steel. (2) Titanium-iron alloy is a typical representative of AB type hydrogen storage alloys. After activation treatment, it can reversibly absorb and release hydrogen at room temperature. Due to its moderate decomposition pressure, large hydrogen storage capacity and abundant raw material reserves, it has always attracted much attention in the materials field.

[0003] The preparation of ferrotitanium alloy currently mainly uses the remelting method and the aluminothermic method. The two raw materials are scrap titanium and rutile. The high price of raw materials leads to high production cost of ferrotitanium alloy.

[0004] China is a country with abundant titanium resources, accounting for 28% of the world's total, and its titanium reserves rank first in the world. China's titanium resources are concentrated, mainly in Panzhihua and Chengde. The titanium resources in the two regions are mainly in the form of vanadium-titanium magnetite, of which Panzhihua reserves 9 billion tons of vanadium-titanium magnetite and Chengde reserves 8.4 billion tons of vanadium-titanium magnetite. Due to the low grade of titanium in China's vanadium-titanium magnetite and the compounding of other elements, the difficulty of mineral processing is great, and it is a low-quality titanium resource.

[0005] The titanium in vanadium-titanium magnetite is not easy to enter the molten iron during the ironmaking process, and most of it enters the slag to form molten slag. Due to the complex composition of the vanadium-titanium DRI electric furnace slag, the titanium grade is not high. There is currently no effective way to utilize this product, and it can only be piled up, which not only occupies a large amount of land resources, but also causes environmental pollution. Summary of the invention

[0006] The object of the present invention is to provide a method for preparing ferrotitanium alloy by melting and separating slag in a vanadium-titanium DRI electric furnace, which not only solves the problem of titanium resource accumulation, but also reduces the production cost of ferrotitanium alloy.

[0007] To achieve the above object, the present invention adopts the following technical solution: A method for preparing ferrotitanium alloy by smelting slag in a vanadium-titanium DRI electric furnace comprises the following steps: (1) Drying the molten slag, titanium concentrate, iron powder and slag-making agent; (2) Evenly mix the dried molten slag, titanium concentrate, iron powder, slag-making agent, aluminum powder and potassium chlorate; (3) Transfer the mixed material to the reactor, place an appropriate amount of magnesium strips on the surface of the material and ignite to start the reaction; after the self-propagating reaction is completed, use an electric arc furnace to heat for more than 20 minutes; (4) After the reaction is completed, the alloy and slag are separated to obtain titanium-iron alloy.

[0008] Furthermore, in the method described in the present invention, the mass ratio of the smelted slag, titanium concentrate, iron powder, slag-forming agent, aluminum powder, and potassium chlorate in step (2) is: 0.1-1 part of smelted slag, 0.01-1 part of titanium concentrate, 0.15-0.34 part of iron powder, 0.1-0.2 part of slag-forming agent, 0.31-0.56 part of aluminum powder, and 0.26-0.52 part of potassium chlorate.

[0009] Furthermore, in the method of the present invention, in step (2), the particle size of the molten slag and titanium concentrate is ≤3 mm, the particle size of the iron powder is ≤2 mm, the particle size of the slag-forming agent is ≤5 mm, the particle size of the aluminum powder is ≤0.2 mm, and the particle size of the potassium chlorate is ≤1 mm.

[0010] Furthermore, the slag-forming agent of the present invention is calcium oxide.

[0011] Furthermore, the slag-forming agent of the present invention is a mixture of calcium oxide and calcium fluoride, and the mass ratio of calcium oxide to calcium fluoride in the mixture is 3-9:1.

[0012] Furthermore, the smelted slag of the present invention is obtained by melting DRI reduced by a hydrogen-based vertical furnace through an electric furnace.

[0013] Furthermore, in the method of the present invention, the drying temperature in step (1) is ≥ 100° C., and the drying time is ≥ 24 hours.

[0014] Furthermore, in the method of the present invention, in the step (3), the height of the material stored in the reactor is less than 3 / 4 of the height of the reactor.

[0015] Furthermore, in the method of the present invention, in the step (4), after the reaction is completed, the product is cooled and allowed to stand for 12-24 hours, and then the slag ingot is crushed and separated to obtain the product ferrotitanium alloy.

[0016] The titanium-iron alloy prepared by the method of the invention has the following contents: Al<9.5%, C<0.4%, Si<5.0%, P<0.08%, S<0.04%, Mn<3.0% and Cu<0.40%.

[0017] The beneficial effects of the present invention are: The present invention uses the molten slag after vanadium-titanium DRI smelting to replace rutile as the raw material for producing ferrotitanium alloy by the aluminothermic process, which not only alleviates the pressure on the environment caused by the storage of molten slag produced in the process of hydrogen-based reduction of vanadium-titanium ore-electric furnace smelting, but also prepares ferrotitanium alloy products that meet the national standard GB / T 3282-2012.

[0018] After the self-propagating reaction is over, the molten pool will gradually cool down. In order to more efficiently settle the metal particles in the slag, the present invention uses an electric arc furnace for supplementary heating. The electric arc furnace can adjust the arc parameters according to production needs. The high temperature generated by the thermite reaction is combined with the precise temperature control capability of electrode heating to achieve a fast and accurate heating process, thereby improving production efficiency and product quality.

[0019] Compared with the traditional aluminothermic method, the present invention uses vanadium-titanium DRI molten slag as the titanium source, and the production cost is lower. DETAILED DESCRIPTION

[0020] The present invention is further described in detail below in conjunction with embodiments, but the protection scope of the present invention is not limited to the described contents. Example 1

[0021] A method for preparing ferrotitanium alloy by smelting slag in a vanadium-titanium DRI electric furnace, the specific steps are as follows: (1) drying the molten slag, titanium concentrate, iron powder and a slag-making agent at 100° C. for 24 hours; the slag-making agent is prepared by mixing calcium oxide and calcium fluoride in a mass ratio of 3:1; (2) Mix the dried slag, titanium concentrate, iron powder, slag-making agent, aluminum powder and potassium chlorate in a mass ratio of 0.75:0.35:0.24:0.15:0.43:0.34; wherein the particle sizes of the materials are as follows: slag, titanium concentrate ≤3 mm; iron powder ≤2 mm; aluminum powder ≤0.2 mm; calcium oxide, calcium fluoride ≤1 mm; potassium chlorate ≤1 mm; (3) The mixed material is placed in a Φ150 high-purity graphite crucible, and a small amount of magnesium rod is added as an igniter. The magnesium rod is ignited to initiate the reaction. After the self-propagating reaction is completed, the electrode is used for heating for 20 minutes; (4) After the reaction is completed, the mixture is allowed to cool for 20 hours, and then the slag ingot is crushed and separated to obtain the product titanium-iron alloy.

[0022] In the titanium-iron alloy prepared in this embodiment, Al contains 9%, C 0.05%, Si 2.5%, P 0.01%, S 0.05%, Mn 1.78%, and Cu 0.05%. Example 2

[0023] A method for preparing ferrotitanium alloy by smelting slag in a vanadium-titanium DRI electric furnace, the specific steps are as follows: (1) drying the molten slag, titanium concentrate, iron powder and a slag-making agent at 150° C. for 24 hours; the slag-making agent is prepared by mixing calcium oxide and calcium fluoride in a mass ratio of 5:1; (2) Mix the dried slag, titanium concentrate, iron powder, slag-making agent, aluminum powder and potassium chlorate in a mass ratio of 0.25:0.08:0.19:0.16:0.39:0.4; wherein the particle sizes of the materials are as follows: slag, iron concentrate ≤3 mm; iron powder ≤2 mm; aluminum powder ≤0.2 mm; calcium oxide, calcium fluoride ≤2 mm; potassium chlorate ≤1 mm; (3) The mixed material is placed in a Φ350 high-purity graphite crucible, and a small amount of magnesium rod is added as an igniter. The magnesium rod is ignited to initiate the reaction. After the self-propagating reaction is completed, the electrode is used for heating for 22 minutes; (4) After the reaction is completed, the mixture is allowed to cool for 12 hours, and then the slag ingot is crushed and separated to obtain the product ferrotitanium alloy.

[0024] In the titanium-iron alloy prepared in this embodiment, Al contains 8.5%, C 0.03%, Si 2.3%, P 0.01%, S 0.06%, Mn 1.80%, and Cu 0.04%. Example 3

[0025] A method for preparing ferrotitanium alloy by smelting slag in a vanadium-titanium DRI electric furnace, the specific steps are as follows: (1) drying the molten slag, titanium concentrate, iron powder and a slag-making agent at 120° C. for 24 hours; the slag-making agent is prepared by mixing calcium oxide and calcium fluoride in a mass ratio of 4:1; (2) Mix the dried slag, titanium concentrate, iron powder, slag-making agent, aluminum powder and potassium chlorate in a mass ratio of 0.3:0.1:0.26:0.15:0.45:0.5; wherein the particle sizes of the materials are as follows: slag, iron concentrate ≤2 mm; iron powder ≤1 mm; aluminum powder ≤0.2 mm; calcium oxide, calcium fluoride ≤1 mm; potassium chlorate ≤1 mm; (3) The mixed materials are placed in a Φ500 high-purity graphite crucible, and a small amount of magnesium bars are added as igniters. The magnesium bars are ignited to initiate the reaction. After the self-propagating reaction is completed, electrodes are used for heating for 25 minutes; (4) After the reaction is completed, the mixture is allowed to cool for 16 hours, and then the slag ingot is crushed and separated to obtain the product titanium-iron alloy.

[0026] In the titanium-iron alloy prepared in this embodiment, Al contains 8.3%, C 0.05%, Si 2.6%, P 0.01%, S 0.04%, Mn 1.75%, and Cu 0.05%. Example 4

[0027] A method for preparing ferrotitanium alloy by smelting slag in a vanadium-titanium DRI electric furnace, the specific steps are as follows: (1) drying the molten slag, titanium concentrate, iron powder and a slag-making agent at 130° C. for 24 hours; the slag-making agent is prepared by mixing calcium oxide and calcium fluoride in a mass ratio of 3:1; (2) The dried material is mixed evenly with aluminum powder and potassium chlorate in a mass ratio of 0.5:0.5:0.3:0.14:0.4:0.5; wherein the particle sizes of the materials are: molten slag, iron concentrate ≤2.5mm; iron powder ≤1.5mm; aluminum powder particle size ≤0.1mm; calcium oxide, calcium fluoride particle size ≤5mm; potassium chlorate particle size ≤0.5mm; (3) The mixed material is placed in a Φ800 high-purity graphite crucible, and a small amount of magnesium rod is added as an igniter. The magnesium rod is ignited to initiate the reaction. After the self-propagating reaction is completed, the electrode is used for heating for 27 minutes; (4) After the reaction is completed, the mixture is allowed to cool for 24 hours, and then the slag ingot is crushed and separated to obtain the product ferrotitanium alloy.

[0028] In the titanium-iron alloy prepared in this embodiment, Al contains 8.0%, C 0.04%, Si 2.3%, P 0.01%, S 0.05%, Mn 1.75%, and Cu 0.05%. Example 5

[0029] A method for preparing ferrotitanium alloy by smelting slag in a vanadium-titanium DRI electric furnace, the specific steps are as follows: (1) drying the molten slag, titanium concentrate, iron powder and a slag-forming agent at 140° C. for 24 hours; the slag-forming agent is calcium oxide; (2) Mix the dried slag, titanium concentrate, iron powder, slag-making agent, aluminum powder and potassium chlorate in a mass ratio of 0.1:0.01:0.15:0.1:0.31:0.26; wherein the particle sizes of the materials are as follows: slag, iron concentrate ≤2.5 mm; iron powder ≤2 mm; aluminum powder ≤0.1 mm; calcium oxide ≤3 mm; potassium chlorate ≤0.5 mm; (3) The mixed material is placed in a Φ800 high-purity graphite crucible, and a small amount of magnesium rod is added as an igniter. The magnesium rod is ignited to initiate the reaction. After the self-propagating reaction is completed, the electrode is used for heating for 24 minutes; (4) After the reaction is completed, the mixture is allowed to cool for 15 hours, and then the slag ingot is crushed and separated to obtain the product titanium-iron alloy.

[0030] In the titanium-iron alloy prepared in this embodiment, Al contains 8.0%, C 0.04%, Si 2.3%, P 0.01%, S 0.02%, Mn 1.79%, and Cu 0.05%. Example 6

[0031] A method for preparing ferrotitanium alloy by smelting slag in a vanadium-titanium DRI electric furnace, the specific steps are as follows: (1) drying the molten slag, titanium concentrate, iron powder and a slag-making agent at 200° C. for 20 hours; the slag-making agent is prepared by mixing calcium oxide and calcium fluoride in a mass ratio of 9:1; (2) Mix the dried slag, titanium concentrate, iron powder, slag-making agent, aluminum powder and potassium chlorate in a mass ratio of 1:1:0.34:0.2:0.56:0.52; wherein the particle sizes of the materials are as follows: slag, iron concentrate ≤2 mm; iron powder ≤1 mm; aluminum powder ≤0.2 mm; calcium oxide, calcium fluoride ≤2 mm; potassium chlorate ≤1 mm; (3) The mixed material is placed in a Φ800 high-purity graphite crucible, and a small amount of magnesium rod is added as an igniter. The magnesium rod is ignited to initiate the reaction. After the self-propagating reaction is completed, the electrode is used for heating for 25 minutes; (4) After the reaction is completed, the mixture is allowed to cool for 22 hours, and then the slag ingot is crushed and separated to obtain the product ferrotitanium alloy.

[0032] In the titanium-iron alloy prepared in this embodiment, Al contains 8.2%, C 0.02%, Si 2.7%, P 0.02%, S 0.03%, Mn 1.68%, and Cu 0.02%.

Claims

1. A method for preparing ferrotitanium alloy by smelting slag in a vanadium-titanium DRI electric furnace, characterized in that: The method comprises the following steps: (1) Drying the molten slag, titanium concentrate, iron powder and slag-making agent; (2) Evenly mix the dried molten slag, titanium concentrate, iron powder, slag-making agent, aluminum powder and potassium chlorate; (3) Transfer the mixed material to the reactor, place an appropriate amount of magnesium strips on the surface of the material and ignite to start the reaction; after the self-propagating reaction is completed, use an electric arc furnace to heat for more than 20 minutes; (4) After the reaction is completed, the alloy and slag are separated to obtain titanium-iron alloy.

2. The method for preparing ferrotitanium alloy by smelting slag in a vanadium-titanium DRI electric furnace according to claim 1, characterized in that: The mass ratio of the smelted slag, titanium concentrate, iron powder, slag-forming agent, aluminum powder and potassium chlorate in step (2) is: 0.1-1 part of smelted slag, 0.01-1 part of titanium concentrate, 0.15-0.34 part of iron powder, 0.1-0.2 part of slag-forming agent, 0.31-0.56 part of aluminum powder and 0.26-0.52 part of potassium chlorate.

3. The method for preparing ferrotitanium alloy by smelting slag in a vanadium-titanium DRI electric furnace according to claim 1, characterized in that: In step (2), the particle size of the molten slag and titanium concentrate is ≤3 mm, the particle size of the iron powder is ≤2 mm, the particle size of the slag-forming agent is ≤5 mm, the particle size of the aluminum powder is ≤0.2 mm, and the particle size of the potassium chlorate is ≤1 mm.

4. The method for preparing ferrotitanium alloy by smelting slag in a vanadium-titanium DRI electric furnace according to claim 1, characterized in that: The slag-forming agent is calcium oxide.

5. The method for preparing ferrotitanium alloy by smelting slag in a vanadium-titanium DRI electric furnace according to claim 1, characterized in that: The slag-forming agent is a mixture of calcium oxide and calcium fluoride, and the mass ratio of calcium oxide to calcium fluoride in the mixture is 3-9:

1.

6. The method for preparing ferrotitanium alloy by smelting slag in a vanadium-titanium DRI electric furnace according to claim 1, characterized in that: The molten slag is obtained by melting DRI reduced in a hydrogen-based vertical furnace through an electric furnace.

7. The method for preparing ferrotitanium alloy by smelting slag in a vanadium-titanium DRI electric furnace according to claim 1, characterized in that: The drying temperature in step (1) is ≥ 100°C and the drying time is ≥ 24 hours.

8. The method for preparing ferrotitanium alloy by smelting slag in a vanadium-titanium DRI electric furnace according to claim 1, characterized in that: In the step (4), after the reaction is completed, the product is cooled and allowed to stand for 12-24 hours, and then the slag ingot is crushed and separated to obtain the product ferrotitanium alloy.

9. The method for preparing ferrotitanium alloy by smelting slag in a vanadium-titanium DRI electric furnace according to claim 1, characterized in that: The titanium-iron alloy prepared by the method has the following characteristics: Al<9.5%, C<0.4%, Si<5.0%, P<0.08%, S<0.04%, Mn<3.0%, and Cu<0.40%.