Vanadium titano-magnetite smelting method and application thereof

Abstract

The invention provides a smelting method of vanadium titano-magnetite and application of the vanadium titano-magnetite. The smelting method comprises the following steps that after a mixed material of vanadium titano-magnetite, pulverized coal and a solvent is subjected to a reduction reaction in a coke oven, the obtained material is subjected to melt separation treatment in an electric furnace, and melt separation slag iron is obtained. The smelting method adopts a new process of coke oven reduction-electric furnace melting separation, compared with a process using hydrogen as a reducing agent, the process has the advantage of low cost of the reducing agent (pulverized coal), the reduced metallized pellets contain carbon and can be subjected to slag pre-adjustment, the electric furnace burden is single burden, and the cost is low. And the problems of large continuous production difficulty and the like caused by raw material fluctuation and excessive raw materials fed into the furnace to electric furnace reduction can be effectively prevented.

Description

Technical Field

[0001] The invention belongs to the technical field of steel smelting, and in particular relates to a non-blast furnace ironmaking process technology, and specifically relates to a smelting method of vanadium-titanium magnetite and application thereof. Background Art

[0002] At present, the non-blast furnace ironmaking processes mainly include gas-based vertical furnace-electric furnace melting process (such as Midrex process, HYL process, PERED process, etc.), COREX process, FINEX process, etc. Among them, the COREX process solves the problem of blast furnace permeability, but its emission reduction potential is small and it still needs to use a large amount of fossil fuels; the raw materials of the FINEX process can directly use iron ore powder, which has great emission reduction potential, but it has problems such as high difficulty in fluidized bed process, low reduction temperature, and low metallization rate. In comparison, the gas-based vertical furnace-electric furnace melting process has become the most widely used non-blast furnace process, with great emission reduction potential. It helps to comprehensively recycle the three resources of iron, vanadium and titanium when smelting vanadium-titanium ore, but there is hydrogen reduction endothermicity, the reaction temperature in the low-temperature zone above the vertical furnace is low, the gas utilization rate is low, and the metallized pellets, solvents and coke and other carbonaceous reducing agents need to be continuously added during the electric furnace melting process. In particular, when using the gas-based vertical furnace-electric furnace melting process for vanadium-titanium magnetite smelting, continuous production is difficult. Summary of the invention

[0003] In view of this, the object of the present invention is to provide a smelting method of vanadium-titanium magnetite and its application. The smelting method reduces the difficulty of continuous production in an electric furnace and has low energy consumption.

[0004] To achieve this object, the present invention adopts the following technical solutions:

[0005] In a first aspect, the present invention provides a method for smelting vanadium-titanium magnetite, comprising the following steps:

[0006] After the mixture of vanadium-titanium magnetite, coal powder and solvent is subjected to reduction reaction in a coke oven, the obtained material is melted in an electric furnace to obtain molten slag iron.

[0007] Preferably, the coal powder includes main coking coal, 1 / 3 coking coal and fat coal.

[0008] Preferably, the mass ratio of the main coking coal, 1 / 3 coking coal and fat coal is (4.5~5):(3~3.5):(2~2.5).

[0009] Preferably, the bonding index G value of the main coking coal is greater than 75, and the thickness Y value of the colloid layer is greater than 16 mm.

[0010] Preferably, the caking index G value of the 1 / 3 coking coal is greater than 65, and the thickness Y value of the colloid layer is ≤25 mm.

[0011] Preferably, the bonding index G value of the fat coal is greater than 85, and the thickness Y value of the colloid layer is greater than or equal to 25 mm.

[0012] Preferably, the solvent is selected from quicklime and / or activated ash.

[0013] Preferably, the mass ratio of the vanadium-titanium magnetite, coal powder and solvent is 1:(0.35~0.40):(0.027~0.047).

[0014] Preferably, the reduction reaction is carried out at a temperature of 1000-1100° C. and for a time of 8-10 h.

[0015] Preferably, in the material obtained after the reduction reaction, the TFe content is 41-45%, the FeO content is 5.3-8.5%, the MFe content is 35-41%, and the C content is 10-13%.

[0016] Preferably, after the reduction reaction is completed, a post-treatment step is also included.

[0017] Preferably, the post-processing step is: cooling the material obtained after the reduction reaction to below 300° C. under an inert atmosphere and crushing it.

[0018] Preferably, the crushing is performed to a particle size of 25 to 50 mm.

[0019] Preferably, the temperature of the melting treatment is 1600-1650° C. and the time is 5-6 h.

[0020] In a second aspect, the present invention also provides an application of the above-mentioned smelting method in the technology of comprehensive recovery of iron, vanadium and titanium resources in non-blast furnace ironmaking process of vanadium-titanium magnetite concentrate.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention provides a smelting method of vanadium-titanium magnetite, which adopts a new process of coke oven reduction-electric furnace smelting. The specific advantages are as follows:

[0023] (1) As a carbon-based reducing agent, coal powder is cheap and easy to obtain;

[0024] (2) In the present invention, the smelting method first reduces the iron oxides in the vanadium-titanium magnetite in a coke oven using fixed carbon in the coal powder and CO gas generated by direct reduction of the oxides by carbon at high temperature in the coke oven. During the reduction process, coke is generated by coal coking while the iron ore powder is agglomerated, thereby eliminating the oxidation roasting process of the pellets, saving energy consumption for oxidation roasting, and reducing the problem of an increase in the reducing agent required for reduction caused by oxidation and reduction of the pellets.

[0025] (3) The present invention adds a solvent and an excess of coal powder during reduction in the coke oven, and completes the slag adjustment and carbon mixing process in the electric furnace in advance, so that the electric furnace can complete the smelting and smelting with a single charge, and increases the uniformity and stability of the raw materials, greatly reducing the difficulty of continuous production in the electric furnace.

[0026] (4) The iron and iron oxides are in good contact with the carbon-based reducing agent, and the kinetic conditions during the melting process are good, which increases the temperature and temperature uniformity of the molten iron in the electric furnace, thereby increasing the carbon content of the molten iron, making the molten iron easier to transport and increasing the transportation distance of the high-temperature molten iron;

[0027] (5) When the material obtained from the coke oven is melted in an electric furnace, vanadium oxide can be reduced to vanadium element by a carbon-based reducing agent and enter the molten iron, thereby improving the recovery rate of vanadium in the molten iron;

[0028] In summary, the present invention has good innovation and promotion prospects. DETAILED DESCRIPTION

[0029] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] The present invention provides a smelting method of vanadium-titanium magnetite, comprising the following steps:

[0031] After the mixture of vanadium-titanium magnetite, coal powder and solvent is subjected to reduction reaction in a coke oven, the obtained material is melted in an electric furnace to obtain melted slag iron. The mass ratio of the vanadium-titanium magnetite, coal powder and solvent is 1:(0.35-0.40):(0.027-0.047).

[0032] In the present invention, the vanadium-titanium magnetite is a vanadium-titanium magnetite concentrate, and the present invention has no particular limitation on its source, and it can be a general commercial product.

[0033] In the present invention, the coal powder includes main coking coal, 1 / 3 coking coal and fat coal, wherein the mass ratio of the main coking coal, 1 / 3 coking coal and fat coal is (4.5-5):(3-3.5):(2-2.5). The amount of the coal powder added will affect the metallization rate.

[0034] In the present invention, the coal powder is used as a carbon-based reducing agent. Compared with hydrogen as a reducing agent, it is cheap and has a low acquisition cost, which is beneficial to reducing smelting costs.

[0035] In the present invention, the bonding index G value of the main coking coal is greater than 75, such as 78, 80, and 84; the gelatinous layer thickness Y value is greater than 16 mm, such as 17 mm, 18 mm, and 20 mm; the bonding index G value of the 1 / 3 coking coal is greater than 65, such as 68, 72, and 76; the gelatinous layer thickness Y value is ≤25 mm, such as 12 mm, 18 mm, and 22 mm; the bonding index G value of the fat coal is greater than 85, such as 86, 88, and 92; the gelatinous layer thickness Y value is ≥25 mm, such as 25 mm, 28 mm, and 30 mm.

[0036] In the present invention, the solvent is selected from quicklime and / or activated ash, but cannot be selected from limestone, because limestone is easy to decompose and absorb heat, and the CO generated by decomposition 2 It will react with the carbon element in the coal powder and consume the coal powder, which is not conducive to the smelting process.

[0037] According to the present invention, vanadium-titanium magnetite, coal powder and solvent are first mixed in the above-mentioned certain ratio, and then the obtained mixture is charged into a coke oven for reduction reaction at 1000-1100° C. for 8-10 hours, preferably at 1020-1050° C. for 8.5-9 hours. In this process, iron oxides are gradually reduced to FeO and metallic iron by carbon and CO generated by reduction.

[0038] In the present invention, the metallized material obtained after the reduction reaction has a TFe content of 41-45%, a FeO content of 5.3-8.5%, an MFe content of 35-41%, a C content of 10-13%, and a metallization rate of iron of 85-90%.

[0039] In some preferred embodiments of the present invention, after the reduction reaction is completed, the material after the reduction reaction is preferably cooled to below 300° C. using an inert gas, and then crushed to a particle size of 25 to 50 mm. This makes it convenient to charge the electric furnace.

[0040] In the present invention, since the solvent and excess coal powder are added during the reduction process in the coke oven, the slag adjustment and carbon adjustment process in the electric furnace is completed in advance, so that the reduced metallized pellets contain carbon and can be pre-adjusted for slag, so they can be used as a single charge to enter the electric furnace, and the uniformity and stability of the raw materials are increased, which can prevent the fluctuation of raw materials and the difficulty of continuous production caused by excessive raw materials entering the furnace. In the present invention, the (crushed) reduced metallized pellets are added to the electric furnace, and the melting temperature is controlled to be 1600~1650℃, preferably 1610~1630℃, and the melting time is 5~6h, preferably 5.5~5.8h, to obtain molten slag iron.

[0041] According to the test, the recovery rate of vanadium in the molten iron obtained by the smelting method of the present invention can reach more than 85%, which is about 3% higher than the commonly used hydrogen-based vertical furnace-electric furnace smelting process in the prior art. In addition, the high carbon content in the molten iron makes the molten iron easier to transport and increases the transportation distance of the high-temperature molten iron.

[0042] It can be seen that the above-mentioned smelting method provided by the present invention is not only low-cost and simple in steps, but also has a technical effect that is better than the hydrogen-based vertical furnace-electric furnace smelting process in the prior art, and has good innovation and promotion prospects.

[0043] Based on this, the present invention also provides an application of the above-mentioned smelting method in the comprehensive recovery of iron, vanadium and titanium resources technology in the non-blast furnace ironmaking process of vanadium-titanium magnetite concentrate.

[0044] In order to further illustrate the present invention, the following examples are used to explain the present invention in detail. The vanadium-titanium magnetite concentrate used in the following examples of the present invention is provided by Panzhihua Iron and Steel.

[0045] The coal powder involved in the following Examples 1 to 3 is: Example 1 - main coking coal, 1 / 3 coking coal and fat coal in a mass ratio of 5:3:2; Example 2 - main coking coal, 1 / 3 coking coal and fat coal in a mass ratio of 4.5:3:2.5; Example 3 - main coking coal, 1 / 3 coking coal and fat coal in a mass ratio of 4.5:3.5:2.

[0046] Among them, the G value of main coking coal is 80, and the Y value of the gelatinous layer thickness is 17 mm; the G value of 1 / 3 coking coal is 72, and the Y value of the gelatinous layer thickness is 15 mm; the G value of fat coal is 83, and the Y value of the gelatinous layer thickness is 27 mm.

[0047] Example 1

[0048] S1: Mix the dried vanadium-titanium magnetite concentrate, coal powder and solvent (quicklime) in a mass ratio of 1:0.35:0.027;

[0049] S2: The mixed materials are loaded into the coke oven at a temperature of 1000°C and a reaction time of 10 h. After the reaction is completed, the reacted materials are cooled to below 300°C using an inert gas and then crushed to a particle size of 25-50 mm.

[0050] S3: Add the crushed material obtained in step S2 into an electric furnace, control the melting temperature to 1600° C., and the melting time to 5.5 h to obtain molten slag iron.

[0051] Example 2

[0052] Compared with Example 1, the only difference is that the vanadium-titanium magnetite concentrate, coal powder and solvent (quicklime) are evenly mixed in a mass ratio of 1:0.35:0.037, and the other parameters and steps are consistent with Example 1.

[0053] Example 3

[0054] Compared with Example 1, the only difference is that the vanadium-titanium magnetite concentrate, coal powder and solvent (quicklime) are evenly mixed in a mass ratio of 1:0.35:0.047, and the other parameters and steps are consistent with Example 1.

[0055] Comparative Example 1

[0056] 100 kg of metallized pellets with a metallization rate of 85% reduced under hydrogen-based vertical furnace conditions were added with 23 kg of diced coke (the ratio of TFe in the pellets to carbon in the diced coke was about 3.3:1, which is basically the same as the iron-carbon ratio of the material in the embodiment) and 6.3 kg of limestone and put into an electric furnace for reduction to obtain molten slag iron.

[0057] The compositions of the molten iron obtained in Examples 1 to 3 and Comparative Example 1 are shown in Table 1 below:

[0058] Table 1

[0059]

[0060] The composition of the molten slag iron obtained in Examples 1 to 3 and Comparative Example 1 is shown in Table 2 below:

[0061] Table 2

[0062]

[0063] It can be seen from Tables 1 and 2 above that the carbon content of molten iron obtained by the method of the present invention is higher than that of the hydrogen-based vertical furnace-electric furnace smelting process, the vanadium element yield is increased by about 3%, and the slag composition is not much different.

[0064] In summary, the main advantages of the present invention are:

[0065] (1) Carbon-based reduction: the reducing agent is cheap and easy to obtain;

[0066] (2) Coal powder is directly used for reduction in the coke oven. During the reduction process, coke is generated by coal coking and iron ore powder is agglomerated at the same time, which saves the oxidation roasting process of the pellets, saves the energy consumption of oxidation roasting, and reduces the problem of increased reducing agent required for reduction caused by oxidation and reduction of the pellets;

[0067] (3) During the reduction in the coke oven, the solvent and excess coal powder are added to complete the slag adjustment and carbon mixing process in the electric furnace in advance, so that the electric furnace can complete the smelting and smelting with a single charge, and the uniformity and stability of the raw materials are increased, which greatly reduces the difficulty of continuous production in the electric furnace.

[0068] (4) The iron and iron oxides are in good contact with the carbonaceous reducing agent, and the kinetic conditions during the melting process are good, which increases the temperature and temperature uniformity of the molten iron in the electric furnace, thereby increasing the carbon content of the molten iron, making the molten iron easier to transport and increasing the transportation distance of the high-temperature molten iron.

[0069] Therefore, the present invention has good innovation and promotion prospects.

[0070] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A smelting method of vanadium-titanium magnetite, characterized in that: The following steps are involved: After the mixture of vanadium-titanium magnetite, coal powder and solvent is subjected to reduction reaction in a coke oven, the obtained material is subjected to melting treatment in an electric furnace to obtain molten slag iron; The coal powder includes main coking coal, 1 / 3 coking coal and fat coal.

2. The smelting method according to claim 1, characterized in that: The mass ratio of the main coking coal, 1 / 3 coking coal and fat coal is (4.5~5):(3~3.5):(2~2.5).

3. The smelting method according to claim 1 or 2, characterized in that: The coking coal has a bonding index G value of >75 and a gelatin layer thickness Y value of >16 mm; The 1 / 3 coking coal has a bonding index G value greater than 65 and a gelatin layer thickness Y value less than or equal to 25 mm; The fat coal has a bonding index G value greater than 85, and a gelatinous layer thickness Y value greater than or equal to 25 mm.

4. The smelting method according to any one of claims 1 to 3, characterized in that: The solvent is selected from quicklime and / or activated ash.

5. The smelting method according to any one of claims 1 to 4, characterized in that: The mass ratio of the vanadium-titanium magnetite, coal powder and solvent is 1:(0.35-0.40):(0.027-0.047).

6. The smelting method according to any one of claims 1 to 5, characterized in that: The reduction reaction temperature is 1000-1100° C. and the time is 8-10 h.

7. The smelting method according to any one of claims 1 to 6, characterized in that: In the material obtained after the reduction reaction, the TFe content is 41-45%, the FeO content is 5.3-8.5%, the MFe content is 35-41%, and the C content is 10-13%.

8. The smelting method according to any one of claims 1 to 7, characterized in that: After the reduction reaction is completed, a post-treatment step is also included; The post-processing step is: cooling the material obtained after the reduction reaction to below 300° C. under an inert atmosphere, and crushing it; The crushing process is performed to a particle size of 25 to 50 mm.

9. The smelting method according to any one of claims 1 to 8, characterized in that: The temperature of the melting treatment is 1600-1650° C. and the time is 5-6 h.

10. Application of the smelting method according to any one of claims 1 to 9 in the technology of comprehensive recovery of iron, vanadium and titanium resources from vanadium-titanium magnetite concentrate in non-blast furnace ironmaking process.

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