Modification method for obtaining melt separation titanium slag based on hydrogen-based shaft furnace reduction-melt separation process

Abstract

The invention discloses a modification method for obtaining melt separation titanium slag based on a hydrogen-based shaft furnace reduction-melt separation process, and belongs to the technical field of titanium-containing melt separation slag modified.The method specifically comprises the steps that S1, high-titanium vanadium-titanium pellets are prepared; s2, high-titanium type vanadium-titanium metallized pellets are prepared, and reduction is conducted through a hydrogen-based shaft furnace; s3, the high-titanium type vanadium-titanium metallized pellets are subjected to melt separation, and titanium-containing melt separation slag is obtained; s4, the titanium-containing molten slag is subjected to modification treatment of silicon extraction and magnesium reduction, and anosovite phase precipitates are obtained; the method provided by the invention lays a foundation for pure steel production; impurities in the smelting process are few, and products are pure; a hydrogen reduction gas product (water) is easy to separate and treat, so that clean production can be realized; iron is extracted and other valuable components are enriched at the same time; when the vanadium titano-magnetite is subjected to hydrogen reduction, TiO2 cannot be reduced, and separation of iron and titanium components in the subsequent process is facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of titanium-containing molten slag modification, and in particular to a modification method for molten titanium slag obtained by a hydrogen-based vertical furnace reduction-melting process. Background Art

[0002] Titanium resources are mainly found in vanadium-titanium magnetite, ilmenite and rutile ores, and titanium resources in vanadium-titanium magnetite account for 95% of the total reserves. They are mainly distributed in Panzhihua-Xichang, Sichuan, Chengde, Hebei and Chaoyang, Liaoning, with reserves of about 24.876 billion tons, of which TiO2 resources are about 1.511 billion tons.

[0003] Researchers have carried out a lot of work on the recovery of titanium resources in titanium-containing blast furnace slag, such as: (1) Using high-temperature carbonization and low-temperature chlorination to recover TiO2 from blast furnace slag. This method is to directly carbonize the blast furnace slag under high temperature conditions, and then use chlorine gas to chlorinate at low temperature to convert TiO2 into titanium tetrachloride for recovery. Since the TiO2 in the titanium-containing blast furnace slag is only 20% to 25%, and it also contains a large amount of calcium, magnesium, aluminum and silicon, the chlorine consumption is large, the cost is very high, and the chlorinated slag produced will cause great pollution to the environment. Therefore, this method has difficulties in processing blast furnace slag with a quantity of tens of millions of tons, and has not yet been realized on a large scale. (2) Titanium dioxide waste acid is used to leaching TiO2 in titanium-containing blast furnace slag, but due to the low acid concentration, slow leaching speed, low leaching rate, and high waste acid consumption, a huge amount of acid leaching slag is produced, which will cause serious environmental pollution. (3) Ore dressing method to recover TiO2 from titanium-containing blast furnace slag. Since TiO2 in slag exists in various forms, it is extremely difficult to separate the main mineral perovskite from the gangue minerals. The process is very complicated. The secondary tailings brought by ultrafine grinding are extremely difficult to handle, and industrialization is very difficult. In summary, the existing technology is used to treat titanium-containing blast furnace slag, which is complex and costly.

[0004] At present, the resource utilization method of molten titanium slag is generally the extraction of titanium, and the titanium extraction process mainly includes pyrometallurgy and wet leaching. The pyrometallurgy titanium extraction process mainly includes high-temperature carbonization-low-temperature selective chlorination, selective precipitation separation technology, and alloying extraction process. The wet leaching titanium extraction process mainly includes sulfuric acid method and hydrochloric acid method. Although the high-temperature carbonization-low-temperature selective chlorination process makes full use of the physical heat of the slag, the problem of excessive power consumption in the carbonization process is still obvious, the cost is high, and there is also a risk of excessive carbon emissions; the alloying extraction process generally produces silicon-titanium-iron alloys. Due to the very limited domestic titanium-silicon alloy application market, the application prospects of this process are difficult to promote; selective precipitation separation technology can achieve clean and pollution-free enrichment of titanium, but the titanium-rich phase has uneven crystal form and the subsequent treatment of the titanium-containing phase is difficult. It cannot be applied to large-scale industrial production at present; the wet leaching titanium extraction process has problems such as large acid consumption, high production cost, serious secondary pollution, and serious corrosion of the reaction vessel. Therefore, exploring a method that effectively utilizes the sensible heat of molten titanium slag, has low energy consumption and environmental protection to treat blast furnace slag containing titanium is a direction facing the urgent needs of enterprises. The invention proposes a novel method for high-temperature modification of molten titanium slag and directional uniform synchronous precipitation of titanium-containing phases. Summary of the invention

[0005] The present invention is intended to provide a modification method for obtaining smelted titanium slag based on a hydrogen-based vertical furnace reduction-smelting process, so as to solve the problems raised in the above-mentioned background technology.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A modification method for obtaining molten titanium slag based on a hydrogen-based shaft furnace reduction-melting process, the specific steps comprising:

[0008] S1. Preparation of high-titanium vanadium-titanium pellets;

[0009] S2, preparation of high-titanium vanadium-titanium metallized pellets, reduction by hydrogen-based vertical furnace;

[0010] S3, melting of high-titanium vanadium-titanium metallized pellets;

[0011] Preferably, the specific steps of step S1 include:

[0012] S11, using a disc pelletizing machine to pelletize the high titanium slag for 10 minutes;

[0013] S12, preheating and roasting it in a tubular furnace, the preheating temperature is 950° C., the time is 15 minutes; the roasting temperature is 1270° C., and the time is 15 minutes;

[0014] S13, taking out the high-titanium vanadium-titanium pellets for later use.

[0015] Preferably, the specific steps of step S2 include:

[0016] S21, preheating the high-titanium vanadium-titanium pellets to 950° C.;

[0017] S22, put it into a hydrogen-based vertical furnace for reduction, the reducing gas is coke oven gas, and the reduction time is 60 minutes;

[0018] S23, after the reduction of the high-titanium vanadium-titanium pellets is completed, nitrogen is introduced to protect the metallized high-titanium vanadium-titanium pellets until they are cooled to room temperature.

[0019] Preferably, the specific steps of step S3 include:

[0020] S31, placing the metallized high-titanium vanadium-titanium pellets obtained in the above step into a graphite crucible, and adjusting the acidity coefficient of the slag phase of the metallized pellets to 1.0 and the FeO content to less than 3.0% by adding MgO and C, so that the V content of the molten slag is reduced to 0.006%;

[0021] S32, heating the metallized pellets placed in the graphite crucible at a rate of 10°C / min, and keeping the temperature at 1500°C for 60 minutes;

[0022] S33. Cool to room temperature and take out the sample.

[0023] Preferably, the specific steps of step S4 include:

[0024] S41, 100 g of a sample containing titanium molten slag having a MgO / SiO2 ratio of 0.87 is ground and placed in a corundum crucible;

[0025] S42, placing in a high temperature tubular heating furnace for heating and heating to 1400° C. at a heating rate of 10° C. / min;

[0026] S43, heating to 1500°C at a heating rate of 5°C / min and keeping the temperature for 1h;

[0027] S45, cool down to 1165℃ at a cooling rate of 10℃ / min and keep at this temperature for 1h;

[0028] S46. Obtain the black titanite phase precipitate

[0029] Preferably, the composition of the coke oven gas in step S22 is hydrogen: 60%, methane: 20%, carbon monoxide: 10%, and nitrogen: 10%.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. From a thermodynamic point of view, elements other than iron are difficult to be reduced by hydrogen, which lays the foundation for the production of pure steel;

[0032] 2. Hydrogen reduction does not use solid C reducing agent, bringing in less P and S, less impurities in the smelting process, and pure products;

[0033] 3. The gas product (water) of hydrogen reduction is easy to separate and process, which can realize clean production;

[0034] 4. The processing of composite ores has advantages, which can achieve simultaneous iron extraction and enrichment of other valuable components. When reducing vanadium-titanium magnetite, TiO2 will not be reduced, which is conducive to the separation of iron and titanium components in subsequent processes;

[0035] 5. Taking advantage of the hydrogen-based vertical furnace, hydrogen-rich coke oven gas is used as the reducing gas to replace the coke and coal that the long process relies on, thus realizing the transformation of the ironmaking process from "carbon reduction" to "hydrogen reduction". BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The present invention is a schematic flow chart of a modification method for obtaining molten titanium slag based on a hydrogen-based vertical furnace reduction-smelting process. DETAILED DESCRIPTION

[0037] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments:

[0038] The specific implementation process is as follows:

[0039] like Figure 1 As shown, the specific steps of the modification method for obtaining molten titanium slag based on the hydrogen-based vertical furnace reduction-melting process are divided into two parts. The first part is to obtain molten titanium slag using the hydrogen-based vertical furnace reduction-melting process; the second part is a method flow for modifying the titanium slag obtained based on the above method;

[0040] The specific steps of the first part are:

[0041] 1. Preparation of high-titanium vanadium-titanium pellets: The high-titanium slag is pelletized by a disc pelletizer for 10 minutes; then, it is preheated and roasted in a tubular furnace at a preheating temperature and time of 950°C for 15 minutes, and a roasting temperature and time of 1270°C for 15 minutes. When the temperature drops to room temperature, the high-titanium vanadium-titanium pellets are taken out for use.

[0042] 2. Preparation of high-titanium vanadium-titanium metallized pellets: preheat the pellets to 950°C; reduce them in a hydrogen-based vertical furnace, using coke oven gas (hydrogen: 60%, methane: 20%, carbon monoxide: 10%, nitrogen: 10%) as the reducing gas, and the reduction time is 60 minutes, wherein the composition of the reducing gas is: finally, after the reduction is completed, nitrogen is passed through for protection until the pellets cool to room temperature.

[0043] 3. Melting of high-titanium vanadium-titanium metallized pellets: Place the metallized pellets in the above step into a graphite crucible, and then adjust the acidity coefficient and FeO content of the slag phase of the metallized pellets to below 1.0 and 3.0% by adding MgO and C, so that the V content of the molten slag is reduced to 0.006%; then, heat the metallized pellets placed in the graphite crucible at 10°C / min, keep the temperature at 1500°C for 60 minutes, and finally cool to room temperature and take out the sample.

[0044] The specific steps of the second part are:

[0045] The slag is modified by “increasing silicon and reducing magnesium”.

[0046] 1. MgO / SiO2 has a significant effect on the precipitation temperature threshold of olivine and spinel. Adjusting the MgO / SiO2 of slag can inhibit their precipitation and reduce their interference with the precipitation of pyroxene phase.

[0047] 2. Regarding the maximum precipitation of pyrophyllite, it was found that increasing the MgO / SiO2 of the slag system helps to reduce the proportion of the glass phase and increase the precipitation amount of the pyrophyllite phase.

[0048] Titanium-containing smelting slag is a by-product obtained by the hydrogen-based vertical furnace reduction-smelting process of vanadium-titanium magnetite. Its TiO2 content can reach about 40%. The chemical composition is shown in Table 1:

[0049] Table 1. Chemical composition of molten titanium slag / mass fraction%

[0050]

[0051] The grade of titanium is much higher than the titanium-containing slag produced by traditional blast furnace smelting. The main titanium-containing phases of titanium smelting slag are rutile, perovskite, and tarnish. During mineral separation, since rutile is not magnetic and the magnetic susceptibility of perovskite is close to that of gangue, the magnetic separation effect is not ideal. At the same time, perovskite coexists with spinel and diopside, which makes the later separation selectivity of gravity separation poor. In order to achieve the enrichment and extraction of Ti in titanium-containing molten slag, tarnish is used as the target ore to temper the titanium-containing molten slag, and then the tarnish phase is separated by gravity separation.

[0052] The MgO content in the titanium slag system is reduced, so that the first precipitate phase during the cooling process of the slag is the magnesium-containing black titanium phase (MgTi2O5), and the cooling temperature is adjusted to maximize the generation of MgTi2O5. Finally, the modified cooled sample is ground and re-selected to separate the concentrate rich in MgTi2O5.

[0053] Based on the hydrogen-based vertical furnace reduction-melting process, 100 g of the sample with different MgO / SiO2 ratios was ground and placed in a corundum crucible (as shown in Table 2), and then placed in a high-temperature tubular heating furnace for heating at a heating rate of 10°C / min to 1400°C; at a heating rate of 5°C / min to 1500°C, and kept warm for 1 hour.

[0054] The sample with MgO / SiO2 ratio of 1.16 was cooled to 1170℃ at a cooling rate of 10℃ / min and kept at this temperature for 1h;

[0055] The sample with MgO / SiO2 ratio of 0.92 was cooled to 1165℃ at a cooling rate of 10℃ / min and kept at this temperature for 1h;

[0056] The sample with MgO / SiO2 ratio of 0.87 was cooled to 1165℃ at a cooling rate of 10℃ / min and kept at this temperature for 1h;

[0057] The sample with MgO / SiO2 ratio of 0.72 was cooled to 1227℃ at a cooling rate of 10℃ / min and kept at this temperature for 1h;

[0058] The sample with MgO / SiO2 ratio of 0.59 was cooled to 1267℃ at a cooling rate of 10℃ / min and kept at this temperature for 1h.

[0059] Table 2. Experimental proportions of different ω(MgO) / ω(SiO2) slags

[0060]

[0061] From the above results, it can be seen that when the ratio of MgO / SiO2 is 0.87, the precipitation amount of black titanium is the highest.

[0062] The above is only an embodiment of the present invention, and the common knowledge such as the known specific technical solutions and / or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several modifications and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A modification method for obtaining molten titanium slag based on a hydrogen-based shaft furnace reduction-melting process, characterized in that: The specific steps include: S1. Preparation of high-titanium vanadium-titanium pellets; S2, preparation of high-titanium vanadium-titanium metallized pellets, reduction by hydrogen-based vertical furnace; S3, melting high-titanium vanadium-titanium metallized pellets to obtain titanium-containing molten slag; S4. The titanium-containing molten slag is subjected to a modification treatment of "increasing silicon and reducing magnesium" to obtain a black titanium stone phase precipitate.

2. The modification method for obtaining molten titanium slag based on a hydrogen-based vertical furnace reduction-melting process according to claim 1 is characterized in that: The specific steps of step S1 include: S11, using a disc pelletizing machine to pelletize the high titanium slag for 10 minutes; S12, preheating and roasting it in a tubular furnace, the preheating temperature is 950° C., the time is 15 minutes; the roasting temperature is 1270° C., and the time is 15 minutes; S13, taking out the high-titanium vanadium-titanium pellets for later use.

3. The modification method for obtaining molten titanium slag based on a hydrogen-based vertical furnace reduction-melting process according to claim 1, characterized in that: The specific steps of step S2 include: S21, preheating the high-titanium vanadium-titanium pellets to 950° C.; S22, put it into a hydrogen-based vertical furnace for reduction, the reducing gas is coke oven gas, and the reduction time is 60 minutes; S23, after the reduction of the high-titanium vanadium-titanium pellets is completed, nitrogen is introduced to protect the metallized high-titanium vanadium-titanium pellets until they are cooled to room temperature.

4. The modification method for obtaining smelted titanium slag based on a hydrogen-based shaft furnace reduction-smelting process according to claim 1, characterized in that: The specific steps of step S3 include: S31, placing the metallized high-titanium vanadium-titanium pellets obtained in the above step into a graphite crucible, and adjusting the acidity coefficient of the slag phase of the metallized pellets to 1.0 and the FeO content to less than 3.0% by adding MgO and C, so that the V content of the molten slag is reduced to 0.006%; S32, heating the metallized pellets placed in the graphite crucible at a rate of 10°C / min, and keeping the temperature at 1500°C for 60 minutes; S33, cooling to room temperature to obtain titanium-containing molten slag.

5. The modification method for obtaining molten titanium slag based on a hydrogen-based vertical furnace reduction-melting process according to claim 1, characterized in that: The specific steps of step S4 include: S41, grinding 100 g of titanium-containing molten slag with a MgO / SiO2 ratio of 0.87 and placing it into a corundum crucible; S42, placing in a high temperature tubular heating furnace for heating and heating to 1400° C. at a heating rate of 10° C. / min; S43, heating to 1500°C at a heating rate of 5°C / min and keeping the temperature for 1h; S45, cool down to 1165℃ at a cooling rate of 10℃ / min and keep at this temperature for 1h; S46. Obtain the black titanite phase precipitate.

6. The modification method for obtaining molten titanium slag based on a hydrogen-based vertical furnace reduction-melting process according to claim 3, characterized in that: The composition of the coke oven gas in step S22 is hydrogen: 60%, methane: 20%, carbon monoxide: 10%, and nitrogen: 10%.

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