Process for producing reduced titanium and activated carbon from ilmenite and applications thereof

Abstract

The application provides a process method and application of ilmenite for preparing reduced titanium and activated carbon, and relates to the field of chemical solid waste treatment technology. Specifically, the method comprises the following steps: 1. ilmenite and a reducing agent are subjected to high-temperature smelting, and then rapidly water-cooled to obtain a cooled reduction product; 2. the reduction product is subjected to screening treatment to obtain returned coal and undersize components; the undersize components are subjected to magnetic separation treatment to obtain reduced titanium and magnetic separation ash; 3. the returned coal and the magnetic separation ash are subjected to high-temperature activation to obtain activated carbon. The application couples the reduction of ilmenite with the production of activated carbon. The reduction reaction in the reduction process is both the reduction process of ilmenite and the carbonization and preliminary activation process in the activated carbon preparation process. The magnetic separation and screening steps remove various impurities in the reduced titanium and the activated carbon, and at the same time, the quality of the reduced titanium and the activated carbon is ensured. The application has high economic value and application prospect.

Description

Technical Field

[0001] This invention relates to the field of chemical solid waste treatment technology, and more specifically, to a process and application for preparing reduced titanium and activated carbon from ilmenite. Background Technology

[0002] Reduction of ilmenite is a common method for the comprehensive utilization and enrichment of titanium and iron resources. The main method involves reacting a reducing agent (such as carbon monoxide gas or coal) with ilmenite at high temperatures (800℃~1200℃), reducing the iron oxides in the ilmenite to elemental iron. The reduction product mainly consists of reduced titanium and unreacted reducing agent, which are separated by magnetic separation and sieving. This unreacted reducing agent is usually returned to the production stage for reuse. However, the reduction temperature of ilmenite is high, and since the reducing atmosphere mainly consists of carbon monoxide and carbon dioxide, when coal is used as a reducing agent, it is already carbonized during the process. Furthermore, the volatile matter in the coal decomposes at high temperatures, and the resulting recycled coal, after sieving, is used as a reducing agent. The extremely low volatile matter content cannot provide a high reduction temperature, reducing the reduction efficiency of ilmenite and failing to fully realize the economic value of the recycled coal.

[0003] In view of this, the present invention is hereby proposed. Summary of the Invention

[0004] The primary objective of this invention is to provide a process for preparing reduced titanium and activated carbon from ilmenite. To achieve the above objective, the following technical solution is adopted, comprising the following steps:

[0005] S1. Ilmenite and reducing agent are smelted at high temperature and then rapidly cooled with water to obtain the cooled reduction product.

[0006] S2. The reduction product is sieved to obtain return coal and undersize components; the undersize components are magnetically separated to obtain reduced titanium and magnetically separated ash.

[0007] S3. The returned coal and the magnetic separation ash are activated at high temperature to obtain activated carbon.

[0008] Preferably, in step S1, the reducing agent is a coal-based reducing agent, which includes at least one of bituminous coal, anthracite, coking coal, lignite, semi-coke, or peat.

[0009] Preferably, in step S1, the mass ratio of the ilmenite to the reducing agent is 0.20 to 0.40:1;

[0010] Preferably, in step S1, the particle size of the reducing agent is 5 mm to 25 mm.

[0011] Preferably, in step S1, the temperature of the high-temperature smelting is 1050℃~1200℃, and the time of the high-temperature smelting is 12h~24h.

[0012] Preferably, the water vapor generated by water cooling is collected in step S1 and used for high-temperature activation in step S3, that is, water vapor is used as an activator in step S3.

[0013] Preferably, in step S2, the aperture of the sieve used for sieving is 15 mesh to 30 mesh.

[0014] Preferably, in step S2, the magnetic field strength of the magnetic separation process is 1500GS to 3500GS.

[0015] Preferably, step S2 further includes: performing a second sieving process on the magnetic ash to obtain the oversize component, which is used as the raw material for magnetic ash in step S3; that is, in this sieving process, a coarser magnetic ash is obtained, while the finer magnetic ash with a higher impurity content is discarded.

[0016] More preferably, the mesh size of the sieve used in the second screening process is 40 to 80 mesh; even more preferably, the mesh size of the sieve used in the second screening process is 60 mesh.

[0017] Preferably, in step S3, the high-temperature activation temperature is 750℃~850℃, and the high-temperature activation time is 2h~4h.

[0018] Preferably, in step S3, the mass ratio of the returned coal to the magnetically separated ash is (10-20):1.

[0019] The second objective of this invention is to provide a method for applying ilmenite, including the process method for preparing reduced titanium and activated carbon from ilmenite.

[0020] This invention utilizes coal-based reduction of ilmenite, combining the recycled coal and high-temperature steam generated during reduction cooling for the preparation of activated carbon. After separating the reduced titanium from the recycled coal and magnetic ash separately, activated carbon is obtained by mixing the recycled coal and magnetic ash and then activating them at high temperature. This invention features a simple process, low cost, and ease of industrial production. Compared with existing technologies, this invention mainly offers the following advantages:

[0021] (1) This invention couples the reduction of ilmenite with the production of activated carbon. The reduction reaction in the reduction process is both the reduction process of ilmenite and the carbonization and preliminary activation process in the preparation of activated carbon. Then, through magnetic separation and sieving steps, various impurities in the reduced titanium and activated carbon are removed, while ensuring the quality of the reduced titanium and activated carbon.

[0022] (2) The combined preparation of reduced titanium and activated carbon in this invention maximizes the use of raw materials and energy in the entire high-temperature reduction process, thereby enhancing the overall economic value; by making reasonable use of the by-product water-cooled steam and the coal-based reducing agent that has not been fully reacted in the reduction process, the reduction by-product resources and heat resources are fully utilized; the combined production of reduction equipment and activation equipment also shortens the industrial process and reduces the difficulty of large-scale production. Attached Figure Description

[0023] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 This is a process flow diagram of Embodiment 1 of the present invention. Detailed Implementation

[0025] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0026] This invention is carried out through the following specific embodiments: a process for preparing reduced titanium and activated carbon from ilmenite, comprising the following steps: S1, smelting ilmenite and a reducing agent at high temperature, followed by rapid water cooling to obtain a cooled reduction product; S2, sieving the reduction product to obtain recycled coal and undersize components; subjecting the undersize components to magnetic separation to obtain reduced titanium and magnetically separated ash; S3, activating the recycled coal and the magnetically separated ash at high temperature to obtain activated carbon.

[0027] Ilmenite has a high reduction temperature and, under a reducing gas atmosphere, the recycled coal is usually carbonized during this process. Simultaneously, the volatile matter in the coal decomposes at high temperature, reducing the impurity content in the recycled coal, making it a potentially high-quality activated carbon raw material. This invention creatively produces high-quality activated carbon by simply adjusting the raw materials and various parameters of the high-temperature activation process, ensuring the pore size, decolorizing power, and other indicators of the recycled coal.

[0028] In the high-temperature activation in step S3 of this invention, the recycled coal, magnetic ash, and steam are mixed and reacted. The reaction principle is as follows:

[0029] C+H2O→H2+CO△H=123.l kJ / mol

[0030] C+2H2O→2H2+CO2△H=79.5kJ / mol

[0031] The main principle is that hot water vapor diffuses into the material and reacts with carbon atoms to generate hydrogen and carbon monoxide or carbon dioxide, while simultaneously creating micropores. As a preferred embodiment, the water vapor generated during water cooling in step S1 is collected and used for high-temperature activation in step S3. This is because ilmenite needs to be cooled before separation after reduction, and water is commonly used as the cooling medium. This stage generates a large amount of water vapor, which can be used for the chemical reactions in the activation process, eliminating the need for an additional steam boiler and achieving resource recycling.

[0032] In a preferred embodiment, in step S1, the mass ratio of the ilmenite to the reducing agent includes, but is not limited to, 0.20:1, 0.25:1, 0.3:1, 0.35:1, and 0.4:1.

[0033] In a preferred embodiment, in step S1, the particle size of the reducing agent is ≤80 mesh, and in some preferred cases, the particle size of the reducing agent is 5 mm to 25 mm; in a more preferred embodiment, for the particle size of the reducing agent, the mass ratio of the component on a 60-mesh sieve should be ≥95%.

[0034] In a preferred embodiment, in step S1, the temperature of the high-temperature smelting includes, but is not limited to, 1050, 1060, 1070, 1080, 1090, 1100, 1110, 1120, 1130, 1140, 1150, 1160, 1170, 1180, 1190, and 1200 (unit: °C), and the time of the high-temperature smelting includes, but is not limited to, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, and 24 (unit: h).

[0035] In a preferred embodiment, in step S2, the aperture of the sieve used for the sieving process includes, but is not limited to, 15, 18, 20, 22, 24, 26, 28, and 30 (unit: mesh).

[0036] In a preferred embodiment, in step S2, the magnetic field strength of the magnetic separation process includes, but is not limited to, 1500, 1800, 2000, 2200, 2400, 2500, 2600, 2800, 3000, 3200, and 3500 (unit: GS).

[0037] In a preferred embodiment, in step S3, the high-temperature activation temperature includes, but is not limited to, 750, 760, 770, 780, 790, 800, 810, 820, 830, 840, and 850 degrees Celsius (°C), and the high-temperature activation time includes, but is not limited to, 2, 2.2, 2.5, 3, 3.2, 3.5, 3.8, and 4 hours (h); the high-temperature activation equipment may be a rotary kiln or an activation converter, etc.

[0038] In a preferred embodiment, in step S3, the mass ratio of the returned coal to the magnetically separated ash is, but is not limited to, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, or 20:1.

[0039] Example 1

[0040] (1) Add ilmenite and coal-based reducing agent to the reduction equipment at a mass ratio of 0.2:1 for reduction. Set the reduction temperature to 1050℃ and the time to 24h.

[0041] (2) The reduction product obtained in step (1) is rapidly cooled by water cooling, and a pipeline is provided to collect the high-temperature water vapor generated during cooling.

[0042] (3) The cooled reduction product is screened through a 20-mesh sieve. The material on the sieve is returned coal, and the material under the sieve is a mixture of reduced titanium and magnetic ash.

[0043] (4) The mixture of reduced titanium and magnetic ash is separated by magnetic separation. The magnetic field strength of the magnetic separator is 1500GS, and the reduced titanium and magnetic ash are obtained independently.

[0044] (5) The magnetic ash is screened through a 60-mesh sieve. The material on the sieve (coarse-grained magnetic ash) is mixed with the returned coal, and the material on the undersize (fine-grained magnetic ash) with a high impurity content is discarded.

[0045] (6) The mixture of coarse magnetic ash and return coal is mixed with the high-temperature steam in step (2) and then introduced into the activation equipment for high-temperature activation. The activation temperature is controlled at 750℃ and the time is 4h.

[0046] (7) The activated carbon powder is cooled to obtain the activated carbon in this embodiment.

[0047] Figure 1 A simplified process flow diagram of this embodiment is provided.

[0048] Example 2

[0049] It is basically the same as Example 1, except that in step (1), the mass ratio of ilmenite to coal-based reducing agent is 0.4:1.

[0050] Example 3

[0051] It is basically the same as Example 1, except that the reduction temperature in step (1) is set to 1200°C and the time is 12h.

[0052] Example 4

[0053] The process is basically the same as in Example 1, except that in step (1), the mass ratio of ilmenite to coal-based reducing agent is 0.3:1, the reduction temperature is set to 1100℃, and the time is 18h.

[0054] Example 5

[0055] It is basically the same as Example 1, except that the magnetic field strength in step (4) is 3500GS.

[0056] Example 6

[0057] It is basically the same as Example 1, except that the magnetic field strength in step (4) is 2500GS.

[0058] Example 7

[0059] It is basically the same as Example 1, except that the activation temperature in step (6) is 850°C and the time is 2h.

[0060] Example 8

[0061] It is basically the same as Example 1, except that the activation temperature in step (6) is 800°C and the time is 3h.

[0062] Test case

[0063] The quality of the reduced titanium and activated carbon obtained in the above embodiments was tested, and the test results are shown in Table 1 below.

[0064] The quality of activated carbon was tested using methylene blue adsorbate, and the specific method is as follows: Prepare a methylene blue solution with a mass concentration of 1.5 g / L. Grind the activated carbon sample until more than 90% can pass through a 0.045 mm test sieve. Mix the sample remaining on the sieve with the methylene blue adsorbate and dry it in a 150℃ electric thermostatic drying oven for 2 hours. Cool it in a desiccator for later use. Weigh 0.1 g ± 0.0004 g of the sample and place it in a 100 mL Erlenmeyer flask. Add 5 mL to 15 mL of methylene blue solution using a dropper, seal the flask tightly, and shake it on a shaker for 30 minutes. Filter the methylene blue solution adsorbed by the sample into a colorimetric tube and mix well. Using a 10 mL cuvette at a wavelength of 665 nm, with water as a reference, measure the absorbance of the filtrate. The absorbance of the filtrate should be within ± 0.020 nm of the absorbance of the copper sulfate standard solution. If it exceeds this range, adjust the amount of methylene blue solution added and repeat the above operation until the requirements are met. The methylene blue adsorption value E is then expressed in mg / g and is calculated as follows: E = cV / m, where c is the concentration of the methylene blue solution in milligrams per milliliter (mg / mL), V is the volume of methylene blue solution consumed by the sample in mL, and m is the mass of the sample in grams (g).

[0065] Table 1

[0066] Example 1 94.28 306.0 Example 2 89.84 324.0 Example 3 93.25 273.0 Example 4 93.73 298.5 Example 5 92.97 307.5 Example 6 94.67 330.0 Example 7 94.09 280.5 Example 8 94.16 286.5

[0067] Although the present invention has been illustrated and described with specific embodiments, it should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, without departing from the spirit and scope of the present invention; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention; therefore, this means that all such substitutions and modifications that fall within the scope of the present invention are included in the appended claims.

Claims

1. A process for preparing reduced titanium and activated carbon from ilmenite, characterized in that, Includes the following steps: S1. Ilmenite and a reducing agent are smelted at high temperature, followed by rapid water cooling to obtain a cooled reduction product. The reducing agent is a coal-based reducing agent, which includes at least one of bituminous coal, anthracite, coking coal, lignite, semi-coke, or peat. The high-temperature smelting temperature is 1050℃~1200℃, and the smelting time is 12h~24h. S2. The reduction product is sieved to obtain recycled coal and undersize components. The undersize components are magnetically separated to obtain reduced titanium and magnetic ash. The magnetic field strength of the magnetic separation is 1800GS~3500GS. S3. The returned coal and the magnetic separation ash are activated at high temperature to obtain activated carbon; The high-temperature activation temperature is 750℃~850℃, and the high-temperature activation time is 2h~4h; In step S1, the water vapor generated by water cooling is collected and used for the high-temperature activation in step S3.

2. The process for preparing reduced titanium and activated carbon from ilmenite according to claim 1, characterized in that, The mass ratio of ilmenite to the reducing agent is 0.20~0.40:

1.

3. The process for preparing reduced titanium and activated carbon from ilmenite according to claim 1, characterized in that, The reducing agent has a particle size of 5mm to 25mm.

4. The process for preparing reduced titanium and activated carbon from ilmenite according to claim 1, characterized in that, In step S2, the mesh size of the sieve used for sieving is 15 mesh to 30 mesh.

5. The process for preparing reduced titanium and activated carbon from ilmenite according to claim 1, characterized in that, Step S2 further includes: performing a second sieving process on the magnetic ash to obtain the oversize component, which is used as the magnetic ash raw material in step S3.

6. The process for preparing reduced titanium and activated carbon from ilmenite according to claim 5, characterized in that, The mesh size of the sieve used in the second screening process is 40 to 80 mesh.

7. The process for preparing reduced titanium and activated carbon from ilmenite according to claim 1, characterized in that, In step S3, the mass ratio of the returned coal to the magnetic ash is (10~20):

1.

8. A method for applying ilmenite, characterized in that, The process for preparing reduced titanium and activated carbon from ilmenite as described in any one of claims 1 to 7.

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