A method for producing a desulfurizer from carbide slag

Abstract

The application discloses a method for producing a desulfurizer from carbide slag. The method comprises the following steps: screening the carbide slag to obtain particles with a particle size of less than or equal to 1 mm; mixing and grinding the screened particles with sucrose and ethanol to a particle size of 400-600 meshes; and mixing and pressing the ground particles, iron powder and activated corncob to form a shape, and calcining to obtain a carbide slag desulfurizer. The carbide slag is ground by sucrose and ethanol, and then carbonized by being pressed into a shape together with iron powder and activated corncob, so that the obtained desulfurizer has a good desulfurization effect and can be recycled. The preparation method is simple and low in cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of desulfurization, in particular to a method for producing desulfurizer from calcium carbide slag. BACKGROUND

[0002] Calcium carbide is used in the production of polyvinyl chloride by the chemical reaction method of calcium carbide (calcium carbide CaC2), which generates acetylene (C2H2) when it comes into contact with water, and then acetylene and hydrogen chloride (HCl) are combined to produce vinyl chloride monomer (CH2=CHCl), and then the vinyl chloride is polymerized to produce polyvinyl chloride - [CH-CHCI]n. Calcium carbide slag is a byproduct of the hydrolysis reaction in the production of polyvinyl chloride (PVC) by the calcium carbide method, and its main component is calcium hydroxide. As a large industrial solid waste, the previous treatment method is to cooperate with the cement plant to produce cement clinker using calcium carbide slag, but with the overcapacity of the cement industry, the cement plant cannot produce at full capacity, resulting in the inability to handle calcium carbide slag, and the large amount of calcium carbide slag stored has an adverse impact on the environment.

[0003] The non-ferrous metal smelting industry is a pillar industry in China, and the characteristics of the smelting flue gas discharged are mainly: high temperature (>1000℃), even after waste heat recovery by a waste heat boiler, the temperature is still 350-450℃; high SO2 content; high dust content. Limestone / gypsum method is the most commonly used flue gas desulfurization method, and the calcium-based content (calcium hydroxide) in calcium carbide slag is as high as 80-85%, which can replace calcium carbonate as a desulfurizer for the desulfurization system of the steel industry, but the composition of the solid particles in calcium carbide slag is very complex, in addition to calcium hydroxide and calcium oxide, it also contains carbon residue, silicon iron and other types of solid particle impurities, and solid particles greater than 0.04mm will cause wear and blockage of the pipeline and desulfurizer circulation system of the desulfurization system. Because the molar volume of the sulfide product CaSO4 (46 cm3 / mol) is greater than that of CaCO3 (36.9 cm3 / mol) and CaO (16.9 cm3 / mol), the sulfide product CaSO4 will block the micropores on the surface of the decomposition product CaO, hindering the further reaction of SO2 and unreacted CaO, resulting in a sulfation degree of calcium of only 25-45%. In order to meet the SO2 emission requirements, enterprises have to increase the calcium-sulfur ratio to compensate for the low utilization rate of calcium-based desulfurizer, which not only wastes desulfurizer but also increases operating costs. Patent No. 201610313802.7 discloses active calcium oxide, desulfurizer, calcium carbide raw material and a preparation method thereof using calcium carbide slag as raw material; patent No. 201110164225.7 discloses a method for producing desulfurizer from calcium carbide slag. The above preparation methods are very complex, resulting in high desulfurization cost. Therefore, a simple method is needed to produce desulfurizer with high desulfurization efficiency from calcium carbide slag. SUMMARY

[0004] In view of the prior art, the present application aims to provide a method for producing desulfurizer from carbide slag. The method comprises the following steps: grinding the carbide slag with sucrose and ethanol, and then compressing and molding the mixture with iron powder and activated corncob to obtain the desulfurizer, which has good desulfurization effect and can be used for a long time, and the preparation method is simple and low in cost.

[0005] To achieve the above object, the present application adopts the following technical solutions:

[0006] In the first aspect of the present application, a method for producing desulfurizer from carbide slag is provided, which comprises the following steps:

[0007] (1) sieving the carbide slag to obtain particles with a particle size of less than or equal to 1 mm;

[0008] (2) mixing and grinding the sieved particles with sucrose and ethanol to a particle size of 400-600 mesh;

[0009] (3) mixing and compressing the ground particles, iron powder and activated corncob to form a shape, and calcining to obtain the carbide slag desulfurizer.

[0010] Preferably, in step (2), the ratio of the added amounts of the sieved particles, sucrose and ethanol is 100g:(5-15)g:(30-50)mL.

[0011] The ethanol is anhydrous ethanol.

[0012] Preferably, in step (3), the activated corncob is prepared by the following method:

[0013] The corncob is ground to 400-600 mesh, heated after adding alkali solution to obtain the activated corncob.

[0014] Preferably, the concentration of the alkali solution is 0.01-0.1 moL / L.

[0015] Preferably, the solid-liquid ratio of the corncob to the alkali solution is 1:(5-15).

[0016] Preferably, the heating temperature is 40-60℃, and the heating time is 10-30 min.

[0017] Preferably, in step (3), the mass ratio of the ground particles, iron powder and activated corncob is 100:(5-15):(50-100).

[0018] Preferably, in step (3), the calcination temperature is 150-250℃, the calcination pressure is 2-10 MPa, and the calcination time is 1-3 h.

[0019] In the second aspect of the present application, the carbide slag desulfurizer prepared by the above method is provided.

[0020] The third aspect of the present application provides application of the stone slag desulfurizer in steel metallurgy desulfurization.

[0021] The beneficial effects of the present application are:

[0022] (1) The present application replaces calcium oxide with carbide slag, and grinds the carbide slag with sucrose and ethanol. The sucrose and ethanol can also play a combustion-supporting effect in the subsequent carbonization, making it easier for the corncob to be carbonized.

[0023] (2) The present application found through research that after the carbide slag powder, iron powder and corncob are pressed and carbonized, the iron powder is oxidized, the corncob is made into biochar, the carbon in the carbide slag powder is further carbonized, and the silicon-iron compounds are oxidized. The obtained mixture can significantly improve the desulfurization effect. The efficiency of the desulfurizer converted into calcium sulfate is greatly improved, and it can be recycled for more than 10 times.

[0024] (3) The preparation method of the present application is simple, and the desulfurization cost is low. The present application not only effectively utilizes the carbide slag, but also reduces the desulfurization cost of the steel metallurgy industry. DETAILED DESCRIPTION

[0025] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs.

[0026] As introduced in the background section, because the molar volume of the sulfidation product CaSO4(46 cm3 / mol) is larger than that of CaCO3(36.9 cm3 / mol) and CaO(16.9 cm3 / mol), the micropores on the surface of the decomposition product CaO are blocked by the sulfidation product CaSO4, hindering the further reaction of SO2 with unreacted CaO, resulting in a degree of calcium sulfation of only 25-45%. In order to meet the SO2 emission requirements, enterprises have to increase the calcium-sulfur ratio to compensate for the low utilization rate of calcium-based desulfurizer, which not only wastes desulfurizer but also increases the operating cost.

[0027] Based on this, the purpose of the present application is to provide a method for producing a desulfurizer from carbide slag. The present application replaces calcium oxide with carbide slag, and through research, it is found that grinding the carbide slag with sucrose and ethanol, and then mixing it with iron powder and corncob for carbonization, the obtained calcium-based desulfurizer has good desulfurization effect without the need to increase the calcium-sulfur ratio. The present inventors found that after the corncob is activated by alkali solution and heated, the activated carbon micropores are uniformly distributed during the subsequent carbonization, and the carbide slag and iron oxide can better combine with the activated carbon, and the three work together to further improve the desulfurization efficiency.

[0028] In order for those skilled in the art to more clearly understand the technical solutions of the present application, the technical solutions of the present application will be described in detail below in conjunction with specific embodiments.

[0029] The test materials used in the embodiments of the present application are all conventional test materials in the art and can be purchased through commercial channels.

[0030] Embodiment 1

[0031] (1) The carbide slag is sieved to obtain particles with a particle size of ≤1 mm.

[0032] (2) 100 g of the sieved particles, 10 g of sucrose and 40 mL of anhydrous ethanol are added to a grinder, mixed and ground for 6 h to a particle size of 400-600 mesh.

[0033] (3) 100 g of corncob is crushed to 400-600 mesh, and 1 L of a sodium hydroxide solution with a concentration of 0.05 moL / L is added to a beaker. Heating to 50°C activates the corncob for 20 min to obtain activated corncob.

[0034] 100 g of the ground particles of step (2), 10 g of iron powder (400-600 mesh) and 75 g of activated corncob are mixed uniformly and placed in a granulator to press into 0.4-2 mm particles. The particles are placed in an autoclave, carbonized at 200°C (heating rate 5°C / min) and a pressure of 6 MPa for 2 h to obtain a carbide slag desulfurizer.

[0035] Embodiment 2

[0036] (1) The carbide slag is sieved to obtain particles with a particle size of ≤1 mm.

[0037] (2) 100 g of the sieved particles, 5 g of sucrose and 50 mL of anhydrous ethanol are added to a grinder, mixed and ground for 9 h to a particle size of 400-600 mesh.

[0038] (3) 100 g of corncob is crushed to 400-600 mesh, and 500 mL of a sodium hydroxide solution with a concentration of 0.1 moL / L is added. Heating to 60°C activates the corncob for 10 min to obtain activated corncob.

[0039] 100 g of the ground particles, 15 g of iron powder (400-600 mesh) and 50 g of activated corncob are mixed uniformly and placed in a granulator to press into 0.4-2 mm particles. Then, the particles are added to an autoclave, carbonized at 250°C (heating rate 5°C / min) and a pressure of 2 MPa for 3 h to obtain a carbide slag desulfurizer.

[0040] Embodiment 3

[0041] (1) The carbide slag is sieved to obtain particles with a particle size of ≤1 mm.

[0042] (2) 100 g of the sieved particles were mixed with 15 g of sucrose and 30 mL of anhydrous ethanol in a grinder and ground for 5 h to a particle size of 400-600 mesh.

[0043] (3) 100 g of the corn cob was ground to 400-600 mesh and 1.5 L of a 0.01 mol / L sodium hydroxide solution was added. The mixture was stirred in a beaker and then heated to 40°C for 30 min to obtain activated corn cob.

[0044] 100 g of the ground particles, 5 g of iron powder (400-600 mesh) and 100 g of the activated corn cob were mixed uniformly and pressed into particles of 0.4-2 mm in a granulator. The particles were then placed in an autoclave and carbonized at 150°C and a pressure of 10 MPa for 1 h to obtain the carbide slag desulfurizer.

[0045] Comparative Example 1

[0046] (1) The carbide slag was sieved to obtain particles having a particle size of ≤1 mm and ground to a particle size of 400-600 mesh.

[0047] (2) 100 g of the corn cob was placed in an autoclave and carbonized at 200°C (at a heating rate of 5°C / min) and a pressure of 6 MPa for 2 h. The carbonized corn cob was mixed with the carbide slag obtained in step (1) to obtain the carbide slag desulfurizer.

[0048] Comparative Example 2

[0049] (1) The carbide slag was sieved to obtain particles having a particle size of ≤1 mm and ground to a particle size of 400-600 mesh.

[0050] (2) 100 g of the corn cob was placed in an autoclave and carbonized at 200°C (at a heating rate of 5°C / min) and a pressure of 6 MPa for 2 h. The carbonized corn cob was mixed with the carbide slag obtained in step (1) to obtain the carbide slag desulfurizer.

[0051] Comparative Example 3

[0052] (1) The carbide slag was sieved to obtain particles having a particle size of ≤1 mm.

[0053] (2) 100 g of the sieved particles were mixed with 10 g of sucrose and 40 mL of anhydrous ethanol in a grinder and ground for 6 h to a particle size of 400-600 mesh. The particles were placed in an autoclave and carbonized at 200°C (at a heating rate of 5°C / min) and a pressure of 6 MPa for 2 h to obtain the carbide slag desulfurizer.

[0054] Comparative Example 4

[0055] (1) The carbide slag was sieved to obtain particles having a particle size of ≤1 mm. The particles were ground for 6 h to a particle size of 400-600 mesh.

[0056] (2) 100 g of corn cob was crushed to 400-600 mesh, 100 g of the granules after grinding in step (1), 10 g of iron powder (400-600 mesh) and 75 g of corn cob were mixed uniformly in a granulator, pressed into granules of 0.4-2 mm, and placed in an autoclave, carbonized at 200°C (the temperature rising rate was 5°C / min) and 6 MPa for 2 h to obtain a carbide slag desulfurizer.

[0057] Comparative Example 5

[0058] (1) The carbide slag was sieved to obtain granules with a particle size of ≤1 mm.

[0059] (2) 100 g of the sieved granules, 10 g of sucrose and 40 mL of anhydrous ethanol were added to a grinder and mixed and ground for 6 h to a particle size of 400-600 mesh.

[0060] (3) 100 g of corn cob was crushed to 400-600 mesh, 100 g of the granules after grinding in step (2), 10 g of iron powder (400-600 mesh) and 75 g of corn cob were mixed uniformly in a granulator, pressed into granules of 0.4-2 mm, and placed in an autoclave, carbonized at 200°C (the temperature rising rate was 5°C / min) and 6 MPa for 2 h to obtain a carbide slag desulfurizer.

[0061] Comparative Example 6

[0062] (1) The carbide slag was sieved to obtain granules with a particle size of ≤1 mm.

[0063] (2) 100 g of the sieved granules, 10 g of sucrose and 40 mL of anhydrous ethanol were added to a grinder and mixed and ground for 6 h to a particle size of 400-600 mesh.

[0064] (3) 100 g of the granules after grinding in step (2), 10 g of iron powder (400-600 mesh) were mixed uniformly in a granulator, pressed into granules of 0.4-2 mm, and placed in an autoclave, carbonized at 200°C (the temperature rising rate was 5°C / min) and 6 MPa for 2 h to obtain a carbide slag desulfurizer.

[0065] Test Example

[0066] The desulfurizers prepared in Examples 1-3 and Comparative Examples 1-6 were placed in a tubular furnace at 1100°C, and simulated steel smelting blast furnace gas was introduced, the sulfur in the blast furnace gas being mainly sulfur dioxide (62.22%), carbonyl sulfur (10.63%) and hydrogen sulfide (8.70%), with N2 as the balance gas, and after 8 min of reaction, the efficiency of conversion of the desulfurizer into calcium sulfate and the number of cycles were counted (the cycle was ended when the efficiency of conversion of the desulfurizer into calcium sulfate was ≤10%).

[0067] Table 1

[0068]

[0069]

[0070] As can be seen from Table 1, the desulfurizer prepared by using Examples 1-3 is used for desulfurization treatment, and the efficiency of conversion of calcium-based desulfurizer into calcium sulfate is extremely high, and can be used for multiple cycles. It is shown that the desulfurization effect of the calcium carbide slag desulfurizer prepared by the present application is remarkable.

[0071] The preferred embodiments of the present application have been described above with the aid of drawings and are not intended to limit the present application. The present application can be variously changed and modified by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of the present application.

Claims

1. A method for producing desulfurizing agent from carbide slag, characterized in that, Includes the following steps: (1) The carbide slag is sieved to obtain particles with a particle size ≤1mm; (2) Mix the screened particles with sucrose and ethanol and grind them to a particle size of 400-600 mesh; (3) The ground particles, iron powder and activated corn cobs are mixed and pressed into shape, and carbonized to obtain carbide slag desulfurizer; the activated corn cobs are prepared by the following method: the corn cobs are crushed to 400~600 mesh, alkali solution is added and heated to obtain activated corn cobs.

2. The method according to claim 1, characterized in that, In step (2), the ratio of the amount of the screened particles to the amount of sucrose and ethanol added is 100g: (5~15)g: (30~50)mL.

3. The method according to claim 1, characterized in that, In step (3), the concentration of the alkaline solution is 0.01~0.1 mol / L.

4. The method according to claim 1, characterized in that, In step (3), the ratio of corn cob to alkali solution is 1:(5~15).

5. The method according to claim 1, characterized in that, In step (3), the heating temperature is 40~60℃ and the heating time is 10~30min.

6. The method according to claim 1, characterized in that, In step (3), the mass ratio of the ground particles, iron powder and activated corn cob is 100:(5~15):(50~100).

7. The method according to claim 1, characterized in that, In step (3), the carbonization temperature is 150~250℃, the carbonization pressure is 2~10MPa, and the carbonization time is 1~3h.

8. The desulfurizing agent for carbide slag prepared by the method of claim 1.

9. The application of the carbide slag desulfurizer according to claim 8 in desulfurization in iron and steel metallurgy.

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