Method for preparing calcium carbide pellet raw material by taking semi-coke powder as raw material

Abstract

The invention discloses a method for preparing a calcium carbide pellet raw material by taking semi-coke powder as a raw material, and relates to the technical field of calcium carbide preparation. The method specifically comprises the following steps: uniformly mixing quick lime, a binder and semi-coke powder, adding a certain amount of water, conveying the mixed material into a high-pressure ball press machine for pelletizing, and drying the prepared pellets to obtain the calcium carbide pellet raw material. The composite binder is low in price, impurities of pellets are not increased, the contact area of carbon and calcium oxide is increased, and the generation rate of calcium carbide is increased. The calcium carbide raw material prepared by the method disclosed by the invention is relatively high in low-temperature compressive strength and high-temperature compressive strength, meets the requirements of low-temperature conveying and high-temperature calcining, ensures that pellets are kept in a block shape in a high-temperature state, and achieves the purpose of recycling wastes of semi-coke powder in production.

Description

Technical Field

[0001] The present invention belongs to the technical field of calcium carbide preparation, and specifically relates to a method for preparing calcium carbide pellet raw materials by using blue carbon powder as raw materials. Background Art

[0002] Calcium carbide is a widely used chemical raw material. The current industrial production method is mainly the arc method, which uses lump coke and lump calcium oxide. It has the disadvantages of "high energy consumption, high temperature, and low production capacity" and consumes a lot of coal, which seriously restricts the development of the calcium carbide industry.

[0003] At present, there are literatures that mention the composite pelletization method, which is to crush the calcium carbide raw materials into powdered raw materials, add a certain binder after mixing, and press them into balls before using them as calcium carbide raw materials. It can improve the utilization rate of raw materials, reduce the cost of calcium carbide raw materials; reduce the power consumption of calcium carbide furnaces; increase the reaction area, increase the reaction speed, and increase the production capacity of calcium carbide furnaces. The utilization value of semi-coke powder as a residual material in calcium carbide production has been ignored. Therefore, how to make full use of a large amount of semi-coke powder and overcome the problem that semi-coke powder cannot be used in calcium carbide furnaces is one of the key issues that need to be solved in this field. Summary of the invention

[0004] In order to solve the above problems existing in the prior art, the purpose of the present invention is to provide a method for preparing calcium carbide pellet raw materials using blue carbon powder as raw material, thereby improving the comprehensive benefits of calcium carbide production and achieving the purpose of efficient utilization of waste.

[0005] The objectives of the present invention are achieved through the following technical solutions.

[0006] A method for preparing calcium carbide pellet raw material using blue carbon powder as raw material comprises the following steps:

[0007] Step (1): mixing quicklime powder and a composite binder in a certain proportion, adding the mixture to a crusher and crushing the mixture to obtain a powdery mixture of quicklime and the composite binder;

[0008] Step (2): adding blue carbon powder to the powdered mixture and stirring evenly in a mixer, then adding water to moisten the mixture and stirring evenly in a mixer;

[0009] Step (3): Seal and store the evenly stirred material for 16-24 hours until the water is completely absorbed by the material;

[0010] Step (4): The sealed and stored material is conveyed to a high-pressure pellet press for pelletizing, and the prepared pellets are conveyed to an oven for drying to obtain calcium carbide pellet raw materials.

[0011] The carbon content of the blue charcoal powder is 75-90wt%. 3. The method for preparing calcium carbide pellet raw material using blue charcoal powder as raw material according to claim 1, characterized in that the mass ratio of the quicklime powder to the blue charcoal powder is (1.5-1.7):1.

[0012] The composite binder is composed of a type A binder and a type B binder, and the amount of the type A binder and the type B binder is 4-6wt% of the sum of the amount of the blue carbon powder and the quicklime powder respectively;

[0013] The type A adhesive is a combination of one or more of sodium bentonite, coal tar, and sodium humate;

[0014] The type B adhesive is one or a combination of polyvinyl alcohol and pregelatinized starch.

[0015] The total amount of water in the blue carbon powder and powder mixture after being moistened with water accounts for 5-10wt% of the total amount.

[0016] The particle sizes of the quicklime powder, blue carbon powder and binder are all less than 0.5 mm.

[0017] In step (2), the material is stirred in the mixer for 15-40 minutes, and the material is stirred after adding water for 15-40 minutes.

[0018] In step (4), when making balls in a high-pressure ball press, the high-pressure sample pressure is 16-25 MPa, and the pressing time is 2-10 min; the drying temperature in the oven is 105-120° C., and the drying time is 5-10 h.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] Since the particle size of the material is small and the composite binder improves the cold strength and hot strength of the pellets, the prepared calcium carbide pellet raw material has high low-temperature compressive strength and high-temperature compressive strength, ensuring that the pellets remain in block shape and do not disperse into powder under high temperature conditions.

[0021] The present invention adds a composite adhesive, in which the A-type adhesive has good thermal stability and adhesiveness at high temperature, thereby improving the thermal strength of the calcium carbide pellets, and the B-type adhesive can form high adhesiveness at low temperature due to the combination with water, thereby improving the cold strength of the calcium carbide pellets. The composite adhesive used in the present invention makes the generated calcium carbide pellet raw material have good compressive resistance, high thermal strength and fast reaction speed. Since the blue carbon powder and calcium oxide have small particle sizes and a large contact area after being combined by the composite adhesive, the reaction speed is accelerated, which can greatly reduce the power consumption of calcium carbide production and improve the comprehensive benefits of calcium carbide production.

[0022] In the present invention, semi-coke powder is used as raw material, and a composite binder is used to keep the semi-coke powder in a block shape at a high temperature, thereby reducing the raw material preparation cost of calcium carbide pellets and achieving the purpose of efficient utilization of waste. DETAILED DESCRIPTION

[0023] The present invention is further described below in the form of specific examples. The examples are only used to explain the present invention and are not used to limit the scope of the present invention. If no specific conditions are specified in the examples, the conventional conditions or the conditions recommended by the manufacturer are followed. If the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially.

[0024] Example 1

[0025] Preparation of composite binder: coal tar, sodium humate and polyvinyl alcohol are weighed in a mass ratio of 1:1:1, crushed and sieved to a particle size of 150 mesh using a crusher, and mixed evenly. Preparation of calcium carbide raw material: composite binder, quicklime powder and blue carbon powder are added in a mass percentage of 10wt%, 50wt% and 30wt% in sequence for mixing, and the mixing time is 30min. Then 10wt% water is added, and the water-wetted materials are mixed for 30min. Among them, the particle size of blue carbon powder is <0.5mm, and the fixed carbon content is 75%. The particle size of quicklime powder is 150 mesh, and the CaO content in quicklime powder is 90%. Finally, the mixed raw materials are added to the mold and conveyed to the high-pressure ball press machine for cold pressing and balling, with a cold pressing pressure of 20MPa and a pressing time of 3min. The pressed green body is demolded. Drying at 120℃ for 6h obtains calcium carbide raw material A1.

[0026] Example 2

[0027] Preparation of composite binder: coal tar, sodium humate and pregelatinized starch are weighed in a mass ratio of 1:1:1, crushed and sieved to a particle size of 150 mesh using a crusher, and mixed evenly. Preparation of calcium carbide raw material: composite binder, quicklime powder and blue carbon powder are added in a mass percentage of 10wt%, 50wt% and 30wt% in sequence for mixing, and each mixing time is 30min. Then 10wt% water is added and the water-wetted materials are mixed for 30min. Among them, the particle size of blue carbon powder is <0.5mm and the fixed carbon content is 75%. The particle size of quicklime powder is 150 mesh, and the CaO content in quicklime powder is 90%. Finally, the mixed raw materials are added to the mold for cold pressing, the cold pressing pressure is 20MPa, and the pressing time is 3min. The pressed body is demolded. Drying at 120℃ for 6h obtains calcium carbide raw material A2.

[0028] Example 3

[0029] Preparation of composite binder: sodium bentonite, sodium humate and polyvinyl alcohol are weighed in a mass ratio of 1:1:1, crushed and sieved to a particle size of 150 mesh using a crusher, and mixed evenly. Preparation of calcium carbide raw material: composite binder, quicklime powder and blue carbon powder are added in a mass percentage of 10wt%, 50wt% and 30wt% in sequence for mixing, and each mixing time is 30min. Then 10wt% water is added, and the water-wetted materials are mixed for 30min. Among them, the particle size of blue carbon powder is <0.5mm, and the fixed carbon content is 75%. The particle size of quicklime powder is 150 mesh, and the CaO content in quicklime powder is 90%. Finally, the mixed raw materials are added to the mold for cold pressing, the cold pressing pressure is 20MPa, and the pressing time is 3min. The pressed body is demolded. Drying at 120℃ for 6h obtains calcium carbide raw material A3.

[0030] Example 4

[0031] Preparation of composite binder: sodium bentonite, sodium humate and pregelatinized starch are weighed in a mass ratio of 1:1:1, crushed and sieved to a particle size of 150 mesh using a crusher, and mixed evenly. Preparation of calcium carbide raw material: composite binder, quicklime powder and blue carbon powder are added in a mass percentage of 10wt%, 50wt% and 30wt% in sequence for mixing, and each mixing time is 30min. Then 10wt% water is added, and the water-wetted materials are mixed for 30min. Among them, the particle size of blue carbon powder is <0.5mm, and the fixed carbon content is 75%. The particle size of quicklime powder is 150 mesh, and the CaO content in quicklime powder is 90%. Finally, the mixed raw materials are added to the mold for cold pressing, the cold pressing pressure is 20MPa, and the pressing time is 3min. The pressed body is demolded. Drying at 120℃ for 6h obtains calcium carbide raw material A4.

[0032] Example 5

[0033] Preparation of composite binder: Weigh coal tar and sodium humate in a mass ratio of 1:1, crush them with a crusher, sieve them to a particle size of 150 mesh, and mix them evenly. Preparation of calcium carbide raw material: Add composite binder, quicklime powder, and blue carbon powder in a mass percentage of 10wt%, 50wt%, and 30wt% in sequence for mixing, and each mixing time is 30min. Add 10wt% water and mix the water-wetted materials for 30min. Among them, the particle size of blue carbon powder is <0.5mm, and the fixed carbon content is 75%. The particle size of calcium oxide is 150 mesh, and the CaO content in quicklime powder is 90%. Finally, add the mixed raw materials into the mold for cold pressing, the cold pressing pressure is 20MPa, and the pressing time is 3min. Demold the pressed body. Dry at 120℃ for 6 hours to obtain calcium carbide raw material A5.

[0034] Example 6

[0035] Preparation of composite binder: Weigh polyvinyl alcohol and sodium humate in a mass ratio of 1:1, crush them with a crusher, sieve them to a particle size of 150 mesh, and mix them evenly. Preparation of calcium carbide raw material: Add composite binder, quicklime powder, and blue carbon powder in a mass percentage of 10wt%, 50wt%, and 30wt% in sequence for mixing, and each mixing time is 30min. Then add 10wt% water and mix the water-wetted materials for 30min. Among them, the particle size of blue carbon powder is <0.5mm, and the fixed carbon content is 75%. The particle size of quicklime powder is 150 mesh, and the CaO content in quicklime powder is 90%. Finally, add the mixed raw materials into the mold for cold pressing, the cold pressing pressure is 20MPa, and the pressing time is 3min. Demold the pressed body. Dry at 120℃ for 6h to obtain calcium carbide raw material A6.

[0036] Example 7

[0037] Preparation of composite binder: coal tar, sodium humate and polyvinyl alcohol are weighed in a mass ratio of 1:1:1, crushed and sieved to a particle size of 150 mesh using a crusher, and mixed evenly. Preparation of calcium carbide raw material: composite binder, quicklime powder and blue carbon powder are added in a mass percentage of 10wt%, 53wt% and 32wt% in sequence for mixing, and each mixing time is 30min. Then 5wt% water is added and the water-wetted materials are mixed for 30min. Among them, the particle size of blue carbon powder is <0.5mm, and the fixed carbon content is 75%. The particle size of quicklime powder is 150 mesh, and the CaO content in quicklime powder is 90%. Finally, the mixed raw materials are added to the mold for cold pressing, the cold pressing pressure is 20MPa, and the pressing time is 3min. The pressed body is demolded. Drying at 120℃ for 6h obtains calcium carbide raw material A7.

[0038] Example 8

[0039] Preparation of composite binder: coal tar, sodium humate and polyvinyl alcohol are weighed in a mass ratio of 1:1:1, crushed and sieved to a particle size of 150 mesh using a crusher, and mixed evenly. Preparation of calcium carbide raw material: composite binder, quicklime powder and blue carbon powder are added in a mass percentage of 10wt%, 50wt% and 30wt% in sequence for mixing, and the mixing time is 30min. Then 10wt% water is added, and the water-wetted materials are mixed for 30min. Among them, the particle size of blue carbon powder is <0.5mm, and the fixed carbon content is 75%. The particle size of quicklime powder is 150 mesh, and the CaO content in quicklime powder is 90%. Finally, the mixed raw materials are added to the mold and conveyed to the high-pressure ball press machine for cold pressing and balling, with a cold pressing pressure of 25MPa and a pressing time of 10min. The pressed green body is demolded. Drying at 105°C for 10h obtains calcium carbide raw material A8.

[0040] Example 9

[0041] Preparation of composite binder: coal tar, sodium humate and polyvinyl alcohol are weighed in a mass ratio of 1:1:1, crushed and sieved to a particle size of 150 mesh using a crusher, and mixed evenly. Preparation of calcium carbide raw material: composite binder, quicklime powder and blue carbon powder are added in a mass percentage of 5wt%, 54wt% and 36wt% in sequence for mixing, and the mixing time is 30min. Then 5wt% water is added, and the water-wetted materials are mixed for 30min. Among them, the particle size of blue carbon powder is <0.5mm, and the fixed carbon content is 80%. The particle size of quicklime powder is 150 mesh, and the CaO content in quicklime powder is 90%. Finally, the mixed raw materials are added to the mold and conveyed to the high-pressure ball press for cold pressing and balling, with a cold pressing pressure of 20MPa and a pressing time of 3min. The pressed green body is demolded. Drying at 110°C for 8h obtains calcium carbide raw material A9.

[0042] Results

[0043] Testing method: The room temperature and high temperature compressive strength of carbide slag pellets are tested in accordance with GB3002-2004 "Test method for high temperature flexural strength of refractory materials". The equipment used is a fully automatic high temperature flexural tester for refractory materials. The number of test samples in each group is 4, and the test temperature is room temperature and a high temperature of 1200°C.

[0044] For the testing steps, please refer to GB3002-2004 "Test method for high temperature flexural strength of refractory materials".

[0045] The test results are shown in Table 1:

[0046]

[0047] According to the compressive strength test results in Table 1, different binders have a greater impact on the strength of the pellets, and the compressive strength of the pellets using the binder ratio of Experimental Example 1 is significantly increased. In Experimental Example 5, due to the absence of Class B binder, the room temperature compressive strength of the pellets is significantly reduced; in Experimental Example 6, there is no coal tar or sodium bentonite, so the high temperature compressive strength is significantly reduced; in Experimental Example 7, due to the reduction in the amount of water added, both the room temperature compressive strength and the high temperature compressive strength are significantly reduced. The composite binder of the invention can be used in the preparation of calcium carbide raw materials with high compressive strength to obtain calcium carbide raw materials with excellent compressive properties: in Experimental Example 8, due to the increase in cold pressing pressure and pressing time, the compressive strength of the pellets is slightly increased; in Experimental Example 9, due to the decrease in the mass ratio of calcium oxide and semi-coke powder, the strength of the pellets is slightly reduced.

Claims

1. A method for preparing calcium carbide pellet raw material using blue carbon powder as raw material, characterized in that: The following steps are involved: Step (1): mixing quicklime powder and a composite binder in a certain proportion, adding the mixture to a crusher and crushing the mixture to obtain a powdery mixture of quicklime and the composite binder; Step (2): adding blue carbon powder to the powdered mixture and stirring evenly in a mixer, then adding water to moisten the mixture and stirring evenly in a mixer; Step (3): Seal and store the evenly stirred material for 16-24 hours until the water is completely absorbed by the material; Step (4): The sealed and stored material is conveyed to a high-pressure pellet press for pelletizing, and the prepared pellets are conveyed to an oven for drying to obtain calcium carbide pellet raw materials.

2. The method for preparing calcium carbide pellet raw material using blue carbon powder as raw material according to claim 1, characterized in that The carbon content in the blue charcoal powder is 75-90wt%.

3. The method for preparing calcium carbide pellet raw material using blue carbon powder as raw material according to claim 1, characterized in that , the mass ratio of quicklime powder to blue carbon powder is (1.5-1.7):

1.

4. The method for preparing calcium carbide pellet raw material using blue carbon powder as raw material according to claim 1, characterized in that The composite binder is composed of a type A binder and a type B binder, and the amount of the type A binder and the type B binder is 4-6wt% of the sum of the amount of the blue carbon powder and the quicklime powder respectively; The type A adhesive is a combination of one or more of sodium bentonite, coal tar, and sodium humate; The type B adhesive is one or a combination of polyvinyl alcohol and pregelatinized starch.

5. The method for preparing calcium carbide pellet raw material using blue carbon powder as raw material according to claim 1, characterized in that: The total amount of water in the blue carbon powder and powder mixture after being moistened with water accounts for 5-10wt% of the total amount.

6. The method for preparing calcium carbide pellet raw material using blue carbon powder as raw material according to claim 1, characterized in that: The particle sizes of the quicklime powder, blue carbon powder and binder are all less than 0.5 mm.

7. The method for preparing calcium carbide pellet raw material using blue carbon powder as raw material according to claim 1, characterized in that: In step (2), the material is stirred in the mixer for 15-40 minutes, and the material is stirred after adding water for 15-40 minutes.

8. The method for preparing calcium carbide pellet raw material using blue carbon powder as raw material according to claim 1, characterized in that: In step (4), when making balls in a high-pressure ball press, the high-pressure sample pressure is 16-25 MPa, and the pressing time is 2-10 min; the drying temperature in the oven is 105-120° C., and the drying time is 5-10 h.

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