An isostatic pressing graphite roasting anti-oxidation charging method

Abstract

The present invention belongs to the technical field of graphite production, and particularly relates to a method for loading a hydrostatic graphite roasting anti-oxidation furnace, which comprises the following steps: loading a crucible into the furnace; loading graphite products into the crucible and filling the gaps between the graphite products with quartz sand; laying an anti-oxidation layer on the top of the products, the anti-oxidation layer including an oxidation rod layer in the lower layer, a paste powder layer in the middle layer and an impregnated rod layer in the upper layer. The oxidation rods are paste powder rods pressed from paste powder, the paste powder is the powder generated during the secondary grinding process of graphite products, and the impregnated rods are obtained by subjecting the oxidation rods to primary roasting and then performing pitch impregnation. Through the setting of the three-layer anti-oxidation layer, the present invention can completely resist the oxidation effect during the long-time roasting process, prevent the upper-layer products from being oxidized, and improve the yield of graphite products.

Description

Technical Field

[0001] The present invention belongs to the technical field of graphite production, and particularly relates to a method for loading an isostatic graphite roasting anti-oxidation furnace. Background Art

[0002] In the production process of conventional graphite products, the anti-oxidation method is to control the thickness of the top layer of quartz sand or metallurgical coke to achieve different anti-oxidation effects. The requirements for the thickness of the top anti-oxidation layer are as follows for the following two methods:

[0003] 1. For a bottom-loading furnace, with an oxygen content < 2%, a 400 - 500 mm space is reserved at the top of the graphite product;

[0004] 2. For an open-top ring furnace, with an oxygen content > 15%, a space greater than 1000 mm is reserved at the top of the graphite product.

[0005] In the second case, that is, when the reserved thickness of the anti-oxidation layer is greater than 1000 mm, there is still a 30% oxidation probability, and the risk of product cracking is extremely high. As the age of the furnace body increases, the brick joints increase, the reserved height at the top layer must be increased, and the risk of product cracking is further increased. At the same time, the furnace loading capacity is greatly reduced. Summary of the Invention

[0006] In order to solve the above technical problems, the present invention provides a method for loading an isostatic graphite roasting anti-oxidation furnace.

[0007] The present invention is realized as follows. A method for loading an isostatic graphite roasting anti-oxidation furnace is provided, including the following steps:

[0008] 1) Loading the crucible into the furnace;

[0009] 2) Loading graphite products into the crucible and filling the gaps between the graphite products with quartz sand;

[0010] 3) Laying an anti-oxidation layer on the top of the products. The anti-oxidation layer includes an oxidation rod layer at the lower layer, a paste powder layer at the middle layer, and an impregnated rod layer at the upper layer. The oxidation rods are paste powder rods pressed from the paste powder, the paste powder is the powder generated during the secondary grinding process of the graphite products, and the impregnated rods are obtained by subjecting the oxidation rods to a first roasting and then impregnating with pitch.

[0011] Preferably, in step 2), the method for loading the graphite products and quartz sand is as follows:

[0012] First, lay a layer of quartz sand at the bottom of the crucible, then lay a layer of graphite products, then lay another layer of quartz sand, and then lay another layer of graphite products, and keep loading until there is a certain distance from the upper end of the crucible. The top layer is quartz sand.

[0013] More preferably, the thickness of the top layer of quartz sand is 200 - 300 mm.

[0014] Further preferably, the paste powder is the powder collected by the dust collector during the secondary grinding process of graphite products, and the composition of the paste powder includes asphalt and raw coke.

[0015] Further preferably, there are two layers of oxidation rod layers; the thickness of the paste powder layer is 40-60 mm.

[0016] Further preferably, the crucible is a square integral crucible.

[0017] Compared with the prior art, the advantages of the present invention are as follows:

[0018] 1. Through the setting of the three-layer anti-oxidation layer, it can completely resist the oxidation effect during the long-term roasting process, prevent the oxidation of the upper-layer products, and improve the yield of graphite products;

[0019] 2. By designing the crucible to be square, firstly, it can increase the capacity of the crucible for loading graphite products, and secondly, it makes the shape of the crucible fit the roasting furnace, eliminating the need to fill metallurgical coke for heat conduction on the outside of the crucible. Instead, quartz sand is directly filled inside for heat conduction, saving energy and having good heat conduction effect. Specific Embodiments

[0020] The following combines specific implementation schemes to further explain and illustrate the present invention, but it is not used to limit the protection scope of the present invention.

[0021] In the present invention, the anti-oxidation layer includes an oxidation rod layer in the lower layer, a paste powder layer in the middle layer, and an impregnated rod layer in the upper layer. The oxidation rod is a paste powder rod pressed from the paste powder, the paste powder is the powder generated during the secondary grinding process of graphite products, and the impregnated rod is obtained by performing asphalt impregnation after the oxidation rod is subjected to a first roasting. The anti-oxidation principle of the three-layer anti-oxidation layer is as follows:

[0022] First, in the prior art, quartz sand layer is used for roasting graphite products. Although the particle size of quartz sand is fine, there are still gaps between particles. The roasting cycle of isostatic pressing large-size graphite products is long, and during the roasting process, oxygen slowly diffuses and penetrates along the gaps, resulting in the gradual oxidation of the products. The oxidation rods and impregnated rods have large diameters and are arranged closely in rows during the placement process, reducing the total void volume and effectively blocking the diffusion and penetration of oxygen. At the same time, the particle size of the paste powder is extremely fine, between 0-30 um, further enhancing the above effect and effectively reducing the oxygen content per unit area.

[0023] Second, the oxidation rod, paste powder, and impregnation rod are all products containing asphalt or asphalt components (with a proportion of 10 - 20%). The main temperature range for roasting and oxidizing the isostatic pressing products is 300 - 550 °C (the volatile temperature range of the asphalt component, during which the product reacts with oxygen, causing oxidation). The above three products all contain a certain proportion of asphalt or asphalt components. Within the main temperature range, their reaction properties and principles are the same as those of the isostatic pressing products. For the asphalt or asphalt components in the oxidation rod, paste powder, and impregnation rod, the volatile light components react with the diffused and permeated oxygen prior to the isostatic pressing products, effectively blocking the diffusion and permeation of oxygen to the isostatic pressing products.

[0024] Example 1:

[0025] This example provides a method for loading an isostatic pressing graphite roasting anti-oxidation furnace, including the following steps:

[0026] 1) Load the crucible into the furnace. The crucible is a square integral crucible.

[0027] 2) Load graphite products into the crucible and fill the gaps between the graphite products with quartz sand. The loading method of the graphite products and quartz sand is as follows:

[0028] First, lay a layer of quartz sand at the bottom of the crucible, then lay a layer of graphite products, then lay another layer of quartz sand, and then lay another layer of graphite products, and keep loading until there is a certain distance from the upper end of the crucible. The top layer is quartz sand, and the thickness of the top quartz sand layer is 200 - 300 mm.

[0029] 3) Lay an anti-oxidation layer on the top of the products. The anti-oxidation layer includes a layer of oxidation rod layer at the lower layer, a paste powder layer in the middle layer, and a layer of impregnation rod layer at the upper layer. The oxidation rod is a paste powder rod pressed from the paste powder. The paste powder is the powder generated during the secondary grinding process of the graphite products. The impregnation rod is obtained by performing asphalt impregnation after the oxidation rod is roasted once. The paste powder is the powder collected by the dust collector during the secondary grinding process of the graphite products. The composition of the paste powder includes asphalt and raw coke. The thickness of the paste powder layer is 40 - 60 mm.

[0030] Example 2:

[0031] The difference from Example 1 is that the oxidation rod layer is two layers.

[0032] Example 3:

[0033] The difference from Example 1 is that the impregnation rod layer is two layers.

[0034] By detecting the upper-layer graphite products prepared by the methods of Example 1, Example 2, and Example 3, it is found that none of them have been oxidized. It can be known that the anti-oxidation effect of the method for loading an isostatic pressing graphite roasting anti-oxidation furnace provided by the present invention is very good.

Claims

1. An isostatic graphite roasting anti-oxidation charging method, characterized in that, It includes the following steps: 1) Load the crucible into the furnace; 2) Load graphite products into the crucible and fill the gaps between the graphite products with quartz sand; 3) Lay an anti-oxidation layer on the top of the products. The anti-oxidation layer includes an oxidation rod layer at the lower layer, a paste powder layer at the middle layer and an impregnated rod layer at the upper layer. The oxidation rods are paste powder rods pressed from the paste powder. The paste powder is the powder generated during the secondary grinding process of the graphite products. The impregnated rods are obtained by subjecting the oxidation rods to a first roasting and then performing pitch impregnation; In step 2), the method for loading the graphite products and quartz sand into the furnace is as follows: First, lay a layer of quartz sand at the bottom of the crucible, then lay a layer of graphite products, then lay a layer of quartz sand, and then lay a layer of graphite products, and keep loading until there is a certain distance from the upper end of the crucible. The top layer is quartz sand; In step 3), the paste powder is the powder collected by the dust collector during the secondary grinding process of the graphite products. The composition of the paste powder includes pitch and raw coke; The crucible is a square integral crucible.

2. The isostatic graphite roasting anti-oxidation charging method according to claim 1, characterized in that, The thickness of the top quartz sand layer is 200 - 300 mm.

3. The isostatic graphite roasting anti-oxidation charging method according to claim 1, characterized in that, In step 3), the oxidation rod layer is two layers; the thickness of the paste powder layer is 40 - 60 mm.