CN117963925A - A method for preparing silicon carbide using silicon carbide smelting waste - Google Patents
A method for preparing silicon carbide using silicon carbide smelting waste Download PDFInfo
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Abstract
The application provides a method for preparing silicon carbide by utilizing silicon carbide smelting spent material, which comprises the following steps: preparing a reaction material; charging; feeding power and smelting; discharging, wherein the method of the charging step comprises the following steps: in silicon carbide smelting furnaces, the charging burden is divided into: new material, spent material and heat preservation material; the heat preservation materials are distributed around the furnace, and are respectively 1 m-1.4 m away from the bottom of the smelting furnace and the furnace wall; the waste material is arranged below the furnace body, is higher than the region of the furnace bottom heat preservation material by 1 m-2 m, and is arranged above the furnace body at a distance of 1 m-2 m from the upper part of the furnace core; and new materials are distributed in the rest part of the furnace body. According to the application, through the design of the spent material charging distribution process, the spent material is reused for smelting silicon carbide, and the effect of recycling waste is achieved.
Description
Technical Field
The invention relates to the technical field of silicon carbide preparation, in particular to a silicon carbide smelting method, and particularly relates to a method for preparing silicon carbide by utilizing silicon carbide smelting waste.
Background
The silicon carbide waste is a mixture composed of low-melting impurities discharged from a reaction high-temperature zone in the middle of the furnace in the silicon carbide smelting process, silicon carbide, calcium oxide, graphite and other substances.
The difference between the spent material and the heat-insulating material is that the formation area of the spent material is between the reaction area and the heat-insulating material area of the silicon carbide smelting furnace, the spent material contains more impurity substances and more complex components.
In the smelting process, impurities in the reaction material, particularly metal impurities, are gasified in the reaction area in the furnace and then discharged to the periphery of the furnace core at high temperature and high pressure, when the impurity gas is about to reach the heat-preserving material area, impurities can be accumulated in the transition area of the reaction material and the heat-preserving material due to the reduction of the temperature, the reaction material in the area is the blank, the impurities discharged in the slag discharging process basically accumulate in the blank in the silicon carbide smelting process, so that the impurities in the blank are more, the carbon-silicon reaction raw materials in the blank area do not fully react, the carbon-silicon specific components are unstable, and the silicon carbide cannot be recycled for the reaction material to smelt silicon carbide. On the other hand, because the silicon carbide smelting furnace is built by refractory bricks, fragments in the refractory bricks can fall into the waste materials, the furnace wall is made of steel, and rust on the furnace wall can also fall into the waste materials. In addition, when the silicon carbide is discharged from the furnace, the furnace type graphite inevitably pollutes the waste materials and the silicon carbide, so that the waste materials cannot be used, and the waste materials cannot be returned to the furnace for continuous smelting.
In addition, the carbon and silicon-based materials are calcined at high temperature in a smelting furnace, the temperature of the area where the spent material is located is lower than that of the furnace core, but the area is still in a high-temperature environment, and the carbonaceous raw materials are changed into carbon materials after being calcined at high temperature, so that the carbonaceous raw materials are conductive, and the structure, physical properties and chemical properties of the spent material and the silicon carbide are changed.
For the reasons, the impurities of the spent materials are complex in composition and easy to conduct, if the spent materials are used for heat preservation materials, the possibility of burning the furnace wall can occur in the smelting process, the spent materials cannot be directly used for reaction materials, and if the spent materials are directly returned to the furnace, the fire spraying phenomenon can occur. Therefore, the conventional treatment method of the reaction waste materials of the silicon carbide is to accumulate in a waste warehouse, so that the waste materials not only occupy space, but also cause resource waste.
For this reason, it is necessary to develop a method for smelting silicon carbide using the spent material.
Disclosure of Invention
The application aims to solve the problem of resource waste caused by unavailable utilization of the existing spent materials, and provides a method for preparing silicon carbide by smelting the spent materials by utilizing the silicon carbide. The application is realized by the following technical scheme.
A method for preparing silicon carbide by utilizing silicon carbide smelting waste, comprising the following steps: preparing reaction materials, charging, power transmission smelting and discharging; wherein, the step of charging specifically comprises: in a silicon carbide smelting furnace, charging materials are divided into: new material, spent material, heat-insulating material and furnace core material; the heat preservation materials are distributed around the silicon carbide smelting furnace, wherein the thickness of the bottom and the side parts is 1 m-1.4 m, and the thickness of the top part is 0.4-0.6 m; the spent material is distributed in the following parts: the area below the furnace core material in the smelting furnace is 1 m-2 m higher than the upper edge of the furnace bottom heat preservation material, and the area which is distributed in the smelting furnace and is 1 m-2 m away from the upper part of the furnace core; the furnace core material is distributed in the center of the smelting furnace in the axial direction, and the new material is distributed in the rest areas of the smelting furnace.
In the application, because the new waste material is added in the furnace burden as the reaction material, but the waste material contains metal impurities, conductive carbon and other components, if the waste material is randomly arranged, the waste material is too short from the furnace wall, the conductive components in the waste material can cause the furnace wall to burn after being conductive, and if the waste material is too short from the furnace core, the conductive components in the waste material can cause the phenomenon of burning of the waste material. Because the horizontal and transverse distance of the silicon carbide smelting furnace is narrower and the vertical height is higher, the spent materials are only suitable for being arranged in the vertical height direction, the phenomenon that the spent materials are too close to the furnace core to cause the furnace burden to fire is avoided, and the phenomenon that the furnace burden is too close to the furnace wall to cause the furnace wall to be burnt is also avoided.
Compared with the common silicon carbide smelting furnace process, the application is further improved in the steps of preparing the reaction materials:
And (3) new material configuration: mixing a carbonaceous raw material and a siliceous raw material, adding water, and stirring to uniformly mix the carbonaceous raw material and the siliceous raw material, wherein the carbon-silicon ratio is 0.67-0.72: 1, a step of;
And (3) preparing a blank: screening the waste material with the thickness of less than 50mm, checking the waste material components, supplementing and preparing a carbonaceous raw material and/or a siliceous raw material according to the waste material components, adding the supplemented raw material and the waste material into water, and uniformly mixing, so that the carbon-silicon ratio in the waste material is 0.67-0.72: 1.
Because the components of the spent material generated in each batch and each region are not consistent, before smelting silicon carbide by the spent material, the components of the spent material are firstly detected, and a certain amount of carbonaceous raw material or siliceous raw material is supplemented in the spent material according to the detection result. Because the impurities in the waste material are mainly metal impurities, in the smelting process, the externally discharged slag is in the slag blocks, and the reaction material is bonded after the metal gas impurities are liquefied, so that the larger the waste material block is, the larger the impurities are, and more than 50mm of waste material is required to be sieved when the waste material is recovered.
Compared with the common silicon carbide smelting furnace process, the application is further improved in that the power transmission smelting step is specifically that after the charging step is completed, the power is electrified and smelted for 12 days, in the electrifying process, the furnace starting power is 62% of the rated power, the power transmission reaches 80% of the rated power after one day of furnace starting, and then the power transmission is stopped and naturally cooled after the power transmission is stably operated for 11 days.
Because the spent material is basically silicon carbide generated by incomplete reaction, the waste of energy consumption is caused when the furnace runs at full load, the temperature of furnace burden can reach 2700-3000 ℃ after the furnace is started and the power reaches 80% of rated power, at the temperature, metal impurities are gasified, and the gasified impurities are diffused to the periphery around the furnace core at high temperature and high pressure.
In the invention, the silicon content of the siliceous raw material is more than or equal to 98 percent; the fixed carbon content in the carbonaceous raw material is more than 83%, the ash content is 2% -7%, and the volatile component is 7% -9.5%.
The components of the spent material are 29-30% of Si and 20-21% of C.
The siliceous raw material is quartz sand, and the carbonaceous raw material is one or more of anthracite and Taixi coal.
The application has the outstanding technical effects that:
1. the application aims to solve the problem that the existing waste materials cannot be utilized and resources are wasted, and provides a method for preparing silicon carbide by smelting waste materials by utilizing silicon carbide.
2. According to the application, through the distributed arrangement of the furnace charges, the lower part and the upper part of the furnace core are provided with the dead materials as the reaction materials, so that the phenomenon of burning of the furnace charges caused by the fact that the dead materials are too close to the furnace core is avoided, the phenomenon of burning of the furnace walls caused by the fact that the furnace charges are too close to the furnace walls is also avoided, and the safe and reasonable utilization of the dead materials as the reaction materials is realized.
3. Because the components of the waste materials generated in each batch and each region are not consistent, before smelting silicon carbide by using the waste materials, firstly, the components of the waste materials are detected, and according to the detection result, a certain amount of carbonaceous raw materials or siliceous raw materials are supplemented in the waste materials, so that the carbon-silicon ratio in the waste materials is ensured to be 0.67-0.72: 1, the material balance ratio of silicon carbide smelting is met.
Drawings
FIG. 1 is a schematic diagram of burden distribution of the preparation method of the application;
FIG. 2 is a schematic diagram of burden distribution of the preparation method of comparative example 7;
in the figure: 1. a furnace wall; 2. heat preservation material; 3. furnace core material; 4. new materials; 5. and (5) material shortage.
Detailed Description
The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
A method for preparing silicon carbide by utilizing silicon carbide smelting waste, comprising the following steps:
Preparing reaction materials, and preparing new materials: mixing a carbonaceous raw material and a siliceous raw material, adding water, and stirring to uniformly mix the carbonaceous raw material and the siliceous raw material, wherein the carbon-silicon ratio is 0.67-0.72: 1, in the new material, the mass ratio of fixed carbon to silicon in the carbonaceous raw material and the siliceous raw material is called carbon-silicon ratio; and (3) preparing a blank: screening the waste material with the thickness of less than 50mm, checking the waste material components, supplementing and preparing a carbonaceous raw material and/or a siliceous raw material according to the waste material components, adding the supplemented raw material and the waste material into water, and uniformly mixing, so that the carbon-silicon ratio in the waste material is 0.67-0.72: 1, the carbon-silicon ratio in the spent material represents the mass ratio of carbon components to silicon components in the spent material; the silicon content of the siliceous raw material is more than or equal to 98 percent; the fixed carbon content in the carbonaceous raw material is more than 83%, the ash content is 2-7%, and the volatile component is 7-9.5%; the components of the spent material are 29-30% of Si and 20-21% of C.
Charging, in the following specific examples, as shown in fig. 1, the size of the inner cross section of the silicon carbide smelting furnace is 6m wide and 8m high, and in the silicon carbide smelting furnace, charging materials are divided into: new material 4, spent material 5, heat preservation material 2 and furnace core material 3; the heat preservation materials 2 are distributed in the silicon carbide smelting furnace along the periphery of the furnace wall 1, wherein the thickness of the bottom and the side parts is 1 m-1.4 m, and the thickness of the top is 0.4-0.6 m; the spent material is distributed in the following steps: the area below the furnace core material in the smelting furnace is 1 m-2 m higher than the upper edge of the furnace bottom heat preservation material, and the area which is distributed in the smelting furnace and is 1 m-2 m away from the upper part of the furnace core; the furnace core material is distributed in the axial center of the smelting furnace, the cross section size of the furnace core material is 0.32mX0.32m, and the rest areas in the smelting furnace are distributed as new materials.
And (3) after the power transmission smelting and charging step is finished, electrifying and smelting for 12 days, wherein in the electrifying process, the furnace starting power is 62% of the rated power, the power transmission reaches 80% of the rated power after one day of furnace starting, and then, after 11 days of stable operation, stopping power transmission, and naturally cooling.
Because the silicon carbide smelting furnace is huge, the carbon-silicon ratio of each region cannot be ensured to be constant in each charging smelting process, and therefore, in the actual charging process, the carbon-silicon ratio in the silicon carbide smelting furnace ranges from 0.67 to 0.72:1
The invention is illustrated by the following specific examples.
Example 1
Preparing reaction materials:
And (3) new material configuration: mixing anthracite and quartz sand, adding water and stirring to uniformly mix carbonaceous raw materials and siliceous raw materials, wherein the carbon-silicon ratio is 0.67-0.72: 1, a step of;
and (3) preparing a blank: screening the waste materials with the grain diameter of less than 50mm, and checking that the waste material components are 29% -30% of Si, 20% -21% of C and the carbon-silicon ratio of the waste material components is 0.67-0.72: 1, a step of;
charging: in a silicon carbide smelting furnace, charging materials are divided into: new material, spent material, heat-insulating material and furnace core material;
the heat preservation materials are distributed around the silicon carbide smelting furnace, wherein the thickness of the bottom and the side parts is 1m, and the thickness of the top part is 0.4m;
the spent material is distributed in the following steps: a region which is 1.3 m-1.7 m below the furnace core material in the smelting furnace and is higher than the upper edge of the furnace bottom heat preservation material, and a region which is distributed in the smelting furnace and is 1.3 m-1.7 m above the furnace core,
The furnace core material is distributed in the axial center of the smelting furnace,
The rest areas in the smelting furnace are distributed as new materials.
And (3) power transmission smelting: after the charging step is finished, electrifying and smelting for 12 days, wherein in the electrifying process, the furnace starting power is 25000kW, the electric power reaches 32000kW after one day of furnace starting, and after the furnace is stably operated for 11 days, the electric power is stopped, and the furnace is naturally cooled.
Discharging: and (5) discharging after natural cooling.
After the furnace is discharged, the products are classified, and the conditions of furnace cores, furnace walls and the like are checked, and are shown in Table 1 in detail.
Example 2
Example 2 differs from example 1 only in that the burden distribution is changed during the charging step, in particular:
charging: in a silicon carbide smelting furnace, charging materials are divided into: new material, spent material, heat-insulating material and furnace core material; the heat preservation materials are distributed around the silicon carbide smelting furnace, wherein the thickness of the bottom and the side parts is 1m, and the thickness of the top part is 0.5m; the spent material is distributed in the following steps: the area below the furnace core material in the smelting furnace is 1-2 m higher than the upper edge of the furnace bottom heat preservation material, and the area which is distributed in the smelting furnace and is 1-2 m away from the upper part of the furnace core. The furnace core material is distributed in the axial center of the smelting furnace, and the rest areas in the smelting furnace are distributed with new materials.
After the furnace is discharged, the products are classified, and the conditions of furnace cores, furnace walls and the like are checked, and are shown in Table 1 in detail.
Example 3
Example 3 differs from examples 1-2 only in that the burden distribution was changed during the charging step, specifically:
Charging: in a silicon carbide smelting furnace, charging materials are divided into: new material, spent material, heat-insulating material and furnace core material; the heat preservation materials are distributed around the silicon carbide smelting furnace, wherein the thickness of the bottom and the side parts is 1.4m, and the thickness of the top part is 0.5m; the spent material is distributed in the following steps: the area below the furnace core material in the smelting furnace is 1-1.5 m higher than the upper edge of the furnace bottom heat preservation material, and the area which is distributed in the smelting furnace and is 1.3-1.7 m away from the upper part of the furnace core. The furnace core material is distributed in the axial center of the smelting furnace, and the rest areas in the smelting furnace are distributed with new materials.
After the furnace is discharged, the products are classified, and the conditions of furnace cores, furnace walls and the like are checked, and are shown in Table 1 in detail.
Example 4
Example 4 differs from examples 1 to 3 only in that the burden distribution is changed during the charging step, in particular:
charging: in a silicon carbide smelting furnace, charging materials are divided into: new material, spent material, heat-insulating material and furnace core material; the heat preservation materials are distributed around the silicon carbide smelting furnace, wherein the thickness of the bottom and the side parts is 1m, and the thickness of the top part is 0.5m; the spent material is distributed in the following steps: the area below the furnace core material in the smelting furnace is 1.5-2 m higher than the upper edge of the furnace bottom heat preservation material, and the area which is distributed in the smelting furnace and is 1.5-2 m away from the upper part of the furnace core; the furnace core material is distributed in the axial center of the smelting furnace, and the rest areas in the smelting furnace are distributed with new materials.
After the furnace is discharged, the products are classified, and the conditions of furnace cores, furnace walls and the like are checked, and are shown in Table 1 in detail.
Comparative example 1
The difference between this comparative example and example 1 is that the carbon to silicon ratio of the spent material configuration in the configuration reaction material is 0.61 to 0.67:1, the other points are the same as in example 1, specifically
Preparing reaction materials:
And (3) preparing a blank: screening the waste materials with the grain diameter of less than 50mm, and checking that the waste materials comprise 29.5% -30.5% of Si, 18.5% -19.5% of C and the carbon-silicon ratio of the waste materials is 0.61-0.67: 1.
After the furnace is discharged, the products are classified, and the conditions of furnace cores, furnace walls and the like are checked, and are shown in Table 1 in detail.
Comparative example 2
The difference between this comparative example and example 1 is that the carbon to silicon ratio in the spent material is 0.72-0.75 in the configured reaction material: 1, the other steps are the same as in example 1, specifically:
Preparing reaction materials:
And (3) preparing a blank: screening the waste materials with the grain diameter of less than 50mm, and checking that the waste materials comprise 28-29% of Si and 21-22% of C, wherein the carbon-silicon ratio of the waste materials is 0.72-0.78: 1.
After the furnace is discharged, the products are classified, and the conditions of furnace cores, furnace walls and the like are checked, and are shown in Table 1 in detail.
Comparative example 3
Comparative example 3 differs from example 1 only in the change in charge distribution, in particular:
charging: in a silicon carbide smelting furnace, charging materials are divided into: new material, spent material, heat-insulating material and furnace core material;
The heat preservation materials are distributed around the silicon carbide smelting furnace, wherein the thickness of the bottom and the side parts is 1m, and the thickness of the top part is 0.4m; the spent material is distributed in the following steps: the area below the furnace core material in the smelting furnace is 1.3 m-1.7 m higher than the upper edge of the furnace bottom heat preservation material, and the area which is distributed in the smelting furnace and is 2 m-2.5 m away from the upper part of the furnace core; the furnace core material is distributed in the axial center of the smelting furnace, and the rest areas in the smelting furnace are distributed with new materials.
After the furnace is discharged, the products are classified, and the conditions of furnace cores, furnace walls and the like are checked, and are shown in Table 1 in detail.
Comparative example 4
Comparative example 4 differs from example 1 only in the change in charge distribution, in particular:
Charging: in a silicon carbide smelting furnace, charging materials are divided into: new material, spent material, heat-insulating material and furnace core material; the heat preservation materials are distributed around the silicon carbide smelting furnace, wherein the thickness of the bottom and the side parts is 1m, and the thickness of the top part is 0.4m; the spent material is distributed in the following steps: the area below the furnace core material in the smelting furnace, which is 1.3 m-1.7 m higher than the upper edge of the furnace bottom heat preservation material, and the area which is distributed in the smelting furnace and is 0.5 m-1.0 m away from the upper part of the furnace core; the furnace core material is distributed in the axial center of the smelting furnace, and the rest areas in the smelting furnace are distributed with new materials.
After the furnace is discharged, the products are classified, and the conditions of furnace cores, furnace walls and the like are checked, and are shown in Table 1 in detail.
Comparative example 5
Comparative example 5 differs from example 1 only in the change in charge distribution, in particular:
Charging: in a silicon carbide smelting furnace, charging materials are divided into: new material, spent material, heat-insulating material and furnace core material; the heat preservation materials are distributed around the silicon carbide smelting furnace, wherein the thickness of the bottom and the side parts is 1m, and the thickness of the top part is 0.4m; the spent material is distributed in the following steps: the area below the furnace core material in the smelting furnace, which is 2 m-2.5 m higher than the upper edge of the furnace bottom heat preservation material, and the area which is distributed in the smelting furnace and is 1.3 m-1.7 m away from the upper part of the furnace core; the furnace core material is distributed in the axial center of the smelting furnace, and the rest areas in the smelting furnace are distributed with new materials.
After the furnace is discharged, the products are classified, and the conditions of furnace cores, furnace walls and the like are checked, and are shown in Table 1 in detail.
Comparative example 6
Comparative example 6 differs from example 1 only in the change in charge distribution, in particular:
Charging: in a silicon carbide smelting furnace, charging materials are divided into: new material, spent material, heat-insulating material and furnace core material; the heat preservation materials are distributed around the silicon carbide smelting furnace, wherein the thickness of the bottom and the side parts is 1m, and the thickness of the top part is 0.4m; the spent material is distributed in the following steps: the area below the furnace core material in the smelting furnace, which is 0.5 m-1 m higher than the upper edge of the furnace bottom heat preservation material, and the area which is distributed in the smelting furnace and is 1.3 m-1.7 m away from the upper part of the furnace core; the furnace core material is distributed in the axial center of the smelting furnace, and the rest areas in the smelting furnace are distributed with new materials.
After the furnace is discharged, the products are classified, and the conditions of furnace cores, furnace walls and the like are checked, and are shown in Table 1 in detail.
Comparative example 7
Comparative example 7 differs from example 1 only in the change in charge distribution, as shown in fig. 2, and specifically:
Charging: in a silicon carbide smelting furnace, charging materials are divided into: new material, spent material, heat-insulating material and furnace core material; the heat preservation materials are distributed around the silicon carbide smelting furnace, wherein the thickness of the bottom and the side parts is 1m, and the thickness of the top part is 0.4m; the spent material is distributed in the following steps: the area below the furnace core material in the smelting furnace, which is 1.3 m-1.7 m higher than the upper edge of the furnace bottom heat preservation material, is distributed in the area 1.3 m-1.7 m above the furnace core in the smelting furnace, and the area which is 0.8 m-1.3 m away from the side wall heat preservation material and is positioned at two sides of the furnace core material; the furnace core material is distributed in the axial center of the smelting furnace, and the rest areas in the smelting furnace are distributed with new materials.
After the furnace is discharged, the products are classified, and the conditions of furnace cores, furnace walls and the like are checked, and are shown in Table 1 in detail.
Comparative example 8
Comparative example 8 differs from example 1 only in that the power feeding smelting process is changed, specifically:
And (3) power transmission smelting: after the charging step is finished, electrifying and smelting for 12 days, wherein in the electrifying process, the furnace starting power is 25000kW, the electric power reaches 28000kW after one day of furnace starting, and after the furnace is stably operated for 11 days, the electric power is stopped, and the furnace is naturally cooled.
Discharging: and (5) discharging after natural cooling.
After the furnace is discharged, the products are classified, and the conditions of furnace cores, furnace walls and the like are checked, and are shown in Table 1 in detail.
Comparative example 9
Comparative example 9 differs from example 1 only in that the power feeding smelting process is changed, specifically:
And (3) power transmission smelting: after the charging step is finished, electrifying and smelting for 12 days, wherein in the electrifying process, the furnace starting power is 25000kW, the electric power reaches 40000kW after one day of furnace starting, and then, after the furnace is stably operated for 11 days, the electric power is stopped, and the furnace is naturally cooled.
Classifying the products after discharging, checking the conditions of furnace cores, furnace walls and the like, and particularly looking at the table 1,
Table 1 shows the product grade distribution and the smelting furnace conditions obtained in each example
From the above embodiments 1 to 4, it can be seen that the application utilizes the waste material to smelt silicon carbide, and through the material proportion, the waste material charging distribution realizes that the waste material is reused for smelting silicon carbide, achieves the effect of recycling waste materials, and does not generate the phenomena of firing of furnace walls and fire in the furnace in the smelting process.
From the above example 1 and comparative examples 1to 2, it was found that only the ratio of silicon carbide in the spent material was 0.67 to 0.72: and 1, the fully reacted materials in the spent materials can be fully reacted, and the final product has higher first-grade product rate.
As can be seen from the above examples 1 to 4 and comparative examples 3 to 8, the problem of abnormal furnace conditions does not occur only in the region below the furnace core material in the silicon carbide smelting furnace, which is 1 to 2m above the upper edge of the furnace bottom insulating material, and in the region within the smelting furnace, which is 1 to 2m above the furnace core, which is distributed with the spent material.
In comparative example 3, the off-material located above the furnace core is too close to the furnace roof, causing the furnace roof insulation and furnace roof to burn.
In comparative example 4, the spent material located above the furnace core was too close to the furnace core, causing a fire spike in the furnace, resulting in a serious degradation of the silicon carbide product quality in and around this region.
In comparative example 5, the spent material located below the furnace core was too close to the furnace core, causing a fire spike in the furnace, resulting in a serious degradation of the silicon carbide product quality in and near this region.
In comparative example 6, the charge located below the furnace was too close to the furnace bottom, causing the furnace bottom to burn.
Comparative example 7 in comparative example 7, in which the both sides of the furnace core were provided with the off-material as the reaction material, the furnace charge on both sides of the furnace core was not only burned, but also the furnace wall was burned, the firing of the furnace wall and the firing in the furnace occurred because the furnace wall was closer to the furnace core, the distance of the off-material from the furnace core and the furnace wall was closer, and the firing of the furnace charge and the firing of the furnace wall occurred.
It was found from example 1 and comparative examples 9 to 10 that example 1 was lower in power and lower in energy consumption than the normal fresh burden smelting. Compared with the conventional silicon carbide smelting process, the embodiment 1 completely adopts quartz sand and anthracite as raw materials, wherein the embodiment 1 fully utilizes the spent materials as reaction materials in the furnace, and the main components in the spent materials are the quartz sand and the anthracite which are not fully reacted and some impurities, so that the embodiment 1 does not influence the silicon carbide smelting of the materials even if the power is reduced compared with the embodiment 1 completely utilizing the quartz sand and the anthracite as the raw materials. The smelting power of comparative example 9 was lowered, resulting in incomplete reaction of the materials, resulting in low primary rate of the product, and the normal smelting power was used in comparative example 10, but the primary rate of the obtained product was less different from that of example 1, so that the power feeding smelting process of example 1 was preferred from the viewpoint of energy saving.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced with equivalents; such modifications and substitutions do not depart from the spirit of the technical solutions according to the embodiments of the present invention.
Claims (6)
1. A method for preparing silicon carbide by utilizing silicon carbide smelting waste, comprising the following steps:
Preparing reaction materials, charging, power transmission smelting and discharging;
the method is characterized by comprising the following steps of:
In a silicon carbide smelting furnace, charging materials are divided into: new material, spent material, heat-insulating material and furnace core material;
The heat preservation materials are distributed around the silicon carbide smelting furnace, wherein the thickness of the bottom and the side parts is 1 m-1.4 m, and the thickness of the top part is 0.4-0.6 m;
The spent material is distributed in the following steps: the area below the furnace core material in the smelting furnace is 1 m-2 m higher than the upper edge of the furnace bottom heat preservation material, and the area which is distributed in the smelting furnace and is 1 m-2 m away from the upper part of the furnace core;
the furnace core material is distributed in the axial center of the smelting furnace,
The rest areas in the smelting furnace are distributed as new materials.
2. The method for smelting silicon carbide by using a sealed environment-friendly silicon carbide smelting furnace as set forth in claim 1, wherein: the reaction material comprises the following steps:
And (3) new material configuration: mixing a carbonaceous raw material and a siliceous raw material, adding water, and stirring to uniformly mix the carbonaceous raw material and the siliceous raw material, wherein the carbon-silicon ratio is 0.67-0.72: 1, a step of;
And (3) preparing a blank: screening the waste material with the thickness of less than 50mm, checking the waste material components, supplementing and preparing a carbonaceous raw material and/or a siliceous raw material according to the waste material components, adding the supplemented raw material and the waste material into water, and uniformly mixing, so that the carbon-silicon ratio in the waste material is 0.67-0.72: 1.
3. The method for preparing silicon carbide by using the silicon carbide smelting spent material according to claim 1, wherein the power transmission smelting step is specifically that after the charging step is completed, the power transmission smelting is carried out for 12 days, in the power transmission process, the furnace starting power is 62% of the rated power, the power transmission power reaches 80% of the rated power after one day of the furnace starting, and then the power transmission is stopped and naturally cooled after 11 days of smooth operation.
4. The method for smelting silicon carbide by using a sealed environment-friendly silicon carbide smelting furnace according to claim 1 or 2, wherein the method comprises the following steps: the silicon content of the siliceous raw material is more than or equal to 98 percent;
The fixed carbon content in the carbonaceous raw material is more than 83%, the ash content is 2% -7%, and the volatile component is 7% -9.5%.
5. The method for smelting silicon carbide by using a sealed environment-friendly silicon carbide smelting furnace according to claim 1 or 2, wherein the method comprises the following steps: the components of the spent material are 29-30% of Si and 20-21% of C.
6. The method for smelting silicon carbide by using the sealed environment-friendly silicon carbide smelting furnace according to claim 4, wherein the method comprises the following steps: the siliceous raw material is quartz sand, and the carbonaceous raw material is one or more of anthracite and Taixi coal.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3887359A (en) * | 1972-01-25 | 1975-06-03 | Elkem Spigerverket As | Reduction of silicon dioxide by means of carbon in electric furnace |
| CN1392118A (en) * | 2002-06-11 | 2003-01-22 | 贾玉东 | Method and device for smelting silicon carbide |
| JP2017052665A (en) * | 2015-09-09 | 2017-03-16 | 太平洋セメント株式会社 | Method for producing silicon carbide |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3887359A (en) * | 1972-01-25 | 1975-06-03 | Elkem Spigerverket As | Reduction of silicon dioxide by means of carbon in electric furnace |
| CN1392118A (en) * | 2002-06-11 | 2003-01-22 | 贾玉东 | Method and device for smelting silicon carbide |
| JP2017052665A (en) * | 2015-09-09 | 2017-03-16 | 太平洋セメント株式会社 | Method for producing silicon carbide |
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