A sorting and impurity removal device for silicon powder waste

Abstract

This utility model discloses a sorting and impurity removal device for silicon powder waste, including a fluidized bed furnace, a cyclone dust collector, and a bag filter dust collector. Several cyclone separators are evenly distributed around the fluidized bed furnace. The upper part of the fluidized bed furnace is connected to each cyclone separator via connecting pipes. An air distribution plate is installed inside the fluidized bed furnace. The dust discharge pipe at the bottom of the cyclone separator is connected to the fluidized bed furnace above the air distribution plate. A gas collecting ring pipe is installed above the fluidized bed furnace. The exhaust pipe at the top of the cyclone separator is connected to the gas collecting ring pipe. The gas collecting ring pipe is connected to the feed pipe of the fluidized bed furnace via a return pipe. The feed pipe has an inlet. The gas collecting ring pipe is connected to an iron separator via an exhaust pipe. The outlet of the iron separator is connected sequentially to the cyclone dust collector and the bag filter dust collector. In summary, this utility model has the advantages of uniform fluidization, high carbon removal efficiency, and thorough carbon removal.

Description

Technical Field

[0001] This utility model relates to the technical field of silicon powder waste sorting and impurity removal equipment, specifically to a silicon powder waste sorting and impurity removal device. Background Technology

[0002] Silicon powder waste, also known as microsilicon powder or silica ash, is produced during the smelting of industrial silicon, ferrosilicon, and silicomanganese. High temperatures reduce silicon dioxide in the raw materials to carbon, generating silicon vapor and carbon monoxide gas. These gases are discharged from the furnace top and rapidly oxidize, cool, and condense in the air, eventually being collected by a bag filter. The main component of silicon powder waste is amorphous silicon dioxide, along with small amounts of unburned carbon and impurities such as iron oxide. It possesses excellent chemical activity and other physicochemical properties and is often used as a very important micro / nano inorganic non-metallic material. Sorting and impurity removal from silicon powder waste is a crucial deep-processing step aimed at improving its purity and value to meet the stringent requirements of high-performance concrete, high-purity silicon materials, and advanced ceramics.

[0003] The core processing technology for separating and removing impurities from microsilica powder is carbon removal. High-temperature calcination is the most mainstream and stable method in industry. Its principle is to convert carbon into carbon dioxide gas through high-temperature oxidation in a fluidized bed furnace. Currently, the following problems often exist when using high-temperature calcination to remove carbon from silicon powder waste: First, because microsilica particles are extremely fine, with an average particle size of approximately 0.1μm to 0.3μm, they have extremely strong cohesive forces and are prone to agglomeration, leading to channeling, blockage, and other phenomena, resulting in uneven fluidization of the material and reduced carbon removal efficiency. Second, because the microsilica powder itself is extremely fine, and the operating gas velocity in the fluidized bed furnace is high, the airflow easily carries the microsilica powder away from the bed, causing serious segregation problems. This results in a large amount of unreacted microsilica powder being instantly carried out of the reaction zone by the airflow, and the residence time of the microsilica powder in the furnace is too short, leading to incomplete carbon removal. Therefore, it is objectively necessary to develop a silicon powder waste separation and impurity removal device that achieves uniform fluidization, high carbon removal efficiency, and thorough carbon removal. Utility Model Content

[0004] The purpose of this invention is to provide a sorting and impurity removal device for silicon powder waste that has uniform fluidization, high carbon removal efficiency, and thorough carbon removal.

[0005] The purpose of this utility model is achieved as follows: it includes a fluidized bed furnace, a cyclone dust collector, and a bag filter dust collector. Several cyclone separators are evenly distributed around the fluidized bed furnace. The upper part of the fluidized bed furnace is connected to each cyclone separator through a connecting pipe. An air distribution plate is installed inside the fluidized bed furnace. The dust discharge pipe at the bottom of the cyclone separator is connected to the fluidized bed furnace above the air distribution plate. A gas collecting ring pipe is installed above the fluidized bed furnace. The air outlet pipe at the top of the cyclone separator is connected to the gas collecting ring pipe. The gas collecting ring pipe is connected to the feed pipe of the fluidized bed furnace through a return pipe. The feed pipe is provided with a feed inlet. The gas collecting ring pipe is connected to an iron remover through an exhaust pipe. The air outlet of the iron remover is connected to the cyclone dust collector and the bag filter dust collector in sequence.

[0006] Furthermore, a screw conveyor is installed above the feed pipe, and the discharge port of the screw conveyor is connected to the inlet port on the feed pipe.

[0007] Furthermore, an agitator is installed inside the feed pipe below the feed inlet.

[0008] Furthermore, a spiral guide plate is installed inside the feed pipe, and the spiral guide plate is located on the side of the feed inlet away from the fluidized bed furnace.

[0009] Furthermore, a jacket is provided on the outer wall of the cyclone separator, and the jackets on each cyclone separator are connected in series. The air outlet of the jacket is connected to the air inlet of the fluidized bed furnace through a pipeline.

[0010] Furthermore, the overflow port of the fluidized bed furnace is connected to a cooler, and the discharge port of the cooler is connected to a magnetic separator.

[0011] Furthermore, a cooler is installed on the pipeline at the air inlet of the cyclone dust collector, and the air outlet of the cooler is connected to the fluidized bed furnace above the air distribution plate through a pipeline.

[0012] In operation, the collected silicon powder waste falls into the feed pipe from the inlet and then enters the fluidized bed furnace. Air or oxygen is introduced through the air inlet of the fluidized bed furnace. After passing through the air distribution plate, the silicon powder waste is lifted, causing it to suspend in the airflow and undergo violent and irregular movement. At this time, the silicon powder waste particles mix with the gas, exhibiting a fluid-like boiling state. The carbon in the silicon powder waste reacts fully with the oxygen to generate carbon dioxide, which is then discharged with the flue gas. Subsequently, the flue gas enters each cyclone separator. The separator separates solids and gases in the flue gas, removing silicon powder and unburned carbon. The separated solids are then returned to the fluidized bed furnace for further calcination. The flue gas after solid separation enters the gas collection ring pipe. Part of the flue gas enters the feed pipe through the return pipe. This part of the flue gas can pick up the silicon powder waste entering the feed pipe and send it into the fluidized bed furnace using the principle of pneumatic conveying. The other part of the flue gas is sent to the cyclone dust collector and bag filter through the exhaust pipe for further filtration of the silicon powder waste contained in the flue gas. In this invention, airflow is introduced into the feed pipe. When silicon powder waste falls into the feed pipe, it is quickly swept up by the airflow and dispersed, thus de-agglomerating the silicon powder waste. This ensures uniform distribution of the silicon powder waste after entering the fluidized bed furnace and avoids channeling and clogging, resulting in uniform fluidization and improved carbon removal efficiency. Secondly, multiple cyclone separators are installed simultaneously to separate unreacted silicon powder waste entrained in the airflow, providing significant processing capacity and separation efficiency. The separated silicon powder waste is then returned to the fluidized bed furnace for further calcination and reaction, solving the current problem of silicon powder waste separation and achieving thorough carbon removal. In summary, this invention has the advantages of uniform fluidization, high carbon removal efficiency, and thorough carbon removal. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0014] Figure 2 for Figure 1 A magnified structural diagram of node A in the middle;

[0015] In the diagram: 1-fluidized bed furnace, 2-cyclone dust collector, 3-bag filter dust collector, 4-cyclone separator, 5-air distribution plate, 6-air collection ring pipe, 7-return pipe, 8-feed pipe, 9-feed inlet, 10-screw conveyor, 11-agitator, 12-spiral guide plate, 13-jacket, 14-air inlet, 15-overflow port, 16-cooler, 17-iron separator, 18-cooler. Detailed Implementation

[0016] The present invention will be further described below with reference to the accompanying drawings, but this description is not intended to limit the present invention in any way. Any changes or improvements made based on the present invention shall fall within the protection scope of the present invention.

[0017] like Figures 1-2 As shown, this utility model includes a fluidized bed furnace 1, a cyclone dust collector 2, and a bag filter 3. The impurities contained in the silicon powder waste include: firstly, carbon impurities, mainly unburned coke particles and carbon black; secondly, metal oxide impurities, mainly including calcium oxide, magnesium oxide, potassium oxide, sodium oxide, etc. The fluidized bed furnace 1, cyclone dust collector 2, and bag filter 3 are all existing technologies. The fluidized bed furnace 1 is used to calcine the silicon powder waste, primarily to oxidize and burn the carbon, causing the carbon to generate carbon dioxide in an aerobic environment and be discharged, thereby removing the carbon from the silicon powder waste and achieving the purpose of carbon removal. Simultaneously, the calcination process can gasify or decompose some low-boiling-point metal impurities, such as potassium and sodium compounds and other volatile substances, playing a certain purification role. The cyclone dust collector 2 and bag filter 3 are both used... To remove silicon powder waste from the flue gas and prevent silicon powder waste, several cyclone separators 4 are evenly distributed around the fluidized bed furnace 1. The cyclone separators 4 are used to separate silicon powder and unreacted carbon from the flue gas and return it to the fluidized bed furnace 1 for further calcination to improve the calcination effect. The upper part of the fluidized bed furnace 1 is connected to each of the cyclone separators 4 through connecting pipes. An air distribution plate 5 is installed inside the fluidized bed furnace 1. The dust discharge pipe at the bottom of the cyclone separator 4 is connected to the fluidized bed furnace 1 above the air distribution plate 5. A gas collecting ring pipe 6 is installed above the fluidized bed furnace 1. The gas outlet pipe at the top of the cyclone separator 4 is connected to the gas collecting ring pipe 6. The gas collecting ring pipe 6 is connected to the feed pipe 8 of the fluidized bed furnace 1 through a return pipe 7. The feed pipe 8 is equipped with a feed inlet 9. The gas collecting ring pipe 6 is connected to the cyclone dust collector 2 and the bag dust collector 3 in sequence through an exhaust pipe.

[0018] In operation, the collected silicon powder waste falls from the inlet 9 into the feed pipe 8, and then enters the fluidized bed furnace 1 through the feed pipe 8. Air or oxygen is introduced through the air inlet 14 of the fluidized bed furnace 1. After passing through the air distribution plate 5, the silicon powder waste is lifted up, causing it to suspend in the airflow and undergo violent and irregular movement. At this time, the silicon powder waste particles are mixed with the gas, exhibiting a fluid-like boiling state. The carbon in the silicon powder waste reacts fully with the oxygen to generate carbon dioxide, which is then discharged with the flue gas. Subsequently, the flue gas enters each cyclone separator 4, where solid-gas separation occurs, separating the silicon powder from the flue gas. Unburned carbon is separated from the flue gas and then returned to the fluidized bed furnace 1 for further calcination. The flue gas after solid separation enters the gas collection ring pipe 6. Part of the flue gas enters the feed pipe 8 through the return pipe 7. This part of the flue gas can pick up the silicon powder waste entering the feed pipe 8 and send the silicon powder waste into the fluidized bed furnace 1 using the principle of pneumatic conveying. At the same time, the heat in the flue gas is used to preheat the silicon powder waste, increase the temperature of the silicon powder waste, and thus increase the reaction rate of the subsequent silicon powder waste and oxygen. Another part of the flue gas is sent to the cyclone dust collector 2 and the bag dust collector 3 through the exhaust pipe to further filter the silicon powder waste contained in the flue gas.

[0019] In this invention, airflow is introduced into the feed pipe 8. When silicon powder waste falls into the feed pipe 8, it is quickly swept up by the airflow and dispersed, which has a deagglomeration effect. This ensures that the silicon powder waste is evenly distributed after entering the fluidized bed furnace 1, and avoids phenomena such as channeling and blockage. This results in uniform fluidization of the silicon powder waste, thereby improving the carbon removal efficiency. Secondly, multiple cyclone separators 4 are set up and operate simultaneously to separate the unreacted silicon powder waste entrained in the airflow. This has a large processing capacity and separation efficiency. The separated silicon powder waste is then returned to the fluidized bed furnace 1 for further calcination and reaction, solving the existing problem of silicon powder waste separation and achieving the goal of thorough carbon removal.

[0020] A screw conveyor 10 is installed above the feed pipe 8. The discharge port of the screw conveyor 10 is connected to the inlet port 9 on the feed pipe 8. The screw conveyor 10 is an existing material quantitative conveying device. In this utility model, it is used to quantitatively and uniformly convey silicon powder waste.

[0021] An agitator 11 is installed in the feed pipe 8 below the feed inlet 9. Since silicon powder waste is prone to agglomeration and clumping, the agitator 11 is installed below the feed inlet 9. When the silicon powder waste falls into the feed pipe 8, it can be agitated by the agitator 11. The mechanical agitation will break up the agglomerated clumps, making the silicon powder waste looser. After entering the fluidized bed furnace 1, it can be fluidized more evenly, thereby improving the carbon removal efficiency.

[0022] A spiral guide plate 12 is installed inside the feed pipe 8. The spiral guide plate 12 is located on the side of the feed inlet 9 away from the fluidized bed furnace 1. When air or oxygen is introduced into the feed pipe 8, a spiral airflow is formed under the action of the spiral guide plate 12, which can better disperse silicon powder waste and better drive the silicon powder waste to be transported, preventing silicon powder waste from settling.

[0023] A jacket 13 is provided on the outer wall of the cyclone separator 4. The jackets 13 on each cyclone separator 4 are connected in series. The air outlet of the jacket 13 is connected to the air inlet 14 of the fluidized bed furnace 1 through a pipeline. The cyclone separator 4 is an existing device used to separate silicon powder waste from flue gas. In this process, since the flue gas contains a lot of heat, the jacket 13 is set up to reduce heat loss. Air or oxygen is introduced into the jacket 13. The air or oxygen is introduced into each jacket 13 in sequence to absorb the heat in the flue gas. While preventing heat waste, it preheats the air or oxygen. The air or oxygen is introduced into the fluidized bed furnace 1 through the air inlet 14 to improve the oxidation efficiency of carbon in the silicon powder waste, thereby improving the carbon removal efficiency.

[0024] The overflow port 15 of the fluidized bed furnace 1 is connected to a cooler 16, and the discharge port of the cooler 16 is connected to a magnetic separator 17. Both the cooler 16 and the magnetic separator 17 are existing equipment. When the present invention is in operation, as the material is continuously fed into the furnace, the amount of material in the bed increases and the bed height rises. When the bed height exceeds the height of the overflow port 15, following the "principle of communicating vessels", the calcined silicon powder waste, whose density has changed, will automatically and continuously overflow from the overflow port 15 like a liquid. At this time, the temperature of the discharged silicon powder waste reaches several hundred degrees Celsius. A spiral cooler or a drum cooler or other cooler 16 can be used to rapidly cool it to maintain its high activity. At the same time, since the silicon powder waste contains a certain amount of iron powder, a high gradient magnetic separator or other magnetic separator 17 can be used to remove the iron powder impurities, thereby improving the purity and value of the silicon powder waste.

[0025] A cooler 18 is installed on the pipeline at the air inlet of the cyclone dust collector 2. The air outlet of the cooler 18 is connected to the furnace chamber of the fluidized bed furnace 1 above the air distribution plate 5 through a pipeline. The cooler 18 is an existing gas-to-gas heat exchanger. A shell-and-tube heat exchanger can be selected, or other types of heat exchangers can be selected as needed. This utility model uses the cooler 18 to cool the exhaust gas, avoiding the burning of the filter bags in the subsequent bag dust collector 3. At the same time, air or oxygen is used to exchange heat with the flue gas, thereby increasing the temperature of the air or oxygen. Then, the preheated air or oxygen is introduced into the furnace chamber of the fluidized bed furnace 1 for makeup air, providing sufficient oxygen in the furnace chamber to ensure that the silicon powder waste in the airflow can be completely burned before leaving the furnace chamber, thereby improving the carbon removal efficiency. At the same time, the preheating of the air or oxygen can also improve the oxidation efficiency of carbon in the silicon powder waste.

Claims

1. A device for sorting and removing impurities from silicon powder waste material, comprising a fluidized bed furnace (1), a cyclone (2) and a bag filter (3), characterized in that: Several cyclone separators (4) are evenly distributed around the fluidized bed furnace (1). The upper part of the fluidized bed furnace (1) is connected to each of the cyclone separators (4) through a connecting pipe. An air distribution plate (5) is provided inside the fluidized bed furnace (1). The dust discharge pipe at the bottom of the cyclone separator (4) is connected to the fluidized bed furnace (1) above the air distribution plate (5). A gas collection ring pipe (6) is provided above the fluidized bed furnace (1). The gas outlet pipe at the top of the cyclone separator (4) is connected to the gas collection ring pipe (6). The gas collection ring pipe (6) is connected to the feed pipe (8) of the fluidized bed furnace (1) through a return pipe (7). An inlet (9) is provided on the feed pipe (8). The gas collection ring pipe (6) is connected to the cyclone dust collector (2) and the bag dust collector (3) in sequence through an exhaust pipe.

2. The silicon powder waste sorting and impurity removal device according to claim 1, characterized in that: A screw conveyor (10) is provided above the feed pipe (8), and the outlet of the screw conveyor (10) is connected to the inlet (9) on the feed pipe (8).

3. The silicon powder waste sorting and impurity removal device according to claim 1, characterized in that: A stirrer (11) is installed in the feed pipe (8) below the feed inlet (9).

4. The silicon powder waste sorting and impurity removal device according to claim 1, characterized in that: The feed pipe (8) is provided with a spiral guide plate (12), which is located on the side of the feed inlet (9) away from the fluidized bed furnace (1).

5. The silicon powder waste sorting and impurity removal device according to claim 1, characterized in that: The outer wall of the cyclone separator (4) is provided with a jacket (13), and the jackets (13) on each cyclone separator (4) are connected in series. The air outlet of the jacket (13) is connected to the air inlet (14) of the fluidized bed furnace (1) through a pipeline.

6. The silicon powder waste sorting and impurity removal device according to claim 1, characterized in that: The overflow port (15) of the fluidized bed furnace (1) is connected to a cooler (16), and the discharge port of the cooler (16) is connected to an iron remover (17).

7. The silicon powder waste sorting and impurity removal device according to claim 1, characterized in that: A cooler (18) is installed on the pipeline at the air inlet end of the cyclone dust collector (2), and the air outlet of the cooler (18) is connected to the furnace of the fluidized bed furnace (1) above the air distribution plate (5) through the pipeline.

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