A method and device for calcining powder material

Abstract

The present invention belongs to the field of material calcination, and discloses a calcination method and a calcination device for powder materials. Without modifying the existing suspension kiln, the reaction time of the powder materials is extended, so that the quality of the powder material finished product meets the required requirements. The calcination method includes: step 1, conveying the raw materials of the powder materials to the suspension calcination furnace for calcination; the temperature of the calcined powder materials is increased to the tempering temperature of the powder materials in the reactor; step 2, opening the feed valve located upstream of the reactor, and closing the discharge valve located downstream of the reactor; conveying the calcined powder materials to the reactor; step 3, when the powder materials accumulate in the reactor and reach the preset material level for the first time, opening the discharge valve, and adjusting the feeding speed of the feed valve and the discharge speed of the discharge valve, so that the actual residence time of the powder materials in the reactor is equal to the preset tempering time; discharging the powder materials in the reactor from the discharge valve to obtain the powder material finished product until the calcination is completed.

Description

Technical Field

[0001] The invention belongs to the field of material calcination, and in particular relates to a method and a device for calcining powder materials. Background Art

[0002] At present, the comprehensive utilization rate of blast furnace slag is about 69% of the total amount, and the recycling and utilization channels are relatively single. Usually, blast furnace slag is used as a mixed material in cement plants; blast furnace slag is used as an admixture in concrete mixing plants. The use of granulated blast furnace slag to prepare blast furnace slag microcrystalline glass has become a new way to utilize blast furnace slag resources. By suspending and calcining the granulated blast furnace slag powder, heating and oxidizing the residual sulfur and unoxidized low-valent iron and other reducing substances, the chemical oxygen demand (abbreviated as: COD) of the granulated blast furnace slag powder is reduced, providing high-performance quality raw materials for the subsequent production of microcrystalline glass.

[0003] The suspension calcining furnace adopts advanced suspension calcining technology. Usually, the crushed block material (generally <80mm) is first ground into fine powder, then preheated by cyclone preheater, calcined in the suspension calcining furnace, and cooled by cyclone cooler to obtain the finished product. Due to the use of powder suspension calcination, the heat exchange area of ​​the material is greatly increased, the reaction rate is fast, and the calcination time is sharply shortened.

[0004] The COD content of blast furnace slag powder used to prepare blast furnace slag glass-ceramics must be less than 1000 mg / kg. The COD content of existing blast furnace slag powder is in the range of 7000 to 10000 mg / kg, and blast furnace slag powder that has not been calcined cannot meet the COD index requirements. If suspended calcined blast furnace slag powder is used, the finished product indicators cannot meet the COD index requirements due to the short calcination time in the suspended calcining furnace. Therefore, how to obtain blast furnace slag powder with a COD content of less than 1000 mg / kg is a technical problem faced by those skilled in the art.

[0005] Some existing manufacturers use flame-muffled rotary kilns or tunnel / roller kilns to calcine kaolin. Although the whiteness of the product can reach the requirement of more than 90%, the rotary kiln has disadvantages such as high heat consumption and large equipment loss. Tunnel kilns or roller kilns have disadvantages such as complicated procedures, long calcination time, low production capacity, etc., and the economic benefits are low. When calcining kaolin in a suspension calcining furnace, it is difficult to ensure that the whiteness of the calcined product can reach the quality requirement of more than 90% due to the short calcination time of the suspension calcining furnace. If the length of the suspension calcining furnace is extended, thereby extending the calcination time, in order to obtain a product with the required whiteness, this solution will greatly increase the equipment investment cost. Therefore, how to obtain kaolin with a whiteness ≥ 90% is also a technical problem faced by technical personnel in this field. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a method and device for calcining powder materials, which can prolong the reaction time of the powder materials without modifying the existing suspension kiln, so that the quality of the powder materials reaches the required requirements.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a method for calcining a powder material, comprising:

[0009] Step 1, transporting the raw materials of the powder material to a suspension calcining furnace for calcining, and raising the temperature of the calcined powder material to the tempering temperature of the powder material in the reactor;

[0010] Step 2, opening the feed valve located upstream of the reactor and closing the discharge valve located downstream of the reactor; conveying the powder material calcined in step 1 to the reactor, and accumulating the powder material in the reactor;

[0011] Step 3: When the powder material accumulates in the reactor and reaches a preset material level for the first time, the discharge valve is opened, and the feeding speed of the feeding valve and the discharging speed of the discharging valve are adjusted so that the actual residence time of the powder material in the reactor is equal to the preset tempering time; the powder material in the reactor is discharged from the discharge valve to obtain a finished powder material until the calcination is completed.

[0012] As a preferred example, in step 1, the calcination time is less than or equal to 10 seconds.

[0013] As a preferred example, the tempering temperature is 850-1000° C.; in step 2, the calcined powder material is separated into gas and solid by a cyclone separator, and the separated powder material is transported to the reactor.

[0014] As a preferred example, in step 3, the preset tempering time is 1 to 120 minutes.

[0015] As a preferred example, in step 3, the discharge speed of the discharge valve and the feeding speed of the feeding valve are adjusted so that the top of the powder material accumulated in the reactor is always located at a preset material level until the calcination is completed.

[0016] As a preferred example, in step 3, after the discharge valve is opened, the reactor continuously discharges and feeds.

[0017] As a preferred example, the step 3 further comprises: using an air cannon to intermittently spray air toward the powder material in the reactor.

[0018] As a preferred example, in step 1, the raw material of the powder material is preheated and then transported to a suspension calcining furnace for calcination; step 3 also includes: discharging the powder material in the reactor from a discharge valve, and cooling it to form a finished powder material.

[0019] As a preferred example, the raw material of the powder material is blast furnace slag or kaolin.

[0020] In a second aspect, the present invention also provides a calcining device for powder materials, characterized in that the calcining device includes a suspension calcining furnace, a cyclone separator, a reactor, a feed valve, a discharge valve, a feed pipe, and a discharge pipe; wherein the outlet of the suspension calcining furnace is connected to the inlet of the cyclone separator, the material outlet of the cyclone separator is connected to the reactor inlet through the feed pipe, the reactor outlet is connected to the discharge pipe, the feed valve is installed on the feed pipe, and the discharge valve is installed on the discharge pipe.

[0021] As a preferred example, the feed port of the reactor is located at the top of the reactor, and the discharge port of the reactor is located at the bottom of the reactor; the reactor includes a feed part, a middle body and a buffer hopper which are connected and communicated with each other from top to bottom, the middle body is a hollow cone with a larger upper part and a smaller lower part, and the buffer hopper is a trumpet-shaped body with a larger upper part and a smaller lower part.

[0022] As a preferred example, a level meter is provided in the reactor, and the level meter is used to detect whether the top of the powder material accumulated in the reactor has reached a preset level.

[0023] As a preferred example, the powder material calcining device further comprises an air cannon, which is connected to the inner cavity of the reactor and is used for intermittently spraying air into the inner cavity of the reactor.

[0024] As a preferred example, the powder material calcining device further comprises a heating device, which is connected to the reactor and is used to increase the temperature of the inner cavity of the reactor.

[0025] Compared with the prior art, the calcination method and calcination device of the powder material of the present invention prolong the reaction time of the powder material and improve the quality of the finished powder material without modifying the existing suspension kiln. The calcination method comprises: step 1, conveying the raw material of the powder material to the suspension calcination furnace for calcination, and the temperature of the calcined powder material is increased to the tempering temperature of the powder material in the reactor; step 2, opening the feed valve located upstream of the reactor, and closing the discharge valve located downstream of the reactor; conveying the powder material calcined in step 1 to the reactor, and the powder material is accumulated in the reactor; step 3, when the accumulation of the powder material in the reactor reaches the preset material level for the first time, opening the discharge valve, and adjusting the feeding speed of the feed valve and the discharge speed of the discharge valve, so that the actual residence time of the powder material in the reactor is equal to the preset tempering time; discharging the powder material in the reactor from the discharge valve to obtain the finished powder material, until the calcination is completed. By arranging a reactor downstream of the suspension calciner, the powder material discharged from the suspension calciner continues to react in the high temperature environment of the reactor, which is equivalent to extending its calcination time in the suspension calciner, thereby obtaining a powder material finished product of the required quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 3 is a schematic diagram of the structure of an embodiment of the present invention, in which the dotted line with an arrow represents the flow direction of the gas, and the solid line with an arrow represents the flow direction of the powder material.

[0027] The figure includes: a feed valve 1, a reactor 2, a feed part 201, a middle body 202, a buffer hopper 203, a level meter 3, an air cannon 4, a cyclone separator 5, a discharge valve 6, a suspension calcining furnace 7, a cooler 8, and a preheater 9. DETAILED DESCRIPTION

[0028] The technical solution of the present invention is described in detail below in conjunction with the accompanying drawings.

[0029] The embodiment of the present invention provides a method for calcining a powder material, comprising:

[0030] Step 1: transport the raw material of the powder material to the suspension calcining furnace 7 for calcining. In the suspension calcining furnace 7, the raw material of the powder material completes chemical reactions such as heating and decomposition. The temperature of the calcined powder material rises to the tempering temperature of the powder material in the reactor 2.

[0031] In step 1, the suspension calcining furnace 7 calcines the raw material of the powder material for a time of less than or equal to 10 seconds. The calcination time of the material in the existing suspension calcining furnace 7 is usually less than or equal to 10 seconds. The present invention prolongs the reaction time of the powder material in a high temperature environment by adding a reactor 2 without modifying the structure of the existing suspension calcining furnace 7. Preferably, in step 1, the temperature of the powder material after calcination in the suspension calcining furnace 7 is increased to the tempering temperature of the powder material in the reactor 2. The powder material reacts under the tempering temperature environment of the reactor 2. If the temperature in the reactor 2 is lower than the tempering temperature, the reactor 2 is heated by a heating device so that the temperature of its inner cavity reaches the tempering temperature. Preferably, the tempering temperature is 850 to 1000°C, for example, 850°C, 880°C, 900°C, 930°C or 1000°C. These high-temperature powder materials enter the reactor 2, still maintain a high temperature state, and continue to react in the reactor 2. If the temperature of the powder material in the reactor 2 decreases, the reactor 2 may be heated by an external heating device to maintain a high temperature environment of the reactor 2 .

[0032] The raw material of the powder material can be blast furnace slag or kaolin, or other materials. As long as the quality of the powder material does not meet the standard after calcination in the suspension calcining furnace 7 and still needs to be in a high temperature environment, the method and device of the present invention can be used for calcination.

[0033] Step 2, open the feed valve 1 located upstream of the reactor 2, and close the discharge valve 6 located downstream of the reactor 2; transport the powder material calcined in step 1 to the reactor 2, and the powder material is accumulated in the reactor 2.

[0034] In step 2, the feed valve 1 is opened to convey the powder material calcined in the suspension calcining furnace 7 to the reactor 2. The powder material falls into the reactor 2 from the top of the reactor 2. Since the discharge valve 6 is closed at this time, the powder material accumulates in the reactor 2, and the accumulation height of the powder material gradually increases.

[0035] Preferably, the calcined powder material is subjected to gas-solid separation by a cyclone separator 5, and the separated powder material is transported to the reactor 2. Since the outlet of the suspension calciner 7 is located at the upper part of the suspension calciner 7, the powder material flows from bottom to top in the suspension calciner 7 along with the airflow, so a cyclone separator 5 is provided to perform gas-solid separation on the powder material and the airflow flowing out of the suspension calciner 7, and the powder material is transported to the reactor 2. The high-temperature airflow separated by the cyclone separator 5 can be used for preheating the raw material of the powder material before being transported to the suspension calciner 7. The raw material of the preheated powder material is transported to the suspension calciner 7 for calcination.

[0036] Step 3: When the powder material accumulates in the reactor 2 and reaches the preset material level for the first time, the discharge valve 6 is opened, and the feeding speed of the feeding valve 1 and the discharging speed of the discharge valve 6 are adjusted so that the actual residence time of the powder material in the reactor 2 is equal to the preset tempering time; the powder material in the reactor 2 is discharged from the discharge valve 6 to obtain a finished powder material until the calcination is completed.

[0037] When the feed valve 1 is opened and the discharge valve 6 is closed, the powder material falls into the reactor 2, accumulates in the reactor 2, and the accumulation height gradually increases. When the accumulation height reaches the preset material level for the first time, the discharge valve 6 is opened to discharge the powder material from the reactor 2. When the discharge valve 6 is opened, the feeding speed of the feed valve 1 and the discharge speed of the discharge valve 6 are adjusted so that the actual residence time of the powder material in the reactor 2 is equal to the preset tempering time. When the actual residence time of the powder material in the reactor 2 reaches the preset tempering time, the powder material completes the reaction under the high temperature environment, and its quality can meet the quality requirements. The actual residence time of the powder material in the reactor 2 reaches the preset tempering time, which is equivalent to extending its calcination time in the suspension calcining furnace 7. Preferably, the preset tempering time is 1 to 120 minutes, for example, 1 minute, 20 minutes, 45 minutes, 60 minutes, 80 minutes, 95 minutes, 110 minutes, 120 minutes. More preferably, the preset tempering time is 80 to 120 minutes. Of course, the preset conditioning time may also exceed 120 minutes, such as 135 minutes, 150 minutes, etc.

[0038] In step 3, when the stacking height of the powder material in the reactor 2 reaches the preset material level for the first time, the actual residence time of the powder material at the bottom of the reactor 2 in the reactor 2 reaches the preset tempering time. At this time, the discharge valve 6 is opened to discharge the powder material at the bottom of the reactor 2. By adjusting the feeding speed of the feeding valve 1 and the discharging speed of the discharge valve 6, the reactor 2 is continuously discharged and continuously fed. The powder material is calcined by the suspension calcining furnace 7 and enters the reactor 2 from the feeding valve 1. In the reactor 2, the powder material gradually sinks from top to bottom and is finally discharged from the reactor 2. The time from the powder material falling into the reactor 2 to the discharge of the reactor 2 is the preset tempering time. After opening the discharge valve 6, the reactor 2 is continuously discharged and continuously fed. This greatly improves the operating efficiency.

[0039] Preferably, in step 3, the discharge speed of the discharge valve 6 and the feeding speed of the feeding valve 1 are adjusted so that the top of the powder material accumulated in the reactor 2 is always located at the preset material level until the calcination is completed. The preset material level can be a height interval or a height value. When the accumulation height of the powder material in the reactor 2 reaches the preset material level for the first time, the discharge valve 6 is opened. The discharge speed of the discharge valve 6 and the feeding speed of the feeding valve 1 are adjusted so that the top of the powder material accumulated in the reactor 2 is always located at the preset material level. In this way, the actual residence time of the powder material in the reactor 2 can be ensured to be the preset tempering time, and continuous feeding and continuous discharging of the reactor 2 can be achieved.

[0040] Preferably, step 3 further comprises: using an air cannon 4 to intermittently spray air toward the powder material in the reactor 2. Using the air cannon 4 to intermittently spray air toward the powder material in the reactor 2 can effectively prevent the powder material from causing material accumulation and blockage in the reactor 2. The spraying cycle of the air cannon 4 can be adjusted according to the working conditions, for example, spraying once every 10 minutes.

[0041] Preferably, in step 1, the raw material of the powder material is preheated and then transported to the suspension calcining furnace 7 for calcination. The heat source for the preheating of the raw material of the powder material can come from the high-temperature airflow separated by the cyclone separator 5. This not only realizes the utilization of the waste heat discharged from the suspension calcining furnace 7, but also reduces the energy consumption of the suspension calcining furnace 7.

[0042] Preferably, step 3 further comprises: discharging the powder material in the reactor 2 from the discharge valve 6, and forming a powder material finished product after cooling treatment. The temperature of the powder material discharged from the reactor 2 is relatively high, so it needs to be cooled. The temperature of the powder material after cooling treatment can be 100-150°C. The cooling treatment adopts conventional technology, such as air cooling. After heat exchange between normal temperature air and the powder material discharged from the reactor 2, the temperature of the powder material decreases and the temperature of the air increases. The air with increased temperature is transported to the air inlet of the suspension calcining furnace 7 to participate in the reaction of the powder material. This in turn reduces the energy consumption of the suspension calcining furnace 7.

[0043] like Figure 1 As shown, the embodiment of the present invention also provides a calcining device for powder materials, including a suspension calcining furnace 7, a cyclone separator 5, a reactor 2, a feed valve 1, a discharge valve 6, a feed pipe and a discharge pipe. The outlet of the suspension calcining furnace 7 is connected to the inlet of the cyclone separator 5, the material outlet of the cyclone separator 5 is connected to the feed inlet of the reactor 2 through the feed pipe, the discharge port of the reactor 2 is connected to the discharge pipe, the feed valve 1 is installed on the feed pipe, and the discharge valve 6 is installed on the discharge pipe. Both the feed valve 1 and the discharge valve 6 can be frequency-controlled.

[0044] The calcining device of this embodiment can extend the high-temperature reaction time of the powder material without modifying the suspension calcining furnace 7. The powder material calcined in the suspension calcining furnace 7 is separated into gas and solid by the cyclone separator 5 and then enters the reactor 2. The powder material discharged from the suspension calcining furnace 7 is kept at a high temperature, which can reach 850-1000°C. After entering the reactor 2, the powder material still maintains a high temperature state. In the reactor 2, the powder material continues to react under high temperature. This prolongs the high-temperature reaction time of the powder material, so that the product after the reaction can reach the required finished product quality. This embodiment prolongs the high-temperature reaction time of the powder material by adding a reactor 2 without modifying the structure of the existing suspension calcining furnace 7. If the reactor 2 is not added, in order to achieve the required finished product quality, the suspension calcining furnace 7 can only be modified to make the furnace body longer, thereby prolonging the reaction time of the powder material in the furnace body. This method is costly and occupies a larger space, which is difficult to implement.

[0045] Preferably, the feed port of the reactor 2 is located at the top of the reactor 2, and the discharge port of the reactor 2 is located at the bottom of the reactor 2. In this way, the powder material can automatically enter the reactor 2 under its own gravity, and can also be automatically discharged from the reactor 2 under its own gravity.

[0046] Preferably, the reactor 2 comprises a feed part 201, a middle body 202 and a buffer hopper 203 which are connected and communicated from top to bottom, the middle body 202 is a hollow cone with a large top and a small bottom, and the buffer hopper 203 is a trumpet-shaped body with a large top and a small bottom. No partition is provided in the reactor 2, and there is only one cavity. In this way, the structure is simpler and more compact. The feed part 201 can be cylindrical, used to receive the powder material discharged from the suspension calcining furnace 7. The feed part 201 is cylindrical, which is conducive to its sealed connection with the feed pipe. The middle body 202 is a hollow cone with a large top and a small bottom. The transverse cross-sectional diameter of the middle body 202 gradually decreases from top to bottom, so that the powder material flows to the discharge port. The top surface of the middle body 202 is adapted to the bottom surface of the feed part 201 and is sealed. The buffer hopper 203 is a trumpet-shaped body with a large top and a small bottom. The discharge port of the reactor 2 is the bottom end of the buffer hopper 203. The top surface of the buffer hopper 203 and the bottom surface of the middle body 202 are adapted and sealed. The bottom surface of the buffer hopper 203 is sealed and connected to the discharge pipe. In order to prevent the powder material in the reactor 2 from generating secondary dust and poor discharge, the middle body 202 is a hollow cone with a larger top and a smaller bottom, and the cone angle is 20° to 35°. The buffer hopper 203 is provided to facilitate smooth material discharge and improve the operating efficiency of the device. Preferably, the feed part 201, the middle body 202 and the buffer hopper 203 are integrally formed to improve the sealing performance.

[0047] Preferably, the reactor 2 is provided with a level meter 3, which is used to detect whether the top of the powder material accumulated in the reactor 2 has reached a preset level. The level meter 3 is used to detect the height of the powder material accumulated in the reactor 2 in real time. When the top of the powder material accumulated in the reactor 2 reaches the preset level for the first time, the discharge valve 6 is opened. After the discharge valve 6 is opened, the discharge speed of the discharge valve 6 and the feeding speed of the feeding valve 1 are adjusted so that the top of the powder material accumulated in the reactor 2 is located at the preset level. If the level meter 3 detects that the top of the powder material accumulated in the reactor 2 is not located at the preset level, the discharge speed of the discharge valve 6 and / or the feeding speed of the feeding valve 1 are adjusted so that the top of the powder material accumulated in the reactor 2 is located at the preset level.

[0048] Preferably, the calcining device for the powder material further comprises an air cannon 4. The air cannon 4 is connected to the inner cavity of the reactor 2, and the air cannon 4 is used to intermittently spray air into the inner cavity of the reactor 2. The middle body 202 of the reactor 2 is a hollow cone that is larger at the top and smaller at the bottom, and the buffer hopper 203 is a trumpet-shaped body that is larger at the top and smaller at the bottom. When the powder material flows in the middle body 202 and the buffer hopper 203, it may be blocked or accumulated on the inner wall of the reactor 2. An air cannon 4 is provided to intermittently spray air into the powder material in the reactor 2. This can effectively prevent the powder material from causing material accumulation and blockage in the reactor 2.

[0049] Preferably, the calcining device for the powder material also includes a heating device. The heating device is connected to the reactor 2, and the heating device is used to increase the temperature of the inner cavity of the reactor 2. In order to reduce the heat dissipation of the reactor 2, a heating device can be added outside the reactor 2. The heating device can be an electric heating rod. The electric heating rod is connected to the wall of the reactor 2. According to the process requirements, heat is transferred to the reactor 2 through the electric heating rod, so that the temperature of the inner cavity of the reactor 2 can be maintained at a high temperature, for example, 850 to 1000°C. This is conducive to the reaction of the powder material in the reactor 2 at a high temperature.

[0050] Preferably, the calcining device for the powder material further comprises a preheater 9. An inlet of the preheater 9 is connected to the air flow outlet of the cyclone separator 5, an outlet of the preheater 9 is a waste gas outlet, and another outlet of the preheater 9 is connected to the feed port of the suspension calcining furnace 7. After the cyclone separator 5 performs gas-solid separation, the separated high-temperature gas is passed into the preheater 9, and after the raw material of the powder material in the preheater 9 is heated, the raw material of the powder material is transported to the suspension calcining furnace 7 for calcination, and the waste gas is discharged from an outlet of the preheater 9.

[0051] Preferably, the calcining device for the powder material further comprises a cooler 8. The feed port of the cooler 8 is connected to the outlet of the discharge pipe, the air inlet of the cooler 8 is communicated with the outside, and the air outlet of the cooler 8 is connected to the air inlet of the suspension calcining furnace 7. During operation, the high-temperature powder material discharged from the discharge pipe exchanges heat with the air in the cooler 8, and the powder material after cooling is discharged from the discharge port of the cooler 8 as a finished product. The heated air is discharged from the air outlet of the cooler 8 and enters the suspension calcining furnace 7 to participate in calcination.

[0052] The calcination method and calcination device of the above embodiment prolong the residence time of the powder material in the high temperature area of ​​the suspension calcination furnace 7 without modifying the suspension calcination furnace 7, and obtain the powder material finished product of the required quality. The calcination device can reduce the operating cost. In order to obtain the powder material finished product of the required quality, it is not necessary to modify the suspension calcination furnace 7, and it is not necessary to increase the length of the suspension calcination furnace 7.

[0053] Six embodiments are given below. All of the six embodiments adopt the calcination method and calcination device provided by the present invention.

[0054] Embodiment 1: A method for calcining granulated blast furnace slag powder, comprising:

[0055] Step 1, conveying the blast furnace slag to the suspension calcining furnace 7 for calcining; the calcining time of the suspension calcining furnace is 9 seconds, the temperature of the granulated blast furnace slag powder after calcination is 950° C., and the tempering temperature is 950° C.;

[0056] Step 2, opening the feed valve 1 located upstream of the reactor 2, and closing the discharge valve 6 located downstream of the reactor 2; conveying the granulated blast furnace slag powder calcined in step 1 to the reactor 2, and accumulating the granulated blast furnace slag powder in the reactor 2;

[0057] Step 3: When the granulated blast furnace slag powder accumulates in the reactor 2 and reaches a preset material level for the first time, the discharge valve 6 is opened, and the feeding speed of the feeding valve 1 and the discharging speed of the discharge valve 6 are adjusted so that the actual residence time of the granulated blast furnace slag powder in the reactor 2 is equal to the preset tempering time; the granulated blast furnace slag powder in the reactor 2 is discharged from the discharge valve 6 to obtain a finished product until the calcination is completed.

[0058] In the above calcination method, the preset tempering time of the granulated blast furnace slag powder in the reactor 2 is 2 hours. Before step 1, the blast furnace slag is preheated, and the temperature of the preheated blast furnace slag is 800°C.

[0059] Example 2: A method for calcining granulated blast furnace slag powder, which is the same as the method in Example 1, except that the preset tempering time of the granulated blast furnace slag powder in the reactor 2 is 1.8 hours.

[0060] Example 3: A method for calcining granulated blast furnace slag powder is the same as the method in Example 1, except that the preset tempering time of the granulated blast furnace slag powder in the reactor 2 is 1.5 hours.

[0061] For the finished products obtained in Examples 1 to 3, 0.5 g of each was taken for COD testing. COD was tested according to the method disclosed in China's National Environmental Protection Standard HJ828-2017. The test results are: the COD content of the finished product obtained in Example 1 is 450 mg / kg; the COD content of the finished product obtained in Example 2 is 780 mg / kg; the COD content of the finished product obtained in Example 3 is 970 mg / kg.

[0062] It can be seen that in Examples 1 to 3, the granulated blast furnace slag powder prepared by the calcination method of the present invention, without modifying the existing suspension kiln, prolongs the reaction time of the granulated blast furnace slag powder under the same calcination temperature, so that the quality of the finished granulated blast furnace slag powder reaches the required requirement, that is, the COD content is less than 1000 mg / kg.

[0063] Embodiment 4: A method for calcining kaolin, comprising:

[0064] Step 1, conveying kaolin to the suspension calcining furnace 7 for calcining; the calcining time of the suspension calcining furnace is 8 seconds, the temperature of the kaolin powder after calcination is 900°C, and the tempering temperature is 900°C;

[0065] Step 2, opening the feed valve 1 located upstream of the reactor 2, and closing the discharge valve 6 located downstream of the reactor 2; conveying the calcined kaolin powder in step 1 to the reactor 2, and accumulating the kaolin powder in the reactor 2;

[0066] Step 3: When the kaolin powder accumulates in the reactor 2 and reaches the preset material level for the first time, the discharge valve 6 is opened, and the feeding speed of the feeding valve 1 and the discharging speed of the discharge valve 6 are adjusted so that the actual residence time of the kaolin powder in the reactor 2 is equal to the preset tempering time; the kaolin powder in the reactor 2 is discharged from the discharge valve 6 to obtain the finished product until the calcination is completed.

[0067] The main chemical components of kaolin are SiO2 and Al2O3. The kaolin used in this embodiment contains 44.6% by mass of SiO2 and 34.1% by mass of Al2O3.

[0068] In the above calcination method, the preset tempering time of the kaolin powder in the reactor 2 is 1.5 hours. Before step 1, the kaolin is preheated, and the temperature of the preheated kaolin is 760°C.

[0069] Example 5: A method for calcining kaolin, which has the same steps as Example 4, except that the preset tempering time of the kaolin powder in the reactor 2 is 1 hour.

[0070] Example 6: A method for calcining kaolin, which has the same steps as Example 4, except that the preset tempering time of the kaolin powder in the reactor 2 is 0.5 hours.

[0071] The whiteness of kaolin is one of the important indicators that determine the use and economic value of kaolin. For the finished products obtained in Examples 4 to 6, 10 grams of each was taken for whiteness test. The whiteness of kaolin was tested using the method in national standard GB / T 5950-2008. The test results are: the whiteness of kaolin in Example 4 is 92%; the whiteness of kaolin in Example 5 is 91%; and the whiteness of kaolin in Example 6 is 90%.

[0072] It can be seen that in Examples 4 to 6, the kaolin powder prepared by the calcination method of the present invention prolongs the reaction time of the kaolin powder without modifying the existing suspension kiln, that is, the reaction and tempering time is not less than 0.5h, so that the quality of the kaolin powder product meets the required requirements, that is, whiteness ≥90%.

[0073] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above specific embodiments. The above specific embodiments and the description in the specification are only for further illustrating the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of the present invention to be protected is defined by the claims and their equivalents.

Claims

1. A method for calcining a powder material, characterized in that: The method comprises: Step 1, conveying the raw material of the powder material to the suspension calcining furnace (7) for calcination, and raising the temperature of the calcined powder material to the tempering temperature of the powder material in the reactor (2); the tempering temperature is 850-1000° C.; The feed inlet of the reactor (2) is located at the top of the reactor (2), and the discharge outlet of the reactor (2) is located at the bottom of the reactor (2); the reactor (2) comprises a feed part (201), a middle body (202) and a buffer hopper (203) which are connected and communicated with each other in sequence from top to bottom, the middle body (202) is a hollow cone-shaped body which is larger at the top and smaller at the bottom, and the buffer hopper (203) is a trumpet-shaped body which is larger at the top and smaller at the bottom; Step 2: opening the feed valve (1) located upstream of the reactor (2), and closing the discharge valve (6) located downstream of the reactor (2); conveying the powder material calcined in step 1 to the reactor (2), and accumulating the powder material in the reactor (2); wherein: The calcined powder material is separated into gas and solid by a cyclone separator (5), and the separated powder material is transported to a reactor (2); Step 3: When the powder material accumulates in the reactor (2) and reaches a preset material level for the first time, the discharge valve (6) is opened, and the feeding speed of the feeding valve (1) and the discharging speed of the discharge valve (6) are adjusted so that the actual residence time of the powder material in the reactor (2) is equal to the preset tempering time; the powder material in the reactor (2) is discharged from the discharge valve (6) to obtain a powder material finished product until the calcination is completed; wherein, Adjusting the discharge speed of the discharge valve (6) and the feeding speed of the feeding valve (1) so that the top of the powder material accumulated in the reactor (2) is always located at a preset material level until the calcination is completed; The step 3 also includes: using an air cannon to intermittently spray air toward the powder material in the reactor (2).

2. The method for calcining powder materials according to claim 1, characterized in that: In the step 1, the calcination time is less than or equal to 10 seconds.

3. The method for calcining powder materials according to claim 1, characterized in that: In step 3, the preset tempering time is 1 to 120 minutes.

4. The method for calcining powder materials according to claim 1, characterized in that: In the step 3, after the discharge valve (6) is opened, the reactor (2) continuously discharges and continuously feeds.

5. The method for calcining powder materials according to claim 1, characterized in that: In the step 1, the raw material of the powder material is preheated and then transported to a suspension calcining furnace (7) for calcination; The step 3 further comprises: discharging the powder material in the reactor (2) from the discharge valve (6), and cooling the powder material to form a finished powder material product.

6. The method for calcining powder materials according to claim 1, characterized in that: The raw material of the powder material is blast furnace slag or kaolin.

7. A calcining device for calcining powder materials using the calcining method according to any one of claims 1 to 6, characterized in that: The calcining device comprises a suspension calcining furnace (7), a cyclone separator (5), a reactor (2), a feed valve (1), a discharge valve (6), a feed pipe, and a discharge pipe; wherein: The outlet of the suspension calcining furnace (7) is connected to the inlet of the cyclone separator (5), the material outlet of the cyclone separator (5) is connected to the inlet of the reactor (2) through a feed pipe, the outlet of the reactor (2) is connected to the discharge pipe, the feed valve (1) is installed on the feed pipe, and the discharge valve (6) is installed on the discharge pipe.

8. The calcining device for powder materials according to claim 7, characterized in that: The reactor (2) is provided with a material level meter (3), and the material level meter (3) is used to detect whether the top of the powder material accumulated in the reactor (2) has reached a preset material level.

9. The calcining device for powder materials according to claim 7, characterized in that: It also comprises an air cannon (4), wherein the air cannon (4) is connected to the inner cavity of the reactor (2), and the air cannon (4) is used to intermittently spray air into the inner cavity of the reactor (2).

10. The calcining device for powder materials according to claim 7, characterized in that: It also comprises a heating device, which is connected to the reactor (2) and is used to increase the temperature of the inner cavity of the reactor (2).

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