Calcination method of powder material, tempering reactor and calcination device

Abstract

The invention belongs to the field of calcination of powder materials, and discloses a calcination method, a tempering reactor and a calcination device of a powder material, which can prolong the reaction time of the powder material and improve the product quality. The calcining method of the powder material comprises the following steps: step 1, conveying raw materials of the powder material into a suspension calcining furnace for calcining; 2, starting the tempering reactor, wherein the tempering reactor rotates along the axis of the tempering reactor; conveying the powder material calcined in the step 1 into a tempering reactor; the tempering reactor is in a horizontal type and is obliquely arranged; in the tempering reactor, a combustion device is used for heating the powder material in the tempering reactor, and the tempering temperature is kept; and along with the rotation of the tempering reactor, the powder material moves from the feed port of the tempering reactor to the discharge port of the tempering reactor, and is discharged from the discharge port to obtain a powder material finished product until the tempering is finished.

Description

Technical Field

[0001] The present invention belongs to the field of calcination of powder materials, and specifically relates to a method for calcining powder materials, a conditioning reactor and a calcination device. Background Art

[0002] Suspension calcination technology has the advantages of low energy consumption, less floor area, simple operation, stability and reliability. In terms of technical principles, the transport theory of gas flow on powder, heat transfer / mass transfer / momentum transfer between gas and solid, and decomposition theory of powder, etc. are common for various powder ores, etc., and have complete replicability and popularization on the technical basic theory level.

[0003] The biggest feature of the suspension kiln is the short calcination residence time. Since the calcination time is in the "second level", for some materials, due to the short calcination time, the finished product indexes cannot fully meet the index requirements, such as the low active aluminum leaching rate of coal gangue.

[0004] The market demand for aluminum is increasing, while bauxite resources are becoming increasingly scarce. Coal gangue contains a large amount of alumina. Therefore, extracting alumina from coal gangue can effectively make up for the shortage of bauxite resources. Using coal gangue as raw material to produce alumina can not only broaden the comprehensive utilization ways of coal gangue, but also provide raw material guarantee for aluminum production. However, since the alumina and silica in coal gangue exist in an orderly kaolinite crystal phase and hardly have chemical reaction activity, it is very difficult to directly extract and utilize them. If the length of the suspension kiln is extended, the equipment investment cost will be greatly increased. Therefore, there is an urgent need for a method to improve the quality of suspension kiln calcination products at low cost. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for calcining powder materials, a conditioning reactor and a calcination device to extend the reaction time of powder materials and improve product quality.

[0006] To solve the above technical problems, the present invention adopts the following technical solutions: In the first aspect, the present invention provides a method for calcining powder materials, including: Step 1, conveying the raw material of the powder material to a suspension calcination furnace for calcination; Step 2, starting the conditioning reactor, and the conditioning reactor rotates along its axis; conveying the powder material calcined in Step 1 to the conditioning reactor; the conditioning reactor is horizontal and inclined; in the conditioning reactor, the powder material in the conditioning reactor is heated by a combustion device and the conditioning temperature is maintained; as the conditioning reactor rotates, the powder material moves from the feed inlet of the conditioning reactor to the discharge outlet of the conditioning reactor and is discharged from the discharge outlet to obtain the finished powder material until the conditioning ends.

[0007] As a preferred example, in the step 1, the calcination time is 5 to 15 seconds; in the step 2, the operating temperature of the conditioning reactor is 750 to 1200 °C; and the conditioning time of the conditioning reactor is 1 to 120 minutes.

[0008] As a preferred example, in the step 2, by controlling the rotation speed of the conditioning reactor, the residence time of the powder material in the conditioning reactor reaches the conditioning time; the rotation speed of the conditioning reactor is determined according to Equation (1): Equation (1) In the formula: n represents the rotation speed of the conditioning reactor, with the unit of rpm ; L represents the length of the conditioning reactor, with the unit of m ; D i represents the effective inner diameter of the conditioning reactor, with the unit of m ; t 2 represents the conditioning time of the powder material in the conditioning reactor, with the unit of min ; α represents the angle between the axis of the conditioning reactor and the horizontal line, with the unit of °; k represents the coefficient related to the density of the powder material.

[0009] As a preferred example, in the conditioning reactor, the flow directions of the powder material and the flue gas are opposite. When the density of the powder material ρ ≤ 1200 kg / m 3 is k , the value of ρ > 1200 kg / m 3 is 2.0; when the density of the powder material k is 。

[0010] the value of 。

[0010] is 1.5 As a preferred example, in the step 2, the calcined powder material is subjected to gas-solid separation by a cyclone separator, and the separated powder material is transported to the conditioning reactor; in the step 2, the conditioning reactor is continuously fed and continuously discharged.

[0011] As a preferred example, in the step 1, the raw material of the powder material is preheated and then transported to a suspension calcination furnace for calcination; it further includes step 3: the powder material discharged from the discharge port of the conditioning reactor is cooled to form a finished powder material product.

[0012] As a preferred example, step 2 further includes: controlling the amount of reducing gas entering the tempering reactor, as well as the combustion time and heating temperature of the combustion device, according to the gas flow rate, gas composition in the flue gas pipeline, and the temperature inside the tempering reactor; or, forming an oxidation environment or a reducing environment by adjusting the combustion-supporting air in the combustion device.

[0013] In a second aspect, the present invention provides a tempering reactor for powder materials, the tempering reactor includes a housing, and a material lifting platform located in the inner cavity of the housing, the material lifting platform is inlaid on the inner wall of the housing; the material lifting platform includes a first refractory unit in an arc shape and a second refractory unit in an arc shape, the first refractory unit and the second refractory unit are respectively arranged along the axial direction of the housing, and the first refractory unit and the second refractory unit are alternately arranged along the circumferential direction of the housing; the height of the second refractory unit is greater than the height of the first refractory unit.

[0014] As a preferred example, the length of the tempering reactor is 10 - 20 m; the effective inner diameter of the tempering reactor is as shown in formula (2): Formula (2) In the formula: D i represents the effective inner diameter of the tempering reactor, with the unit of m; G represents the daily processing capacity of the tempering reactor, with the unit of t / d; L represents the length of the tempering reactor, with the unit of m; represents the correction coefficient of the tempering reactor.

[0015] As a preferred example, the number of the first refractory units is equal to the number of the second refractory units; the central angle corresponding to each first refractory unit is equal to the central angle corresponding to each second refractory unit; the height of the second refractory unit is 1.5 - 2 times the height of the first refractory unit; when the effective inner diameter of the tempering reactor is less than 4 m, the height of the first refractory unit is 200 - 250 mm; when the effective inner diameter of the tempering reactor is greater than or equal to 4 m, the height of the first refractory unit is 250 - 300 mm.

[0016] In a third aspect, the present invention provides a calcination device, the calcination device includes a tempering reactor, a suspension calciner, and a cyclone separator; the outlet of the suspension calciner is connected to the inlet of the cyclone separator, the material outlet of the cyclone separator is connected to the feed inlet of the tempering reactor, the tempering reactor is arranged obliquely, a combustion device is provided at the discharge port of the tempering reactor, the flue gas outlet of the tempering reactor and the flue gas outlet of the cyclone separator are connected through a flue gas pipeline, the material outlet of the tempering reactor is located at the lower end of the tempering reactor; the flue gas outlet of the tempering reactor and the feed inlet of the tempering reactor are both located at the higher end of the tempering reactor.

[0017] As a preferred example, there are N tempering reactors, and the N tempering reactors are connected in series and arranged vertically; N is an integer greater than or equal to 2; the feed inlet of the tempering reactor located downstream is connected to the discharge outlet of the tempering reactor located upstream; the feed inlet of the tempering reactor located at the most upstream is connected to the material outlet of the cyclone separator.

[0018] As a preferred example, the included angle between the axis of the tempering reactor and the horizontal line is 1.5 - 3°.

[0019] As a preferred example, the calcination device further includes a cooling device and a preheating device. Among them, the discharge outlet of the tempering reactor is connected to the feed inlet of the cooling device, and the air outlet of the cooling device is connected to the air inlet of the suspension calcination furnace; the discharge outlet of the preheating device is connected to the feed inlet of the suspension calcination furnace, and the flue gas outlet of the cyclone separator is connected to the preheating device.

[0020] As a preferred example, the calcination device further includes a reducing gas pipeline with a control valve and a reducing gas source. The reducing gas source is connected to the end of the tempering reactor through the reducing gas pipeline and is located at the same end of the tempering reactor as the combustion device; a slide valve and a detection sensor are provided in the flue gas pipeline.

[0021] Compared with the prior art, the calcination method, tempering reactor and calcination device for powder materials of the present invention can extend the reaction time of the powder materials and improve the product quality. By arranging the inclined tempering reactor, during the rotation of the tempering reactor, the powder materials located in the tempering reactor are turned over and move towards the discharge outlet of the tempering reactor. This makes the powder materials heat more evenly and react more fully in the tempering reactor. Without modifying the structure of the existing suspension calcination furnace, the high-temperature reaction time of the powder materials is extended, and the quality of the finished powder materials is improved. Description of the Drawings

[0022] Figure 1 is a structural sectional view of the tempering reactor filled with powder materials in the embodiment of the present invention; Figure 2 is a structural schematic diagram of the calcination device in the embodiment of the present invention.

[0023] In the figure: tempering reactor 1, outer shell 11, material lifting platform 12, first refractory unit 121, second refractory unit 122, suspension calcination furnace 2, cyclone separator 3, cooling device 4, preheating device 5, combustion device 6, reducing gas source 7, slide valve 8, detection sensor 9, powder material 10. Detailed Embodiments

[0024] The technical solutions of the present invention will be described in detail below with reference to the drawings.

[0025] An embodiment of the present invention provides a method for calcining powder materials, including: Step 1: Transport the raw materials of the powder materials to the suspension calciner 2 for calcination.

[0026] Step 2: Start the conditioning reactor 1, and the conditioning reactor 1 rotates along its axis; transport the powder materials 10 calcined in Step 1 to the conditioning reactor 1; the conditioning reactor 1 is horizontal and arranged obliquely; In the conditioning reactor 1, use the combustion device 6 to heat the powder materials 10 in the conditioning reactor 1 and maintain the conditioning temperature; as the conditioning reactor 1 rotates, the powder materials 10 move from the feed port of the conditioning reactor 1 to the discharge port of the conditioning reactor 1 and are discharged from the discharge port to obtain the finished product of the powder materials 10 until the conditioning is completed.

[0027] In Step 1, the time for the suspension calciner 2 to calcine the raw materials of the powder materials is in the order of seconds, preferably 5 to 15 seconds, such as 5 seconds, 8 seconds, 10 seconds, 12 seconds, 15 seconds. Without modifying the structure of the existing suspension calciner, the present invention extends the reaction time of the powder materials 10 in the high-temperature environment by adding the conditioning reactor 1.

[0028] The powder materials 10 continue to react under the conditioning temperature environment in the conditioning reactor 1. If the temperature in the conditioning reactor 1 is lower than the conditioning temperature, heat the conditioning reactor 1 through the combustion device 6 to make the inner cavity temperature reach the conditioning temperature. Preferably, the conditioning temperature is 750 to 1200 °C, that is, the operating temperature of the conditioning reactor 1 is 750 to 1200 °C. For example, 750 °C, 800 °C, 950 °C, 1000 °C, 1050 °C, 1100 °C, 1150 °C or 1200 °C. Preferably, the conditioning time of the conditioning reactor 1 is 1 to 120 minutes. Adjust the conditioning time according to the quality requirements of the powder materials to make the quality of the finished product meet the requirements.

[0029] The powder materials calcined by the suspension calciner 2 enter the conditioning reactor 1 and remain in a high-temperature state, and continue to react in the conditioning reactor 1. Heat the conditioning reactor 1 through the combustion device 6 to maintain the high-temperature environment of the conditioning reactor 1. As long as the quality of the powder materials does not meet the standard after being calcined by the suspension calciner 2 and the powder materials still need to be in a high-temperature environment, the method and device of the present invention can be used to continue the calcination.

[0030] Preferably, in Step 2, by controlling the rotation speed of the conditioning reactor 1, the residence time of the powder materials 10 in the conditioning reactor 1 reaches the conditioning time. The rotation speed of the conditioning reactor 1 is determined according to Equation (1): Equation (1) Where:n represents the rotational speed of the conditioning reactor 1, with the unit of rpm ; L represents the length of the conditioning reactor 1, with the unit of m ; D i represents the effective inner diameter of the conditioning reactor 1, with the unit of m ; t 2 represents the conditioning time of the powder material 10 in the conditioning reactor 1, with the unit of min ; α represents the angle between the axis of the conditioning reactor 1 and the horizontal line, with the unit of °; k represents the coefficient related to the density of the powder material. Preferably, in the conditioning reactor 1, the powder material 10 and the flue gas flow in opposite directions, and the density of the powder material ρ ≤ 1200 kg / m 3 when k takes the value of 2.0; when the density of the powder material ρ > 1200 kg / m 3 when k takes the value of 1.5 。

[0031] By setting the rotational speed of the conditioning reactor 1, the residence time of the powder material 10 in the conditioning reactor 1 reaches the conditioning time, ensuring that the quality of the powder material finished product meets the requirements.

[0032] Preferably, in step 2, the calcined powder material is subjected to gas-solid separation by the cyclone separator 3, and the separated powder material is transported to the conditioning reactor 1. The suspension calcination furnace 2 is vertically arranged, and the outlet is located at the upper part of the suspension calcination furnace 2. The powder material flows upward with the gas flow during the calcination process in the suspension calcination furnace 2. The cyclone separator 3 is provided to perform gas-solid separation on the powder material and the gas flow flowing out of the suspension calcination furnace 2, and the powder material is transported to the conditioning reactor 1. The high-temperature gas flow separated by the cyclone separator 3 can be used for preheating the raw material of the powder material before being transported to the suspension calcination furnace 2. The preheated raw material of the powder material is transported to the suspension calcination furnace 2 for calcination.

[0033] Preferably, in step 2, the conditioning reactor 1 is continuously fed and continuously discharged. The inlet of the conditioning reactor 1 is continuously fed, and the outlet of the conditioning reactor 1 is continuously discharged. This improves the working efficiency. The conditioning reactor 1 is inclined. When the conditioning reactor 1 rotates, the powder material 10 flips in the conditioning reactor 1 and moves from the inlet of the conditioning reactor 1 to the outlet of the conditioning reactor 1. The time from when the powder material 10 enters the conditioning reactor 1 to when it is discharged from the conditioning reactor 1 is the conditioning time of the powder material 10 in the conditioning reactor 1.

[0034] Preferably, in step 1, after the raw material of the powder material is preheated, it is transported to the suspension calcination furnace 2 for calcination. The heat source for the preheating treatment of the raw material of the powder material can come from the high-temperature gas flow separated by the cyclone separator 3. This not only realizes the utilization of the waste heat discharged from the suspension calcination furnace 2 but also reduces the energy consumption of the suspension calcination furnace 2.

[0035] Preferably, the calcination method further includes step 3: the powder material discharged from the discharge port of the conditioning reactor 1 forms a finished powder material after being cooled. The temperature of the powder material discharged from the conditioning reactor 1 is relatively high, and cooling treatment is carried out to reduce its temperature. The temperature of the powder material after cooling treatment can be 100-150 °C. The cooling treatment adopts conventional technologies, such as air cooling. After the powder material discharged from the conditioning reactor 1 exchanges heat with the outside air, the temperature of the powder material decreases and the temperature of the air increases. The heated air is transported to the air inlet of the suspension calcination furnace 2 to participate in the reaction of the powder material. This can further reduce the energy consumption of the suspension calcination furnace 2.

[0036] Preferably, to form a reducing environment in the conditioning reactor 1, step 2 further includes: controlling the amount of reducing gas entering the conditioning reactor 1, as well as the combustion time and heating temperature of the combustion device 6 according to the gas flow rate, gas composition in the flue gas pipeline, and the temperature in the conditioning reactor 1. By controlling the amount of reducing gas entering the conditioning reactor 1, a reducing environment is formed in the conditioning reactor 1. In addition, when no reducing gas is introduced, there is combustion of fuel gas and air in the conditioning reactor 1. By adjusting the combustion-supporting air in the combustion device 6, a reducing environment or an oxidizing environment is formed in the conditioning reactor 1. When more combustion-supporting air is introduced, an oxidizing environment is formed in the conditioning reactor 1; when less combustion-supporting air is introduced, a reducing environment is formed in the conditioning reactor 1.

[0037] The powder material 10 flips and moves in the reducing atmosphere environment of the conditioning reactor 1. In the reducing atmosphere (such as CO, H 2 etc.) and high-temperature conditions, high-valence iron oxides (such as hematite Fe 2 O 3 , limonite FeO(OH)) are gradually reduced to phases with stronger magnetism. The reducing atmosphere significantly enhances the magnetism of iron ore by converting weakly magnetic iron oxides (such as Fe 3+ ) into strongly magnetic Fe 3 O 4 or metallic Fe, combined with crystal structure and electron state changes.

[0038] The flue gas generated by the powder material 10 in the tempering reactor 1 under high-temperature environment flows from the tempering reactor 1 to the flue gas pipeline. One end of the flue gas pipeline is connected to the tempering reactor 1, and the other end is connected to the gas outlet of the cyclone separator 3. The flow direction of the flue gas in the tempering reactor 1 is opposite to the flow direction of the powder material 10 in the tempering reactor 1. The tempering reactor 1 is in a negative pressure state, and the flue gas pipeline is also in a negative pressure state, and the absolute value of the air pressure in the flue gas pipeline is greater than the absolute value of the air pressure in the tempering reactor 1, so that the flue gas flows from the tempering reactor 1 to the flue gas pipeline. According to the gas flow rate and gas composition in the flue gas pipeline, the amount of reducing gas entering the tempering reactor 1 can be adjusted. When the content of the reducing gas detected by the detection sensor is lower than the target value, the amount of reducing gas entering the tempering reactor 1 is increased; when the content of the reducing gas detected by the detection sensor is higher than the target value, the amount of reducing gas entering the tempering reactor 1 is reduced or shut off. When the working temperature in the tempering reactor 1 does not reach the tempering temperature, the combustion device 6 is started to raise the temperature of the tempering reactor 1 to the tempering temperature.

[0039] As Figure 1 shown, the tempering reactor used in the calcination method of the above embodiment includes a housing 11 and a material lifting platform 12 located in the inner cavity of the housing 11. The material lifting platform 12 is inlaid on the inner wall of the housing 11; the material lifting platform 12 includes a first refractory unit 121 in an arc shape and a second refractory unit 122 in an arc shape. The first refractory unit 121 and the second refractory unit 122 are respectively arranged along the axial direction of the housing 11, and the first refractory unit 121 and the second refractory unit 122 are alternately arranged along the circumferential direction of the housing 11; the height of the second refractory unit 122 is greater than the height of the first refractory unit 121.

[0040] In the above tempering reactor, the material lifting platform 12 includes first refractory units 121 and second refractory units 122 arranged alternately, and the height of the second refractory units 122 is greater than that of the first refractory units 121. A first refractory unit 121 is provided between two adjacent second refractory units 122. The end face of the material lifting platform 12 is in the shape of an annular gear. After the powder material 10 is conveyed into the tempering reactor, the tempering reactor rotates, and part of the powder material falls on the first refractory unit 121 and is located between two adjacent second refractory units 122. This part of the powder material is the first material. The second material is located above the first material. The second material is located above the second refractory unit 122. When the tempering reactor starts to rotate, the first material and the second material rotate with the material lifting platform 12. After rotating a certain angle, the second material begins to fall successively and lands on the first refractory unit 121 at the lower part and is located between two adjacent second refractory units 122; due to the blocking of the wall surface of the second refractory unit 122, the first material continues to rotate with the material lifting platform 12. When rotating to a larger angle until the highest point, the first material falls successively. Part of the first material covers the second material, and the rest of the first material lands on the first refractory unit 121 at the lower part and is located between two adjacent second refractory units 122. The tempering reactor rotates continuously, and the powder material 10 continuously circulates and flips in the tempering reactor 1. During the flipping process, due to the inclined arrangement of the tempering reactor, the powder material 10 flips while moving towards the discharge port of the tempering reactor.

[0041] In the tempering reactor with this structure, by flipping the powder material 10, the reaction of the powder material 10 in the tempering reactor 1 becomes more uniform and sufficient. Part of the powder material is located below, and through flipping, it is located above. Similarly, part of the powder material is located above, and through flipping, it is located below. The continuous rotation of the tempering reactor causes the powder material 10 to flip continuously, so that the reaction of the powder material 10 is more sufficient, avoiding the accumulation of the powder material 10 in the tempering reactor 1, making it difficult for the powder material accumulated inside to react sufficiently and difficult to meet the required quality requirements.

[0042] Preferably, the length of the tempering reactor is 10 - 20 m. The effective inner diameter of the tempering reactor is as shown in formula (2): Formula (2) In the formula: D i represents the effective inner diameter of the tempering reactor, with the unit of m; G represents the daily processing capacity of the tempering reactor, with the unit of t / d; L represents the length of the tempering reactor, with the unit of m; represents the correction coefficient of the tempering reactor. Among them, the effective inner diameter of the tempering reactor refers to the average diameter of the flow passage inside the tempering reactor.

[0043] Preferably, the number of the first refractory units 121 is equal to the number of the second refractory units 122. For example, the number of the first refractory units 121 is 5 to 8. Preferably, both the first refractory units 121 and the second refractory units 122 are made of refractory bricks. Since the powder material in the conditioning reactor 1 has a certain mass, in order to prevent the second refractory units 122 from being broken by the powder material 10, the second refractory units 122 have a certain length. Preferably, 5 to 8 second refractory units 122 are arranged in the conditioning reactor 1. Preferably, the central angle corresponding to each first refractory unit 121 is equal to the central angle corresponding to each second refractory unit 122. In this way, the flipping of the powder material 10 will be more uniform, making the powder material 10 react more fully in the conditioning reactor 1.

[0044] Preferably, the height of the second refractory units 122 is 1.5 to 2 times the height of the first refractory units 121; when the effective inner diameter of the conditioning reactor is less than 4 m, the height of the first refractory units 121 is 200 to 250 mm; when the effective inner diameter of the conditioning reactor is greater than or equal to 4 m, the height of the first refractory units 121 is 250 to 300 mm. The first refractory units 121 and the second refractory units 122 are set in this height range to increase the actual conditioning heat exchange volume of the conditioning reactor 1 and improve the output while taking into account lower heat loss, and at the same time ensure a certain refractory maintenance cycle.

[0045] As Figure 2 shown, the present invention also provides a calcination device for powder materials, including the conditioning reactor 1 of the above embodiments or preferred examples. The calcination device further includes a suspension calcination furnace 2 and a cyclone separator 3. The outlet of the suspension calcination furnace 2 is connected to the inlet of the cyclone separator 3, the material outlet of the cyclone separator 3 is connected to the feed inlet of the conditioning reactor 1, the conditioning reactor 1 is arranged obliquely, a combustion device 6 is provided at the material outlet of the conditioning reactor 1, the flue gas outlet of the conditioning reactor 1 and the flue gas outlet of the cyclone separator 3 are connected through a flue gas pipeline, the material outlet of the conditioning reactor 1 is located at the lower end of the conditioning reactor 1; the flue gas outlet of the conditioning reactor 1 and the feed inlet of the conditioning reactor 1 are both located at the higher end of the conditioning reactor 1.

[0046] When the powder material enters the suspension calcination furnace 2 and under suitable atmosphere conditions, heating and pre-oxidation are completed. After calcination and decomposition, it enters the cyclone separator 3 with the airflow for solid-gas separation. The separated powder material remains in a high-temperature state and enters the conditioning reactor 1. The conditioning reactor 1 is arranged obliquely. The powder material 10 is fed from the feed inlet of the conditioning reactor 1. Due to the certain inclination angle of the conditioning reactor 1, during the rotation of the conditioning reactor 1, the powder material 10 slowly rolls towards the discharge port. The material lifting platform in the conditioning reactor 1 greatly increases the lifting height of the powder material 10. At the same time, the material lifting platform increases the flow resistance of the powder material 10 in the conditioning reactor 1, which is beneficial to extending the conditioning reaction time of the powder material 10 in the conditioning reactor 1. A combustion device 6 is arranged at the discharge port of the conditioning reactor 1. The high-temperature flue gas generated by fuel combustion exchanges heat with the powder material 10 in countercurrent. The high-temperature flue gas flows into the flue gas pipeline located outside the conditioning reactor 1 and then into the rising flue of the cyclone separator 3. According to the characteristics and grades of the powder material, parameters such as the conditioning reaction time, conditioning temperature, and conditioning atmosphere can be accurately controlled, so as to make the finished product of the powder material meet the quality requirements.

[0047] By setting the combustion device 6 on the conditioning reactor 1, the conditioning reaction temperature in the conditioning reactor 1 can be adjusted. At the same time, it is also beneficial to reducing the calcination temperature of the suspension calcination furnace 2, which is conducive to protecting the service life of the refractories in the suspension calcination furnace 2. Since the combustion device 6 can increase the ambient temperature in the conditioning reactor 1, it is not necessary for the powder material discharged from the suspension calcination furnace 2 to reach the required conditioning temperature, and the temperature in the suspension calcination furnace 2 can be appropriately reduced.

[0048] To extend the conditioning reaction time of the powder material, there are N conditioning reactors 1, and the N conditioning reactors 1 are connected in series and arranged vertically; N is an integer greater than or equal to 2; the feed inlet of the conditioning reactor 1 located downstream is connected to the discharge port of the conditioning reactor 1 located upstream; the feed inlet of the conditioning reactor 1 located at the most upstream is connected to the material outlet of the cyclone separator 3. By setting multiple conditioning reactors 1 and having multiple conditioning reactors 1 working simultaneously, the turning path of the powder material 10 is extended, and thus its conditioning reaction time is extended. In this preferred example, it is not necessary to extend the length of the conditioning reactor 1. In the case of limited ground space, arranging multiple conditioning reactors 1 vertically can extend the conditioning reaction time of the powder material 10 to make its quality meet the required standards.

[0049] Preferably, the angle between the axis of the conditioning reactor 1 and the horizontal line is 1.5° to 3°. The conditioning reactor 1 is arranged obliquely, and the material outlet of the conditioning reactor 1 is located at the lower end of the conditioning reactor 1; the flue gas outlet and the feed inlet of the conditioning reactor 1 are both located at the higher end of the conditioning reactor 1. If the angle between the axis of the conditioning reactor 1 and the horizontal line is too large, the powder material will flow too fast and it is difficult to achieve the conditioning purpose; if it is too small, the powder material will flow too slowly and it is also difficult to achieve the conditioning purpose. In this preferred example, the angle between the axis of the conditioning reactor 1 and the horizontal line is 1.5° to 3°. In this way, by adjusting the rotation speed of the conditioning reactor 1, the reaction time of the powder material in the conditioning reactor 1 can reach the conditioning time.

[0050] Preferably, the calcination device further includes a cooling device 4 and a preheating device 5. The discharge port of the conditioning reactor 1 is connected to the feed inlet of the cooling device 4, and the air outlet of the cooling device 4 is connected to the air inlet of the suspension calciner 2. When there are multiple conditioning reactors 1, the discharge port of the conditioning reactor 1 located at the most downstream is connected to the feed inlet of the cooling device 4. The discharge port of the preheating device 5 is connected to the feed inlet of the suspension calciner 2, and the flue gas outlet of the cyclone separator 3 is connected to the preheating device 5. The air inlet of the cooling device 4 communicates with the outside. During operation, the high-temperature powder material discharged from the conditioning reactor 1 exchanges heat with air in the cooling device 4, and the cooled powder material is discharged as a finished product from the discharge port of the cooling device 4. The heated air is discharged from the air outlet of the cooling device 4 and enters the suspension calciner 2 to participate in the calcination. The air inlet of the preheating device 5 is connected to the gas flow outlet of the cyclone separator 3. One outlet of the preheating device 5 is the waste gas outlet, and the other outlet of the preheating device 5 is connected to the feed inlet of the suspension calciner 2. After the cyclone separator 3 performs gas-solid separation, the separated high-temperature gas is introduced into the preheating device 5 to heat the raw material of the powder material in the preheating device 5, and then the heated raw material of the powder material is transported to the suspension calciner 2 for calcination, and the waste gas is discharged from the waste gas outlet of the preheating device 5.

[0051] Preferably, the calcination device further includes a reducing gas pipeline with a control valve and a reducing gas source 7. The reducing gas source 7 is connected to the end of the conditioning reactor 1 through the reducing gas pipeline and is located at the same end of the conditioning reactor 1 as the combustion device 6; an insertion valve 8 and a detection sensor 9 are provided in the flue gas pipeline. The amount of reducing gas entering the conditioning reactor 1 is controlled by the control valve. The reducing gas can be hydrogen, CO, etc. By introducing the reducing gas into the conditioning reactor 1, under the reducing atmosphere and high temperature conditions, the high-valent iron oxides are gradually reduced to phases with stronger magnetism. The reducing atmosphere converts weakly magnetic iron oxides (such as Fe 3+ ) into strongly magnetic Fe 3 O 4Or metallic Fe, combined with the crystal structure and electron state changes, significantly enhances the magnetism of iron ore. The flue gas after the reaction of the powder material flows out of the conditioning reactor 1 and into the flue gas pipeline. The composition and flow rate of the flue gas are detected by the detection sensor 9 provided in the flue gas pipeline, so as to control the opening and closing degree of the gate valve 8 and the inflow rate of the reducing gas into the conditioning reactor 1. A gate valve 8 is provided on the flue gas pipeline for conditioning the flue gas volume. A temperature sensor is also provided in the conditioning reactor 1 to detect the temperature in the conditioning reactor 1. If the detected temperature is lower than the required conditioning temperature, then the combustion device 6 is turned on to increase the temperature in the conditioning reactor 1 to the conditioning temperature.

[0052] In the above embodiments, the conditioning reactor 1 prolongs the residence time of the powder material in the high-temperature zone and improves the product quality. The above embodiments can reduce the calcination residence time of the powder material in the suspension calciner 2, reduce the length of the suspension calciner 2, and reduce the operating cost and investment cost. The above embodiments increase the controllable process adjustment parameters, and can control the conditioning temperature of the conditioning reactor 1, the rotation speed of the conditioning reactor 1, and the reaction residence time of the powder material in the conditioning reactor 1, further expanding the application range of the suspension calciner.

[0053] The following are examples.

[0054] Using the method of the present invention, the aluminum leaching rate of coal gangue is increased. The alumina and silica in coal gangue exist in an ordered kaolinite crystal phase and have almost no chemical reactivity. Therefore, it must be subjected to high-temperature calcination activation treatment to decompose the kaolinite crystal phase into amorphous semi-crystalline or amorphous, and then extract alumina after improving its chemical reactivity. In the coal gangue used in Examples 1 to 3 below, the mass content of SiO 2 is 45%, and the mass content of Al 2 O 3 is 36%.

[0055] Example 1 A calcination method for coal gangue, comprising: Step 1: Preheat the raw material of coal gangue in powder form, and the temperature of the preheated coal gangue is 800 °C. The preheated coal gangue is transported to the suspension calciner 2 for calcination. The calcination time is 8 seconds and the calcination temperature is 950 °C; the particle size of the coal gangue raw material is less than 200 mesh.

[0056] Step 2: Start the tempering reactor 1, and the tempering reactor 1 rotates along its axis; convey the coal gangue calcined in Step 1 into the tempering reactor 1; the tempering reactor 1 is horizontal, and the angle between the axis of the tempering reactor 1 and the horizontal line is 2°. The length of the tempering reactor 1 is 10 m, the effective inner diameter of the tempering reactor 1 is 3.5 m, five first refractory units 121 and five second refractory units 122 are respectively arranged, and the central angle corresponding to each first refractory unit 121 and the central angle corresponding to each second refractory unit 122 are both 36°. The height of the first refractory unit 121 is 240 mm, and the height of the second refractory unit 122 is 450 mm. In the tempering reactor 1, use the combustion device 6 to heat the coal gangue in the tempering reactor 1 and keep the tempering temperature at 1100°C; rotate the tempering reactor 1, and the coal gangue moves from the feed port of the tempering reactor 1 to the discharge port of the tempering reactor 1 and is discharged from the discharge port. The tempering time of the coal gangue in the tempering reactor 1 is 30 min.

[0057] Step 3: Cool the coal gangue discharged from the discharge port of the tempering reactor 1 through a cooling device to obtain the coal gangue finished product.

[0058] Example 2: A method for calcining coal gangue is the same as the method in Example 1, except that: in Step 2, the tempering time of the coal gangue in the tempering reactor 1 is 60 min.

[0059] Example 3: A method for calcining coal gangue is the same as the method in Example 1, except that: in Step 2, the tempering time of the coal gangue in the tempering reactor 1 is 120 min.

[0060] The acid leaching rate of active aluminum in the samples before and after calcination is measured by hydrochloric acid acid leaching to characterize the chemical activity of the calcined product. Pour 2 g of the samples before and after calcination in Examples 1-3 into conical flasks containing 100 mL of hydrochloric acid with a mass concentration of 20% (i.e., the leaching solution), place them in a heating magnetic stirrer and carry out constant-temperature acid leaching at 90°C for 1 h, and the stirring speed is 500 r / min. After the acid leaching is completed, carry out solid-liquid separation, and the aluminum content in the leaching solution is measured by an inductively coupled plasma (ICP) spectrometer (produced by Leeman Company, USA, model: Prodigy XP), and then the acid leaching rate of active aluminum is calculated. The acid leaching rate of active aluminum is calculated according to the following formula:

[0061] In the formula: represents the acid leaching rate of active aluminum, and the unit is %; C represents the aluminum content in the leaching solution of the sample after calcination, and the unit is μg / ml; represents the Al 2 O 3 content in the leaching solution of the sample before calcination, and the unit is μg / ml.

[0062] The results are as follows: the leaching rate of active aluminum in Example 1 is 78%, the leaching rate of active aluminum in Example 2 is 83%, and the leaching rate of active aluminum in Example 3 is 86%. The leaching rate of active aluminum can reach over 75%.

[0063] It can be seen that in Examples 1 to 3, the finished coal gangue products made by the calcination method of the present invention, without modifying the existing suspension calciner, extend the high-temperature conditioning reaction time of the coal gangue powder, so that the quality of the finished coal gangue powder meets the required standards, that is: the leaching rate of active aluminum can reach over 75%.

[0064] By using the method of the present invention, the magnetism of hematite is enhanced. After the weakly magnetic mineral hematite is roasted, it is transformed into a strongly magnetic mineral. In the following Examples 4 to 6, the main components of hematite are: the total iron content is 61%, mainly in the form of Fe 2 O 3 ; the mass fraction of SiO 2 content is 2.5%.

[0065] Example 4 A calcination method for hematite Fe 2 O 3 , comprising: Step 1: Preheat the powdery hematite raw material. The temperature of the preheated hematite is 600°C. The preheated hematite is transported to the suspension calciner 2 for calcination. The calcination time is 10 seconds and the calcination temperature is 750°C; the particle size of the hematite raw material is less than 200 mesh.

[0066] Step 2: Start the conditioning reactor 1, and the conditioning reactor 1 rotates along its axis; transport the hematite calcined in Step 1 to the conditioning reactor 1; the conditioning reactor 1 is horizontal, and the angle between the axis of the conditioning reactor 1 and the horizontal line is 3°. The length of the conditioning reactor 1 is 15 m, the effective inner diameter of the conditioning reactor 1 is 5 m, 6 first refractory units 121 and 6 second refractory units 122 are respectively arranged, and the central angle corresponding to each first refractory unit 121 and the central angle corresponding to each second refractory unit 122 are both 30°. The height of the first refractory unit 121 is 300 mm, and the height of the second refractory unit 122 is 450 mm. In the conditioning reactor 1, use the combustion device 6 to heat the hematite in the conditioning reactor 1 and keep the conditioning temperature at 750°C; rotate the conditioning reactor 1, and the hematite moves from the feed port of the conditioning reactor 1 to the discharge port of the conditioning reactor 1 and is discharged from the discharge port. During this process, introduce CO reducing gas into the conditioning reactor 1, so that the high-valent iron oxides are gradually reduced to phases with stronger magnetism. The conditioning time of hematite in the conditioning reactor 1 is 15 min.

[0067] Step 3: Cool the hematite discharged from the discharge port of the tempering reactor 1 to obtain the finished hematite product.

[0068] Example 5: A method for calcining hematite, which is the same as the method of Example 1, except that: in Step 2, the tempering time of the hematite in the tempering reactor 1 is 60 min.

[0069] Example 6: A method for calcining hematite, which is the same as the method of Example 1, except that: in Step 2, the tempering time of the hematite in the tempering reactor 1 is 100 min.

[0070] The magnetic conversion rate refers to the ratio of weakly magnetic minerals (such as hematite and limonite) converted into strongly magnetic minerals (such as magnetite and maghemite) after roasting. Magnetic detection was performed on the samples before and after calcination in Examples 4 to 6. The detection method was carried out according to the wet magnetic separation tube method of the prior art. The calculation formula is: Magnetic conversion rate = content of strongly magnetic minerals after roasting / content of weakly magnetic minerals in the raw ore × 100%. The detection results are shown in Table 1: Table 1

[0071] It can be seen from Table 1 that after calcination using the method of the present application, the weakly magnetic mineral hematite is converted into the strongly magnetic mineral maghemite.

[0072] 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 by the above specific embodiments, and the above specific embodiments and the descriptions in the specification are only for further explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of the present invention claimed 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 (2) for calcination; Step 2, starting the conditioning reactor (1), and rotating the conditioning reactor (1) along its axis; conveying the powder material calcined in step 1 to the conditioning reactor (1); the conditioning reactor (1) is horizontal and arranged obliquely; In the tempering reactor (1), the combustion device (6) is used to heat the powder material in the tempering reactor (1) and maintain the tempering temperature; as the tempering reactor (1) rotates, the powder material moves from the inlet of the tempering reactor (1) to the outlet of the tempering reactor (1) and is discharged from the outlet to obtain a finished powder material until the tempering is completed.

2. The method for calcining powder materials according to claim 1, characterized in that: In the step 1, the calcination time is 5 to 15 seconds; In the step 2, the working temperature of the tempering reactor (1) is 750 to 1200° C.; the tempering time of the tempering reactor (1) is 1 to 120 minutes.

3. The method for calcining powder materials according to claim 1, characterized in that: In the step 2, the rotation speed of the conditioning reactor (1) is controlled so that the residence time of the powder material in the conditioning reactor (1) reaches the conditioning time; the rotation speed of the conditioning reactor (1) is determined according to formula (1): Formula (1) Where: n represents the rotation speed of the conditioning reactor (1), in units of rpm ; L represents the length of the conditioning reactor (1), in units of m ; D i represents the effective inner diameter of the conditioning reactor (1), in units of m ; t 2 It represents the conditioning time of the powder material in the conditioning reactor (1), in units of min ; α represents the angle between the axis of the conditioning reactor (1) and the horizontal line, in degrees; k Indicates the coefficient related to the density of powder material.

4. The method for calcining powder materials according to claim 3, characterized in that: In the conditioning reactor (1), the powder material and the flue gas flow in opposite directions, and the density of the powder material is ρ≤1200kg / m 3 hour, k The value is 2.0; the density of powder material ρ >1200kg / m 3 hour, k The value is 1.

5.

5. The method for calcining powder materials according to claim 1, characterized in that: In the step 2, the calcined powder material is separated into gas and solid by a cyclone separator (3), and the separated powder material is transported to a conditioning reactor (1); In the step 2, the conditioning reactor (1) is continuously fed with materials and continuously discharged with materials.

6. 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 the suspension calcining furnace (2) for calcination; The method further comprises step 3: the powder material discharged from the discharge port of the tempering reactor (1) is cooled to form a powder material finished product.

7. The method for calcining powder materials according to claim 1, characterized in that: The step 2 also includes: According to the gas flow rate, gas composition and temperature in the conditioning reactor (1) in the flue gas pipeline, the amount of reducing gas entering the conditioning reactor (1), as well as the combustion time and heating temperature of the combustion device (6) are controlled; or, By adjusting the combustion-supporting air in the combustion device (6), an oxidizing environment or a reducing environment is formed.

8. A tempering reactor for powder materials, characterized in that: The tempering reactor comprises an outer shell (11), and a material raising platform (12) located in the inner cavity of the outer shell (11), and the material raising platform (12) is embedded on the inner wall of the outer shell (11); the material raising platform (12) comprises a first refractory unit (121) in the shape of an arc and a second refractory unit (122) in the shape of an arc, the first refractory unit (121) and the second refractory unit (122) are respectively arranged along the axial direction of the outer shell (11), and the first refractory unit (121) and the second refractory unit (122) are alternately arranged along the circumference of the outer shell (11); the height of the second refractory unit (122) is greater than the height of the first refractory unit (121).

9. The quenching and tempering reactor for powder materials according to claim 8, characterized in that: The length of the conditioning reactor is 10 to 20 m. The effective inner diameter of the conditioning reactor is as shown in formula (2): Formula (2) Where: D i It represents the effective inner diameter of the conditioning reactor, in m; G It indicates the daily processing capacity of the conditioning reactor, in t / d; L It indicates the length of the conditioning reactor in m; Represents the correction factor for the tempering reactor.

10. The quenching and tempering reactor for powder materials according to claim 8, characterized in that: The number of the first refractory units (121) is equal to the number of the second refractory units (122); The central angle corresponding to each of the first refractory material units (121) is equal to the central angle corresponding to each of the second refractory material units (122); The height of the second refractory unit (122) is 1.5 to 2 times the height of the first refractory unit (121); when the effective inner diameter of the tempering reactor is less than 4 m, the height of the first refractory unit (121) is 200 to 250 mm; when the effective inner diameter of the tempering reactor is greater than or equal to 4 m, the height of the first refractory unit (121) is 250 to 300 mm.

11. A calcining device comprising a tempering reactor according to any one of claims 8 to 10, characterized in that: The calcining device comprises a tempering reactor (1), a suspension calcining furnace (2), and a cyclone separator (3); the outlet of the suspension calcining furnace (2) is connected to the inlet of the cyclone separator (3), the material outlet of the cyclone separator (3) is connected to the inlet of the tempering reactor (1), the tempering reactor (1) is arranged obliquely, a combustion device (6) is provided at the outlet of the tempering reactor (1), the flue gas outlet of the tempering reactor (1) and the flue gas outlet of the cyclone separator (3) are connected through a flue gas pipeline, and the material outlet of the tempering reactor (1) is located at the lower end of the tempering reactor (1); the flue gas outlet of the tempering reactor (1) and the inlet of the tempering reactor (1) are both located at the higher end of the tempering reactor (1).

12. The calcining device according to claim 11, characterized in that: The number of the conditioning reactors (1) is N, and the N conditioning reactors (1) are connected in series and arranged vertically; N is an integer greater than or equal to 2; the feed inlet of the conditioning reactor (1) located downstream is connected to the feed outlet of the conditioning reactor (1) located upstream; and the feed inlet of the conditioning reactor (1) located most upstream is connected to the material outlet of the cyclone separator (3).

13. The calcining device according to claim 11, characterized in that: The angle between the axis of the conditioning reactor (1) and the horizontal line is 1.5-3°.

14. The calcining device according to claim 11, characterized in that: It also includes a cooling device (4) and a preheating device (5), wherein: The material outlet of the conditioning reactor (1) is connected to the material inlet of the cooling device (4), and the air outlet of the cooling device (4) is connected to the air inlet of the suspension calcining furnace (2); The discharge port of the preheating device (5) is connected to the feed port of the suspension calcining furnace (2), and the smoke outlet of the cyclone separator (3) is connected to the preheating device (5).

15. The calcining device according to claim 11, characterized in that: It also includes a reducing gas pipeline with a control valve and a reducing gas source (7), wherein the reducing gas source (7) is connected to the end of the conditioning reactor (1) through the reducing gas pipeline and is located at the same end of the conditioning reactor (1) as the combustion device (6); and a gate valve (8) and a detection sensor (9) are provided in the flue gas pipeline.

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