A method and device for decarbonizing coal gangue

Abstract

The present invention discloses a method and device for decarbonizing coal gangue, including a feeding bin, a cyclone preheating separator, and a cyclone separator. The feeding bin is connected to the cyclone preheating separator, and an auxiliary heating device is provided on the cyclone preheating separator; the cyclone preheating separator is connected to a suspension furnace, and the cyclone preheating separator is connected to the suspension furnace through the cyclone separator; one end of the suspension furnace is connected to a hot air blower, and the other end is connected to the cyclone separator; the cyclone separator is connected to a blower; the invention realizes calcination at a sintering temperature not higher than 1050°C to solve the problems of excessive loss on ignition and sintering, effectively controlling the loss on ignition below 0.5% while controlling the carbon content below 0.3%; it also enables the coal gangue powder to be calcined at 250 mesh without reducing the plasticity index of the coal gangue powder.

Description

Technical Field

[0001] The present invention relates to the technical field of solid waste treatment, and particularly relates to a method and device for decarbonizing coal gangue. Background Art

[0002] Coal gangue is a by-product discharged during coal mining and washing. Coal gangue belongs to bulk industrial solid waste, and its main mineral components are inorganic silicates and kaolin minerals. At present, China has become the country with the largest stockpile and annual output of coal gangue. The direct stacking of coal gangue not only causes waste of resources, but also occupies land and causes environmental pollution.

[0003] In order to promote the resource utilization process of coal gangue, previous scholars have carried out a large number of studies; application and treatment research have been achieved in multiple fields, but large-scale utilization of coal gangue has not been realized. In existing industrial applications, coal gangue is used to prepare cement. After decarbonization processing of coal gangue, it is used as a raw material for cement preparation. The silicate minerals in coal gangue generate hydrated calcium silicate and hydrated calcium aluminosilicate, etc. These hydrated products can improve the strength of coal gangue cement. Therefore, the application of coal gangue in cement has been widely studied and is one of the effective ways of resource utilization.

[0004] The existing technology for decarbonizing coal gangue usually adopts the sintering treatment method, and its technical route is one is granular decarbonization technology, and the other is powdered decarbonization technology.

[0005] The main process of granular decarbonization technology is to crush coal gangue to a certain particle size and then calcine it in a roasting machine for decarbonization. Since the material is granular, a higher sintering temperature is required to achieve decarbonization of the granular material. However, due to the high calcination temperature, the material is sintered, resulting in incomplete decarbonization of the granular material in the sintered block, a relatively high carbon content, and easy occurrence of black core material, reducing the quality of cement; at the same time, the loss on ignition is also relatively high during the calcination process at this high calcination temperature, reducing the utilization rate.

[0006] Based on the physical properties of coal gangue, the sintering temperature of coal gangue is about 1050°C, the refractoriness is 1300 - 1350°C, the density is 1.8 g / cm3, and the viscosity is about 1.1; after being finely crushed, coal gangue has plasticity. When crushed to 250 mesh, its plasticity index can reach 2.8 - 3.0, and the corresponding moisture content is 23% - 25%.

[0007] Regarding the decarbonization research of coal gangue, most are the technical routes of powdered decarbonization technology. For example, Chinese Patent CN118896488A discloses that at a calcination temperature of 1100°C, the loss on ignition is 0.34%; although the loss on ignition is less than 0.5%, the high calcination temperature causes the material to sinter.

[0008] Chinese Patent CN119349910A discloses that the loss on ignition at a calcination temperature of 1100°C is 1.18%, and the excessive calcination temperature causes sintering of the material; it also discloses that the loss on ignition at a sintering temperature of 1050°C is 1.5%; while the loss on ignition at a calcination temperature lower than the sintering temperature is higher than 1.5%, and in order to pursue a better calcination effect, the particles are less than 300 mesh, resulting in a decrease in its plasticity index.

[0009] At the same time, when sintering is caused by a temperature higher than 1050°C of sintering, it is also easy to cause blockage of the calcination equipment.

[0010] However, in the process of implementing the inventive technical solution in the embodiments of the present application, the inventors found that the above technologies have at least the following technical problems: high loss on ignition, high carbon content and reduced plasticity index. Summary of the Invention

[0011] The embodiments of the present application provide a decarbonization device for coal gangue, which solves the problems of excessive loss on ignition and sintering in the prior art, realizes effective control of the loss on ignition below 0.5% and the carbon content below 0.3%, and at the same time enables the coal gangue powder to be calcined at 250 mesh, retaining the pozzolanic activity of the coal gangue after thermal activation without reducing the plasticity index of the coal gangue powder.

[0012] The embodiments of the present application provide a decarbonization device for coal gangue, including a feeding bin (1), a cyclone preheater (2), and a cyclone separator (3). The feeding bin (1) is connected to the cyclone preheater (2), and an auxiliary heating device (10) is provided on the cyclone preheater (2);

[0013] The cyclone preheater (2) is connected to a suspension furnace (4), and the cyclone preheater (2) is connected to the suspension furnace (4) through the cyclone separator (3);

[0014] One end of the suspension furnace (4) is connected to a hot air blower (5), and the other end is connected to the cyclone separator (3);

[0015] The cyclone separator (3) is connected to a blower (6).

[0016] Preferably, the cyclone preheater (2) includes a first cyclone preheater (21), a second cyclone preheater (22), a third cyclone preheater (23), and a fourth cyclone preheater (24);

[0017] The cyclone separator (3) includes a first cyclone separator (31), a second cyclone separator (32), and a third cyclone separator (33).

[0018] Preferably, the length of the suspension furnace (4) is 15 - 25 m, the effective inner diameter of the suspension furnace is 325 - 360 mm, the thickness of the refractory material is 190 - 205 mm, and the thickness of the thermal insulation material is 95 - 105 mm.

[0019] Preferably, a first coal feeder (7) and a natural gas supply mechanism (8) are connected to the suspension furnace (4).

[0020] Preferably, the discharge port of the feeding bin (1) is connected to the rising pipeline from the air outlet of the second cyclone preheater (22) to the air inlet of the first cyclone preheater (21);

[0021] The discharge port of the first cyclone preheater (21) is connected to the rising pipeline from the air outlets of the third cyclone preheater (23) and the fourth cyclone preheater (24) to the air inlet of the second cyclone preheater (22);

[0022] The discharge port of the second cyclone preheater (22) is connected to the rising pipeline from the air outlet of the first cyclone separator (31) to the air inlet of the third cyclone preheater (23);

[0023] The discharge port of the third cyclone preheater (23) is connected to the rising pipeline from the air outlet of the first cyclone separator (31) to the air inlet of the fourth cyclone preheater (24);

[0024] The discharge port of the fourth cyclone preheater (24) is connected to the rising pipeline from the air outlet of the second cyclone separator (32) to the suspension furnace (4).

[0025] Preferably, the discharge port of the first cyclone separator (31) is connected to the rising pipeline from the air blower (6) to the air inlet of the second cyclone separator (32).

[0026] Preferably, the air inlet of the third cyclone separator (33) is connected to the end of the suspension furnace (4); the air outlet of the third cyclone separator (33) is connected to the air inlet of the first cyclone separator (31).

[0027] Preferably, the rising pipeline from the air blower (6) to the air inlet of the second cyclone separator (32) passes through the hot air blower (5).

[0028] Preferably, the hot air blower (5) is connected to a second coal feeder (9).

[0029] A decarbonization method for coal gangue, based on the foregoing decarbonization device, to achieve the decarbonization of coal gangue, includes the following steps:

[0030] S1. The device is preheated. Hot air is sent into the suspension furnace (4) through the hot air blower (5). The hot air passes through the end of the suspension furnace (4) and flows through the cyclone separator (3) to the cyclone preheating separator (2).

[0031] S101. The hot air flowing out of the end of the suspension furnace (4) passes through the third cyclone separator (33) and flows to the first cyclone separator (31). After being separated by the first cyclone separator (31), the hot air flows to the third cyclone preheating separator (23) and the fourth cyclone preheating separator (24). After flowing out, it flows through the second cyclone preheating separator (22) to the first cyclone preheating separator (21).

[0032] S2. The air blower (6) is started. The air blower (6) sends fresh air through the pipeline, heats it in the suspension furnace (4), and then sends it to the second cyclone separator (32), and then flows into the suspension furnace (4).

[0033] S3. The auxiliary heating device (10) is started. After the device preheating is completed in step S1, the auxiliary heating device (10) is used to adjust the cyclone preheating separator (2), and respectively adjust the temperatures of the first cyclone preheating separator (21), the second cyclone preheating separator (22), the third cyclone preheating separator (23), and the fourth cyclone preheating separator (24).

[0034] S4. The first coal feeder (7) and the natural gas supply mechanism (8) are started. When the material is blown into the suspension furnace (4) through the rising pipeline from the air outlet of the second cyclone separator (32) to the suspension furnace (4), the first coal feeder (7) and the natural gas supply mechanism (8) simultaneously blow the mixed fuel into the suspension furnace (4).

[0035] S5. The feeding bin (1) is started. The feeding bin (1) conveys the coal gangue powder of 250 meshes to the cyclone preheating separator (2).

[0036] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0037] 1. Since a four-stage cyclone preheating separator is adopted to adjust the preheating temperature, and then through the way of suspension calcination, the calcination temperature is effectively controlled below the sintering temperature of 1050 °C to solve the problem of excessive loss on ignition, and further solve the sintering problem caused by the calcination temperature higher than the sintering temperature at the same time. The technical solution of the present application realizes calcination at a sintering temperature not greater than 1050 °C, effectively controls the loss on ignition below 0.5%, and at the same time controls the carbon content below 0.3%.

[0038] 2. By adopting a four-stage cyclone preheater to adjust the preheating temperature and then through the method of suspension calcination, the gangue powder can be calcined at a sintering temperature of not more than 1050°C with a mesh size of 250, which can achieve the purpose of decarbonization without reducing the plasticity index of the gangue powder. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic structural diagram of the device in the embodiment of the present application;

[0040] Figure 2 It is a schematic structural diagram of the cyclone preheater in the embodiment of the present application;

[0041] Figure 3 It is a schematic structural diagram of the cyclone separator in the embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0042] In the embodiment of the present application, by providing a decarbonization method and a decarbonization device for gangue, the problems in the prior art are solved, that is, in order to improve the decarbonization effect, calcination is carried out at a sintering temperature higher than 1050°C, resulting in too high loss on ignition and sintering problems; and in order to improve the decarbonization effect, the powder is mostly larger than 250 mesh, and when calcined at a sintering temperature higher than 1050°C, the plasticity index of the gangue powder is reduced.

[0043] The technical solution in the embodiment of the present application to solve the above problems is generally as follows:

[0044] By adopting a four-stage cyclone preheater to adjust the preheating temperature, and then through the method of suspension calcination, calcination is carried out in a suspension furnace at a sintering temperature of not more than 1050°C. At the same time, due to the tubular design of the suspension furnace, the gangue powder to be calcined is calcined in the tubular suspension furnace for a long time, so that the calcination is sufficient and the decarbonization effect is effectively improved.

[0045] The calcination temperature in the above suspension furnace is not more than 1050°C of the sintering temperature, which solves the sintering problem caused by the calcination temperature higher than the sintering temperature.

[0046] In this way, the gangue powder can be calcined in the suspension furnace with a mesh size of 250, that is, the purpose of decarbonization can be achieved without reducing the plasticity index of the gangue powder.

[0047] In order to better understand the above technical solution, the above technical solution will be described in detail below in combination with the drawings in the specification and specific embodiments.

[0048] Embodiment 1

[0049] An embodiment of the present application provides a decarbonization device for coal gangue, including a feeding bin (1), a cyclone preheater-separator (2), and a cyclone separator (3). The feeding bin (1) is connected to the cyclone preheater-separator (2), and an auxiliary heating device (10) is provided on the cyclone preheater-separator (2); the cyclone preheater-separator (2) is connected to a suspension furnace (4), and the cyclone preheater-separator (2) is connected to the suspension furnace (4) through the cyclone separator (3); one end of the suspension furnace (4) is connected to a hot air blower (5), and the other end is connected to the cyclone separator (3); the cyclone separator (3) is connected to a blower (6).

[0050] In this embodiment, the cyclone separator (3) includes a first cyclone separator (31), a second cyclone separator (32), and a third cyclone separator (33). The discharge port of the first cyclone separator (31) is connected to the rising pipeline from the blower (6) to the air inlet of the second cyclone separator (32).

[0051] The air inlet of the third cyclone separator (33) is connected to the end of the suspension furnace (4), and the air outlet of the third cyclone separator (33) is connected to the air inlet of the first cyclone separator (31).

[0052] The blower (6) sends fresh air into the suspension furnace (4) through the second cyclone separator (32) to mix with the hot air sent into the suspension furnace (4) by the hot air blower (5). And through the long cylindrical suspension furnace (4), the hot air is blown into the third cyclone separator (33) at the end of the suspension furnace (4). Solid-gas separation is carried out through the third cyclone separator (33) to separate product 1 of solid particles. Then the separated hot gas is transported to the first cyclone separator (31) for solid-gas separation again. The hot air separated by the first cyclone separator (31) is transported to the cyclone preheater-separator (2), and the separated solid particles enter the second cyclone separator (32) through the pipeline for solid-gas separation to separate solid product 2.

[0053] The solid dust carried in the hot air after solid-gas separation by the third cyclone separator (33) is separated through two stages of the first cyclone separator (31) and the second cyclone separator (32), and solid-gas separation is more fully realized.

[0054] The hot air blower (5) is connected to a second coal feeder (9) to enable the hot air blower (5) to transport hot air into the suspension furnace (4).

[0055] Embodiment Two

[0056] In the embodiments of the present application, the cyclone preheater separator (2) includes a first cyclone preheater separator (21), a second cyclone preheater separator (22), a third cyclone preheater separator (23), and a fourth cyclone preheater separator (24).

[0057] The feeding bin (1) is connected to the cyclone preheater separator (2). The coal gangue powder in the feeding bin (1) is connected to the rising pipeline from the air outlet of the second cyclone preheater separator (22) to the air inlet of the first cyclone preheater separator (21) through the discharge port of the feeding bin (1), and enters the first cyclone preheater separator (21) for solid-gas separation.

[0058] It should be noted that the gas after solid-gas separation in the first cyclone preheater separator (21) enters the bag filter through a pipeline for dust collection, and the gas separated by the bag filter is transported to the chimney after being processed by a centrifugal fan.

[0059] The solid powder after solid-gas separation by the first cyclone preheater separator (21) enters the rising pipeline from the air outlets of the third cyclone preheater separator (23) and the fourth cyclone preheater separator (24) to the air inlet of the second cyclone preheater separator (22) connected to the discharge port of the first cyclone preheater separator (21), enters the second cyclone preheater separator (22) for solid-gas separation, and the hot air enters the first cyclone preheater separator (21).

[0060] The solid powder after solid-gas separation by the second cyclone preheater separator (22) enters the rising pipeline from the air outlet of the first cyclone separator (31) to the air inlet of the third cyclone preheater separator (23) connected to the discharge port of the second cyclone preheater separator (22), enters the third cyclone preheater separator (23) for solid-gas separation, and the hot air enters the second cyclone preheater separator (22).

[0061] The solid powder after solid-gas separation by the third cyclone preheater separator (23) enters the rising pipeline from the air outlet of the first cyclone separator (31) to the air inlet of the fourth cyclone preheater separator (24) connected to the discharge port of the third cyclone preheater separator (23), enters the fourth cyclone preheater separator (24) for solid-gas separation, and the hot air enters the second cyclone preheater separator (22).

[0062] The solid powder after solid-gas separation by the fourth cyclone preheater separator (24) enters the rising pipeline from the air outlet of the second cyclone separator (32) to the suspension furnace (4) connected to the discharge port of the fourth cyclone preheater separator (24).

[0063] In this example, during the upward movement of the hot air, it passes through the third cyclone preheating separator (23) and the fourth cyclone preheating separator (24), and then successively through the second cyclone preheating separator (22) and the first cyclone preheating separator (21). As a result, there is heat loss in the hot air. Therefore, the housing of the cyclone preheating separator (2) is designed as a double-layer structure, with an auxiliary heating device (10) arranged in the middle. The auxiliary heating device (10) is an electric heating device in the prior art and is used to assist in adjusting and increasing the temperature.

[0064] Embodiment Three

[0065] In the embodiment of the present application, the length of the suspension furnace (4) is 15 - 25 m, the effective inner diameter of the suspension furnace is 325 - 360 mm, the thickness of the refractory material is 190 - 205 mm, and the thickness of the heat insulation material is 95 - 105 mm.

[0066] More preferably, the length of the suspension furnace (4) is 20 m, the effective inner diameter of the suspension furnace 4 is 350 mm, and the hot air drives the coal gangue powder to travel in the suspension furnace (4) at a flow rate of 1.5 m / min to achieve suspension heat exchange.

[0067] The thickness of the refractory material on the inner wall of the suspension furnace 4 is 200 mm, and the thickness of the heat insulation material on the outer wall is 100 m, so that the temperature inside the suspension furnace 4 can be controlled at 950 - 1050 °C.

[0068] Embodiment Four

[0069] In the embodiment of the present application, a first coal feeder (7) and a natural gas supply mechanism (8) are connected to the suspension furnace (4). When the hot air drives the coal gangue powder to travel in the suspension furnace (4) at a flow rate of 1.5 m / min, the first coal feeder (7) blows pulverized coal into the suspension furnace (4) through a pipeline. At the same time, the natural gas supply mechanism (8) is connected to the pipeline for blowing pulverized coal. When entering the suspension furnace (4), the pulverized coal is mixed with natural gas and blown into the suspension furnace (4), and is ignited under the hot air in the suspension furnace (4) and undergoes suspension calcination with the coal gangue powder.

[0070] Embodiment Five

[0071] In the embodiment of the present application, the upward pipeline from the air blower (6) to the air inlet of the second cyclone separator (32) passes through the hot air blower (5). The air blower (6) blows fresh air into the second cyclone separator (32) to ensure the oxygen for the combustion of the pulverized coal and natural gas mixture in the suspension furnace (4). And passing the pipeline through the hot air blower (5) enables the coal in the hot air blower 5 to heat the pipeline when burning, so as to ensure the temperature of the fresh air sent by the air blower (6) and prevent it from affecting the temperature fluctuation in the suspension furnace (4).

[0072] Embodiment Six

[0073] Embodiments of the present application provide a decarbonization method for coal gangue. Based on the aforementioned decarbonization device, a method for realizing coal gangue decarbonization includes the following steps:

[0074] S1. Device preheating: Hot air is sent into the suspension furnace (4) through a hot air blower (5), and the hot air flows through the cyclone separator (3) at the end of the suspension furnace (4) and then flows to the cyclone preheating separator (2).

[0075] S101. The hot air flowing out from the end of the suspension furnace (4) flows through the third cyclone separator (33) to the first cyclone separator (31). After being separated by the first cyclone separator (31), the hot air flows to the third cyclone preheating separator (23) and the fourth cyclone preheating separator (24), and then flows to the first cyclone preheating separator (21) via the second cyclone preheating separator (22).

[0076] S2. Start the air blower (6). The air blower (6) heats fresh air in the suspension furnace (4) through a pipeline and then sends it to the second cyclone separator (32), and then flows into the suspension furnace (4).

[0077] S3. Start the auxiliary heating device (10). After the device preheating in step S1 is completed, the auxiliary heating device (10) is used to adjust the cyclone preheating separator (2), and the temperatures of the first cyclone preheating separator (21), the second cyclone preheating separator (22), the third cyclone preheating separator (23), and the fourth cyclone preheating separator (24) are adjusted respectively.

[0078] S4. Start the first coal feeder (7) and the natural gas supply mechanism (8). When materials are blown into the suspension furnace (4) through the rising pipeline from the air outlet of the second cyclone separator (32) to the suspension furnace (4), the first coal feeder (7) and the natural gas supply mechanism (8) blow the mixed fuel into the suspension furnace (4) simultaneously.

[0079] S5. Start the feeding bin (1). The feeding bin (1) conveys 250-mesh coal gangue powder to the cyclone preheating separator (2).

[0080] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0081] 1. Since a four-stage cyclone preheating separator is used to adjust the preheating temperature and then through the method of suspension calcination, the calcination temperature is effectively controlled below the sintering temperature of 1050 °C to solve the problem of excessive loss on ignition, and further solve the sintering problem caused by the calcination temperature higher than the sintering temperature. The technical solution of the present application realizes calcination at a sintering temperature not greater than 1050 °C, effectively controls the loss on ignition below 0.5%, and at the same time controls the carbon content below 0.3%.

[0082] 2. Since a four-stage cyclone preheater is adopted to adjust the preheating temperature and then through the way of suspension calcination, the gangue powder can be calcined at a sintering temperature of not more than 1050 °C with 250 mesh, so as to achieve the purpose of decarbonization and at the same time not reduce the plasticity index of the gangue powder.

[0083] Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications to these embodiments once they know the basic creative concept. Therefore, the appended claims are intended to be construed as including the preferred embodiments and all changes and modifications falling within the scope of the present invention.

[0084] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the

[0085] spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and its equivalent technologies, the present invention is also intended to include these changes and modifications.

Claims

1. A decarbonization device for coal gangue, comprising a feeding bin (1), a cyclone preheater separator (2), and a cyclone separator (3), characterized in that, The feeding bin (1) is communicated with the cyclone preheater (2), and an auxiliary heating device (10) is arranged on the cyclone preheater (2); The cyclone preheater (2) is communicated with the suspension furnace (4), and the cyclone preheater (2) is communicated with the suspension furnace (4) through the cyclone separator (3); One end of the suspension furnace (4) is communicated with the hot air blower (5), and the other end is communicated with the cyclone separator (3); The cyclone separator (3) is communicated with the air supply blower (6); The cyclone preheater (2) includes a first cyclone preheater (21), a second cyclone preheater (22), a third cyclone preheater (23), and a fourth cyclone preheater (24); The cyclone separator (3) includes a first cyclone separator (31), a second cyclone separator (32), and a third cyclone separator (33); A first coal feeder (7) and a natural gas supply mechanism (8) are communicated with the suspension furnace (4); The discharge port of the feeding bin (1) is communicated in the rising pipe from the air outlet of the second cyclone preheater (22) to the air inlet of the first cyclone preheater (21); The discharge port of the first cyclone preheater (21) is communicated in the rising pipe from the air outlets of the third cyclone preheater (23) and the fourth cyclone preheater (24) to the air inlet of the second cyclone preheater (22); The discharge port of the second cyclone preheater (22) is communicated in the rising pipe from the air outlet of the first cyclone separator (31) to the air inlet of the third cyclone preheater (23); The discharge port of the third cyclone preheater (23) is communicated in the rising pipe from the air outlet of the first cyclone separator (31) to the air inlet of the fourth cyclone preheater (24); The discharge port of the fourth cyclone preheater (24) is communicated in the rising pipe from the air outlet of the second cyclone separator (32) to the suspension furnace (4); The discharge port of the first cyclone separator (31) is communicated in the rising pipe from the air supply blower (6) to the air inlet of the second cyclone separator (32); The air inlet of the third cyclone separator (33) is communicated with the end of the suspension furnace (4); the air outlet of the third cyclone separator (33) is communicated with the air inlet of the first cyclone separator (31); The rising pipe from the air supply blower (6) to the air inlet of the second cyclone separator (32) passes through the hot air blower (5).

2. The decarbonization device according to claim 1, characterized in that, The length of the suspension furnace (4) is 15 - 25 m, the effective inner diameter of the suspension furnace is 325 - 360 mm, the thickness of the refractory material is 190 - 205 mm, and the thickness of the heat insulation material is 95 - 105 mm.

3. The decarbonization device according to claim 1, wherein, The hot air blower (5) is communicated with a second coal feeder (9).

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