Process for resource utilization of coal gangue and extraction of heat of coal gangue

Abstract

The invention relates to the technical field of coal gangue recycling, in particular to a process for recycling coal gangue and extracting heat of the coal gangue. The coal gangue raw material is subjected to component analysis, SiO2 + Al2O3 is larger than or equal to 65% by weight, and CaO + Na2O + K2O is smaller than or equal to 5% by weight; performing calorific value analysis, and determining the initial air supplement amount of each workshop section according to the calorific value; coal gangue particles are prepared; feeding the coal gangue particles into a preheating section for drying and preheating, wherein the flowing direction of the coal gangue particles is the same as that of the preheated flue gas; then entering a fixed carbon removal calcining section, wherein the flowing direction of coal gangue particles in the section is opposite to the flowing direction of the preheated flue gas; the flowing direction of coal gangue particles in the cooling section is opposite to the flowing direction of fresh air, one part of flue gas generated in the cooling section enters the preheating section to be preheated, and the other part of flue gas enters the fixed carbon removal and calcination section to support combustion. According to the invention, stable combustion of the coal gangue raw material with a relatively low heat value can be realized, and full utilization of heat is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of coal gangue recycling, and specifically relates to a process for resource utilization of coal gangue and extraction of its heat. Background Art

[0002] Coal gangue is mainly composed of inorganic matter and contains various oxides and mineral components. Among them, SiO2 (silicon dioxide) and Al2O3 (aluminum trioxide) are the main oxide components, representing silicate minerals and aluminosilicate minerals respectively. In addition, it also contains oxides such as Fe2O3 (iron trioxide), CaO (calcium oxide), MgO (magnesium oxide) and trace rare metal elements.

[0003] The mineral components in coal gangue are complex and diverse, including various clay minerals such as kaolinite, illite, chlorite, montmorillonite and silicate minerals such as quartz and feldspar. These mineral components determine the chemical stability and reactivity of coal gangue.

[0004] The calorific value of coal gangue is relatively low and usually cannot be directly used as fuel. However, in some cases, the heat in coal gangue can be recovered by burning it or used for power generation and other purposes, but pretreatment is required to improve its combustion efficiency. Summary of the Invention

[0005] In order to solve the defects in the prior art, the present invention provides a process for resource utilization of coal gangue and extraction of its heat, which is specifically realized through the following technical solutions: A process for resource utilization of coal gangue and extraction of its heat, comprising the following steps: Conduct a component analysis on the coal gangue raw material, with SiO2 + Al2O3 ≥ 65% by weight and CaO + Na2O + K2O ≤ 5%; Conduct a calorific value analysis on the coal gangue raw material and determine the initial air supply volume for each section according to the calorific value; Pelletize the coal gangue raw material to obtain coal gangue pellets; Feed the coal gangue pellets into the preheating section for drying and preheating, where the flow direction of the coal gangue pellets is the same as that of the preheating flue gas; The coal gangue pellets processed by the preheating section enter the fixed carbon removal and calcination section, where the flow direction of the coal gangue pellets is opposite to that of the preheating flue gas; The coal gangue pellets processed by the fixed carbon removal and calcination section enter the cooling section, where the flow direction of the coal gangue pellets is opposite to that of the fresh air. Part of the flue gas generated in the cooling section enters the preheating section for preheating, and part enters the fixed carbon removal and calcination section for combustion support.

[0006] The calorific value of the coal gangue raw material ≥ 300 kcal / kg.

[0007] The flue gas entering the preheating section has a temperature of 300 - 500 °C.

[0008] The preheating section maintains the temperature of the generated flue gas at 500 - 900 °C by adjusting the amount of fresh air introduced.

[0009] The fixed - carbon removal and calcination section maintains the temperature of the generated flue gas at 700 - 900 °C by adjusting the amount of fresh air introduced.

[0010] The flue gas generated in the preheating section enters the fixed - carbon removal and calcination section for combustion, and the flue gas generated in the fixed - carbon removal and calcination section is led out from the side of this section.

[0011] After the flue gas generated in the fixed - carbon removal and calcination section is led out, it enters the waste - heat utilization module for waste - heat recovery, and then is discharged from the chimney after being treated by the flue - gas treatment module.

[0012] The preheating section, the fixed - carbon removal and calcination section, and the cooling section are arranged in sequence from top to bottom.

[0013] The particle size of the coal gangue particles is 5 - 50 mm.

[0014] The technical solution of the present invention has the following advantages: When the calorific value of the coal gangue is 300 kcal / kg, there is no need to adopt an additional heat source, and the combustion temperature can be maintained by its own calorific value. As the calorific value of the coal gangue increases, the temperature in the calcination zone will be too high. At this time, several additional air - supply pipes need to be added to the side of the combustion device to increase the amount of air entering and reduce the temperature of its calcination environment, ensuring that the time curve of slow calcination at low temperature is consistent with the time curve of the evolution and combustion of volatile components and fixed carbon in the coal gangue.

[0015] The indexes of the calcined products such as strength, water absorption rate, loss on ignition, etc. all meet the requirements of relevant standards. It can be used as lightweight aggregate and applied to industries such as municipal road and bridge, prefabricated building, sewage treatment, catalyst carrier, desertification control, soil remediation, etc.

[0016] The generated high - temperature flue gas can enter the waste - heat boiler to produce steam or for other purposes, further realizing economic value. The flue gas after temperature reduction is discharged up to standard after flue - gas treatment measures such as desulfurization, denitrification, and dust removal. Brief Description of the Drawings

[0017] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the accompanying drawings required for the description of the specific embodiments or the prior art. Obviously, the accompanying drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1 It is a structural schematic diagram of a combustion device.

[0019] In the figure, 1 - upper shell, 2 - feed inlet, 3 - first conveyor, 4 - screening machine, 5 - second conveyor, 6 - crusher, 7 - hopper, 8 - waste heat utilization module, 9 - flue gas treatment module, 10 - chimney, 11 - discharge outlet, 12 - lower shell, 13 - fan. Specific Embodiments

[0020] The following will clearly and completely describe the technical solutions of the present invention. Obviously, the described embodiments are some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0021] The present invention provides a process for resource utilization of coal gangue and extraction of its heat. By adopting a scientific and reasonable thermal system and raw material ratio, the self-heat value and mineral composition are fully utilized to achieve the dual goals of its resource utilization and environmental protection. When the calorific value of coal gangue ≥ 300 kcal / kg, additional heat sources are not required, and it can maintain combustion by its own calorific value and produce high-temperature flue gas at 600 - 800 °C for secondary utilization of waste heat.

[0022] First, conduct a component analysis on the coal gangue raw material. First, conduct component, calorific value tests and small-scale tests on the incoming coal gangue. Determine the sintering temperature according to the mineral components such as silicon, aluminum, iron, and calcium in the raw material, and determine the amount of supplementary air and extraction air in the system according to its calorific value.

[0023] Mainly analyze the component substances such as SiO2, Al2O3, Fe2O3, CaO, Na2O, and K2O. By weight, it is required that SiO2 + Al2O3 ≥ 65%, and its sintering temperature is 900 - 1100 °C. Components such as CaO, Na2O, and K2O can play a role in fluxing, but it is required that CaO + Na2O + K2O ≤ 5%.

[0024] The calorific value test of coal gangue is carried out in accordance with the standard GB / T 213 - 2003 "Determination Method for Calorific Value of Coal".

[0025] After detecting the calorific value, the amount of supplementary air is determined according to the calorific value to maintain stable combustion. This is specifically achieved through air supply and air extraction. The air supply and air extraction are for balancing the temperature field uniformity inside the device within a reasonable range, neither too high nor too low. When the temperature is higher than the set temperature (the temperature determined according to the composition in the early stage), air supply is required.

[0026] Then the material is processed so that its particle size is between 5 - 50 mm. The processing method can be to crush large pieces of the material; it can also be to grind the material and then granulate the ground material.

[0027] Then the processed material is sent to a screening machine to be screened into various particle sizes for storage in the warehouse for later use.

[0028] During classification, according to the application requirements of the product, it is crushed to an appropriate particle size. Generally, there are 3 specifications for the product, which are 5 - 10 mm, 10 - 20 mm, and 20 - 50 mm respectively. The particle size of each specification of material balls should be uniform, and the ratio of the largest ball to the smallest ball diameter is about 2. Otherwise, the small balls are filled between the large balls, increasing the resistance of subsequent calcination and affecting the control of ventilation and temperature field. Each level of material balls is used separately. For example, only the 5 - 10 mm material balls are crushed and used this time, and the 10 - 20 mm material balls are used next time.

[0029] Drying and preheating: The material enters the drying and preheating section for drying and preheating. The material flows from top to bottom in the drying and preheating section, and the high - temperature flue gas used for heating the material also flows from top to bottom. By adjusting the amount of fresh air introduced, the temperature of this section is adjusted to ensure that the temperature of the flue gas generated in this section is between 500 - 900 °C. Specifically, in the drying and preheating section, the material and the preheated flue gas are in a parallel - flow mode, and the inlet air temperature is 300 - 500 °C, which comes from the waste heat generated by cooling the product. The volatile components in the coal gangue are released and burned at this temperature. Because the hot air and the material move in the same direction, the heat generated by the combustion of volatile components and fixed carbon is further used for the evaporation of moisture in the material and the heating of the material. At the same time, according to the calorific value of the coal gangue raw material, one or more blowers are added in the drying and preheating section to adjust the temperature of this work order and ensure that the flue gas temperature range in the drying and preheating section is 500 - 900 °C, avoiding excessive temperature and causing over - burning and agglomeration. Since mainly the volatile components in the coal gangue are released and burned and a small amount of internal fixed carbon burns to preheat the granular material here, the temperature inside the material ball is close to 500 - 900 °C. This section adopts the parallel - flow mode, and the unburned gas components in the drying and preheating section enter the next section with the flue gas and are further burned, solving the problem of excessive emissions of combustible gases such as CO and CH4 in the tail gas in the past when using the counter - flow mode.

[0030] During the drying preheating process, the control of high-temperature flue gas mainly consists of two parts: air volume and temperature. The amount of feed determines the amount of air volume, with 1 Nm³ of air volume matched for every 1 kg of material. When the moisture content of the material ≤ 10%, the inlet air temperature is 300 - 400 °C; when the moisture content of the material is 10 - 20%, the inlet air temperature is 400 - 500 °C.

[0031] According to the calorific value in the gangue raw material, the specific method of adding one or more blowers in the drying preheating section is as follows: when the calorific value of gangue is 300 - 1000 kcal / kg, one blower is set for every 100 - 150 kcal. When the calorific value of gangue is 300 kcal, no blower needs to be added on the side. Starting from 300 kcal, for every increase of 100 - 150 kcal, one blower 13 needs to be added on the side. That is, when the calorific value is 400 - 450 kcal, one blower 13 is added for air inlet on the side; when the calorific value is 450 - 600 kcal, two blowers 13 are added for air inlet on the side.

[0032] For the removal of fixed carbon combustion, the material processed in the drying preheating section enters the fixed carbon removal calcination section. In this section, the flow direction of the material is opposite to the flow direction of the high-temperature flue gas used for combustion support. By adjusting the amount of fresh air introduced, the temperature of this section is adjusted to ensure that the flue gas temperature generated in this section is within 700 - 900 °C. Specifically, in this section, the flue gas and the material move in opposite directions, which is a countercurrent mode. The material moves downward, and the flue gas moves upward from bottom to top. At the same time, according to the calorific value of the fixed carbon in the gangue raw material, one or more blowers are added in the decarbonization calcination section to adjust the temperature of this work order, ensuring that the temperature range of the low-temperature slow-burning flue gas is 700 - 900 °C and avoiding excessive temperature resulting in overburning and agglomeration. Since coal combustion is used to heat the flue gas here, the internal temperature of the material ball is 800 - 1100 °C. This method can ensure uniform temperature distribution throughout the combustion device.

[0033] Temperature detectors are installed at both the upper and lower ends of the fixed carbon removal calcination section. The control of high-temperature flue gas is mainly achieved through temperature. The flue gas moves upward from bottom to top. When the temperature detector at the lower end detects that the flue gas temperature > 800 °C, air supply starts; when the temperature detector at the upper end detects a temperature ~ 800 °C, the ventilation volume is reduced to keep the temperature between the two temperature detectors around 800 °C.

[0034] For the combustion cooling at the end of the material, the material processed in the fixed carbon removal combustion section enters the cooling section. In this section, the flow direction of the material is opposite to the flow direction of the fresh air. Specifically, in this section, the material and the air adopt a countercurrent flow. During the falling process of the material, the cold air just moves upward, and the temperature gradually increases. Part of the generated hot air enters the preheating section for preheating, and part enters the fixed carbon removal calcination section for combustion support.

[0035] During the combustion and cooling process at the end of the material, the amount of feed determines the amount of air volume, with 1 Nm³ of air volume matched to 1 kg of material; the temperature increase of the air preheated after cooling the product is controlled within the range of 400 - 500 °C.

[0036] The high-temperature air generated in the combustion and cooling section at the end of the material is distributed to the preheating section for preheating and the fixed carbon removal and calcination section in a 1:1 ratio. When these high-temperature air flows to the preheating section, the temperature is not lower than 300 °C.

[0037] The processing duration of each section is determined according to the calorific value of the material. The durations of the above-mentioned sections are shown in Table 1 below.

[0038] Table 1 Duration distribution of each section under different calorific value conditions of the material (hours)

[0039] Among them, the fixed carbon removal and calcination section can be further divided into an upper decarbonization section and a lower sintering section, and the duration of the sintering section is 1 hour.

[0040] The flue gas generated in the preheating section enters the fixed carbon removal and calcination section for combustion. The high-temperature flue gas generated in the fixed carbon removal and calcination section is led out from the side of this section, with the temperature ranging from 600 - 800 °C, and enters the waste heat utilization module 8 for waste heat recovery. After waste heat recovery, the temperature of the flue gas drops below 150 °C, and then it enters the flue gas treatment module 9 for waste gas treatment and is finally discharged from the chimney 10.

[0041] In this technical solution, the preheating section, the fixed carbon removal and calcination section, and the cooling section are arranged in sequence from top to bottom. The coal gangue particles are fed from the top of the preheating section, flow downward until they are discharged from the cooling section. The fresh air in the cooling section is introduced from the lower part of this section. Part of the generated high-temperature flue gas enters the fixed carbon removal and calcination section through the discharge end of the fixed carbon removal and calcination section, and the other part is led out from the upper part of the cooling section and then enters the preheating section through the hot flue gas pipe.

[0042] When the fans 13 in each section are working, first, the initial air volume is provided according to the calorific value data of the coal gangue principle, and then the number of fans 13 started and the power are adjusted according to the flue gas temperature generated in each section to achieve stable combustion in each section.

[0043] From an engineering perspective, the combustion in this calcination process is smokeless combustion. Almost all the heat generated from the combustion of coal gangue is used to heat the raw materials and evaporate the moisture. A small amount of hot materials near the surface of the combustion device will dissipate heat through the surface of the equipment. Since the combustion device is stationary, it is easy to take heat preservation measures. The high-temperature flue gas generated by calcination is discharged at the high-temperature area of the device, that is, the central part of the section for removing fixed carbon by calcination. In this system, the upper materials move downward by gravity, the high-temperature combustion-supporting air moves downward by gravity, and the heat carried by the high-temperature flue gas evaporates the moisture and preheats the materials. The heat is concentrated and then dispersed to avoid the rapid combustion caused by the precipitation of volatile components, resulting in local high temperature. The lower materials move downward by gravity, and the combustion-supporting air moves upward by gravity. The movement process is reasonable and the heat loss is small. Its thermal engineering principle is reasonable.

[0044] In the calcination of coal gangue, there are problems such as difficult preheating and ignition in the early stage, and easy overburning and caking due to excessive heat concentration in the later stage. By adopting the segmented combustion and the up-and-down movement mode of materials and air, the full contact surface between materials and air can be ensured, which is easy to burn and generate heat. The vertical structure plays a role in heat preservation and heat storage to the greatest extent in the early stage, keeping the temperature stable within a reasonable range. A blast system is added to each section to disperse the local high-temperature phenomenon and maintain the temperature stability inside the device. Finally, feeding and discharging are realized simultaneously.

[0045] When the calorific value of coal gangue is 300 kcal / kg, no additional heat source is required, and the combustion temperature can be maintained by its own calorific value. As the calorific value of coal gangue increases, the temperature in the calcination area will be too high. At this time, several additional air supply pipes need to be added to each section to increase the air intake and reduce the temperature of its calcination environment, ensuring that the time curve of slow calcination at low temperature is consistent with the time curve of the precipitation and combustion of volatile components and fixed carbon in coal gangue.

[0046] The indexes such as strength, water absorption rate, and loss on ignition of the calcined product all meet the relevant standard requirements (GB / T 17431.1 - 2010). It can be used as lightweight aggregate and applied to industries such as municipal roads and bridges, prefabricated buildings, sewage treatment, catalyst carriers, desertification control, and soil remediation.

[0047] The generated high-temperature flue gas can enter the waste heat boiler to produce steam or for other uses, further realizing economic value. After the flue gas is cooled, it is discharged up to standard after flue gas treatment measures such as desulfurization, denitrification, and dust removal.

[0048] The above entire process is carried out in a vertical burner, and the structure of this burner is as shown in the attachment Figure 1 It includes an upper shell 1 and a lower shell 12; a feed inlet is provided at the top of the upper shell 1, the bottom of the upper shell 1 is communicated with the top of the lower shell 12, and a discharge port 11 is provided at the bottom of the lower shell 12 for discharging the final product.

[0049] The drying preheating section and the fixed carbon removal and calcination section are arranged in sequence from top to bottom inside the upper shell 1, and the cooling section is arranged inside the lower shell 12.

[0050] On the side walls of the upper shell 1 corresponding to the drying preheating section and the fixed carbon removal and calcination section, first air ducts are installed, and these air ducts are connected to the corresponding fans 13. The fans 13 are variable frequency fans, which are convenient for controlling the air intake volume.

[0051] On the side wall of the lower shell 12, a second air duct is installed, and this lower shell 12 is also connected to the corresponding fan 13.

[0052] On the side wall of the upper shell 1 corresponding to the fixed carbon removal and calcination section, a smoke exhaust pipe is also installed, and this drain pipe is sequentially connected to the waste heat utilization module 8, the flue gas treatment module 9, and the chimney 10 in sequence.

[0053] At the upper part of the lower shell 12, a hot flue gas pipe is also installed. One end of this hot flue gas pipe away from the lower shell 12 is fixedly connected to the upper shell 1, and its connection point corresponds to the drying preheating section.

[0054] The aforementioned feed inlet 2 is located below the discharging end of the first conveyor 3, and the feeding end of the first conveyor 3 is located below the discharging opening of the hopper 7; the feeding opening of the hopper 7 is located below the discharging opening of the screening machine 4; the feeding opening of the screening machine 4 is located below the discharging end of the second conveyor 5; the feeding end of the second conveyor 5 is located below the discharging opening of the crusher 6.

[0055] Example 1 1) In this example, the composition of the coal gangue raw material is as shown in Table 2 below.

[0056] Table 2 Composition Table of Coal Gangue in Example 1

[0057] 2) Lower calorific value: 817 kcal / kg.

[0058] 5) Particle size: 5 - 10 mm.

[0059] 6) Feed rate: 200 kg / h.

[0060] 7) In the drying preheating section, 2 fans are installed on the side, and the air intake flow of each fan is 214 Nm³ / h. The incoming air is normal temperature air, and the internal flue gas temperature ranges from 200 - 700 °C from top to bottom, and the material temperature is 100 - 900 °C.

[0061] 8) In the fixed carbon removal combustion section, 2 fans are installed on the side, and the make-up air flow of each fan is: 208 Nm³ / h. The incoming air is normal temperature air.

[0062] 9) The flue gas temperature in the fixed carbon removal combustion section is 700 - 800 °C, and the material temperature is 800 - 900 °C.

[0063] 10) Air flow rate in the cooling section: 196 Nm³ / h.

[0064] 11) Product output: 170 - 180 kg / h.

[0065] Table 3 Final product test results of Example 1

[0066] Example 2 1) In this example, the coal gangue raw material composition is as shown in Table 4 below.

[0067] Table 4 Coal gangue composition table in Example 2

[0068] 2) Lower calorific value: 589 kcal / kg. 5) Particle size: 5 - 10 mm.

[0069] 6) Feed rate: 200 kg / h.

[0070] 7) In the drying and preheating section, 1 fan is installed on the side, the inlet air flow rate is 275 Nm³ / h, the inlet air is normal temperature air, and the internal flue gas temperature ranges from 200 - 700 °C from top to bottom, and the material temperature is 100 - 900 °C.

[0071] 8) On the side of the fixed carbon removal combustion section, 1 fan, and the make-up air flow rate for each fan: 265 Nm³ / h. The inlet air is normal temperature air.

[0072] 9) The flue gas temperature in the fixed carbon removal combustion section is 700 - 800 °C, and the material temperature is 800 - 900 °C.

[0073] 10) Air flow rate in the cooling section: 205 Nm³ / h.

[0074] 11) Product output: 175 - 185 kg / h.

[0075] Table 5 Final product test results of Example 2

[0076] Example 3 1) In this example, the coal gangue raw material composition is as shown in Table 6 below.

[0077] Table 6 Coal gangue composition table in Example 3

[0078] 2) Net calorific value: 413 kcal / kg.

[0079] 5) Particle size: 5 - 10 mm.

[0080] 6) Feed rate: 200 kg / h.

[0081] 7) In the drying and preheating section, 1 fan is installed on the side, the inlet air flow rate is 157 Nm³ / h, the inlet air is normal temperature air, the internal flue gas temperature ranges from 200 to 700 °C from top to bottom, and the material temperature is 100 - 900 °C.

[0082] 8) In the section for removing fixed carbon combustion, 1 fan is installed on the side, the make-up air flow rate: 220 Nm³ / h. The inlet air is normal temperature air.

[0083] 9) In the section for removing fixed carbon combustion, the flue gas temperature is 700 - 800 °C, and the material temperature is 800 - 900 °C.

[0084] 10) Air flow rate in the cooling section: 180 Nm³ / h.

[0085] 11) Product output: 180 - 190 kg / h.

[0086] Table 7 Test results of the final product in Example 3

[0087] Obviously, the above embodiments are merely examples given for clear illustration and not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or alterations can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or alterations derived therefrom are still within the protection scope of this invention.

Claims

1. A process for resource utilization of coal gangue and extraction of its heat, characterized in that, It includes the following steps: Conduct a composition analysis on the coal gangue raw material, with SiO2 + Al2O3 ≥ 65% and CaO + Na2O + K2O ≤ 5% by weight; Conduct a calorific value analysis on the coal gangue raw material and determine the initial make-up air volume for each section according to the calorific value; Pelletize the coal gangue raw material to obtain coal gangue pellets; Feed the coal gangue pellets into the preheating section for drying and preheating, where the flow direction of the coal gangue pellets is the same as that of the preheating flue gas; The coal gangue pellets treated in the preheating section enter the fixed carbon removal and calcination section, where the flow direction of the coal gangue pellets is opposite to that of the preheating flue gas; The coal gangue pellets treated in the fixed carbon removal and calcination section enter the cooling section, where the flow direction of the coal gangue pellets is opposite to that of the fresh air. Part of the flue gas generated in the cooling section enters the preheating section for preheating, and part enters the fixed carbon removal and calcination section for combustion support.

2. The process for resource utilization of coal gangue and extraction of its heat according to claim 1, characterized in that, The calorific value of the coal gangue raw material ≥ 300 kcal / kg.

3. The process for resource utilization of coal gangue and extraction of its heat according to claim 1, characterized in that, The temperature of the flue gas entering the preheating section is 300 - 500 °C.

4. The process for resource utilization of coal gangue and extraction of its heat according to claim 1 or 3, characterized in that, The preheating section maintains the temperature of the generated flue gas at 500 - 900 °C by adjusting the amount of fresh air introduced.

5. The process for resource utilization of coal gangue and extraction of its heat according to claim 1 is characterized in that, The fixed carbon removal and calcination section maintains the temperature of the generated flue gas at 700 - 900 °C by adjusting the amount of fresh air introduced.

6. The process for resource utilization of coal gangue and extraction of its heat according to claim 1, characterized in that, The flue gas generated in the preheating section enters the fixed carbon removal and calcination section for combustion, and the flue gas generated in the fixed carbon removal and calcination section is led out from the side of this section.

7. The process for resource utilization of coal gangue and extraction of its heat according to claim 6, characterized in that, The flue gas generated in the fixed carbon removal and calcination section is led out and enters the waste heat utilization module (8) for waste heat recovery, and then is discharged from the chimney (10) after being treated by the flue gas treatment module (9).

8. The process for resource utilization of coal gangue and extraction of its heat according to claim 1, characterized in that The preheating section, the fixed carbon removal and calcination section, and the cooling section are arranged in sequence from top to bottom.

9. The process for resource utilization of coal gangue and extraction of its heat according to claim 1, characterized in that, The particle size of the coal gangue pellets is 5 - 50 mm.

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