A coal gangue thermal activation calcination process and system based on cement burning system

Abstract

The present invention discloses a coal gangue thermal activation calcination process based on a cement burning system, specifically, the coal gangue is first pretreated, then calcined and cooled, and then ultra-finely ground to obtain a high-activity calcined coal gangue mixed material; wherein, the low calorific value coal gangue is first sent to an indirect pre-burning device for rotary pre-burning, then sent to a rotary kiln for thermal activation calcination, and then sent to a grate cooler for cooling; the drying heat source of the indirect pre-burning device is the hot flue gas at the tail of the rotary kiln; the high calorific value coal gangue is directly sent to an indirect thermal activation device for thermal activation and rotary calcination, and then enters a single-drum cooler for cooling; the drying heat source of the indirect thermal activation device is the hot flue gas from the grate cooler of a normal cement clinker cement burning system; the volatile organic waste gas generated in the indirect pre-burning device and the indirect thermal activation device is sent to the kiln head for combustion. The present invention solves the environmental emission problem of volatile organic matter and the risk problem of suspended calcination of coal gangue in a preheater.

Description

Technical Field

[0001] The invention relates to the technical field of new dry-process cement production, and in particular to a coal gangue thermal activation calcining process and system based on a cement burning system. Background Art

[0002] Gangue is a kind of black-gray rock with low carbon content and harder than coal that is associated with coal seams during the coal formation process. It is generally a general solid waste generated in the production process of coal mining and excavation. Gangue contains a variety of minerals: kaolinite, quartz, mica, calcite and iron-containing minerals, among which quartz and kaolinite are the main mineral components. The existing idea of ​​recycling gangue is generally to use gangue as a cement admixture. Since gangue contains a certain amount of organic carbon to a greater or lesser extent, this will cause the surface of cement and concrete products to be dyed black; the presence of organic carbon will also lead to an increase in the use of concrete water reducers, which also affects the scope of use of gangue as an admixture. In addition, gangue can be added to cement raw materials as a silicon-aluminum supplementary raw material, but since gangue contains a certain calorific value, if its calorific value in the raw material is ≥100Kcal / kg, when the admixture is greater than 5%, it will cause the preheater to be blocked, resulting in instability in cement production and even safety accidents.

[0003] Chinese Patent Publication No. CN113045227A discloses a method for calcining activated gangue, in which the mixture sphere is calcined and activated at a temperature of 900-1000°C during the calcination process. However, since the activation calcination temperature of kaolinite in gangue is generally not higher than 850°C, the calcination temperature adopted in this patent will cause the activity of metakaolin in the calcined gangue to drop significantly, and the significance of thermal activation to improve activity is lost. Chinese Patent Publication No. CN103864325A discloses a production system for calcining gangue in a suspended state, but the system is suitable for gangue with low calorific value. The energy consumption of the suspended calcination of a general gangue preheater is 500Kcal / kg, which can barely operate for gangue with a calorific value of ≤500Kcal / kg; when the calorific value of the gangue is greater than 500Kcal / kg, the heat brought by the combustion of organic carbon and volatile organic matter is greater than the amount required by the system. In this case, the existing suspended calcination system does not provide a solution. The volatilization temperature range of organic volatiles in coal gangue is generally 260-550℃. In the case of suspended calcination in the preheater, the coal gangue may reach the volatilization temperature range of organic matter in the first to third stage preheaters before entering the decomposition furnace. Since the oxygen content in the flue gas in the preheater is 3-5%, a large amount of organic volatiles will cause deflagration and even burn through the preheater, causing safety accidents. If the calorific value of coal gangue is relatively high, the risk is even greater. In addition, when coal gangue is calcined in the cement rotary kiln system, due to poor heat exchange efficiency, it is easy to under-burn or over-burn, with much organic carbon residue and poor activity. Both of the above patents are suitable for using coal gangue with low calorific value as raw materials. For coal gangue with high calorific value, these two patents fail to provide solutions. In addition, neither of the above two patents mentions the disposal of volatile organic compounds, because the volatile organic compounds that are not completely burned during suspended calcination will enter the flue gas. There is also the problem of volatile organic compounds entering the flue gas at the tail of cement kiln when directly calcining coal gangue, which involves environmental emission issues.

[0004] In summary, the difficulty in thermal activation of coal gangue is that it contains volatile organic matter and organic carbon. High calorific value coal gangue is difficult to adapt to the preheater suspension calcination system. If the calcination is not complete, the residual organic carbon in the product will affect the color of the product. Direct calcination in a cement rotary kiln has the risk of overburning due to the long time after calcination, which limits the activity. Calcination in a preheater suspension calcination system will cause volatile organic matter to deflagrate before entering the decomposition furnace, and cause the preheater to be crusted and blocked, or even burn through. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the purpose of the present invention is to provide a coal gangue thermal activation calcination process based on a cement burning system. The process flow is simple and can use the existing burning equipment, dust collector, waste heat power generation system, flue gas treatment system and grinding system of the cement burning system. It is low in cost and easy to implement, providing an effective way for the efficient utilization of large amounts of solid waste coal gangue.

[0006] Another object of the present invention is to provide a coal gangue thermal activation calcination system based on a cement burning system.

[0007] The present invention is realized by a coal gangue thermal activation calcination process based on a cement burning system, wherein the coal gangue is first pretreated, then calcined and cooled, and then enters a grinding system for ultrafine grinding after cooling, so as to obtain a high-activity calcined coal gangue mixed material;

[0008] Among them, the low calorific value coal gangue is first sent to the indirect pre-burning equipment for rotary pre-burning, and then sent to the rotary kiln for thermal activation calcination after the rotary pre-burning is completed. After the thermal activation calcination is completed, it is sent to the grate cooler for cooling; the drying heat source of the indirect pre-burning equipment is the hot flue gas from the dust-removed tail of the rotary kiln;

[0009] The high calorific value coal gangue is directly sent to the indirect thermal activation equipment for thermal activation and rotary calcination. After the thermal activation and rotary calcination, it enters the single-drum cooler for cooling. The drying heat source of the indirect thermal activation equipment is the dust-free hot flue gas from the grate cooler of the cement burning system for normal production of cement clinker.

[0010] The volatile organic waste gas generated in the indirect pre-burning equipment and the indirect thermal activation equipment is sent to the kiln head of the rotary kiln as combustion air, so that the volatile organic matter (VOC) is burned at high temperature in the kiln;

[0011] The hot flue gas after heat exchange in the indirect pre-burning equipment and the indirect thermal activation equipment enters the waste heat power generation system, and the flue gas from the waste heat power generation enters the flue gas treatment system for treatment before meeting the emission standards.

[0012] Preferably, the pretreatment of the coal gangue is to crush and screen the raw coal gangue ore to obtain a material with particles ≤ 5 mm.

[0013] Preferably, an appropriate amount of protective gas is introduced when the low calorific value coal gangue is rotary pre-burned in the indirect pre-burning equipment and when the high calorific value coal gangue is thermally activated and rotary calcined in the indirect thermal activation equipment.

[0014] Preferably, the rotary pre-burning temperature of low calorific value coal gangue in the indirect pre-burning equipment is 500-600°C, the pre-burning time is 25-40min, and the rotation speed is 3-5r / min; the thermal activation calcination temperature in the rotary kiln is 800-900°C, the calcination time is 20-35min, and the kiln rotation speed is 3-5r / min; the hot flue gas temperature of the drying heat source of the indirect pre-burning equipment is 500-700°C.

[0015] Preferably, for low calorific value coal gangue, the waste heat after the grate cooler cools the coal gangue is also sent to the waste heat power generation system.

[0016] Preferably, the indirect pre-firing equipment is made of high temperature resistant 310 stainless steel with a heat resistance temperature range of ≥1100°C and a length-to-diameter ratio of 3-5.

[0017] Preferably, the thermal activation rotary calcination temperature of high calorific value coal gangue in the indirect thermal activation equipment is 750-900°C, the calcination time is 35-55min, and the rotation speed is 2-5r / min; the hot flue gas temperature of the drying heat source of the indirect thermal activation equipment is 900-1050°C.

[0018] Preferably, the indirect thermal activation equipment is made of high temperature resistant 310 stainless steel with a heat resistant temperature range of ≥1100°C and a length-to-diameter ratio of 5-10.

[0019] Preferably, the specific surface area of ​​the high-activity calcined coal gangue mixed material is 550-700m 2 / kg, activity index ≥90%.

[0020] A coal gangue thermal activation calcination system based on a cement burning system, comprising a rotary kiln, a grate cooler, a dust collection system, a grinding system, a waste heat power generation system and a flue gas treatment system of an existing cement burning system;

[0021] For low calorific value coal gangue, an indirect pre-burning device is also included, wherein the material outlet of the indirect pre-burning device is connected to the rotary kiln, and the kiln tail of the rotary kiln is connected to the hot flue gas inlet of the indirect pre-burning device through a dust collection system;

[0022] For high calorific value coal gangue, it also includes indirect thermal activation equipment and a single-drum cooler; the material outlet of the indirect thermal activation equipment is connected to the single-drum cooler, the material outlet of the single-drum cooler is connected to the grinding system, and the flue gas outlet of the grate cooler is connected to the hot flue gas inlet of the indirect thermal activation equipment through the dust collection system;

[0023] The volatile organic matter waste gas outlets of the indirect pre-burning equipment and the indirect thermal activation equipment are both connected to the kiln head of the rotary kiln, the hot flue gas outlets of the indirect pre-burning equipment and the indirect thermal activation equipment are both connected to the waste heat power generation system, and the indirect pre-burning equipment and the indirect thermal activation equipment are both provided with a protective gas inlet.

[0024] The present invention has the following advantages and beneficial effects:

[0025] 1. The present invention uses indirect pre-burning equipment and indirect thermal activation equipment to volatilize all volatile organic compounds (VOC) in coal gangue at 500-700°C, and sends the waste gas containing volatile organic compounds to the kiln head of the rotary kiln for burning, thereby solving the problems of emission and explosion risk of volatile organic compounds; the hot flue gas after heat exchange by the indirect pre-burning equipment and the indirect thermal activation equipment enters the existing waste heat power generation system, thereby improving energy utilization efficiency.

[0026] 2. The indirect pre-burning process of the present invention can dehydroxylate 50%-70% of kaolinite for low calorific value coal gangue, and then the secondary calcination in the rotary kiln can achieve rapid calcination, so that the activity of coal gangue is stimulated, and organic carbon can be quickly removed, which generally increases the material raising and heat exchange effects and effectively prolongs the thermal activation calcination time. In addition, it also avoids the phenomenon of over-burning caused by excessive temperature when volatile organic matter burns on the surface of coal gangue in the kiln, thereby reducing the activity of calcined coal gangue. Sending volatile organic matter to the kiln head for burning can appropriately reduce the amount of fuel sprayed into the kiln by the burner.

[0027] In the indirect thermal activation equipment, high calorific value coal gangue can first undergo kaolinite dehydroxylation reaction in an air-tight environment, and then the volatile VOC in the coal gangue will also evaporate, and finally the dehydroxylation reaction and active excitation reaction will be completed. All the volatilized VOCs will be sent to the kiln head for use as fuel, which will not affect the normal burning of cement clinker.

[0028] 3. For coal gangue with a calorific value of 0-500Kcal / kg, the indirect pre-burning scheme of the present invention can more effectively release the organic volatiles in the coal gangue, and then the waste gas containing volatile organics is sent to the kiln head for burning, forming a good cycle, and can also increase the waste heat power generation. For coal gangue with a calorific value of 500-2000Kcal / kg, the present invention adopts the indirect thermal activation calcination method to run simultaneously with cement clinker production, and the indirectly volatilized organic matter is sent to the kiln head for burning, saving energy consumption, and at the same time, cement clinker and high-activity mixed materials can be obtained.

[0029] 4. In view of the unique volatilization temperature range of 320-550°C of volatile organic compounds in coal gangue, the present invention adopts an innovative process of indirect heat exchange pre-burning of flue gas at the tail or head of the kiln, and sends the volatilized volatile organic compounds to the head of the kiln for burning. Firstly, it solves the environmental emission problem of volatile organic compounds, and secondly, it solves the risk problem caused by suspended calcination of coal gangue in the preheater. It is very suitable for preparing high-activity coal gangue mixed material products by simple modification of existing cement rotary kiln firing systems.

[0030] 5. The present invention mostly utilizes the existing equipment of the cement burning system, has simple process, low investment, and is easy to promote. It provides an effective method for large-scale disposal of coal gangue and low-carbon emissions in the cement industry, and has significant economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a flow chart of a low calorific value coal gangue thermal activation calcination system provided in Example 1 of the present invention;

[0032] Figure 2 This is a thermal analysis diagram of low calorific value coal gangue provided in Example 1 of the present invention;

[0033] Figure 3 This is a flow chart of a high calorific value coal gangue thermal activation calcination system provided in Example 2 of the present invention;

[0034] Figure 4 This is a thermal analysis diagram of high calorific value coal gangue provided in Example 2 of the present invention. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0036] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] The characteristics of the coal gangue in this embodiment are as follows: calorific value range: 0-2000Kcal / kg, volatilization temperature range of organic matter in the coal gangue: 320-550°C, Al2O3≥18%.

[0038] The embodiment of the present invention provides a coal gangue thermal activation calcination process based on a cement burning system. The calcination process comprises the following steps: firstly, the coal gangue ore is crushed and screened to obtain a material with particles ≤ 5 mm, and then calcined and cooled. After cooling, the material is subjected to ultrafine grinding in a grinding system to obtain a high-activity calcined coal gangue mixed material. The specific surface area of ​​the high-activity calcined coal gangue mixed material is 550-700m 2 / kg, activity index ≥90%.

[0039] Among them, the low calorific value coal gangue is first sent to the indirect pre-burning equipment for rotary pre-burning, and then sent to the rotary kiln for thermal activation calcination after the rotary pre-burning is completed. After the thermal activation calcination is completed, it is sent to the grate cooler for cooling; the drying heat source of the indirect pre-burning equipment is the hot flue gas from the dust-removed tail of the rotary kiln;

[0040] The high calorific value coal gangue is directly sent to the indirect thermal activation equipment for thermal activation and rotary calcination. After the thermal activation and rotary calcination, it enters the single-drum cooler for cooling. The drying heat source of the indirect thermal activation equipment is the dust-free hot flue gas from the grate cooler of the cement burning system for normal production of cement clinker.

[0041] The volatile organic waste gas generated in the indirect pre-burning equipment and the indirect thermal activation equipment is sent to the kiln head of the rotary kiln as combustion air, so that the volatile organic matter (VOC) is burned at high temperature in the kiln;

[0042] The hot flue gas after heat exchange in the indirect pre-burning equipment and the indirect thermal activation equipment enters the waste heat power generation system, and the flue gas from the waste heat power generation enters the flue gas treatment system for treatment before meeting the emission standards.

[0043] Among them, when the low calorific value coal gangue is rotary pre-burned in the indirect pre-burning equipment, and when the high calorific value coal gangue is thermally activated and rotary calcined in the indirect thermal activation equipment, an appropriate amount of protective gas is introduced. The introduction of an appropriate amount of protective gas can prevent explosion caused by air leakage.

[0044] The rotary pre-burning temperature of low calorific value coal gangue in the indirect pre-burning equipment is 500-600℃, the pre-burning time is 25-40min, and the rotation speed is 3-5r / min; the thermal activation calcination temperature in the rotary kiln is 800-900℃, the calcination time is 20-35min, and the kiln rotation speed is 3-5r / min; the hot flue gas temperature of the drying heat source of the indirect pre-burning equipment is 500-700℃.

[0045] For low calorific value coal gangue, the waste heat after the grate cooler cools the coal gangue is also sent to the waste heat power generation system. The waste heat of the grate cooler enters the existing waste heat power generation system, further improving the energy utilization efficiency.

[0046] The indirect pre-firing equipment is made of high-temperature resistant 310 stainless steel, with a heat-resistant temperature range of ≥1100°C and an aspect ratio of 3-5.

[0047] The thermal activation rotary calcination temperature of high calorific value coal gangue in the indirect thermal activation equipment is 750-900℃, the calcination time is 35-55min, and the rotation speed is 2-5r / min; the hot flue gas temperature of the drying heat source of the indirect thermal activation equipment is 900-1050℃.

[0048] The indirect thermal activation equipment is made of high temperature resistant 310 stainless steel, with a heat resistance temperature range of ≥1100°C and an aspect ratio of 5-10. The aspect ratio is used to adjust the thermal activation time. A larger aspect ratio is set for a high calorific value to extend the thermal activation time. The indirect pre-burning equipment and the indirect thermal activation equipment can also use the same equipment.

[0049] A coal gangue thermal activation calcination system based on a cement burning system, comprising a rotary kiln, a grate cooler, a dust collection system, a grinding system, a waste heat power generation system and a flue gas treatment system of an existing cement burning system;

[0050] For low calorific value coal gangue, an indirect pre-burning device is also included, wherein the material outlet of the indirect pre-burning device is connected to the rotary kiln, and the kiln tail of the rotary kiln is connected to the hot flue gas inlet of the indirect pre-burning device through a dust collection system;

[0051] For high calorific value coal gangue, it also includes indirect thermal activation equipment and a single-drum cooler; the material outlet of the indirect thermal activation equipment is connected to the single-drum cooler, the material outlet of the single-drum cooler is connected to the grinding system, and the flue gas outlet of the grate cooler is connected to the hot flue gas inlet of the indirect thermal activation equipment through the dust collection system;

[0052] The volatile organic matter waste gas outlets of the indirect pre-burning equipment and the indirect thermal activation equipment are both connected to the kiln head of the rotary kiln, the hot flue gas outlets of the indirect pre-burning equipment and the indirect thermal activation equipment are both connected to the waste heat power generation system, and the indirect pre-burning equipment and the indirect thermal activation equipment are both provided with a protective gas inlet.

[0053] The present invention is further described in detail below.

[0054] Example 1

[0055] For low calorific value coal gangue with calorific value of 286.7Kcal / kg and organic matter volatilization temperature range of 326.02-515.22℃ (see Figure 2 As shown), Al2O3≥18%. Under the condition that the cement burning system does not produce cement clinker, a coal gangue thermal activation calcination system based on the cement burning system, such as Figure 1 As shown, a coal gangue thermal activation calcination system is formed by utilizing the cement plant's existing rotary kiln, grate cooler, dust collection system, grinding system, crushing equipment, waste heat power generation system, flue gas treatment system, and newly added indirect pre-burning equipment.

[0056] After crushing and screening (particles ≤ 5mm), the gangue ore is sent to the indirect pre-burning equipment, the pre-burning temperature is 500-600℃, the pre-burning time is 25-40min, the kiln speed is 3-5r / min, and the protective gas is introduced into the indirect pre-burning equipment during pre-burning. After the pre-burning is completed, it enters the rotary kiln for secondary thermal activation calcination. The thermal activation calcination temperature is 800-900℃, the calcination time is 20-35min, and the kiln speed is 3-5r / min. After the thermal activation calcination is completed, it enters the grate cooler for cooling, and then enters the grinding system after cooling. After ultra-fine grinding, it enters the storage, thereby obtaining a specific surface area of ​​550-700m 2 / kg, high-activity calcined coal gangue mixed material with activity index ≥90%.

[0057] The indirect pre-firing equipment used is made of high temperature resistant 310 stainless steel, with a heat resistance temperature range of ≥1100°C and a length-to-diameter ratio of 3-5.

[0058] Flue gas flow sequence: The hot flue gas at 500-700℃ after dust removal from the rotary kiln tail enters the indirect pre-burning equipment. The hot flue gas at 250-300℃ and the waste heat of the grate cooler from the indirect pre-burning equipment enter the waste heat power generation system. The flue gas from the waste heat power generation enters the flue gas treatment system for treatment and meets the emission standards. The waste gas containing volatile organic compounds that is isolated from the air inside the indirect pre-burning equipment is sent to the rotary kiln head for burning, saving energy consumption.

[0059] Example 2

[0060] For high calorific value coal gangue with calorific value of 760.8Kcal / kg and organic matter volatilization temperature range of 354.22-508.19℃ (see Figure 4 As shown), Al2O3≥18%. Under the condition that the cement burning system normally produces cement clinker, a coal gangue thermal activation calcination system based on the cement burning system, such as Figure 3 As shown, the existing rotary kiln, grate cooler, dust collection system, grinding system, crushing equipment, waste heat power generation system, flue gas treatment system of the cement plant are utilized together with the newly added indirect thermal activation equipment and single-drum cooler to form a coal gangue thermal activation calcination system.

[0061] After crushing and screening (particles ≤ 5mm), the gangue ore is sent to the indirect thermal activation equipment. The thermal activation calcination temperature is 750-900℃, the calcination time is 35-55min, and the speed is 2-5r / min. After calcination, it enters the single-drum cooler for cooling, and then enters the grinding system. After ultra-fine grinding, it enters the storage, thus obtaining a specific surface area of ​​550-700m 2 / kg, high-activity calcined coal gangue mixed material with activity index ≥90%.

[0062] The indirect thermal activation equipment used is made of high temperature resistant 310 stainless steel, with a heat resistance temperature range of ≥1100°C and a length-to-diameter ratio of 5-10.

[0063] Flue gas flow sequence: The hot flue gas at 900-1050℃ after dust removal from the grate cooler at the kiln head enters the indirect thermal activation equipment, and the hot flue gas at 450-500℃ exiting the indirect thermal activation equipment enters the waste heat power generation system. The flue gas from the waste heat power generation enters the flue gas treatment system for treatment and then meets the emission standards. The waste gas containing high concentration of volatile organic compounds that is isolated from the air inside the indirect thermal activation equipment is sent to the rotary kiln head for burning. The volatile gas generated by the high calorific value coal gangue can provide calorific value for the cement rotary kiln head and save energy.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents, and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A coal gangue thermal activation calcination process based on a cement burning system, characterized in that: The calcination process is to pre-treat the gangue first to obtain materials with particles ≤ 5mm, and then calcine and cool them. After cooling, they enter the grinding system for ultra-fine grinding to obtain a high-activity calcined gangue mixed material. Among them, the low calorific value coal gangue is first sent to the indirect pre-burning equipment for rotary pre-burning, and then sent to the rotary kiln for thermal activation calcination after the rotary pre-burning is completed. After the thermal activation calcination is completed, it is sent to the grate cooler for cooling; the drying heat source of the indirect pre-burning equipment is the hot flue gas from the tail of the rotary kiln after dust removal; the rotary pre-burning temperature of the low calorific value coal gangue in the indirect pre-burning equipment is 500-600℃, the pre-burning time is 25-40min, and the rotation speed is 3-5r / min; the thermal activation calcination temperature in the rotary kiln is 800-900℃, the calcination time is 20-35min, and the kiln rotation speed is 3-5r / min; the hot flue gas temperature of the drying heat source of the indirect pre-burning equipment is 500-700℃; The high calorific value coal gangue is directly sent to the indirect thermal activation equipment for thermal activation and rotary calcination. After the thermal activation and rotary calcination is completed, it enters the single-drum cooler for cooling; the drying heat source of the indirect thermal activation equipment is the hot flue gas after dust removal from the grate cooler of the cement burning system for normal production of cement clinker; the thermal activation and rotary calcination temperature of the high calorific value coal gangue in the indirect thermal activation equipment is 750-900℃, the calcination time is 35-55min, and the rotation speed is 2-5r / min; the hot flue gas temperature of the drying heat source of the indirect thermal activation equipment is 900-1050℃; The volatile organic waste gas generated in the indirect pre-burning equipment and the indirect thermal activation equipment is sent to the kiln head of the rotary kiln as combustion air, so that the volatile organic matter (VOC) is burned at high temperature in the kiln; The hot flue gas after heat exchange in the indirect pre-burning equipment and the indirect thermal activation equipment enters the waste heat power generation system, and the flue gas from the waste heat power generation enters the flue gas treatment system for treatment before meeting the emission standards.

2. The coal gangue thermal activation calcination process based on the cement burning system according to claim 1, characterized in that: The pretreatment of coal gangue is to crush and screen the raw coal gangue ore.

3. The coal gangue thermal activation calcination process based on the cement burning system according to claim 1, characterized in that: When low calorific value coal gangue is rotary pre-burned in the indirect pre-burning equipment and when high calorific value coal gangue is thermally activated and rotary calcined in the indirect thermal activation equipment, an appropriate amount of protective gas is introduced.

4. The coal gangue thermal activation calcination process based on the cement burning system according to claim 1, characterized in that: For low calorific value coal gangue, the waste heat after the grate cooler cools the coal gangue is also sent to the waste heat power generation system.

5. The coal gangue thermal activation calcination process based on cement burning system according to claim 1, characterized in that: The indirect pre-firing equipment is made of high-temperature resistant 310 stainless steel, with a heat-resistant temperature range of ≥1100°C and an aspect ratio of 3-5.

6. The coal gangue thermal activation calcination process based on the cement burning system according to claim 1, characterized in that: The indirect thermal activation equipment is made of high-temperature resistant 310 stainless steel, with a heat-resistant temperature range of ≥1100°C and a length-to-diameter ratio of 5-10.

7. The coal gangue thermal activation calcination process based on cement burning system according to claim 1, characterized in that: The specific surface area of ​​the high-activity calcined coal gangue mixed material is 550-700m 2 / kg, activity index ≥90%.

8. A coal gangue thermal activation calcining system of a cement burning system based on the calcining process according to any one of claims 1 to 7, comprising a rotary kiln, a grate cooler, a dust collection system, a grinding system, a waste heat power generation system and a flue gas treatment system of an existing cement burning system; characterized in that: For low calorific value coal gangue, an indirect pre-burning device is also included, wherein the material outlet of the indirect pre-burning device is connected to the rotary kiln, and the kiln tail of the rotary kiln is connected to the hot flue gas inlet of the indirect pre-burning device through a dust collection system; For high calorific value coal gangue, it also includes indirect thermal activation equipment and single-drum coolers; The material outlet of the indirect thermal activation device is connected to the single-drum cooler, the material outlet of the single-drum cooler is connected to the grinding system, and the flue gas outlet of the grate cooler is connected to the hot flue gas inlet of the indirect thermal activation device through the dust collection system; The volatile organic matter waste gas outlets of the indirect pre-burning equipment and the indirect thermal activation equipment are both connected to the kiln head of the rotary kiln, the hot flue gas outlets of the indirect pre-burning equipment and the indirect thermal activation equipment are both connected to the waste heat power generation system, and the indirect pre-burning equipment and the indirect thermal activation equipment are both provided with a protective gas inlet.

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