Process for preparing high-strength lightweight aggregate from high-calorific-value coal gangue

Abstract

The invention relates to the technical field of coal gangue, in particular to a process for preparing high-strength lightweight aggregate from high-calorific-value coal gangue, which comprises a drying link, a pyrolysis link, a decarburization link, a sintering link and a cooling link, and is characterized in that wet coal gangue pellets are sequentially subjected to drying, pyrolysis, decarburization and cooling to obtain water-retaining ceramsite; sequentially drying, pyrolyzing, decarbonizing, sintering and cooling the wet coal gangue pellets to obtain the high-strength ceramsite. High-temperature hot air of the cooling link is introduced into the sintering link, low-temperature hot air of the cooling link is introduced into the decarburization link, and tail gas of each link serves as high-temperature flue gas to be recycled towards the front link, so that the overall energy consumption of a process production line is reduced; in the pyrolysis link, gas separated out of the coal gangue is collected and serves as fuel to be introduced into the sintering kiln, so that the whole production line does not need additional energy input, in addition, the carbon content in the ceramsite is effectively reduced through pyrolysis and decarburization, and the product quality is improved.

Description

Technical Field

[0001] The invention relates to the field of coal gangue technology, and in particular to a technology for preparing high-strength lightweight aggregate from high-calorific value coal gangue. Background Art

[0002] Coal gangue is solid waste discharged during coal mining and coal washing. It is a black-gray rock with a low carbon content and harder than coal that accompanies coal seams during the coal formation process.

[0003] The main component of coal gangue is silicate (SiO2 content greater than 63%, Al2O3 content greater than 18%), which is very suitable for firing expanded clay (high-strength lightweight aggregate). And because it has a certain carbon content, it contains calorific value, which can reduce the use of fuel during the firing process.

[0004] However, the current coal gangue used to make ceramsite in China is generally low-calorific value coal gangue, and its calorific value is generally controlled within 500kcal / kg. When the calorific value of coal gangue reaches 1000kcal / kg, it can neither meet the conditions for direct combustion of coal nor have a good way to use it. It is generally directly stored and discharged as solid waste.

[0005] The main reason is that in the process of firing expanded clay using high calorific value coal gangue, as the temperature rises, volatile combustible gas will be precipitated from the coal gangue. After the precipitate, the combustible gas will burn violently, instantly raising the ambient temperature to over 1000°C, causing the surface of the ball to melt rapidly to form a layer of vitrified hard shell, which prevents air from entering the interior of the ball and reacting with the fixed carbon in the coal gangue for oxidation. On the one hand, it leads to the presence of unburned fixed carbon in the product, making the product quality substandard. On the other hand, the volatile gas precipitated from the coal gangue is not effectively utilized, resulting in energy waste. Summary of the invention

[0006] In order to solve the aforementioned technical problems, the present invention provides a process for producing high-strength lightweight aggregate from high-calorific value coal gangue. The process for recycling coal gangue resources timely separates the volatile gas precipitated from the coal gangue and transfers it to the sintering stage. On the one hand, it avoids the problem of substandard product quality caused by real-time combustion of volatile gases, and on the other hand, it achieves effective utilization of volatile gases and avoids the problem of energy waste. This is specifically achieved through the following technical scheme.

[0007] The present invention discloses a process for preparing high-strength lightweight aggregate from high calorific value coal gangue, comprising the following steps: S1. Crush and grind the gangue, add water, stir and granulate to obtain wet gangue balls, put the wet balls into a dryer, and introduce the first flue gas into the dryer to obtain dry gangue balls and the first tail gas.

[0008] S2. Put the dry gangue balls into a pyrolysis kiln, and introduce the second flue gas into the kiln to pyrolyze the dry gangue balls to obtain first solid balls, a first gas and a second tail gas. The first gas is collected under anaerobic conditions, and the second tail gas is cooled to obtain the first flue gas.

[0009] S3, putting the first solid ball into a decarbonizing machine while it is still hot, and introducing the third flue gas and the first hot air into the decarbonizing machine to decarbonize the first solid ball, so as to obtain the second solid ball and the second flue gas.

[0010] S4, putting the second solid pellet into a sintering kiln while it is still hot, and introducing the first gas and the second hot air into the kiln to sinter the second solid pellet, so as to obtain a third solid pellet and the third flue gas.

[0011] S5. Put the third solid pellet into a cooler while it is still hot, blow room temperature air into the cooler for cooling, and obtain finished pellets, the first hot air, and the second hot air.

[0012] Preferably, in step S2, the pyrolysis kiln is a double-layer cylinder structure with an inner and outer shell, the gangue dry material balls move in the inner cylinder, the second flue gas passes through the gap between the inner cylinder and the outer cylinder, the interior of the inner cylinder is an anaerobic environment, and the inner cylinder is connected to a sealed air chamber, and the sealed air chamber can collect the first gas.

[0013] Preferably, in step S4, the sintering kiln is a waterfall-type rotary kiln, and the kiln body is a streamlined structure with three-leaf protrusions arranged inside.

[0014] Preferably, in step S5, the specific operation steps of cooling the third solid pellets are: Step 1. Divide the cooler into high temperature zone, low temperature zone and finished product zone.

[0015] Step 2, the finished material balls discharged from the bottom of the waterfall rotary kiln are put into the high temperature zone while they are still hot, and air is blown into the high temperature zone by the first blower to obtain the first cooled finished product and the second hot air.

[0016] Step 3, transferring the first cooled finished product to a low temperature zone, and blowing air into the low temperature zone through a second blower to obtain a second cooled finished product and the first hot air.

[0017] Step 4: Transfer the second cooled finished product to the finished product area for air cooling to obtain finished product balls.

[0018] Preferably, in step S1, the internal temperature of the dryer is 120-160°C, and the temperature of the first flue gas is 200°C.

[0019] Preferably, in step S2, the pyrolysis temperature in the pyrolysis kiln is 300-500°C, the temperature of the second flue gas introduced is 700°C, the temperature of the first solid pellets obtained is 400°C, the temperature of the second tail gas is 500°C, and the first gas is the volatile gas precipitated from coal gangue.

[0020] Preferably, in step S3, the decarbonization temperature in the decarbonizer is 650-720°C, the temperature of the third flue gas introduced is 900°C, the temperature of the first hot air introduced is 250°C, and the temperature of the second solid ball obtained is 700°C.

[0021] Preferably, in step S4, the sintering temperature in the sintering kiln is 1050-1150°C, the temperature of the second hot air introduced is 500°C, and the temperature of the obtained third solid is 950°C.

[0022] Preferably, in step 2, the temperature of the first cooled finished product is 550°C, in step 3, the temperature of the second cooled finished product is 300°C, and in step 4, the temperature of the obtained finished product balls is 80°C.

[0023] Preferably, in step S2, the second tail gas is passed into a waste heat recovery device to be cooled to obtain the first flue gas.

[0024] After adopting the above technical solution, the beneficial effects of the present invention are: 1. This process effectively utilizes the high energy content in high calorific value coal gangue, so that the production line does not need to use additional heat sources, which is economical and environmentally friendly.

[0025] 2. By separating the volatile gas precipitated from the gangue from the gangue solid, the violent combustion of the volatile gas in the heating stage which causes the temperature to rise too fast can be avoided, so that the moisture in the solid gangue ball can be completely dried, and the fixed carbon in the solid ball can be completely oxidized and consumed, thus ensuring the product quality.

[0026] 3. Through the different process temperatures of the decarbonizer and sintering kiln, two products, water-retaining expanded clay and high-strength expanded clay, are produced, giving the products a wider range of application scenarios.

[0027] 4. The excess heat from the final solid ball cooling, sintering, decarbonization and pyrolysis stages is recycled in a timely manner through flue gas circulation, greatly reducing the overall energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 The present invention is a process flow chart of a process for producing high-strength lightweight aggregate from high calorific value coal gangue. DETAILED DESCRIPTION

[0030] The features and exemplary embodiments of various aspects of the present invention will be described in detail below. In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present invention and are not configured to limit the present invention. For those skilled in the art, the present invention can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present invention by illustrating examples of the present invention.

[0031] The present invention provides a process for preparing high-strength lightweight aggregate from high calorific value coal gangue. Figure 1 The process of preparing high-strength lightweight aggregate from high calorific value coal gangue specifically comprises the following steps: S1. Grinding coal gangue to obtain coal gangue powder, adding water to the coal gangue powder, stirring and mixing, and granulating to form wet coal gangue balls, putting the wet balls at room temperature into a dryer, and simultaneously introducing a first flue gas into the dryer to obtain dry coal gangue balls and a first tail gas.

[0032] In this process, gangue shale crusher, gangue pulverizer, gangue mill and other equipment are used to realize the powder processing of gangue, and appropriate amount of water is added to the gangue powder and stirred to granulate to obtain gangue wet material balls.

[0033] The wet gangue balls are put into a dryer to dry the moisture in the wet balls to prepare dry gangue balls. During the above drying process, the temperature in the dryer is maintained at 120-160°C because the moisture in the wet gangue balls can evaporate quickly within this temperature range and the relative stability of other components in the balls is guaranteed, paving the way for subsequent process steps.

[0034] The first flue gas is the residual tail gas generated by the subsequent process, and the residual tail gas is cooled to 200° C. before being introduced into the dryer as a heat source for the dryer.

[0035] Among them, the temperature of the dried coal gangue balls is about 60°C, and the temperature of the first tail gas is about 120°C.

[0036] S2. The dry gangue balls obtained in S1 are put into a pyrolysis kiln, and a second flue gas is introduced into the pyrolysis kiln to decompose the components of the gangue to obtain first solid balls, a first gas and a second tail gas. The first solid balls continue to flow downward, the first gas is collected under anaerobic conditions, and the second tail gas is cooled to obtain the first flue gas.

[0037] In the above reaction process, the second flue gas is introduced into the pyrolysis kiln before the gangue dry material balls are put into the pyrolysis kiln, the purpose of which is to keep the temperature of the pyrolysis kiln stable within a certain range, so that the pyrolysis kiln is always in the high-efficiency pyrolysis temperature range.

[0038] Among them, the structural shape of the pyrolysis kiln is a double-layer cylinder structure with inner and outer cylinders. The dry material balls move in the inner cylinder, and the second flue gas passes through the gap between the inner cylinder and the outer cylinder, and transfers heat to the inner cylinder, thereby heating the inner cylinder. The inner cylinder is in an anaerobic environment, and the inner cylinder is fixedly connected and communicated with the sealed air chamber, so that the first gas is output and collected in the sealed air chamber.

[0039] Among them, the temperature of the second flue gas introduced is about 700°C, the temperature of the inner tube is maintained at 300-500°C, the temperature of the obtained first solid pellets is about 400°C, and the temperature of the collected first gas is about 200°C.

[0040] The first gas is volatile gas precipitated from coal gangue, and its main components are CH4 and CO.

[0041] This process step transfers heat through the inner cylinder wall, and effectively separates the second flue gas and the volatilized first gas through the inner cylinder wall, so as to collect high-concentration first gas (calorific value> 1000kcal / Nm³) as fuel for subsequent process steps, realizing energy recovery and utilization. The first gas is collected under anaerobic conditions, and the violent combustion of combustible gases such as methane in the gas can also be avoided to cause the surface of the ball to melt and form a vitrified hard shell.

[0042] In addition, after the second flue gas passes through the gap between the inner tube and the outer tube and transfers part of the heat to the inner tube, a second exhaust gas with a temperature of about 500°C is obtained. The second exhaust gas is sent to waste heat recovery equipment such as a boiler to recover part of the heat and further reduce the temperature of the second exhaust gas to 200°C to obtain the first flue gas.

[0043] S3, putting the first solid ball obtained in S2 into a decarbonizer while it is still hot, and introducing the third flue gas and the first hot air into the decarbonizer to decarbonize the first solid ball, thereby obtaining a second solid ball and a second flue gas.

[0044] Among them, the decarbonizer is a crawler-type static decarbonization equipment. The first solid balls are evenly distributed on the crawler, so that the third flue gas and the first hot air introduced can evenly penetrate the crawler, allowing the surface of the balls to fully contact the gas, thereby stably burning and removing the fixed carbon in the coal gangue.

[0045] Among them, the optimal temperature of the decarbonization reaction is 650-720°C. Technical personnel in this field can flexibly adjust the air intake ratio of the third flue gas and the first hot air to adjust the temperature of the decarbonizer, thereby ensuring the efficient decarbonization process.

[0046] Among them, the temperature of the third flue gas introduced is about 900°C, the temperature of the first hot air introduced is about 250°C, and the temperature of the obtained second solid ball is about 700°C.

[0047] During the above reaction process, the coal gangue balls complete the decarbonization process and realize the crystal phase transformation by using their own fixed carbon calorific value. Part of the silicate components form glass such as mullite, so that the obtained second solid balls have higher strength and strong water absorption performance, and can be used as water-retaining expanded clay and used in deserts, arid areas, etc. as a soil improvement additive to improve the water retention performance of the soil and improve the local environment.

[0048] Of course, when the second solid pellets are used as water-absorbing ceramsite, the second solid pellets obtained in this step only need to be directly air-cooled to room temperature without the need to perform the following steps.

[0049] S4, putting the second solid pellet obtained in S3 into a sintering kiln while it is still hot, introducing the first gas and the second hot air for further sintering processing, and obtaining third solid pellets and third flue gas.

[0050] The temperature of the second hot air introduced is about 500°C, the specific sintering temperature in the sintering kiln is 1050-1150°C, and the temperature of the obtained third solid is about 950°C.

[0051] Among them, the sintering kiln adopts a waterfall-type rotary kiln. The kiln body adopts a streamlined structure design and is provided with three-leaf protrusions in the kiln. Therefore, the waterfall-type rotary kiln can lift the second solid material ball and let it fall downstream at a low rotation speed, so that the second solid material ball can fully contact the flue gas in the waterfall-type rotary kiln, thereby improving the heat exchange efficiency, facilitating product firing, and preventing the material from melting and sticking under high temperature conditions.

[0052] During this process, the second solid ball quickly exchanges heat with the flue gas in the waterfall rotary kiln through convection, producing a thermal reaction. Under the high temperature conditions in the waterfall rotary kiln, the mineral components in the second solid ball gradually soften and melt, breaking the original weak connections between the particles and rearranging the crystals to form a new crystal structure with higher strength, generating a new mineral phase, and changing the original composition and properties of the raw materials. As a result, the fired third solid ball has higher mechanical strength and lower water absorption, and can be used as high-strength expanded clay to replace stone as a building aggregate.

[0053] S5. Put the third solid pellet obtained in S4 into a cooler while it is still hot, blow room temperature air into the cooler for cooling, and obtain finished pellets, first hot air and second hot air.

[0054] The temperature of the finished pellets after cooling is about 80°C.

[0055] In the above process, the finished balls discharged from the bottom of the waterfall rotary kiln are put into a cooler, and air is blown into the cooler by a blower to cool the finished balls.

[0056] Among them, the cooler is divided into a high-temperature zone, a low-temperature zone and a finished product zone. The finished material balls unloaded from the bottom of the waterfall rotary kiln are first put into the high-temperature zone while they are hot. The first blower blows air into the high-temperature zone to cool down the finished material balls while heating the room temperature air to obtain the second hot air.

[0057] When the finished pellets in the high temperature zone are cooled to about 550° C., the finished pellets are transferred to the low temperature zone, and air is blown into the low temperature zone by the second blower to obtain the first hot air.

[0058] When the finished pellets in the low temperature zone are cooled to about 300°C, they are transferred to the finished product zone and continue to be air-cooled to about 80°C to obtain the final finished pellets.

[0059] To facilitate understanding of the present invention, several embodiments of the present invention are given below.

[0060] Example 1 The present embodiment provides a process for producing high-strength lightweight aggregate from high calorific value coal gangue, which specifically includes the following steps: S1, crushing and grinding the coal gangue, adding water and stirring to granulate, obtaining wet coal gangue balls, putting the wet balls at room temperature into a dryer at 120°C, and introducing the first flue gas at 200°C into the dryer, obtaining dry coal gangue balls at 60°C and the first tail gas at 120°C; S2, putting the dry coal gangue pellets into a 300°C pyrolysis kiln while they are still hot, and introducing a second flue gas at 700°C into the pyrolysis kiln to pyrolyze the dry coal gangue pellets, to obtain first solid pellets at 400°C, a first gas at 200°C, and a second tail gas at 500°C, the first gas is collected under anaerobic conditions, and the second tail gas is cooled to 200°C by a waste heat recovery device to obtain the first flue gas; S3, putting the first solid pellet into a decarburizer at 650°C while it is still hot, and introducing a third flue gas at 900°C and a first hot air at 250°C into the decarburizer to decarburize the first solid pellet, thereby obtaining a second solid pellet at 700°C and a second flue gas at 700°C; S4, putting the second solid pellet into a sintering kiln at 1050°C while it is still hot, introducing the first gas at 200°C and the second hot air at 500°C to sinter the second solid pellet, to obtain a third solid pellet at 950°C and a third flue gas at 900°C; S5. Put the third solid pellet into a cooler while it is still hot, blow room temperature air into the cooler for cooling, and obtain finished pellets at 80° C., first hot air at 250° C., and second hot air at 500° C.

[0061] The second solid pellet obtained in S3 is cooled and used as water-retaining ceramsite. The water absorption rate, compressive strength and cylinder pressure strength data measured according to different stacking densities are as follows:

[0062] The third solid pellet obtained in S4 is cooled and used as high-strength ceramsite. The water absorption rate, compressive strength and cylinder pressure strength data measured according to different stacking densities are as follows:

[0063] Example 2 This embodiment is based on the embodiment 1, and the temperature of the dryer, the temperature of the pyrolysis kiln, the temperature of the decarbonizer, and the temperature of the sintering kiln in the embodiment 1 are adjusted. The process of preparing high-strength lightweight aggregate from high calorific value coal gangue in this embodiment specifically includes the following steps: S1, crushing and grinding the coal gangue, adding water and stirring to granulate, obtaining wet coal gangue balls, putting the wet balls at room temperature into a dryer at 140°C, and introducing the first flue gas at 200°C into the dryer, obtaining dry coal gangue balls at 60°C and the first tail gas at 120°C; S2, putting the dry coal gangue pellets into a 400°C pyrolysis kiln while they are still hot, and introducing a second flue gas at 700°C into the pyrolysis kiln to pyrolyze the dry coal gangue pellets, to obtain first solid pellets at 400°C, a first gas at 200°C, and a second tail gas at 500°C, the first gas is collected under anaerobic conditions, and the second tail gas is cooled to 200°C by a waste heat recovery device to obtain the first flue gas; S3, putting the first solid pellet into a decarburizer at 680°C while it is still hot, and introducing a third flue gas at 900°C and a first hot air at 250°C into the decarburizer to decarburize the first solid pellet, thereby obtaining a second solid pellet at 700°C and a second flue gas at 700°C; S4, putting the second solid pellet into a sintering kiln at 1000°C while it is still hot, introducing the first gas at 200°C and the second hot air at 500°C to sinter the second solid pellet, to obtain a third solid pellet at 950°C and a third flue gas at 900°C; S5. Put the third solid pellet into a cooler while it is still hot, blow room temperature air into the cooler for cooling, and obtain finished pellets at 80° C., first hot air at 250° C., and second hot air at 500° C.

[0064] The second solid pellets obtained in S3 were cooled and used as water-retaining ceramsite, and the bulk density was adjusted to be the same as that in Example 1. The water absorption rate, compressive strength, and cylinder pressure strength data were as follows:

[0065] The third solid pellet obtained in S4 is cooled and used as high-strength ceramsite, and the water absorption rate, compressive strength, and cylinder pressure strength data are measured after adjusting the bulk density to be the same as that in Example 1 as follows:

[0066] Example 3 This embodiment is based on the embodiment 1, and the dryer temperature, pyrolysis kiln temperature, decarbonizer temperature, and sintering kiln temperature in the embodiment 1 are adjusted. The above parameters in this embodiment are different from those in the embodiment 2. The process of making high-strength lightweight aggregate from high calorific value coal gangue in this embodiment specifically includes the following steps: S1, crushing and grinding the coal gangue, adding water and stirring to granulate, obtaining wet coal gangue balls, putting the wet balls at room temperature into a dryer at 160°C, and introducing the first flue gas at 200°C into the dryer, obtaining dry coal gangue balls at 60°C and the first tail gas at 120°C; S2, putting the dry coal gangue pellets into a pyrolysis kiln at 500°C while they are still hot, and introducing a second flue gas at 700°C into the pyrolysis kiln to pyrolyze the dry coal gangue pellets, to obtain first solid pellets at 400°C, a first gas at 200°C, and a second tail gas at 500°C, the first gas is collected under anaerobic conditions, and the second tail gas is cooled to 200°C by a waste heat recovery device to obtain the first flue gas; S3, putting the first solid pellet into a decarburizer at 720°C while it is still hot, and introducing a third flue gas at 900°C and a first hot air at 250°C into the decarburizer to decarburize the first solid pellet, thereby obtaining a second solid pellet at 700°C and a second flue gas at 700°C; S4, putting the second solid pellet into a sintering kiln at 1150°C while it is still hot, introducing the first gas at 200°C and the second hot air at 500°C to sinter the second solid pellet, to obtain a third solid pellet at 950°C and a third flue gas at 900°C; S5. Put the third solid pellet into a cooler while it is still hot, blow room temperature air into the cooler for cooling, and obtain finished pellets at 80° C., first hot air at 250° C., and second hot air at 500° C.

[0067] The second solid pellets obtained in S3 were cooled and used as water-retaining ceramsite, and the bulk density was adjusted to be the same as that in Example 1. The water absorption rate, compressive strength, and cylinder pressure strength data were as follows:

[0068] The third solid pellet obtained in S4 is cooled and used as high-strength ceramsite, and the water absorption rate, compressive strength, and cylinder pressure strength data are measured after adjusting the bulk density to be the same as that in Example 1 as follows:

[0069] According to the embodiments of the present invention as described above, these embodiments do not describe all the details in detail, nor do they limit the invention to specific embodiments. Obviously, many modifications and changes can be made based on the above description. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can make good use of the present invention and the modified use based on the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A process for preparing high-strength lightweight aggregate from high calorific value coal gangue, characterized in that The following steps are involved: S1, crushing and grinding the coal gangue, adding water and stirring to granulate, obtaining wet coal gangue balls, putting the wet balls into a dryer, and introducing the first flue gas into the dryer, obtaining dry coal gangue balls and the first tail gas; S2, putting the dry gangue pellets into a pyrolysis kiln, and introducing a second flue gas into the kiln to pyrolyze the dry gangue pellets to obtain first solid pellets, a first gas, and a second tail gas, wherein the first gas is collected under anaerobic conditions, and the second tail gas is cooled to obtain the first flue gas; S3, putting the first solid pellets into a decarbonizer while they are still hot, and introducing the third flue gas and the first hot air into the decarbonizer to decarbonize the first solid pellets, thereby obtaining second solid pellets and the second flue gas; S4, putting the second solid pellet into a sintering kiln while it is still hot, and introducing the first gas and the second hot air into the kiln to sinter the second solid pellet, so as to obtain a third solid pellet and the third flue gas; S5. Put the third solid pellet into a cooler while it is still hot, blow room temperature air into the cooler for cooling, and obtain finished pellets, the first hot air, and the second hot air.

2. The process for producing high-strength lightweight aggregate from high calorific value coal gangue according to claim 1, characterized in that: In step S2, the pyrolysis kiln is a double-layer cylinder structure with an inner and outer shell, the dry coal gangue balls move in the inner cylinder, the second flue gas passes through the gap between the inner cylinder and the outer cylinder, the interior of the inner cylinder is an anaerobic environment, and the inner cylinder is connected to a sealed air chamber, and the sealed air chamber can collect the first gas.

3. The process for producing high-strength lightweight aggregate from high calorific value coal gangue according to claim 1, characterized in that: In step S4, the sintering kiln adopts a waterfall type rotary kiln, the kiln body is a streamlined structure, and three-leaf protrusions are arranged inside.

4. The process for producing high-strength lightweight aggregate from high calorific value coal gangue according to claim 1, characterized in that: In step S5, the specific operation steps of cooling the third solid pellets are as follows: Step 1. Divide the cooling machine into high temperature zone, low temperature zone and finished product zone; Step 2, the finished product balls discharged from the bottom of the waterfall rotary kiln are put into the high temperature zone while they are still hot, and the first blower is used to blow air into the high temperature zone to obtain the first cooled finished product and the second hot air; Step 3, transferring the first cooled finished product to a low temperature zone, and blowing air into the low temperature zone through a second blower to obtain a second cooled finished product and the first hot air; Step 4: Transfer the second cooled finished product to the finished product area for air cooling to obtain finished product balls.

5. The process for producing high-strength lightweight aggregate from high calorific value coal gangue according to claim 1, characterized in that: In step S1, the internal temperature of the dryer is 120-160°C, and the temperature of the first flue gas is 200°C.

6. The process for producing high-strength lightweight aggregate from high calorific value coal gangue according to claim 2, characterized in that: In step S2, the pyrolysis temperature in the pyrolysis kiln is 300-500°C, the temperature of the second flue gas introduced is 700°C, the temperature of the first solid ball obtained is 400°C, the temperature of the second tail gas is 500°C, and the first gas is the volatile gas precipitated from coal gangue.

7. The process for producing high-strength lightweight aggregate from high calorific value coal gangue according to claim 2, characterized in that: In step S3, the decarburization temperature in the decarburizer is 650-720°C, the temperature of the third flue gas introduced is 900°C, the temperature of the first hot air introduced is 250°C, and the temperature of the second solid ball obtained is 700°C.

8. The process for producing high-strength lightweight aggregate from high calorific value coal gangue according to claim 3, characterized in that: In step S4, the sintering temperature in the sintering kiln is 1050-1150°C, the temperature of the second hot air introduced is 500°C, and the temperature of the obtained third solid is 950°C.

9. The process for producing high-strength lightweight aggregate from high calorific value coal gangue according to claim 4, characterized in that: In step 2, the temperature of the first cooling product is 550°C, in step 3, the temperature of the second cooling product is 300°C, and in step 4, the temperature of the finished product ball is 80°C.

10. The process for producing high-strength lightweight aggregate from high calorific value coal gangue according to claim 4, characterized in that: In step S2, the second tail gas is passed through a waste heat recovery device to be cooled to obtain the first flue gas.

Images