Coal gangue-based light high-strength unfired ceramsite and preparation method thereof

Abstract

The invention discloses coal gangue-based light high-strength unfired ceramsite and a preparation method thereof, and relates to the technical field of preparation of building materials. The gangue-based light high-strength unfired ceramsite is prepared from the following components in parts by weight: 30 to 40 parts of gangue, 20 to 30 parts of cement, 30 to 50 parts of a composite admixture, 40 parts of water, 0.5 to 2 parts of an air entraining agent, 0.05 to 0.2 part of a foam stabilizer, 0.1 to 0.25 part of a waterproof agent and 0.5 to 2.0 parts of carboxymethyl cellulose. The coal gangue, the steel slag and the high-calcium fly ash selected in the invention have relatively high content of SiO2 and Al2O3, the slag contains a large amount of CaO, the industrial byproduct gypsum promotes generation of ettringite by exciting the slag, a silicon-aluminum compound is depolymerized under the action of alkalinity and sulfate, and is subjected to hydration reaction with alkaline components, so that the content of the silicon-aluminum compound is reduced; and polymerizing to generate gelling hydration products such as hydrated calcium silicate gel, hydrated calcium aluminosilicate gel and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of building materials, and particularly relates to a gangue-based lightweight high-strength unfired ceramsite and a preparation method thereof. Background Art

[0002] Coal gangue is a solid waste produced in the coal mining process and eliminated after coal selection. It generally accounts for about 15% of coal production. Its main components are Al2O3 and SiO2.

[0003] Clay is the aggregate for building thermal insulation walls. It is made of clay and mudstone as the main raw materials, mixed with binders and additives, and then fired. Traditional ceramsite not only wastes a lot of land resources, but also wastes fuel energy during the sintering process. The production process of unfired ceramsite is simple and energy-saving. It does not require high-temperature sintering. It is made into unfired ceramsite after curing based on the characteristics of the raw materials. For this reason, we propose a coal gangue-based lightweight and high-strength unfired ceramsite and its preparation method. Summary of the invention

[0004] The purpose of the present invention is to provide a gangue-based lightweight, high-strength, unfired ceramsite and a preparation method thereof. Through research and development and improvement, a lightweight, high-strength, unfired ceramsite with gangue as the main component and a preparation device thereof are proposed. The ceramsite can not only improve the technical performance of the existing gangue ceramsite, but the device can also improve the ceramsite forming rate and ensure the strength of the ceramsite.

[0005] To achieve the above object, the present invention provides the following technical solutions: A gangue-based lightweight high-strength unfired ceramsite and a preparation method thereof, wherein the gangue-based lightweight high-strength unfired ceramsite comprises the following components in parts by weight: 30-40 parts of gangue, 20-30 parts of cement, 30-50 parts of composite admixture, 40 parts of water, 0.5-2 parts of air entraining agent, 0.05-0.2 parts of foam stabilizer, 0.1-0.25 parts of waterproofing agent, and 0.5-2.0 parts of carboxymethyl cellulose; Further, the gangue powder is obtained by crushing the gangue with a jaw crusher, selecting gangue particles with a particle size of less than 3 mm, adding sulfuric acid according to a solid-liquid mass ratio of 1:5, soaking for 2 hours, filtering and washing, and drying the gangue in an electric blast drying oven to control the water content below 1%. A ball mill is used to add a chemical activator of 1.5% of the mass of the gangue to mechanically grind the gangue for 30 minutes to obtain mechanochemically activated gangue powder; Furthermore, the composite admixture comprises: 40% slag, 15% industrial by-product gypsum, 35% steel slag, and 10% high-calcium fly ash; Furthermore, the chemical composition of the coal gangue is as follows in terms of weight percentage: SiO2 50.8%, Al2O3 28.1%, Fe2O3 6.2%, CaO 3.7%, loss on ignition 7.9%, and fineness above 300 mesh; Further, the slag is granulated blast furnace slag powder, with a 28d activity index of 98%, a specific surface area of ​​429 m2 / kg, the chemical composition of the steel slag is as follows: SiO2 21%, Al2O3 9%, Fe2O3 14.35%, CaO 44%, and the chemical composition of the high-calcium fly ash is as follows: SiO2 54.66%, Al2O3 10.05%, Fe2O3 7.06%, CaO 19.45%; Furthermore, the air entraining agent comprises 5% aluminum nitrate, 15% ammonium nitrate, 15% sodium nitrite, 25% urea, 40% sodium bicarbonate and 0.02% citric acid; Furthermore, the foam stabilizer is 50% lauryl diethanolamine, 20% dodecanol, 5% sodium tripolyphosphate, 20% fatty alcohol polyoxyethylene ether phosphate potassium salt, and 5% carboxymethyl starch ether; Furthermore, the waterproofing agent is 50% methyl MQ silicone resin, 25% dodecyltrimethoxysilane, and 25% sodium polyacrylate.

[0006] A gangue-based lightweight high-strength unburned ceramsite and a preparation method thereof, comprising a raw material dry powder mixing structure, the raw material dry powder mixing structure comprising a support frame, four support frames are provided, and are fixedly connected to the ground in an axially symmetrical shape, a mixing barrel is fixedly connected to the top of the support frame, a feeding port is fixedly connected to one side of the mixing barrel, a dust suction port is fixedly connected to the other side of the top of the mixing barrel, a first rotating shaft is vertically provided at the middle position inside the mixing barrel, a stirring blade is fixedly installed on the outside of the first rotating shaft, a first motor is fixedly connected above the first rotating shaft, a discharge port is fixedly connected to the bottom of the mixing barrel, a first transport crawler is fixedly connected to the bottom of the discharge port, a feed port of a granulator is fixedly connected to the output end of the first transport crawler, a second rotating shaft is vertically provided at the middle position inside the granulator, and the A stirring blade is fixedly installed on the outside of the second rotating shaft, a rotating mechanism is fixedly connected above the second rotating shaft, a second motor is fixedly connected above the rotating mechanism, a spring is fixedly connected to the upper end of the granulator, and an extrusion disk is fixedly connected to the lower end of the spring, a granulator is fixedly connected to a ceramsite extrusion port at the bottom, a particle outlet is connected to the lower part of the ceramsite extrusion port, the extrusion disk squeezes the mud material out of the particle outlet and the cutting group cuts the mud material after the particle outlet reaches the cutting length, a second transport track is fixedly connected to the bottom of the ceramsite extrusion port, a dust spray port is fixedly connected to one side of the second transport track, a particle inlet of a rotary curing barrel is fixedly connected to the output end of the second transport track, a carbon dioxide cylinder is fixedly connected to the rotary curing barrel, a particle outlet is fixedly connected to the bottom of the rotary curing barrel, and a water tank is fixedly connected to the top of the rotary curing barrel.

[0007] Preferably, the length of the first blade is greater than that of the second blade, and the outer edge of the first blade is in contact with the inner wall of the mixing barrel.

[0008] Preferably, the dust suction port collects the floating raw materials in the mixing barrel, and the dust spraying port sprays the collected raw materials in the dust storage tank onto the semi-finished ceramsite.

[0009] Preferably, the second motor is fixedly connected to the second rotating shaft via a rotating mechanism, and when the second motor starts working, the rotating mechanism drives the second rotating shaft and the third blade to rotate continuously inside the granulator, and the third blade is a butterfly-shaped stirring blade that is larger at the top and smaller at the bottom.

[0010] Preferably, after the third blade of the extrusion disc is folded and retracted, the extrusion disc is pressed downward by a spring so that the mud material is extruded from the particle discharge disc more evenly.

[0011] Preferably, the particle discharging disk has extrusion holes with different radii, which are evenly distributed on circular ring lines with different radii of the extrusion disk and are maintained at the same horizontal plane with the cutting knife group.

[0012] Preferably, the number of cutters in the cutter group is 4, and the 4 cutters are evenly distributed on the particle outlet disc turntable.

[0013] Preferably, the rotary curing barrel can keep rotating at a fixed speed after the third motor is powered on and started.

[0014] Preferably, the carbon dioxide cylinder continuously delivers carbon dioxide to the interior of the rotary curing barrel when the rotary curing barrel starts working.

[0015] A gangue-based lightweight high-strength unfired ceramsite and a preparation method thereof, comprising the following steps: Step 1: Use a jaw crusher to crush the gangue, select the gangue particles with a particle size of less than 3 mm, add sulfuric acid according to the solid-liquid mass ratio of 1:5, soak for 2 hours, filter and wash, use an electric heating blast drying oven to dry the gangue, and control the moisture content below 1%. Use a ball mill to add 1.5% of the gangue mass of chemical activator to mechanically grind the gangue for 30 minutes to obtain mechanochemically activated gangue powder; Step 2: Weigh 30-40 parts of coal gangue, 20-30 parts of cement, 30-50 parts of composite admixture, 40 parts of water, 0.5-2 parts of air entraining agent, 0.05-0.2 parts of foam stabilizer, 0.1-0.25 parts of waterproofing agent, and 0.5-2.0 parts of carboxymethyl cellulose according to weight parts; Step 3: adding coal gangue, cement, composite admixture, air entraining agent, foam stabilizer, waterproofing agent, and carboxymethyl cellulose raw materials into the mixing barrel through the feed port, and the first motor drives the first rotating shaft after being powered on, and the first rotating shaft drives the stirring blade to stir and mix the raw materials in the mixing barrel, so that the added coal gangue, cement, composite admixture, air entraining agent, foam stabilizer, waterproofing agent, and carboxymethyl cellulose raw materials can be mixed evenly. When the mixing barrel is started, the first fan transports the floating raw materials in the mixing barrel to the dust storage tank through the dust pipe for reuse; Step 4: The mixed raw materials enter the granulator through the first transport crawler, the granulator starts working, the second motor drives the rotating mechanism, the rotating mechanism drives the second rotating shaft and the third blade to stir the raw materials, after the mud is mixed evenly, the third blade is folded and retracted, the extrusion disc extrude the mud downward, after reaching the cutting length through the particle plate, the cutter cuts the mud into semi-finished ceramsite by rotation; Step 5: The semi-finished expanded clay is transported to the rotary curing barrel after the second transport crawler is started. The rotary curing barrel rotates at a fixed speed until the finished expanded clay is formed. When the rotary curing barrel is started, the water tank transports water vapor into the rotary curing barrel, and the carbon dioxide cylinder transports carbon dioxide into the rotary curing barrel. When the second transport crawler transports the semi-finished expanded clay, the second fan sprays the raw materials collected in the dust storage tank onto the surface of the semi-finished expanded clay through the dust pipe.

[0016] Preferably, during the natural curing process of the rotary curing barrel, the temperature is controlled at 20±2°C and the relative humidity is 50±5%RH; during the high temperature curing process, the temperature is controlled at 60-80°C and the humidity is 45±5%RH; during the carbonization curing process, the pressure range is controlled at 0.3Mpa and the humidity is controlled at 60±5%RH.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. The selected coal gangue, steel slag and high calcium fly ash have high contents of SiO2 and Al2O3. Slag contains a large amount of CaO. Steel slag undergoes high temperature calcination during its formation process. Its chemical composition is similar to that of cement clinker, containing C2S, C3S, C4AF and C2F, etc. It has certain volcanic ash activity. The hydration reaction of steel slag will produce a large amount of OH- and Ca2+. Slag generates a large amount of ettringite through hydration reaction, which consumes Ca2+ and further promotes the hydration reaction of steel slag. Industrial by-product gypsum promotes the formation of ettringite by stimulating slag. Silica-alumina compounds depolymerize under the action of alkalinity and sulfate, and hydrate with alkaline components, and then polymerize to form gelling hydration products such as hydrated calcium silicate gel and hydrated calcium alumina silicate gel. Carboxymethyl cellulose can play an auxiliary bonding role by crossing the particle interface region due to its macromolecular structure.

[0018] 2. The aluminum nitrate selected as the foaming agent can act as a catalyst to accelerate the reaction of ammonium nitrate and sodium nitrite to generate nitrogen. Sodium bicarbonate and citric acid can react violently under the action of water to generate a large amount of carbon dioxide. Urea can be used as an auxiliary foaming material for the foaming agent. By lowering the foaming temperature and improving the performance of the foaming agent, the nitrogen and carbon dioxide finally generated are uniform in size and moderately distributed.

[0019] 3. The lauroyl diethanolamine selected as the foam stabilizer has strong hydrophilicity. The amine groups in its chemical structure can form a thin film on the bubble surface to stabilize the bubbles under the action of van der Waals force. Dodecanol can be used as an auxiliary agent to slow down the internal drainage speed of the bubbles and enhance the stability of the bubbles. Sodium tripolyphosphate can reduce the surface tension between the material and the bubbles and promote a more uniform dispersion of the substances. Fatty alcohol polyoxyethylene ether phosphate potassium salt can be used as an anionic surfactant. Its chemical structure contains fatty alcohol groups and polyoxyethylene ether groups, which can change the internal arrangement of molecules, so that the surfactant is evenly distributed on the bubble surface and increase the elasticity of the bubble surface. Carboxymethyl starch ether has a network structure and has a good synergistic effect with carboxymethyl cellulose. It can form a thin film between the solid particles and the bubbles, which can not only increase the fluidity of the slurry but also increase the stability of the bubbles.

[0020] 4. Methyl MQ silicone resin is composed of monofunctional siloxane linkage (M) and tetrafunctional siloxane linkage (Q), with Si-O bond as the skeleton to establish the molecular structure, which has moisture resistance and water repellency. Dodecyl trimethoxy silane is composed of three methoxy long-chain silanes and is hydrophobic. Sodium polyacrylate can generate a network structure to inhibit water penetration and has water absorption.

[0021] 5. The first motor is powered on to start and drive the first rotating shaft, and the first rotating shaft drives the long first blade and the short second blade to rotate and stir inside the mixing barrel, thereby effectively enhancing the uniformity of the raw material dry powder mixing mechanism for mixing coal gangue, cement, composite admixtures, air entraining agent, foam stabilizer, waterproofing agent, and carboxymethyl cellulose raw materials.

[0022] 6. Through the setting, ceramsite with different radius can be produced at the same time, and the clay can be extruded more evenly and cut under the action of the extrusion disk, which can not only improve the production efficiency but also ensure the high forming rate of ceramsite.

[0023] 7. By setting the second motor to drive the second rotating shaft and the third blade to rotate inside the granulator, the mud inside the granulator is continuously stirred, so that the stirring range is larger, the mud stirring effect is more uniform, and the quality of the ceramsite is guaranteed.

[0024] 8. The floating raw materials inside the mixing barrel are collected by setting up a dust suction port, and the collected raw material dust is reused through the transport track to prevent the raw materials from flying dust during mixing. At the same time, the raw materials can be reused to avoid waste of resources.

[0025] 9. By setting the semi-finished ceramsite to be sprayed with a layer of raw material powder by the dust spraying port before falling into the rotary curing box barrel, and the rotary curing barrel can keep rotating at a certain speed when working, the adhesion between the ceramsites can be effectively prevented. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings: Figure 1 It is a structural schematic diagram of the present invention; Figure 2 It is a structural schematic diagram of the particle discharging plate of the present invention; Figure 3 It is a structural schematic diagram of the rotating mechanism of the present invention; Figure 4 It is a structural cross-sectional view of the rotary curing box of the present invention; Figure 5 It is a schematic diagram of the workflow of the present invention; In the figure: 1. Raw material dry powder mixing structure; 101. Support frame; 102. Mixing barrel; 103. Feed inlet; 104. Dust suction port; 105. Discharge port; 106. First rotating shaft; 107. Stirring blade; 108. First blade; 109. Second blade; 110. First motor; 111. Valve; 112. First material transport crawler; 2. Granulator; 201. Feed inlet; 202. Ceramic extrusion port; 203. Discharge plate; 2031. Extrusion hole; 2032. Cutter group; 204. Second rotating shaft; 205. Stirring blade; 206. Third blade; 2 07. Rotating mechanism; 2071. Gear plate; 2072. First gear; 2073. Second gear; 208. Second motor; 209. Spring; 210. Extrusion disc; 211. Second transport crawler; 212. Dust outlet; 3. Rotating curing barrel; 301. Grain inlet; 302. Third motor; 303. Rotating roller; 304. Curing liner; 305. Grain outlet; 306. Water tank; 4. Carbon dioxide cylinder; 5. Dust storage tank; 501. First dust duct; 502. Second dust duct; 503. First fan; 504. Second fan. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] See also Figure 1-5 The present invention provides a technical solution: a gangue-based lightweight high-strength unfired ceramsite and a preparation method thereof, wherein the gangue-based lightweight high-strength unfired ceramsite comprises the following components in parts by weight: 30-40 parts of gangue, 20-30 parts of cement, 30-50 parts of composite admixture, 40 parts of water, 0.5-2 parts of air entraining agent, 0.05-0.2 parts of foam stabilizer, 0.1-0.25 parts of waterproofing agent, and 0.5-2.0 parts of carboxymethyl cellulose; Further, the gangue powder is obtained by crushing the gangue with a jaw crusher, selecting gangue particles with a particle size of less than 3 mm, adding sulfuric acid according to a solid-liquid mass ratio of 1:5, soaking for 2 hours, filtering and washing, and drying the gangue in an electric blast drying oven to control the water content below 1%. A ball mill is used to add a chemical activator of 1.5% of the mass of the gangue to mechanically grind the gangue for 30 minutes to obtain mechanochemically activated gangue powder; Furthermore, the composite admixture comprises: 40% slag, 15% industrial by-product gypsum, 35% steel slag, and 10% high-calcium fly ash; Furthermore, the chemical composition of the coal gangue is as follows in terms of weight percentage: SiO2 50.8%, Al2O3 28.1%, Fe2O3 6.2%, CaO 3.7%, loss on ignition 7.9%, and fineness above 300 mesh; Further, the slag is granulated blast furnace slag powder, with a 28d activity index of 98%, a specific surface area of ​​429 m2 / kg, the chemical composition of the steel slag is as follows: SiO2 21%, Al2O3 9%, Fe2O3 14.35%, CaO 44%, and the chemical composition of the high-calcium fly ash is as follows: SiO2 54.66%, Al2O3 10.05%, Fe2O3 7.06%, CaO 19.45%; Furthermore, the air entraining agent comprises 5% aluminum nitrate, 15% ammonium nitrate, 15% sodium nitrite, 25% urea, 40% sodium bicarbonate and 0.02% citric acid; Furthermore, the foam stabilizer is 50% lauryl diethanolamine, 20% dodecanol, 5% sodium tripolyphosphate, 20% fatty alcohol polyoxyethylene ether phosphate potassium salt, and 5% carboxymethyl starch ether; Furthermore, the waterproofing agent is 50% methyl MQ silicone resin, 25% dodecyltrimethoxysilane, and 25% sodium polyacrylate.

[0029] A gangue-based lightweight high-strength unburned ceramsite and a preparation method thereof, comprising a dry powder mixing mechanism 1, wherein the dry powder mixing mechanism 1 comprises a support frame 101, wherein the support frames 101 have a total of 4, which are fixedly connected to the ground in an axially symmetrical manner, the top of the support frame 101 is fixedly connected to the bottom of a mixing barrel 102, one side of the top of the mixing barrel 102 is fixedly connected to a feed port 103, and the other side of the top of the mixing barrel 102 is fixedly connected to a dust suction port 104. When the mixing barrel 102 is started, the dust suction port 104 can blow the floating raw material dust through the fan and recycle it to the dust storage tank 5 for secondary utilization, thereby avoiding unnecessary dust emission. The bottom of the mixing barrel 102 is fixedly connected to a discharge port 105, and a first rotating shaft 106 is vertically arranged in the middle position inside the mixing barrel 102, and the first rotating shaft 10 6 is fixedly connected with a first motor 110 at the top, a stirring blade 107 is fixedly installed on the outer side of the first rotating shaft 106, a first blade 108 and a second blade 109 are fixedly installed on the stirring blade 107 with a spacer sleeve, the length of the first blade 108 is in contact with the inner wall of the mixing barrel 102, the length of the second blade 109 is half of the first blade 108, a first transport crawler 112 is fixedly connected to the bottom of the discharge port 105, and the first transport crawler 112 is fixedly connected to the granulator 2. When working, the staff adds coal gangue, cement, composite admixture, air entraining agent, foam stabilizer, waterproofing agent, and carboxymethyl cellulose into the mixing barrel 102 through the feed port 103, at which time the first motor 110 is powered on and started, and when the first motor 110 rotates, it drives the first rotating shaft 106 on the fixed rotating output shaft. The first rotating shaft 106 drives the stirring blade 107 to rotate inside the mixing barrel 102 to stir and mix the coal gangue, cement, composite admixture, air entraining agent, foam stabilizer, waterproofing agent and carboxymethyl cellulose added into the mixing barrel 102. The first blade 108 and the second blade 109 of different lengths can greatly improve the uniformity of raw material mixing.

[0030] The output end of the first transport crawler 112 is fixedly connected to the granulator 2, the feed port 201 of the granulator 2 is fixedly connected to the first transport crawler 112, the bottom of the granulator 2 is fixedly connected to the ceramsite extrusion port 202, and a pelletizing plate 203 is fixedly installed at the bottom of the ceramsite extrusion port 202, and the pelletizing plate 203 is composed of an extrusion hole 2031 and a cutting knife group 2032. A second rotating shaft 204 is vertically arranged in the middle of the granulator 2, and a rotating mechanism 207 is fixedly connected to the upper end of the second rotating shaft 204, and a second motor 208 is fixedly connected to the upper end of the rotating mechanism 207. A third blade 206 is fixedly installed on the outer side of the shaft 204. After the second motor 208 starts working, the rotating mechanism 207 can drive the second rotating shaft 204 and the third blade 206 to rotate continuously inside the granulator 2, thereby increasing the stirring range and making the mud stirring effect more uniform. The third blade 206 is a butterfly-shaped stirring blade that is larger at the top and smaller at the bottom, which increases the uniformity of mud mixing and stirring and facilitates the folding of the third blade 206. A spring 209 is fixedly connected to the upper end of the granulator 2 through the second rotating shaft 207. The spring 209 is fixedly connected to the extrusion disk 210. When the third blade 206 is in motion, the second rotating shaft 204 and the third blade 206 are in motion. After the three blades 206 are folded, the extrusion disc 210 extrude the mixed mud at a uniform speed after the spring 209 is opened, and the mud is squeezed to the ceramsite extrusion port 202. The particle plate 203 has extrusion holes 2031 of different sizes. The cutter group 2031 can evenly cut the mud that extends out of the extrusion hole 2031 to the cutting length at a relatively fast speed. The ceramsite extrusion port 202 is fixedly connected to the second transport crawler 211. When working, the mixing barrel 102 fully mixes the raw materials. The fully mixed coal gangue, cement, and composite materials in the mixing barrel 102 are The admixture, air entraining agent, foam stabilizer, waterproofing agent and carboxymethyl cellulose are conveyed into the interior of the granulator 2 by the first transport crawler 112, and the second motor 208 is started to drive the rotating mechanism 207, and the rotating mechanism 207 drives the second rotating shaft 204 and the third blade 206 to stir the mixed raw materials. After the mud is evenly mixed, the third blade 206 is folded and retracted, and the extrusion disk 210 squeezes the mud evenly downward, and the cutting knife group 2031 evenly cuts the mud that extends out of the extrusion hole 2031 to the cutting length to form granular semi-finished expanded clay.

[0031] The output end of the second transport crawler 211 is fixedly connected to the rotary curing barrel 3, and the second transport crawler 211 is fixedly connected to the dust spray port 212. During the process of the second transport crawler 211 conveying the semi-finished ceramsite, the dust spray port 211 evenly sprays the raw material dust collected in the dust storage tank to the surface of the semi-finished ceramsite through the fan, which can effectively prevent the semi-finished ceramsite from sticking during the curing process. The inner wall of the rotary curing barrel 3 is fixedly connected to the curing liner 304 through the rotating roller 303. After the rotary curing barrel 3 is started, the curing liner 304 keeps rotating at a certain speed, and the water tank 306 conveys water vapor to the curing liner 304. The semi-finished expanded clay is cured under suitable humidity. After the rotary curing barrel 3 starts working, the carbon dioxide cylinder 4 transports carbon dioxide into the curing inner tank 304. The bottom of the rotary curing barrel 3 is fixedly connected with a particle outlet 305. During operation, the second transport crawler 211 starts working to transport the semi-finished expanded clay to the feed port 301 of the rotary curing barrel 3. The rotary inner tank 304 starts working and starts to rotate. The carbon dioxide cylinder 4 transports carbon dioxide into the curing inner tank 304, so that the semi-finished expanded clay is cured in a carbon dioxide environment. When the semi-finished expanded clay reaches the curing age, it is discharged through the particle outlet 305.

[0032] A gangue-based lightweight high-strength unfired ceramsite and a preparation method thereof, comprising the following steps: Step 1: Use a jaw crusher to crush the gangue, select the gangue particles with a particle size of less than 3 mm, add sulfuric acid according to the solid-liquid mass ratio of 1:5, soak for 2 hours, filter and wash, use an electric heating blast drying oven to dry the gangue, and control the moisture content below 1%. Use a ball mill to add 1.5% of the gangue mass of chemical activator to mechanically grind the gangue for 30 minutes to obtain mechanochemically activated gangue powder; Step 2: Weigh 30-40 parts of coal gangue, 20-30 parts of cement, 30-50 parts of composite admixture, 40 parts of water, 0.5-2 parts of air entraining agent, 0.05-0.2 parts of foam stabilizer, 0.1-0.25 parts of waterproofing agent, and 0.5-2.0 parts of carboxymethyl cellulose according to weight parts; Step 3: adding coal gangue, cement, composite admixture, air entraining agent, foam stabilizer, waterproofing agent, and carboxymethyl cellulose raw materials into the mixing barrel through the feed port, and the first motor drives the first rotating shaft after being powered on, and the first rotating shaft drives the stirring blade to stir and mix the raw materials in the mixing barrel, so that the added coal gangue, cement, composite admixture, air entraining agent, foam stabilizer, waterproofing agent, and carboxymethyl cellulose raw materials can be mixed evenly. When the mixing barrel is started, the first fan transports the floating raw materials in the mixing barrel to the dust storage tank through the dust pipe for reuse; Step 4: The mixed raw materials enter the granulator through the first transport crawler, the granulator starts working, the second motor drives the rotating mechanism, the rotating mechanism drives the second rotating shaft and the third blade to stir the raw materials, after the mud is mixed evenly, the third blade is folded and retracted, the extrusion disc extrude the mud downward, after reaching the cutting length through the particle plate, the cutter cuts the mud into semi-finished ceramsite by rotation; Step 5: The semi-finished expanded clay is transported to the rotary curing barrel after the second transport crawler is started. The rotary curing barrel rotates at a fixed speed until the finished expanded clay is formed. When the rotary curing barrel is started, the water tank transports water vapor into the rotary curing barrel, and the carbon dioxide cylinder transports carbon dioxide into the rotary curing barrel. When the second transport crawler transports the semi-finished expanded clay, the second fan sprays the raw materials collected in the dust storage tank onto the surface of the semi-finished expanded clay through the dust pipe.

[0033] Preferably, during the natural curing process of the rotary curing barrel, the temperature is controlled at 20±2°C, the relative humidity is 50±5%RH, and the curing time is 12h; the high temperature curing temperature is controlled at 60-80°C, the humidity is 45±5%RH, and the curing time is 8h; during the carbonization curing process, the pressure range is controlled at 0.3Mpa, the humidity is 60±5%RH, and the curing time is 3h. Example

[0034] Step 1: Use a jaw crusher to crush the gangue, select the gangue particles with a particle size of less than 3 mm, add sulfuric acid according to the solid-liquid mass ratio of 1:5, soak for 2 hours, filter and wash, use an electric heating blast drying oven to dry the gangue, and control the moisture content below 1%. Use a ball mill to add 1.5% of the gangue mass of chemical activator to mechanically grind the gangue for 30 minutes to obtain mechanochemically activated gangue powder; Step 2: Weigh 30 parts of coal gangue, 20 parts of cement, 50 parts of composite admixture, 40 parts of water, 0.5 parts of air entraining agent, 0.05 parts of foam stabilizer, 0.1 parts of waterproofing agent, and 0.5 parts of carboxymethyl cellulose according to weight parts; Step 3: adding coal gangue, cement, composite admixture, air entraining agent, foam stabilizer, waterproofing agent, and carboxymethyl cellulose raw materials into the mixing barrel through the feed port, and the first motor drives the first rotating shaft after being powered on, and the first rotating shaft drives the stirring blade to stir and mix the raw materials in the mixing barrel, so that the added coal gangue, cement, composite admixture, air entraining agent, foam stabilizer, waterproofing agent, and carboxymethyl cellulose raw materials can be mixed evenly. When the mixing barrel is started, the first fan transports the floating raw materials in the mixing barrel to the dust storage tank through the first dust pipe for reuse; Step 4: The mixed raw materials enter the granulator through the first transport crawler, the granulator starts working, the second motor drives the rotating mechanism, the rotating mechanism drives the second rotating shaft and the third blade to stir the raw materials, after the mud is mixed evenly, the third blade is folded and retracted, the extrusion disc extrude the mud downward, after reaching the cutting length through the particle plate, the cutter cuts the mud into semi-finished ceramsite by rotation; Step 5: The semi-finished expanded clay is transported to the rotary curing barrel after the second transport crawler is started. The rotary curing barrel rotates at a fixed speed until the finished expanded clay is formed. When the rotary curing barrel is started, the water tank transports water vapor into the rotary curing barrel, and the carbon dioxide cylinder transports carbon dioxide into the rotary curing barrel. When the second transport crawler transports the semi-finished expanded clay, the second fan sprays the raw materials collected in the dust storage tank onto the surface of the semi-finished expanded clay through the dust pipe.

[0035] Preferably, during the natural curing process of the rotary curing barrel, the temperature is controlled at 20±2°C, the relative humidity is 50±5%RH, and the curing time is 12h; the high temperature curing temperature is controlled at 60°C, the humidity is 45±5%RH, and the curing time is 8h; during the carbonization curing process, the pressure range is controlled at 0.3Mpa, the humidity is 60±5%RH, and the curing time is 3h. Example

[0036] Step 1: Use a jaw crusher to crush the gangue, select the gangue particles with a particle size of less than 3 mm, add sulfuric acid according to the solid-liquid mass ratio of 1:5, soak for 2 hours, filter and wash, use an electric heating blast drying oven to dry the gangue, and control the moisture content below 1%. Use a ball mill to add 1.5% of the gangue mass of chemical activator to mechanically grind the gangue for 30 minutes to obtain mechanochemically activated gangue powder; Step 2: Weigh 35 parts of coal gangue, 25 parts of cement, 40 parts of composite admixture, 40 parts of water, 1 part of air entraining agent, 0.1 part of foam stabilizer, 0.15 part of waterproofing agent, and 1 part of carboxymethyl cellulose according to weight proportions; Step 3: add coal gangue, cement, composite admixture, air entraining agent, foam stabilizer, waterproofing agent, and carboxymethyl cellulose raw materials into the mixing barrel through the feed port, and the first motor drives the first rotating shaft after being powered on, and the first rotating shaft drives the stirring blade to stir and mix the raw materials in the mixing barrel, so that the added coal gangue, cement, composite admixture, air entraining agent, foam stabilizer, waterproofing agent, and carboxymethyl cellulose raw materials can be mixed evenly. When the mixing barrel is started, the first fan transports the floating raw materials in the mixing barrel to the dust storage tank through the first dust pipe 501 for reuse; Step 4: The mixed raw materials enter the granulator through the first transport crawler, the granulator starts working, the second motor drives the rotating mechanism, the rotating mechanism drives the second rotating shaft and the third blade to stir the raw materials, after the mud is mixed evenly, the third blade is folded and retracted, the extrusion disc extrude the mud downward, after reaching the cutting length through the particle plate, the cutter cuts the mud into semi-finished ceramsite by rotation; Step 5: The semi-finished expanded clay is transported to the rotary curing barrel after the second transport crawler is started. The rotary curing barrel rotates at a fixed speed until the finished expanded clay is formed. When the rotary curing barrel is started, the water tank transports water vapor into the rotary curing barrel, and the carbon dioxide cylinder transports carbon dioxide into the rotary curing barrel. When the second transport crawler transports the semi-finished expanded clay, the second fan sprays the raw materials collected in the dust storage tank onto the surface of the semi-finished expanded clay through the second dust duct 502.

[0037] Preferably, during the natural curing process of the rotary curing barrel, the temperature is controlled at 20±2°C, the relative humidity is 50±5%RH, and the curing time is 12h; the high temperature curing temperature is controlled at 60°C, the humidity is 45±5%RH, and the curing time is 8h; during the carbonization curing process, the pressure range is controlled at 0.3Mpa, the humidity is 60±5%RH, and the curing time is 3h. Example

[0038] Step 1: Use a jaw crusher to crush the gangue, select the gangue particles with a particle size of less than 3 mm, add sulfuric acid according to the solid-liquid mass ratio of 1:5, soak for 2 hours, filter and wash, use an electric heating blast drying oven to dry the gangue, and control the moisture content below 1%. Use a ball mill to add 1.5% of the gangue mass of chemical activator to mechanically grind the gangue for 30 minutes to obtain mechanochemically activated gangue powder; Step 2: Weigh 40 parts of coal gangue, 30 parts of cement, 30 parts of composite admixture, 40 parts of water, 1.5 parts of air entraining agent, 0.15 parts of foam stabilizer, 0.2 parts of waterproofing agent, and 1.5 parts of carboxymethyl cellulose according to weight parts; Step 3: adding coal gangue, cement, composite admixture, air entraining agent, foam stabilizer, waterproofing agent, and carboxymethyl cellulose raw materials into the mixing barrel through the feed port, and the first motor drives the first rotating shaft after being powered on, and the first rotating shaft drives the stirring blade to stir and mix the raw materials in the mixing barrel, so that the added coal gangue, cement, composite admixture, air entraining agent, foam stabilizer, waterproofing agent, and carboxymethyl cellulose raw materials can be mixed evenly. When the mixing barrel is started, the first fan transports the floating raw materials in the mixing barrel to the dust storage tank through the dust pipe for reuse; Step 4: The mixed raw materials enter the granulator through the first transport crawler, the granulator starts working, the second motor drives the rotating mechanism, the rotating mechanism drives the second rotating shaft and the third blade to stir the raw materials, after the mud is mixed evenly, the third blade is folded and retracted, the extrusion disc extrude the mud downward, after reaching the cutting length through the particle plate, the cutter cuts the mud into semi-finished ceramsite by rotation; Step 5: The semi-finished expanded clay is transported to the rotary curing barrel after the second transport crawler is started. The rotary curing barrel rotates at a fixed speed until the finished expanded clay is formed. When the rotary curing barrel is started, the carbon dioxide cylinder transports carbon dioxide into the rotary curing barrel, and the water tank transports water vapor into the rotary curing barrel. When the second transport crawler transports the semi-finished expanded clay, the second fan sprays the raw materials collected in the dust storage tank onto the surface of the semi-finished expanded clay through the dust pipe.

[0039] Preferably, during the natural curing process of the rotary curing barrel, the temperature is controlled at 20±2°C, the relative humidity is 50±5%RH, and the curing time is 12h; the high temperature curing temperature is controlled at 60°C, the humidity is 45±5%RH, and the curing time is 8h; during the carbonization curing process, the pressure range is controlled at 0.3Mpa, the humidity is 60±5%RH, and the curing time is 3h. Example

[0040] Step 1: Use a jaw crusher to crush the gangue, select the gangue particles with a particle size of less than 3 mm, add sulfuric acid according to the solid-liquid mass ratio of 1:5, soak for 2 hours, filter and wash, use an electric heating blast drying oven to dry the gangue, and control the moisture content below 1%. Use a ball mill to add 1.5% of the gangue mass of chemical activator to mechanically grind the gangue for 30 minutes to obtain mechanochemically activated gangue powder; Step 2: Weigh 40 parts of coal gangue, 20 parts of cement, 40 parts of composite admixture, 40 parts of water, 2 parts of air entraining agent, 0.2 parts of foam stabilizer, 0.25 parts of waterproofing agent, and 2 parts of carboxymethyl cellulose according to weight parts; Step 3: adding coal gangue, cement, composite admixture, air entraining agent, foam stabilizer, waterproofing agent, and carboxymethyl cellulose raw materials into the mixing barrel through the feed port, and the first motor drives the first rotating shaft after being powered on, and the first rotating shaft drives the stirring blade to stir and mix the raw materials in the mixing barrel, so that the added coal gangue, cement, composite admixture, air entraining agent, foam stabilizer, waterproofing agent, and carboxymethyl cellulose raw materials can be mixed evenly. When the mixing barrel is started, the first fan transports the floating raw materials in the mixing barrel to the dust storage tank through the dust pipe for reuse; Step 4: The mixed raw materials enter the granulator through the first transport crawler, the granulator starts working, the second motor drives the rotating mechanism, the rotating mechanism drives the second rotating shaft and the third blade to stir the raw materials, after the mud is mixed evenly, the third blade is folded and retracted, the extrusion disc extrude the mud downward, after reaching the cutting length through the particle plate, the cutter cuts the mud into semi-finished ceramsite by rotation; Step 5: The semi-finished expanded clay is transported to the rotary curing barrel after the second transport crawler is started. The rotary curing barrel rotates at a fixed speed until the finished expanded clay is formed. When the rotary curing barrel is started, the water tank transports water vapor into the rotary curing barrel, and the carbon dioxide cylinder transports carbon dioxide into the rotary curing barrel. When the second transport crawler transports the semi-finished expanded clay, the second fan sprays the raw materials collected in the dust storage tank onto the surface of the semi-finished expanded clay through the dust pipe.

[0041] Preferably, during the natural curing process of the rotary curing barrel, the temperature is controlled at 20±2°C, the relative humidity is 50±5%RH, and the curing time is 12h; the high temperature curing temperature is controlled at 80°C, the humidity is 45±5%RH, and the curing time is 8h; during the carbonization curing process, the pressure range is controlled at 0.3 Mpa, the humidity is 60±5%RH, and the curing time is 3h.

[0042] The properties of the gangue-based lightweight high-strength ceramsite prepared in Examples 1-4 were measured in accordance with the light aggregate test method in Part 2 of GB / T17431 "Light Aggregates and Test Methods Thereof". The measurement results are shown in Table 1.

[0043] Table 1 Performance results of coal gangue-based lightweight high-strength ceramsite in Examples 1-4 It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-limiting in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes within the meaning and scope of the equivalent elements of the claims be included in the present invention. Any reference numeral in a claim should not be regarded as limiting the claim to which it relates.

Claims

1. Lightweight, high-strength, unburned ceramsite based on coal gangue. It is characterized in that The gangue-based lightweight high-strength unfired ceramsite comprises the following components in parts by weight: 30-40 parts of gangue, 20-30 parts of cement, 30-50 parts of composite admixtures, 40 parts of water, 0.5-2 parts of air entraining agent, 0.05-0.2 parts of foam stabilizer, 0.1-0.25 parts of waterproofing agent, and 0.5-2.0 parts of carboxymethyl cellulose.

2. A gangue-based lightweight, high-strength, unfired ceramsite according to claim 1, It is characterized in that The slag is granulated blast furnace slag powder, with a 28-day activity index of 98% and a specific surface area of ​​429 m2 / kg. The chemical composition of the steel slag is as follows: SiO2 21%, Al2O3 9%, Fe2O3 14.35%, and CaO 44%. The chemical composition of the high-calcium fly ash is as follows: SiO2 54.66%, Al2O3 10.05%, Fe2O3 7.06%, and CaO 19.45%.

3. A gangue-based lightweight, high-strength, unfired ceramsite according to claim 1, It is characterized in that The chemical composition of the coal gangue is as follows by weight percentage: SiO2 50.8%, Al2O3 28.1%, Fe2O3 6.2%, CaO 3.7%, loss on ignition 7.9%, and fineness above 300 meshes.

4. The gangue-based lightweight, high-strength, unfired ceramsite according to claim 1, It is characterized in that The air entraining agent component consists of 5% aluminum nitrate, 15% ammonium nitrate, 15% sodium nitrite, 25% urea, 40% sodium bicarbonate and 0.02% citric acid added externally; the foam stabilizer consists of 50% lauryl diethanolamine, 20% dodecanol, 5% sodium tripolyphosphate, 20% fatty alcohol polyoxyethylene ether phosphate potassium salt, and 5% carboxymethyl starch ether; the waterproofing agent consists of 50% methyl MQ silicone resin, 25% dodecyl trimethoxy silane, and 25% sodium polyacrylate; the chemical stimulator consists of 60% Na2SO4 and 40% CaSO4·2H2O; and the composite admixture component consists of 40% slag, 15% industrial by-product gypsum, 35% steel slag, and 10% high-calcium fly ash.

5. The method for preparing the gangue-based lightweight, high-strength, unfired ceramsite according to claim 1, It is characterized in that The method comprises the following preparation steps: Step 1: Use a jaw crusher to crush the gangue, select the gangue particles with a particle size of less than 3 mm, add sulfuric acid according to the solid-liquid mass ratio of 1:5, soak for 2 hours, filter and wash, use an electric heating blast drying oven to dry the gangue, and control the moisture content below 1%. Use a ball mill to add 1.5% of the gangue mass of chemical activator to mechanically grind the gangue for 30 minutes to obtain mechanochemically activated gangue powder; Step 2: Weigh 30-40 parts of coal gangue, 20-30 parts of cement, 30-50 parts of composite admixture, 40 parts of water, 0.5-2 parts of air entraining agent, 0.05-0.2 parts of foam stabilizer, 0.1-0.25 parts of waterproofing agent, and 0.5-2.0 parts of carboxymethyl cellulose according to weight parts; Step 3: adding coal gangue, cement, composite admixture, air entraining agent, foam stabilizer, waterproofing agent, and carboxymethyl cellulose raw materials into the mixing barrel (102) through the feed port (103); the first motor (110) drives the first rotating shaft (106) after being powered on; the first rotating shaft drives the stirring blade (107) to stir and mix the raw materials in the mixing barrel (102), so that the added coal gangue, cement, composite admixture, air entraining agent, foam stabilizer, waterproofing agent, and carboxymethyl cellulose raw materials can be mixed evenly; when the mixing barrel (102) is started, the first fan (503) transports the raw materials floating in the mixing barrel (102) to the inside of the dust storage tank (5) through the first dust pipe (501) for reuse; Step 4: The uniformly mixed raw materials enter the granulator (2) through the first transport crawler (112), the granulator (2) starts to work, the second motor (208) drives the rotating mechanism (207), the rotating mechanism (207) drives the second rotating shaft (204) and the third blade (206) to stir the raw materials, after the mud is uniformly mixed, the third blade (206) is folded and retracted, the extrusion disc (210) extrude the mud downward, and after the mud reaches the cutting length through the pellet discharge disc (203), the cutting knife group (2032) cuts the mud into semi-finished ceramsite by rotating; Step 5: After the second transport crawler (211) is started, the semi-finished ceramsite is transported to the rotary curing barrel (3), and the rotary curing barrel (3) rotates at a fixed rotation speed until the finished ceramsite is formed. When the rotary curing barrel (3) is started, the water tank (306) transports water vapor into the rotary curing barrel (3), and the carbon dioxide cylinder (4) transports carbon dioxide into the rotary curing barrel (3). When the semi-finished ceramsite is transported by the second transport crawler (211), the second fan (504) sprays the raw materials collected in the dust storage tank (5) onto the surface of the semi-finished ceramsite through the second dust pipe (502).

6. The preparation method according to claim 5, It is characterized in that The rotating curing barrel (3) controls the temperature at 20±2°C and the relative humidity at 50±5%RH during natural curing; the temperature at 60-80°C and the humidity at 45±5%RH during high temperature curing; and the pressure at 0.3Mpa and the humidity at 60±5%RH during carbonization curing.

7. The preparation method according to claim 5, It is characterized in that The invention comprises a raw material dry powder stirring structure (1), wherein the raw material dry powder stirring structure (1) comprises a support frame (101), wherein the support frame (101) has four support frames (101) fixed to the ground in an axially symmetrical manner, wherein a mixing barrel (102) is fixedly connected to the top of the support frame (101), wherein one side of the mixing barrel (102) is fixedly connected to a feeding port (103), the bottom of the mixing barrel (102) is fixedly connected to a discharging port (105), and the top of the mixing barrel (102) is fixedly connected to a dust suction port (104), and a first rotating shaft (106) is vertically arranged in the middle of the interior of the mixing barrel (102), and a stirring blade (107) is fixedly installed on the outer side of the first rotating shaft (106), and the stirring blade (107) is provided with a The spacer sleeve is provided with a first blade (108) and a second blade (109), the upper end of the first rotating shaft (106) is fixedly connected to a first motor (110), the discharge port (104) is fixedly connected to a first transport crawler (112) via a connecting channel, the first material transport crawler (112) is fixedly connected to a granulator (2) via a crawler, the feed port (201) of the granulator (2) is fixedly connected to the first material transport crawler (112), the bottom of the granulator (2) is fixedly connected to a ceramsite extrusion port (202), the bottom of the ceramsite extrusion port (202) is fixedly connected to a granulation plate (203), and the granulation plate (203) is provided with a plurality of extrusion holes (2031) of different sizes uniformly distributed on circular rings of different radii The granulator (2) is provided with a second rotating shaft (204) vertically arranged in the middle of the interior of the granulator (2), a stirring blade (205) is fixedly installed on the outside of the second rotating shaft (204), and a third blade (206) is arranged on the stirring blade (205) with a spacer sleeve, and a rotating mechanism (207) is fixedly connected to the upper end of the second rotating shaft (204), and a second motor (208) is fixedly connected to the upper end of the rotating mechanism (207), and a spring (209) is fixedly connected to the upper end of the interior of the granulator (2) through the second rotating shaft (207), and the spring (209) is fixedly connected to the extrusion disk (210), and the ceramsite extrusion port (202) is connected to the ceramsite extrusion port (202) through the second rotating shaft (207). The second transport crawler (211) is fixedly connected to the conveyor belt (211), the second transport crawler (211) is fixedly connected to a dust spray port (212) through a connecting channel, the second transport crawler (211) is fixedly connected to a rotating curing barrel (3) through the crawler belt, one side of the rotating curing barrel (3) is fixedly connected to a grain inlet (301), and the other side is fixedly connected to a third motor (302), a rotating roller (303) is fixedly mounted on the inner wall of the rotating curing barrel (3) through a connecting rod, the rotating curing barrel (3) is fixedly connected to a curing liner (304) through the rotating roller (303), the bottom of the rotating curing barrel (3) is fixedly connected to a grain outlet (305), and the top of the rotating curing barrel (3) is fixedly connected to a water tank (306),The rotary curing barrel (3) is fixedly connected to a carbon dioxide cylinder (4) via a connecting pipe, the dust suction port (104) is fixedly connected to one side of a dust storage tank (5) via a first dust passage pipe (501), the first dust passage pipe (501) is fixedly connected to a first fan (503), the dust ejection port (212) is fixedly connected to the other side of the dust storage tank (5) via a second dust passage pipe (502), and the second dust passage pipe (502) is fixedly connected to a second fan (504).

8. The preparation method according to claim 7, It is characterized in that The feed port (103) is in the shape of a bottomless container with a trapezoidal shape that is larger at the top and smaller at the bottom. The feed port (103) is custom-made in one piece in the factory. The connection between the feed port (103) and the mixing barrel (102) is welded. The discharge port (105) is in the shape of a funnel that is wider at the top and gradually narrows at the bottom. It is horizontally arranged at the center of the bottom of the mixing barrel (102). The upper end of the discharge port (105) is welded to the bottom of the mixing barrel (102). A valve (111) is installed at the lower end of the discharge port. The feed port (201) is in the shape of a trumpet that gradually shrinks and narrows from the top to the bottom. It is welded to the granulator (2).

9. The preparation method according to claim 7, It is characterized in that The outermost side of the first blade (108) is flush with the inner wall edge of the mixing barrel (102); the length of the second blade (109) is shorter than that of the first blade (108); the upper part of the third blade (206) is a large blade oriented obliquely upward, and the lower part is a small blade oriented obliquely downward; the third blade (206) is symmetrically distributed on the second rotating shaft (204) in a butterfly shape, and can be folded on the second rotating shaft (204).

10. The preparation method according to claim 7, It is characterized in that The rotating mechanism (207) comprises a gear plate (2071), a first gear (2072) and a second gear (2073), wherein the lower end of the first gear (2072) is fixedly connected to the second rotating shaft (204), and the upper end of the second gear (2073) is fixedly connected to the second motor (208).

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