Method and device for preparing silicate cement by using low-carbon ash and carbide slag

Abstract

The application belongs to the technical field of Portland cement preparation, and discloses a method and device for preparing Portland cement by using low-carbon ash and carbide slag, which comprises the following steps: step S10: crushing and screening the low-carbon ash and the carbide slag; step S20: drying the carbide slag, wherein the drying is carried out in a high-temperature negative-pressure drying stage in the early stage and a medium-temperature normal-pressure drying stage in the later stage; step S30: mixing the pretreated low-carbon ash and carbide slag with calcareous raw materials and argillaceous raw materials in a certain proportion, and grinding the mixture to prepare raw materials; step S40: calcining the raw materials in a rotary kiln to obtain Portland cement clinker; and step S50: cooling the calcined clinker to room temperature, and then grinding the clinker together with desulfurization gypsum and mixed materials to obtain Portland cement; in the scheme, the high-temperature negative-pressure drying in the early stage is adopted to accelerate the evaporation of water by using a higher temperature and a negative-pressure environment, and then the medium-temperature normal-pressure drying is carried out to further remove the residual water; and the application solves the problem of poor drying efficiency of the carbide slag.

Description

Technical Field

[0001] This solution belongs to the field of silicate cement preparation technology, specifically involving a method and apparatus for preparing silicate cement using low-carbon ash and carbide slag. Background Technology

[0002] See the existing public (announcement) background technology with CN113526885B, Road Silicate Cement (GBT13693-2017 Road Silicate Cement), which belongs to special cement and is mainly used in the construction of airport runways and highway pavements. It has good wear resistance and drying shrinkage resistance, and can effectively control the internal and external temperature differences during the hardening process of large-area concrete, significantly reducing the probability of concrete cracking.

[0003] The method for preparing silicate cement from low-carbon ash and carbide slag involves pretreating the low-carbon ash and carbide slag, then mixing them with calcareous and clayey raw materials in a certain proportion. This mixture is then ground into raw meal, which is calcined in a cement kiln until partially melted. After cooling, silicate cement clinker is obtained. Finally, the clinker is ground together with an appropriate amount of desulfurized gypsum and other admixtures to obtain silicate cement. Low-carbon ash, as a supplementary calcareous raw material in silicate cement production, provides the required CaO. Carbide slag, on the other hand, is an industrial waste, its main component being calcium hydroxide, which reacts at high temperatures to form calcium oxide. Rational utilization of these materials can not only reduce production costs but also decrease environmental pollution, achieving resource recycling. This preparation method, while meeting the performance requirements of silicate cement, contributes to the sustainable development of the cement industry.

[0004] See the existing publication (announcement) number CN113526885A, which discloses a road silicate cement and its preparation method. The method includes the following steps: (1) drying and grinding the raw materials to obtain raw meal with a sieve residue percentage of 16-20% on an 80-micron square hole sieve; (2) homogenizing, preheating, decomposing, calcining and cooling the raw meal obtained in step (1) in sequence to obtain clinker; (3) mixing the clinker obtained in step (2) with desulfurized gypsum, blast furnace slag and blast furnace steel slag, and then grinding them.

[0005] Because the raw material (carbide slag) has a high moisture content, typically 30%-40%, it needs to be dried to reduce the moisture content to ≤1% and then crushed and screened to a suitable particle size. However, due to the high moisture content of carbide slag, existing technologies often use a dryer with hot air to dry it, which results in a long drying time and poor drying efficiency. Summary of the Invention

[0006] The purpose of this solution is to provide a method for preparing silicate cement using low-carbon ash and carbide slag, in order to solve the problem of poor drying efficiency of carbide slag.

[0007] To achieve the above objectives, this solution provides a method for preparing silicate cement using low-carbon ash and carbide slag, comprising the following steps:

[0008] Step S10: Crush and screen the low-carbon ash and carbide slag to a size of 80 micrometers;

[0009] Step S20: Drying the carbide slag. In the early drying stage, the drying temperature is 150-200℃, the drying time is 1-2 hours, and the negative pressure is -0.05 to -0.1MPa. In the later drying stage, the drying temperature is 100-120℃, the drying time is 1-2 hours, and the pressure is atmospheric pressure.

[0010] Step S30: Mix the pretreated low-carbon ash and carbide slag with limestone and clayey raw materials in a certain proportion, and grind them into raw meal;

[0011] Step S40: Calcine the raw materials in a rotary kiln at a temperature of 1300-1500℃ for 1-2 hours to obtain silicate cement clinker.

[0012] Step S50: Cool the calcined clinker to room temperature, and then grind it together with desulfurized gypsum and mixed materials to obtain silicate cement.

[0013] The principle and effect of this scheme are as follows: (1) The low carbon ash and carbide slag are crushed and screened to 80 micrometers. This step can increase the specific surface area of ​​the material, which is beneficial to subsequent drying. Then, the carbide slag is dried in stages. In the early stage, high temperature negative pressure drying is used to accelerate the evaporation of moisture by using a higher temperature and negative pressure environment. In the later stage, medium temperature and normal pressure drying is used to further remove the remaining moisture. In the subsequent steps, the pretreated low carbon ash and carbide slag are mixed with limestone raw materials and clay raw materials, and then ground into raw materials. Then, they are calcined in a rotary kiln to obtain silicate cement clinker. Finally, they are ground together with desulfurized gypsum and mixed materials to obtain silicate cement. (2) This scheme adopts high temperature negative pressure drying in the early stage to accelerate the evaporation of moisture by using a higher temperature and negative pressure environment. Then, medium temperature and normal pressure drying is used to further remove the remaining moisture. The drying time is reduced and the drying efficiency is improved by using a staged drying method.

[0014] Furthermore, in step S20, during the initial drying stage, the drying temperature is 180℃, the drying time is 1.5 hours, and the negative pressure is -0.08MPa; during the later drying stage, the drying temperature is 110℃, the drying time is 1.5 hours, and the pressure is atmospheric pressure.

[0015] Furthermore, in step S30, the calcareous raw material is limestone, and the clayey raw material is clay; the total weight ratio of low-carbon ash and carbide slag in the raw material is 30%-50%; in step S50, the gypsum addition is 3-5% of the clinker weight, and the mixed material is slag or fly ash, with an addition amount of 10-20% of the clinker weight.

[0016] An apparatus for preparing silicate cement using low-carbon ash and carbide slag includes a crushing mechanism, a screening mechanism, a drying mechanism, a mixing mechanism, a rotary kiln, and a ball mill connected in sequence; the drying mechanism includes:

[0017] frame;

[0018] A drying tank, which is mounted on a frame;

[0019] A hot air blower, which is connected to a drying tank via a pipe;

[0020] A vacuum pump, which is connected to the drying tank via a pipeline.

[0021] The principle and effect of this scheme are as follows: The crushing, screening, stirring, rotary kiln, and ball mill in this scheme are all existing technologies and will not be elaborated on further. The drying mechanism adopts a segmented drying method for the calcium carbide slag. Due to the high moisture content of the calcium carbide slag, a vacuum pump is used to draw the drying tank into a negative pressure state to lower the low boiling point of water, making it easier for the moisture inside the calcium carbide slag to evaporate, thus accelerating the evaporation rate. In the later stage, medium-temperature and normal-pressure drying is used to avoid the calcium carbide slag from clumping due to excessive temperature. Through segmented drying, the drying time of the calcium carbide slag is reduced, and the drying efficiency is improved.

[0022] Furthermore, the screening mechanism includes a support leg and a bracket. One end of the support leg is fixedly connected to the drying tank, and the other end is rotatably connected to the bracket. One end of the bracket is equipped with a cylinder, and the piston rod of the cylinder is rotatably connected to the bracket. A screen cylinder is provided on the bracket, and a drive assembly for driving the screen cylinder to rotate is connected to the screen cylinder.

[0023] The principle and effect of this scheme are as follows: (1) Existing screening mechanisms usually set the screen cylinder to be inclined, which helps the material to move along the screen surface under the action of gravity, reduces the residence time of the material on the screen surface, and makes the material better dispersed during the screening process. However, the wear of the screen cylinder is mainly during the screening stage when the screen cylinder drives the material to rotate. When the material is fed from the feed end (high place) of the screen cylinder, it will flow to the other end (low place). As the screen cylinder rotates, the material has a shorter residence time at the high place (feed end) and a longer residence time at other positions, which leads to uneven wear of the screen cylinder. That is, the feed end wears less and the other positions wear more. This uneven wear shortens the life of the screen cylinder. (2) This scheme sets the other end of the support as a cylinder and controls the extension and retraction of the cylinder piston rod to control the left and right ends of the screen cylinder to tilt alternately. In the initial stage of drying (high temperature and negative pressure), one end of the screen cylinder is tilted, while in the later stage of drying (medium temperature and normal pressure), the other end of the screen cylinder is tilted. This avoids the screen cylinder being tilted at one end all the time, allowing for a more even distribution of wear on the screen cylinder and preventing excessive local wear caused by long-term unidirectional tilting, thus extending the service life of the screen cylinder.

[0024] Furthermore, the screening mechanism is located inside the drying tank; the cylinder includes a cylinder body with an opening at the top and a piston located inside the cylinder body, the piston and the cylinder body enclose a movable chamber, one end of the piston is fixedly connected to the piston rod, and the other end of the piston rod is rotatably connected to the support.

[0025] The principle and effect of this scheme are as follows: (1) The existing screening and drying stages use separate equipment for single operation. This scheme places the screening mechanism in the drying tank, which can screen the carbide slag at the same time during the drying process, reducing the material transfer links. (2) Because the screen cylinder is set in the drying tank. In the initial state, the piston rod of the cylinder is in the retracted state. When the carbide slag is put into the screen cylinder, the carbide slag moves to the other end of the screen cylinder (the end close to the cylinder). When the drying tank is drawn to a negative pressure state, the piston moves towards the cylinder opening, driving the piston rod to extend. When the piston rod extends to the maximum stroke, the end of the screen cylinder is lifted, making the other end lower than the first end. As the screen cylinder rotates, the material moves to the other end. When the drying tank returns to the normal pressure state, the piston drives the piston rod to reset to the initial position, so that the end that was originally lifted by the piston rod is reset to the low position, while the other end is in the high position. As the screen cylinder continues to rotate, the material moves to the cylinder end again. (3) This scheme adjusts the tilt of the screen cylinder by setting the screening mechanism inside the drying tank, so that the carbide slag is more evenly distributed in the screen cylinder. Most importantly, it avoids the problem of uneven wear caused by the long-term unidirectional tilt of the screen cylinder and extends the service life of the screen cylinder.

[0026] Furthermore, a receiving trough is provided below the screen cylinder, and a filter screen is provided inside the receiving trough. A drain pipe is connected to the bottom of the receiving trough through a pipe. The water outlet of the drain pipe is located outside the drying tank. A drain valve is provided on the drain pipe. The drain valve is electrically connected to a push switch. The piston rod is configured to cooperate with the push switch.

[0027] The principle and effect of this scheme are as follows: (1) A receiving trough and a filter screen are set up to receive the carbide slag screened by the screen cylinder. Water is deposited at the bottom of the receiving trough through the filter screen and discharged to the outside of the drying tank through the pipe. (2) When the drying tank is under normal pressure, the piston rod retracts to the limit position, thereby resisting the press switch and the drain valve is in the open state; when the drying tank is under negative pressure, the piston rod extends, the press switch loses resistance, the drain valve is closed, and the negative pressure environment of the drying tank is maintained. When the drying tank is under normal pressure in the later stage of drying, the drain valve is opened again to drain water.

[0028] Furthermore, a support plate is provided on one side of the screen cylinder, the screen cylinder is formed by a flexible screen mesh, the fixed end of the screen mesh is fixedly connected to the support plate, the support plate is provided with an Archimedean spiral structure guide groove, and the movable end of the screen mesh is slidably disposed in the guide groove; the support plate is provided with a drive unit for driving the movable end.

[0029] The principle and effect of this scheme are as follows: (1) When the existing screen cylinder is used to process materials with high moisture content, such as carbide slag, it only relies on the rotation of the screen cylinder to make the material roll and come into contact with hot air, which does not make the material dry faster. In this scheme, after the carbide slag is fed into the screen cylinder, the moving end is driven by the drive unit to move along the guide groove, so that the screen shrinks inward, reducing the internal space of the screen cylinder, so that the screen can squeeze the material, squeeze out some of the moisture of the carbide slag first, and then dry the material with hot air, so that the drying speed will be faster. (2) As the screen shrinks inward, the screen holes will overlap, so that the aperture of the screen holes will become smaller, so that when the screen squeezes the carbide slag inside, the carbide slag will not be squeezed out of the screen. In the later stage of drying, the carbide slag needs to be screened. By controlling the shrinkage state of the screen, that is, controlling the aperture of the screen, the carbide slag of the appropriate particle size can be screened.

[0030] Furthermore, the drive unit includes a winding roller and a motor. The winding roller is coaxially and fixedly connected to the output shaft of the motor. The motor is electrically connected to a push switch. A steel cable is fixedly mounted on the winding roller, and the free end and the movable end of the steel cable are fixedly connected.

[0031] The principle and effect of this scheme are as follows: after the carbide slag is put into the screen cylinder, the motor is started by pressing the switch, which drives the winding roller to rotate. The moving end moves along the guide groove through the coiled steel cable, thereby causing the screen to shrink.

[0032] Furthermore, the support plate is provided with a limiting groove, which is set along the path of the guide groove; the end of the guide groove is provided with a limiting block that cooperates with the movable end; the surface of the fixed end that contacts the movable end is a snap-fit ​​structure.

[0033] The principle and effect of this solution are as follows: the limiting groove is used to provide positioning and guidance for the movement of the screen's movable end along the guide groove; the limiting block is used to limit the extreme position of the movable end's movement and prevent it from dislodging; the movable end and the fixed end are a snap-fit ​​structure in the initial state, so that the fixed end can fix the movable end of the screen. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the drying mechanism of the present invention;

[0035] Figure 2 This is a schematic diagram of the screening mechanism of the present invention. Figure 1 ;

[0036] Figure 3 This is a schematic diagram of the screening mechanism of the present invention. Figure 2 ;

[0037] Figure 4 This is a schematic diagram of the internal structure of the cylinder of the present invention;

[0038] Figure 5 This is a schematic diagram of the internal structure of the receiving trough of the present invention;

[0039] Figure 6 This is a cross-sectional view of the sieve cylinder of the present invention;

[0040] Figure 7 This is a schematic diagram of the structure of the sieve cylinder of the present invention. Figure 1 ;

[0041] Figure 8 This is a schematic diagram of the structure of the sieve cylinder of the present invention. Figure 2 .

[0042] The reference numerals in the accompanying drawings include: drying mechanism 1, frame 11, drying tank 12, screening mechanism 2, support leg 21, bracket 22, cylinder 23, piston rod 231, cylinder body 232, piston 233, movable chamber 234, screen cylinder 24, fixed end 241, movable end 242, winding roller 243, steel cable 244, support plate 25, guide groove 251, limiting groove 252, limiting block 253, receiving groove 3, filter screen 31, drain pipe 32, and push switch 33. Detailed Implementation

[0043] The following will describe the concept and technical effects of the present invention clearly and completely with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0044] Example 1:

[0045] A method for preparing silicate cement using low-carbon ash and carbide slag includes the following steps:

[0046] Step S10, Crushing and Screening:

[0047] Raw materials such as dry carbide slag, low-carbon ash (gasification furnace slag), kiln ash, silica sand, silica powder, and fly ash are initially crushed by jaw crushers and then screened to a particle size of ≤80 micrometers by vibrating screeners.

[0048] Step S20, drying in stages:

[0049] High-temperature negative pressure drying stage: The screened dry carbide slag is put into the drying tank (12) of the drying mechanism (1), the vacuum pump is started to make the negative pressure value inside the tank reach -0.08MPa, and at the same time, 180℃ hot air is introduced through the hot air blower for 1.5 hours; Medium-temperature normal pressure drying stage: The vacuum pump is turned off, the normal pressure is maintained, the drying temperature is adjusted to 110℃ for 1.5 hours, and the moisture content is further reduced to ≤1%;

[0050] Step S30: Mixing raw materials:

[0051] According to the mixing ratio scheme in Table 1, select any one of the following ratios (taking number 1 as an example) for mixing:

[0052] Dry carbide slag: 49.0±5.0%; kiln ash: 0.1%; silica sand: 0.09%; silica powder: 0.09%; low-carbon ash (gasification furnace slag): 0.05%; fly ash: 0.16%; copper slag: 2.00±0.20%; limestone: to be added to 100% of the total mix (approximately 48.51%).

[0053] After the above raw materials are mixed evenly in a mixing mechanism, they are ground in a ball mill until the raw meal fineness is ≤15% residue on an 80-micron square-hole sieve, resulting in homogeneous raw meal. The raw meal must meet the following control indicators.

[0054] CaO content: 51.00±0.30%, Fe2O3 content: 3.10±0.20%, KH (lime saturation coefficient): 0.93±0.02, silicon content (n): 2.45±0.1, aluminum content (p): 1.35±0.1

[0055] Step S40, calcining clinker:

[0056] The raw materials are fed into a rotary kiln and calcined at 1450℃ for 1.5 hours. During the calcination process, the raw materials undergo a solid-phase reaction to generate mineral phases such as tricalcium silicate (C3S) and dicalcium silicate (C2S), ultimately yielding silicate cement clinker.

[0057] Step S50, Grind the finished product:

[0058] After the clinker is cooled to room temperature, 4% desulfurized gypsum and 15% fly ash are added by weight of the clinker, and the mixture is ground together in a ball mill until the specific surface area is ≥350m² / kg, thus producing silicate cement that meets the GB / T 175-2007 standard.

[0059]

[0060] Table 1

[0061] Example 2:

[0062] Please see Figure 1 and Figure 2 An apparatus for preparing silicate cement using low-carbon ash and carbide slag includes a crushing mechanism, a screening mechanism 2, a drying mechanism 1, a mixing mechanism, a rotary kiln, and a ball mill connected in sequence. The crushing mechanism, mixing mechanism, rotary kiln, and ball mill are not shown in the figures and are all prior art.

[0063] Please see Figure 1 The drying mechanism 1 includes a frame 11, a drying tank 12, a hot air blower, and a vacuum pump. The hot air blower and vacuum pump are existing technologies and are not shown in the figures. The drying tank 12 is mounted on the frame 11. The hot air blower and vacuum pump are connected to the drying tank 12 via pipes. The vacuum pump draws the drying tank 12 into a negative pressure state, reducing water consumption and making it easier for moisture inside the carbide slag to evaporate, thus accelerating the evaporation rate. Medium-temperature, ambient-pressure drying is used in the later stages to prevent the carbide slag from clumping due to excessively high temperatures. Segmented drying reduces the drying time of the carbide slag and improves drying efficiency.

[0064] Please see Figures 1-4The screening mechanism 2 is located inside the drying tank 12. The screening mechanism 2 includes a support leg 21 and a bracket 22. One end of the support leg 21 is fixedly connected to the drying tank 12, and the other end is rotatably connected to the bracket 22. One end of the bracket 22 is provided with a cylinder 23. The cylinder 23 includes a cylinder body 232 with an opening at the top and a piston 233 located inside the cylinder body 232. The piston 233 and the cylinder body 232 enclose a movable chamber 234. The piston 233 is fixedly connected to one end of the piston rod 231. A balance is provided inside the cylinder body 232. A spring (not shown in the figure) has one end fixedly connected to the inner wall of the cylinder 232, and its free end fixedly connected to the piston 233. The other end of the piston rod 231 is rotatably connected to the bracket 22. A screen cylinder 24 is mounted on the bracket 22, and a drive assembly for driving the screen cylinder 24 to rotate is connected to it. The drive assembly consists of a drive motor and a drive shaft. The output shaft of the drive motor is coaxially and fixedly connected to the drive shaft. A drive gear is connected to the drive shaft. A toothed ring is provided on the outer wall of the screen cylinder 24, and the toothed ring meshes with the drive gear. The drive motor drives the drive shaft and drive gear to rotate, thereby driving the screen cylinder 24 to rotate.

[0065] Specific working principle: The screening mechanism 2 is placed inside the drying tank 12, which can screen the calcium carbide slag simultaneously during the drying process, reducing material transfer links. Since the screen cylinder 24 is set inside the drying tank 12, initially, the piston rod 231 of the cylinder 23 is in the retracted state. When the calcium carbide slag is put into the screen cylinder 24, it moves to the other end of the screen cylinder 24 (the end closer to the cylinder 23). When the drying tank 12 is drawn to a negative pressure state, the piston 233 moves towards the opening of the cylinder 23, driving the piston rod 231 to extend. When the piston rod 231 extends to its maximum stroke, that end of the screen cylinder 24 is lifted, making the other end lower than that end. As the screen cylinder 24 rotates, the material moves to the other end. When the drying tank 12 returns to a normal pressure state, the piston 233 drives the piston rod 231 to return to the initial position, thus restoring the end that was originally lifted by the piston rod 231 to the low position, while the other end is in the high position. As the screen cylinder 24 continues to rotate, the material moves back to the end of the cylinder 23. By setting the screening mechanism 2 inside the drying tank 12, the tilting state of the screen cylinder 24 is adjusted, making the carbide slag more evenly distributed inside the screen cylinder 24. Most importantly, it avoids the problem of uneven wear caused by the long-term unidirectional tilting of the screen cylinder 24, thus extending the service life of the screen cylinder 24.

[0066] Please see Figure 2 , Figure 3 and Figure 5A receiving trough 3 is located below the screen cylinder 24, and a filter screen 31 is installed inside the receiving trough 3. The receiving trough 3 and the filter screen 31 are used to collect the carbide slag screened by the screen cylinder 24. Water is deposited at the bottom of the receiving trough 3 through the filter screen 31 and discharged to the outside of the drying tank 12 through a pipe. The bottom of the receiving trough 3 is connected to a drain pipe 32 through a pipe. The outlet end of the drain pipe 32 is located outside the drying tank 12. A drain valve (not shown in the figure) is installed on the drain pipe 32. The drain valve is electrically connected to a push switch 33. A piston rod 231 is configured to cooperate with the push switch 33. When the drying tank 12 is under normal pressure, the piston rod 231 retracts to its limit position, thereby abutting the push switch 33, and the drain valve is in the open state. When the drying tank 12 is under negative pressure, the piston rod 231 extends, the push switch 33 loses its abutment, the drain valve closes, and the negative pressure environment of the drying tank 12 is maintained. In the later stage of drying, when the drying tank 12 is under normal pressure, the drain valve is reopened to drain water.

[0067] Please see Figure 3 and Figures 6-8 A support plate 25 is provided on one side (right side) of the sieve cylinder 24. The sieve cylinder 24 is formed by a flexible sieve mesh. Those skilled in the art can set the sieve mesh to have low rigidity, so that the sieve mesh can be wound and contracted. The fixed end 241 of the sieve mesh is fixedly connected to the support plate 25. The support plate 25 is provided with an Archimedean spiral structure (similar to a mosquito coil structure) guide groove 251. The movable end 242 of the sieve mesh is slidably disposed in the guide groove 251. The support plate 25 is provided with a limiting groove 252, which is set along the path of the guide groove 251. The limiting groove 252 is used to provide positioning and guidance for the movable end 242 of the sieve mesh to move along the guide groove 251. The end of the guide groove 251 is provided with a limiting block 253 that cooperates with the movable end 242 to limit the extreme position of the movable end 242 and prevent it from dislodging. The surface of the fixed end 241 that contacts the movable end 242 is a snap-fit ​​structure, so that the fixed end 241 can fix the movable end 242 of the screen in the initial state. The support plate 25 is provided with a drive unit for driving the movable end 242. The drive unit includes a winding roller 243 and a motor. The winding roller 243 is coaxially fixedly connected to the output shaft of the motor. The motor is electrically connected to the push switch 33. A steel cable 244 is fixedly provided on the winding roller 243. The free end of the steel cable 244 is fixedly connected to the movable end 242.

[0068] Specific working principle: After the carbide slag is fed into the screen cylinder 24, pressing the switch 33 controls the motor to start, thereby driving the winding roller 243 to rotate. This, through the coiled steel cable 244, drives the movable end 242 of the screen along the guide groove 251, causing the screen to contract inwards. This reduces the internal space of the screen cylinder 24, allowing the screen to squeeze the material, first squeezing out some of the moisture from the carbide slag, and then drying the material with hot air, resulting in faster drying. Because the screen contracts inwards, the screen holes overlap (see [reference]). Figure 7and Figure 8 This reduces the aperture of the sieve, preventing the calcium carbide slag from being squeezed out of the sieve during the drying process. In the later stages of drying, the calcium carbide slag needs to be screened. By controlling the sieve's shrinkage state, i.e., controlling the sieve's aperture, calcium carbide slag of suitable particle size can be selected.

[0069] The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. An apparatus for preparing silicate cement using low-carbon ash and carbide slag, comprising a crushing mechanism, a screening mechanism (2), a drying mechanism (1), a stirring mechanism, a rotary kiln, and a ball mill connected in sequence; characterized in that, The drying mechanism (1) includes: Rack (11); Drying tank (12), which is mounted on frame (11); A hot air blower, which is connected to the drying tank (12) via a pipe; A vacuum pump, which is connected to the drying tank (12) via a pipe; The screening mechanism (2) includes a support leg (21) and a bracket (22). One end of the support leg (21) is fixedly connected to the drying tank (12), and the other end is rotatably connected to the bracket (22). One end of the bracket (22) is provided with a cylinder (23), and the piston rod (231) of the cylinder (23) is rotatably connected to the bracket (22). A screen cylinder (24) is provided on the bracket (22), and the screen cylinder (24) is connected to a drive assembly for driving the screen cylinder (24) to rotate. The screening mechanism (2) is located inside the drying tank (12); the cylinder (23) includes a cylinder body (232) with an opening at the top and a piston (233) located inside the cylinder body (232). The piston (233) and the cylinder body (232) enclose a movable chamber (234). One end of the piston (233) is fixedly connected to the piston rod (231), and the other end of the piston rod (231) is rotatably connected to the support (22). A support plate (25) is provided on one side of the sieve cylinder (24). The sieve cylinder (24) is formed by a flexible sieve mesh. The fixed end (241) of the sieve mesh is fixedly connected to the support plate (25). The support plate (25) is provided with an Archimedean spiral structure guide groove (251). The movable end (242) of the sieve mesh is slidably disposed in the guide groove (251). The support plate (25) is provided with a drive unit for driving the movable end (242). The drive unit includes a winding roller (243) and a motor. The winding roller (243) is coaxially and fixedly connected to the output shaft of the motor. The motor is electrically connected to a push switch (33). A steel cable (244) is fixedly provided on the winding roller (243). The free end of the steel cable (244) is fixedly connected to the movable end (242).

2. The apparatus for preparing silicate cement using low-carbon ash and carbide slag according to claim 1, characterized in that: The screen cylinder (24) is provided with a receiving trough (3) below it. The receiving trough (3) is provided with a filter screen (31). The bottom of the receiving trough (3) is connected to a drain pipe (32) through a pipe. The water outlet of the drain pipe (32) is located outside the drying tank (12). The drain pipe (32) is provided with a drain valve. The drain valve is electrically connected to a push switch (33). The piston rod (231) is configured to cooperate with the push switch (33).

3. The apparatus for preparing silicate cement using low-carbon ash and carbide slag according to claim 1, characterized in that: The support plate (25) is provided with a limiting groove (252), which is set along the path of the guide groove (251); the end of the guide groove (251) is provided with a limiting block (253) that cooperates with the movable end (242); the surface of the fixed end (241) that contacts the movable end (242) is a snap-fit ​​structure.

4. A method for preparing silicate cement using low-carbon ash and carbide slag, comprising using an apparatus for preparing silicate cement using low-carbon ash and carbide slag as described in any one of claims 1-3, characterized in that, Includes the following steps: Step S10: Crush and screen the low-carbon ash and carbide slag to a size of 80 micrometers; Step S20: Drying the carbide slag. In the early drying stage, the drying temperature is 150-200℃, the drying time is 1-2 hours, and the negative pressure is -0.05 to -0.1MPa. In the later drying stage, the drying temperature is 100-120℃, the drying time is 1-2 hours, and the pressure is atmospheric pressure. Step S30: Mix the pretreated low-carbon ash and carbide slag with limestone and clayey raw materials in a certain proportion, and grind them into raw meal; Step S40: Calcine the raw materials in a rotary kiln at a temperature of 1300-1500℃ for 1-2 hours to obtain silicate cement clinker. Step S50: Cool the calcined clinker to room temperature, and then grind it together with desulfurized gypsum and mixed materials to obtain silicate cement.

5. The method for preparing silicate cement using low-carbon ash and carbide slag according to claim 4, characterized in that: In step S20, during the initial drying stage, the drying temperature is 180℃, the drying time is 1.5 hours, and the negative pressure is -0.08MPa; during the later drying stage, the drying temperature is 110℃, the drying time is 1.5 hours, and the pressure is atmospheric pressure.

6. The method for preparing silicate cement using low-carbon ash and carbide slag according to claim 4, characterized in that: In step S30, the calcareous raw material is limestone, and the clayey raw material is clay; the total weight ratio of low-carbon ash and carbide slag in the raw material is 30%-50%; in step S50, the amount of desulfurized gypsum added is 3-5% of the clinker weight, and the mixed material is slag or fly ash, with an addition amount of 10-20% of the clinker weight.

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