A high-temperature grinding device and method for improving red mud gelling activity

Abstract

The present invention discloses a high-temperature grinding device and method for improving the gelling activity of red mud. The high-temperature grinding device comprises a grinding cylinder and a grinding shaft arranged in the grinding cylinder. The grinding cylinder comprises an outer shell, a heat insulation layer, a heater and an inner shell arranged in sequence from the outside to the inside, and the heater heats the red mud through the inner shell; the grinding shaft is provided with a grinding sheet, the outer surface of the grinding sheet is provided with a metal protective layer, and the grinding sheets are arranged at varying angles from a fan shape to a circle along the axial direction of the grinding shaft, and the grinding sheets grind the material while heating the red mud; when the present invention grinds the red mud, the red mud is simultaneously heated and dried and ventilated and dried, thereby improving the gelling activity of the red mud. The high temperature further accelerates the chemical reaction rate, increases the speed of stimulating the gelling activity of the red mud, and the crushed red mud fine particles are more easily stimulated at high temperature, so that the properties of the final product are uniform.

Description

Technical Field

[0001] The invention relates to the technical field of comprehensive utilization of industrial waste residues and building materials, and in particular to a device and method for improving the gelling activity of red mud through high-temperature grinding. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art.

[0003] With the rapid development of the economy, the alumina industry, as one of the pillar industries of the economy, has become increasingly important. Red mud, as a waste residue produced by the alumina industry, has the characteristics of low activity and heavy pollution, and is mainly stored in the form of piles. Currently, the existing red mud waste stockpile exceeds 1.3 billion tons, with an annual increase of over 100 million tons, but the utilization rate is less than 10%, making it difficult to solve the problem of its comprehensive utilization, significantly affecting the environment and restricting the sustainable development of the economy and society. Although the main chemical composition of red mud varies from place to place, its main components are Fe2O3, SiO2, CaO, Al2O3, etc., which have potential gelling activity.

[0004] The use of red mud as raw material to activate and then prepare red mud-based cementitious materials, filling materials, etc. meets the development needs of the environmental protection industry and the green construction industry, and is an inevitable requirement of "ecological civilization" and the society's "green development, circular development, and low-carbon development."

[0005] To process and utilize red mud, improving its gelling activity is a primary goal. Currently, methods for improving red mud gelling activity use a single grinding and heating device. In devices that heat first, then grind, the red mud enters the device and is heated in an oven, resulting in uneven heating and inconsistent activation properties. Small, well-heated red mud particles exhibit stronger gelling activity, while large, unevenly heated particles exhibit weaker gelling activity, impacting the quality of the final product. In devices that grind first, then heat, the red mud has a higher water content, resulting in incomplete grinding upon entry, causing adhesion between red mud particles and failing to effectively alter the physical and chemical properties of the fine red mud particles. Summary of the Invention

[0006] In response to the problems existing in the prior art, the present invention provides a high-temperature grinding device and method for improving the gelling activity of red mud. The device can grind the red mud while heating it, thereby improving the physical and chemical properties of the red mud, thereby improving the gelling activity of the red mud and converting the red mud into a new type of gelling material.

[0007] The technical solutions of the present invention are as follows:

[0008] In a first aspect of the present invention, a high-temperature grinding device for improving the gelling activity of red mud is provided, comprising a grinding cylinder and a grinding shaft arranged in the grinding cylinder, wherein the grinding cylinder comprises an outer shell, a heat insulating layer, a heater and an inner shell arranged in sequence from the outside to the inside, and the heater heats the red mud through the inner shell; the grinding shaft is provided with a grinding sheet, the outer surface of the grinding sheet is provided with a metal protective layer, and the grinding sheets are arranged along the axial direction of the grinding shaft at varying angles from fan-shaped to circular, so that the material is fully ground while heating the red mud.

[0009] In some embodiments of the present invention, a connecting piece is provided on the inner diameter of the grinding sheet, and the grinding sheet is mounted on the grinding shaft via the connecting piece.

[0010] In some embodiments of the present invention, a ventilation cavity is formed between the inner side surface of the grinding sheet and the outer diameter of the grinding shaft.

[0011] In some embodiments of the present invention, both ends of the grinding cylinder are blocked by two heat insulation plates.

[0012] In some embodiments of the present invention, a circular hole for the grinding shaft to pass through is provided at the center of each of the two insulation plates, a feed port is provided on one of the insulation plates, and a discharge port is provided on the other insulation plate.

[0013] In some embodiments of the present invention, a fan is provided on the grinding shaft, and the fan is located outside the grinding cylinder and is provided on a side close to the heat insulation board with the feed inlet.

[0014] In some embodiments of the present invention, the feed port is connected to a feed pipe, and two rollers are provided at the feed end of the feed pipe, and the two rollers rotate towards each other under the drive of a motor.

[0015] In some embodiments of the present invention, the heater is an annular heating tube group coiled on the outside of the inner shell, and the inner shell is a steel cylinder.

[0016] In some embodiments of the present invention, the angle of the grinding sheet increases at equal angles along the advancing direction of the red mud.

[0017] In a second aspect of the present invention, a method for improving the gelling activity of red mud is provided, comprising grinding the red mud with a grinding sheet while heating the red mud with a heater to perform a secondary sintering on the red mud to stimulate its potential gelling activity; the grinding sheet grinds the coarse particles of red mud to break the inert film that may be attached to the outside of the large pieces of red mud, thereby further improving the gelling activity of the red mud.

[0018] One or more technical solutions of the present invention have the following beneficial effects:

[0019] (1) The high-temperature grinding device provided by the present invention combines an oven with a grinder, which can heat the red mud while grinding it, thereby improving the physical and chemical properties of the red mud and enhancing the gelling activity of the red mud, shortening the industrial production process and improving efficiency.

[0020] (2) In the high-temperature grinding device provided by the present invention, the grinding discs are arranged on the grinding shaft at angles varying from fan-shaped to circular, which can adapt to red mud with different physical and chemical properties in different regions, improve the grinding efficiency, and save electricity; at the same time, by providing a metal protective layer on the grinding discs, fine red mud particles can be adsorbed during the grinding process, thereby changing the physical and chemical properties of the red mud and better stimulating the gelling activity of the well-heated red mud particles.

[0021] (3) In the high-temperature grinding device provided by the present invention, a ventilation cavity is formed between the grinding shaft and the grinding disc. Driven by a fan, dry air can enter the high-temperature grinding cylinder through the ventilation cavity, and water vapor can be discharged from the grinding cylinder, thereby achieving rapid drying of red mud.

[0022] (4) The high-temperature grinding device provided by the present invention uses rollers to accelerate the speed of adding red mud raw materials, and adjusts the inclination angle of the high-temperature grinding cylinder by adjusting the bracket, thereby solving the problem of red mud blocking the pipeline and damaging the grinder, and improving the safety of the device.

[0023] (5) The high-temperature grinding device provided by the present invention heats and dries the red mud while grinding it, and simultaneously ventilates and dries it, thereby improving the gelling activity of the red mud. The high temperature further accelerates the chemical reaction rate and increases the rate of activation of the red mud gelling activity. The crushed red mud fine particles are more easily activated at high temperatures, making the properties of the final product uniform and consistent, and the gelling activity is thoroughly activated, thereby increasing the gelling activity by 60-80%. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is an overall perspective view of the high-temperature grinding device of the present invention;

[0025] Figure 2 is a perspective view of a high temperature grinding apparatus according to the present invention;

[0026] Figure 3 is a cross-sectional view of a high-temperature grinding device according to the present invention;

[0027] Figure 4 is an axial view of the high temperature grinding device of the present invention;

[0028] Figure 5 Schematic diagram of the grinding shaft structure with grinding sheets of the high-temperature grinding device of the present invention;

[0029] Figure 6 This is a schematic structural diagram of the feed port of the high-temperature grinding device of the present invention;

[0030] Figure 7 Schematic diagram of the structure of a 120° sector-shaped abrasive sheet (single) of the present invention;

[0031] Figure 8 It is a structural schematic diagram of the grinding shaft of the present invention.

[0032] In the figure: 1- bracket, 2- high-temperature grinding cylinder, 3- baffle, 4- fan, 5- fan protection cover, 6- discharge port pipe, 7- grinding shaft, 8- first bearing, 9- feed port pipe, 10- control box, 11- motor, 12- second bearing, 21- heater, 22- first heat insulation board, 23- second heat insulation board, 24- steel cylinder, 25- heat insulation cylinder, 26- shell, 71- grinding sheet, 72- ventilation chamber, 73- connecting sheet, 74- retractable block; 75, long hole; 76, disassembly hole; 77, pin; 91- roller, 92- linkage motor. DETAILED DESCRIPTION

[0033] The present invention will be described below with reference to the accompanying drawings.

[0034] Example 1

[0035] In a typical embodiment of the present invention, a high temperature grinding device for improving the gelling activity of red mud is proposed, such as Figure 1-3 As shown, it includes a high-temperature grinding cylinder 2 and a grinding shaft 7 arranged in the high-temperature grinding cylinder 2. The grinding shaft 7 can rotate along a fixed axis in the high-temperature grinding cylinder 2 under the drive of the motor 11, and can grind the red mud into fine particles of uniform size. Specifically, the high-temperature grinding cylinder 2 serves as a grinding chamber for the red mud and is arranged on a bracket 1. The bracket 1 provides support for the entire device, as shown in FIG. Figure 4 As shown, the high-temperature grinding cylinder 2 includes an outer shell 26, an insulation layer, a heater 21 and an inner shell arranged in sequence from the outside to the inside. The two ends of the high-temperature grinding cylinder 2 are blocked by two insulation plates, specifically including a first insulation plate 22 and a second insulation plate 23. The center positions of the first insulation plate 22 and the second insulation plate 23 are both provided with circular holes for the grinding shaft 7 to pass through, wherein the first insulation plate 22 is provided with a feed port, and the second insulation plate 23 is provided with a discharge port.

[0036] like Figure 5As shown, the grinding shaft 7 is provided with a grinding sheet 71, and the outer surface of the grinding sheet 71 is provided with a metal protective layer. The grinding sheet 71 is arranged at different angles from arc to circle along the axial direction of the grinding shaft. The angle of the grinding sheet 71 increases at different angles along the forward direction of the red mud, that is, the angle of the grinding sheet close to the feed port is the smallest, and the grinding sheet close to the discharge port is circular, that is, 360°. The circular grinding sheet is tightly connected to the grinding shaft to prevent insufficiently ground red mud from being discharged from the discharge port through the ventilation cavity. Specifically, it can be fixed by welding.

[0037] Furthermore, one ends of the plurality of grinding plates are aligned so that the other ends of the plurality of grinding plates are distributed in a stepped manner, and the grinding efficiency of the grinding plates on red mud is improved by the stepped structure.

[0038] In this embodiment, a plurality of grinding plates are provided, and adjacent grinding plates are tightly fitted with no gaps. The red mud raw material enters from the feed port, is gradually ground by the grinding plates and is discharged from the discharge port. During the process, the red mud is ground between the outer contour of the grinding plate and the inner wall of the grinding chamber. If there are gaps between the grinding plates, the ground red mud will accumulate in the gaps between the grinding plates, which will not only affect the grinding process, but also easily damage the grinding shaft, leading to grinding failures. By setting the grinding plates as single-piece grinding plates with gradually increasing angles, a specific grinding plate can be replaced and adjusted, avoiding the waste of materials and costs caused by overall replacement.

[0039] In a specific embodiment of this embodiment, there are 15 grinding discs in total, and the angle is fan-shaped from 120°. With each additional grinding disc, the fan-shaped angle increases by 16°, and the last grinding disc is 360°. The grinding discs increase at equal angles from fan-shaped to circular, which can increase the cavity between the grinding cylinder and the grinding discs. Compared with other structures, the grinding efficiency of red mud is improved. For example, the use of cylindrical grinding discs will cause the red mud entering from the feed port to accumulate between the grinding discs and the narrow gap between the grinding discs and the inner wall of the grinding chamber, and the grinding efficiency is low in this case. The setting of grinding discs with increasing angles can form a larger cavity. The red mud accumulates in the cavity. As the grinding and blasting process proceeds, the red mud will move toward the discharge port. The red mud in the large cavity will also continue to be transferred to the narrow gap between the grinding discs and the inner wall for grinding, which can greatly improve the grinding efficiency and the integrity of the grinding process. In addition, this design maximizes the contact area between the red mud and the grinding discs, improving the grinding efficiency.

[0040] In this embodiment, the feed port is connected to the feed pipe, and the discharge port is connected to the discharge pipe. Both the feed pipe and the discharge pipe are L-shaped structures, wherein the feed end of the feed pipe is set upward, and the discharge end of the discharge pipe is set downward. The feed end is a large square opening to facilitate the addition of red mud raw materials. Small holes are opened on both sides of the feed end to install rollers; Figure 6As shown, two rollers 91 are provided at the feed end, which are connected to the small hole at the feed end and are connected to a linkage motor 92 at one end. The two rollers 91 rotate towards each other under the drive of the linkage motor 92, and the feed speed can be adjusted to improve the grinding efficiency.

[0041] The uniformly rotating roller avoids the problem that the red mud raw material cannot enter the high-temperature grinding cylinder by its own gravity, and solves the problem of blockage of the feed port. The roller can pre-crush the large adhesive blocks in the red mud raw material, reducing the wear of the grinding shaft. The bracket is retractable and the inclination angle of the high-temperature grinding cylinder can be adjusted to speed up or slow down the grinding speed of the red mud raw material, making the grinding time controllable.

[0042] In this embodiment, the insulation layer adopts an insulation tube 25, which is located between the heater 21 and the outer shell 26, and can reduce heat dissipation; the inner shell adopts a steel cylinder 25, and a cavity is formed between the steel cylinder 25 and the grinding shaft 7, which can accommodate red mud and rotate together with the grinding shaft for grinding; the heater 21 is located inside the high-temperature grinding cylinder 2, between the steel cylinder 24 and the insulation tube 25, and the heater 21 adopts an annular heating tube group, through which heat can be conducted to the inside of the steel cylinder 24 to heat the red mud.

[0043] Furthermore, the insulation materials of the insulation cylinder 25, the first insulation board 22 and the second insulation board 23 are made of composite thermal insulation materials; wherein, the shell 28 is located at the outermost side of the high-temperature grinding cylinder, which can protect the high-temperature insulation cylinder from contamination.

[0044] In this embodiment, the metal protective layer on the grinding sheet is a high-temperature resistant ceramic wear-resistant coating, which is obtained by compounding high-performance wear-resistant ceramic particles with modified toughened heat-resistant resin.

[0045] Furthermore, a circular hole is left in the center of the grinding sheet, and the diameter of the circular hole of the grinding sheet 71 is larger than the diameter of the grinding shaft 7. The grinding sheet 71 is detachably arranged on the grinding shaft 7, and the type of the grinding sheet 71 can be replaced to adapt to red mud waste of different properties. Figure 7 As shown, the grinding sheet 71 and the connecting sheet 73 are a whole, the connecting sheet is conical, and retractable blocks 74 are symmetrically arranged on the two sides of the connecting sheet. The retractable blocks 74 can be retracted inside the connecting sheet under external pressure, and protrude outside the connecting sheet when there is no external pressure. This part of the structure adopts the existing structure, such as a spring component can be set in the connecting sheet to achieve the above function.

[0046] The upper surface of the retractable block is arc-shaped and can fit with the inner wall surface of the grinding shaft, and there is a certain distance between the upper surface of the retractable block and the inner arc surface of the grinding sheet, so that a ventilation cavity 72 is formed between the outer surface of the grinding shaft and the inner arc surface of the grinding sheet to allow air to circulate.

[0047] The positions of the connecting pieces of the multiple grinding sheets are arranged in a straight line. The connecting piece 73 can be tightly connected to the grinding shaft 7 in an embedded form as a whole. When the grinding shaft 7 rotates, the grinding sheet 71 will be driven to rotate at the same time through the connecting piece 73.

[0048] The structure of the grinding shaft 7 is as follows Figure 8 As described, a long hole 75 is provided on the grinding shaft for installing a connecting piece. The radial width of the long hole is the same as the distance between the retractable blocks on both sides of the connecting piece. The connecting piece cannot completely enter the grinding shaft, so that the inner arc wall of the grinding piece and the outer wall of the grinding shaft are separated by a certain distance to form a ventilation cavity. A disassembly hole 76 is provided at one end of the long hole. The disassembly hole is connected to the long hole. The radial width of the disassembly hole is the sum of the radial width of the long hole and the width of the two retractable blocks, so that when the two retractable blocks protrude from the connecting piece, they can be pulled out of the disassembly hole.

[0049] The specific installation and removal method of the grinding sheet is as follows: the connecting piece on the grinding sheet can be directly installed in the designated position through the elongated hole. During the installation process, the retractable blocks on both sides of the connecting piece retract into the connecting piece under the pressure of the grinding shaft wall. When the retractable blocks fully enter the grinding shaft, they return to their original position and adhere to the inner wall of the grinding shaft, thus fixing the grinding sheet to the grinding shaft. Positioning pins 77 are provided on both sides of the circumferential direction of the removal hole to prevent the connecting piece from moving into the removal hole. During removal, after removing the positioning pins, each grinding sheet can be slid into the removal hole and pulled out of the grinding shaft.

[0050] As an alternative, the retractable stopper and the connecting piece can be provided as an integral structure. When installing, they are inserted into the disassembly hole and slid to the designated position. When disassembling, they are slid to the disassembly holes in turn to pull out the grinding piece.

[0051] The grinding shaft 7 is equipped with a fan 4, located outside the high-temperature grinding cylinder and near the heat shield with the feed port. The diameter of the circular hole at the center of the first and second heat shields 22 and 23 is larger than the diameter of the grinding shaft. Dry air can enter the grinding cylinder through the cavity between the grinding shaft and the grinding disc, and the gap between the grinding disc and the grinding cylinder, while water vapor is expelled from the grinding cylinder, achieving rapid drying of the red mud. The fan is operated by an independent small motor.

[0052] Furthermore, a fan protection cover 5 is provided on the outside of the fan, and the fan protection cover 5 is connected to the outer shell 26 of the high-temperature grinding cylinder 2 .

[0053] In this embodiment, the grinding shaft 7 is mounted on the bracket 1 through a first bearing 8 and a second bearing 12 , and one end of the grinding shaft 7 is connected to a motor 11 and rotates under the drive of the motor 11 .

[0054] In this embodiment, the bracket 1 can be extended and retracted, and the inclination height of the high-temperature grinding cylinder 2 can be adjusted, so as to speed up / slow down the grinding speed of the red mud raw material and make the grinding time controllable. The control box 10 is set on the baffle 3 on the bracket 1 to control the operation of the device.

[0055] The method of using the high temperature grinding device provided in this embodiment is as follows:

[0056] Power the motor to start the grinding shaft rotating.

[0057] Turn on the heater to preheat the steel cylinder.

[0058] In a specific embodiment, the motor 11 and the linked motor 92 are turned on, the drum 91 rotates in opposite directions at a uniform speed, the fan 4 rotates at a speed of 10 revolutions per second, and the preheating temperature of the heater 21 is set to 300 degrees Celsius. After the temperature reaches the required level, the red mud raw material is added from the feed port 9, the drum 91 rotates faster, the red mud raw material is added at a higher speed, and the red mud raw material enters the steel cylinder 24 of the high-temperature grinding cylinder 2 through a pipeline. The grinding shaft 7 rotates at a uniform speed. After 12 minutes, the activated red mud is discharged from the discharge port 6 through grinding and heating, thereby increasing the gelling activity by 60%-70%.

[0059] The working principle of the high temperature grinding device provided in this embodiment is as follows:

[0060] When red mud waste is fed into the feed port, the waste slag fills the steel cylinder through the arc-shaped grinding discs. Part of the red mud will enter between the steel cylinder and the grinding shaft under the action of pressure, and will be ground into fine particles. During the grinding process, the heater group transfers heat to the red mud fine particles through the steel cylinder, raising the temperature of the red mud and subjecting it to high-temperature secondary sintering to stimulate its potential gelling activity. In addition, when the grinding shaft rotates, the red mud particles will be ground by the grinding discs on the grinding shaft, thereby changing their physical and chemical properties during the grinding process and achieving an increase in their gelling activity. Finally, they enter the finished product tank through the discharge port.

[0061] In this embodiment, the red mud is first preheated before entering the device, and the water content will be reduced. The grinding disc destroys the inert film on the surface of the red mud fine particles, and the high temperature reconstructs the physical and chemical properties of the red mud, thereby improving the gelling activity of the red mud. The high temperature further accelerates the chemical reaction rate and increases the speed of stimulating the gelling activity of the red mud. The crushed red mud fine particles are more easily stimulated at high temperature, making the properties of the final product uniform and consistent, and the gelling activity is thoroughly stimulated, increasing the gelling activity by 60-70%.

[0062] Example 2

[0063] A method for improving the gelling activity of red mud, wherein a grinding disc grinds the red mud while a heater heats the red mud. The grinding disc destroys the inert film on the surface of the fine red mud particles and stimulates the gelling activity of the red mud through high-temperature reconstruction, thereby improving the gelling activity of the red mud.

[0064] The embodiments described above provide a detailed description of the technical solutions of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, supplements or similar substitutions made within the scope of the principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high-temperature grinding device for improving the gelling activity of red mud, characterized in that: The invention comprises a grinding cylinder and a grinding shaft arranged in the grinding cylinder. The grinding cylinder comprises an outer shell, a heat insulating layer, a heater and an inner shell arranged in sequence from the outside to the inside. The heater heats the red mud through the inner shell. The grinding shaft is provided with a grinding sheet, and the outer surface of the grinding sheet is provided with a metal protective layer. The grinding sheets are arranged along the axial direction of the grinding shaft at varying angles from fan-shaped to circular, so that the material is fully ground while heating the red mud.

2. The high-temperature grinding device for improving the gelling activity of red mud according to claim 1, characterized in that: A connecting piece is provided on the inner diameter of the grinding piece, and the grinding piece is mounted on the grinding shaft through the connecting piece.

3. The high-temperature grinding device for improving the gelling activity of red mud according to claim 2, characterized in that: A ventilation cavity is formed between the inner side surface of the grinding sheet and the outer diameter of the grinding shaft.

4. The high-temperature grinding device for improving the gelling activity of red mud according to claim 1, characterized in that: Both ends of the grinding cylinder are sealed by two heat insulation plates.

5. The high-temperature grinding device for improving the gelling activity of red mud according to claim 4, characterized in that: A circular hole for the grinding shaft to pass through is provided at the center of each of the two heat insulation plates, a feed port is provided on one of the heat insulation plates, and a discharge port is provided on the other heat insulation plate.

6. The high-temperature grinding device for improving the gelling activity of red mud according to claim 5, characterized in that: The grinding shaft is provided with a fan, which is located outside the grinding cylinder and is arranged on a side close to the heat insulation board with the feed inlet.

7. The high-temperature grinding device for improving the gelling activity of red mud according to claim 5, characterized in that: The feed port is connected to a feed pipe, and two rollers are provided at the feed end of the feed pipe. The two rollers rotate towards each other under the drive of a motor.

8. The high-temperature grinding device for improving the gelling activity of red mud according to claim 1, characterized in that: The heater adopts an annular heating tube group, which is coiled on the outside of the inner shell, and the inner shell adopts a steel cylinder.

9. The high-temperature grinding device for improving the gelling activity of red mud according to claim 1, characterized in that: The angle of the grinding sheet increases at equal angles along the advancing direction of the red mud.

10. A method for improving the gelling activity of red mud, which is achieved by using the high-temperature grinding device according to any one of claims 1 to 9, characterized in that: While the grinding disc grinds the red mud, the heater heats the red mud and performs secondary sintering on the red mud to stimulate its potential gelling activity; the grinding disc grinds the coarse particles of red mud into fine particles, destroying the inert film that may be attached to the outside of the large pieces of red mud, and further improving the gelling activity of the red mud.

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