CN113680460B - Sand powder roller mill for high-efficiency preparation of waste concrete recycled sand powder and using method thereof - Google Patents

Abstract

The invention discloses a sand powder roller mill for efficiently preparing waste concrete recycled sand powder and a using method thereof.A waste concrete sand-slurry particle heating and feeding device heats sand-slurry particles before grinding and regulates and controls the throughput of sand powder to carry out continuous feeding; the waste concrete sand-slurry particle stripping and shaping mechanism selectively crushes material layers of the heated waste concrete sand-slurry particle groups, phase splitting and stripping are carried out on the cement slurry wrapped on the surface of sand particles, then the granular cement slurry is grinded into fine powder, the protruded edges and corners on the sand particles are grinded, and the regenerated coarse sand, the regenerated medium sand, the regenerated fine sand and the regenerated fine powder are sorted out through screening. The invention is of a totally enclosed structure, operates under micro negative pressure, and has no dust during the production process; the intelligent production equipment can be realized, the large-scale production is facilitated, the production energy consumption is reduced, and the economic benefit of enterprises is improved.

Description

Sand powder roller mill for high-efficiency preparation of waste concrete recycled sand powder and using method thereof

technical field

The invention relates to the technical field of building solid waste regeneration and recycling, in particular to a sand powder roller mill for efficient preparation of waste concrete recycled sand powder and a method for using the same.

Background technique

my country is actively promoting the recycling of waste concrete and has achieved certain results. However, in the past, the recycling of waste concrete focused on recycled aggregates. The technology and equipment for crushing and screening waste concrete to process coarse and fine aggregates have been relatively mature and have been recognized. The process is mainly two-stage crushing and one-stage shaping. Jaw or gyratory crushers are mainly used for primary crushing, cone or impact crushers are mainly used for secondary crushing, and vertical shaft impact crushers are used for shaping machines. The by-products produced in the processing process-poor gradation of recycled sand, poor sphericity, many edges and corners, rough surface, and hardened cement mortar in the components, the recycled concrete prepared by using it has a large water consumption, low strength, and low elastic modulus. Moreover, the durability properties such as impermeability, frost resistance, carbonation resistance, shrinkage, creep and chloride ion penetration resistance are all lower than ordinary concrete, and waste concrete blocks produce a large number of microcracks inside due to damage accumulation during the crushing process. As a result, regenerated sand itself has large porosity, high water absorption, low bulk density, and high crushing index value, and its performance is obviously inferior to natural sand; the by-product produced in the processing process-regenerated micropowder has large fluctuations in composition, low activity, and difficult dispersion. It has not been effectively utilized in the concrete industry. At present, recycled sand powder is mainly used for roadbed backfill, filling materials, concrete bricks, blocks, etc., which is simple and extensive, and is essentially a waste of resources.

With the continuous deepening and development of the research on the recycling of waste concrete, about 30-40% of the waste concrete sand powder produced in the process of crushing and processing recycled aggregates has not been effectively utilized due to its low quality. Focusing on the recycling of all components of waste concrete, some crushing, grinding and sorting processes and equipment are introduced from ore processing, cement grinding and other industries, such as the impact and hammer crushing used by Hazemag in Germany for waste concrete crushing The ultra-fine crushing cone crusher of Babbitless in France and the top horizontal bar cone crusher of Kurimoto Iron Works in Japan are mainly used for fine crushing sand making. The existing equipment is still mainly suitable for impact/counter-attack crushing of homogeneous materials, resulting in a large number of micro-cracks in the aggregate, low activity of recycled sand powder, strong water absorption of recycled sand powder, low aggregate strength, and serious environmental pollution. Problems, technical innovation and equipment function improvement have not been carried out from the perspective of effective separation of waste concrete components. At the same time, part of the residual cement slurry is wrapped on the surface of recycled sand powder, resulting in high water absorption rate, poor gradation, low density of recycled sand, low activity of recycled micropowder, and poor product quality. equipment.

In recent years, with the vigorous development of my country's construction industry, the demand for building materials has increased dramatically. In concrete raw materials, aggregate accounts for about 75% of the total amount of concrete, and the source of aggregate is mainly to excavate rocks from mountains, which are processed into sand and gravel, or directly excavated sand, pebbles and gravel from the river, which damages the natural environment. Serious destruction. In addition, the distribution of natural sand and gravel resources in my country is uneven, and sand and gravel are extremely scarce in some areas. Therefore, with the country's emphasis on environmental protection and urban mineral resources, the recycling of waste concrete sand powder will be an important part of the layout of urban mineral resources. It is urgent to develop a high-efficiency preparation technology and equipment for waste concrete recycled sand powder to realize Green, energy-saving, and large-scale production can not only promote the full-component, high-quality utilization of waste concrete, but also effectively alleviate the shortage of sand and mineral admixture resources for construction projects, which meets the major needs of the country's sustainable development.

As a high-efficiency and energy-saving material layer grinding equipment, the vertical mill is widely used in cement, electric power, non-mining and other industries and industrial waste treatment. After the extrusion force, the particles are crushed by extrusion and shear force between the particles, and the material is ground many times during the rolling process of the grinding roller, the roundness of the particles is better, and the crushing and grinding energy utilization efficiency of the vertical mill is high Because of the crushing of the material layer of the cone crusher and higher than the single particle crushing of the ball mill, the vertical mill is widely accepted and used as a grinding equipment to produce fine powder. However, as a more efficient and energy-saving grinding equipment, it is feasible to efficiently prepare high-quality recycled sand powder from waste concrete. It is feasible to analyze the principle of selective crushing of the material layer. It is necessary to innovate the original vertical mill in principle and in terms of structure. In terms of function and function, innovative design is planned to solve the problem of poor gradation of regenerated sand, poor sphericity, large amount of hardened cement paste on the surface, large porosity, high water absorption, low bulk density, high crushing index value and fluctuations in the composition of regenerated fine powder. Large, low activity, difficult to disperse and other problems.

Contents of the invention

The purpose of the present invention is to make up for the defects of the prior art, to provide a sand powder roller mill for the efficient preparation of waste concrete recycled sand powder and its use method, to replace the traditional crushing methods (such as jaw breaking, impact breaking, vertical shaft impact breaking, Cone crusher, roller crusher, ball mill, etc.), the equipment can realize large-scale production of high-quality regenerated sand and high-activity regenerated micropowder. It has the advantages of high stability, low energy consumption, and long life. The demand for engineering sand can also replace some mineral admixtures, alleviate the shortage of natural river sand and mineral admixture resources, and improve the recycling level of waste concrete resources.

The invention makes full use of the differences in physical properties such as hardness, brittleness, grindability, and thermal expansion coefficient caused by the surface of sand powder wrapped with cement slurry. According to the bond strength of the sand-slurry interface, based on the principle of selective crushing of the material layer under the action of a multi-dimensional force field, heating is used. , crushing, peeling, grinding, shaping, breaking up and other methods, heating the cement paste wrapped on the sand surface to dehydrate, embrittle, and produce cracks; the extrusion force is directly applied to the material particles, because the crushing force is between the materials The bulk material is directly crushed, and the finely crushed material is squeezed to form a material bed for crushing between particle groups; further applying extrusion force and shear force to the compacted material layer, the hardness of the particle group in the material layer The low-grade material is crushed first, and the hardest material forms reclaimed sand; then the friction force is applied to the peeled particle group to carry out grinding and shaping, so as to realize the efficient peeling of waste concrete sand-slurry particles, and the sand-slurry peeling efficiency reaches 90%. Above, increase the apparent density of reclaimed sand, reduce the water absorption rate of reclaimed sand, and improve the quality of reclaimed sand and regenerated micropowder.

The present invention is achieved through the following technical solutions:

A sand powder roller mill for high-efficiency preparation of waste concrete recycled sand powder, including a waste concrete sand-slurry particle heating and feeding device, and a waste concrete sand-slurry particle stripping and shaping mechanism;

The waste concrete sand-slurry particle heating and feeding device heats the sand-slurry particles before entering the mill, and controls the throughput of sand powder for continuous feeding;

The waste concrete sand-slurry particle peeling and shaping mechanism performs selective material layer crushing on the heated waste concrete sand-slurry particle group, phase-separates and peels the cement paste wrapped on the surface of the sand particles, and then separates the particles The shaped cement paste is ground into fine powder, and the protruding corners and edges of the sand grains are ground off, and the regenerated coarse sand, regenerated medium sand, regenerated fine sand and regenerated fine powder are sorted out through screening.

The waste concrete sand-slurry particle heating and feeding device includes a reverse baffle high-efficiency heater and a feeder, and the reverse baffle high-efficiency heater is located above the feeder and connected by a flange;

The reverse baffle high-efficiency heater includes a heating chamber shell, a bulk material stepped grate plate, a movable baffle plate and an insulating layer; the top of the heating chamber shell is provided with a feeding port and an air outlet, There is a material collection hopper at the bottom, and an inclined air inlet in the middle. The two connecting lines between the feeding inlet and the collecting hopper, the air inlet and the center of the air outlet are distributed in an X shape; the multiple bulk material ladders The grate plates are evenly arranged from top to bottom below the feeding port and close to the air inlet side of the heating chamber shell, and each bulk material stepped grate plate has a certain angle with the horizontal plane, and is connected to the heating chamber shell by a plug-in method; The mobile baffles are arranged below the air outlet, and consist of multiple baffles that are evenly distributed from top to bottom and integrated with the side panels on both sides. Each baffle has a certain angle with the horizontal plane, and the inclination direction The stepped grate plates for bulk materials are opposite and correspond to each other at an angle of 75°-105°. The side plates on both sides are connected with multiple sets of horizontal groove holes on the heating chamber shell through bolts; the insulation layer is laid on the heating chamber shell. outside the body;

The feeder includes a feeding pipe, a feeding pipe and an adjusting bolt; the feeding pipe is arranged under the collecting hopper of the heating chamber shell and is connected by a flange; the feeding pipe is set on the feeding The lower part of the pipe is connected with the flange through a plurality of said adjusting bolts.

The waste concrete sand-slurry particle stripping and shaping mechanism includes an integral base, a main transmission device, a frame, a lower casing, a grinding disc, a plurality of grinding rollers, a transmission arm, a pressurizing device, a limiting device and an upper casing .

The integral base includes a main reducer base and a frame base, two of which are connected by bolts or welded as a whole; the integral base is located on the concrete foundation, and is fixed by grouting embedded in the foundation hole with anchor bolts;

The main transmission device includes a main motor base, a main motor, a shaft coupling, a main reducer and a frequency converter. The main motor base is located on a concrete foundation, and is fixed by grouting embedded in the foundation hole with anchor bolts; The main motor described above is installed on the base of the main motor, and the output shaft of the main motor is axially connected with the input shaft of the main reducer through a coupling in the horizontal direction; the described main reducer is located on the base of the main reducer, and the The vertical output thrust plate of the main reducer is connected to the lower plane of the grinding plate through a flange; the frequency converter is connected to the main motor through a cable.

There are at least three frames, and the frames are located on the base of the frame and fixed on the concrete foundation through anchor bolts; the lower shell is located on the upper plane of the frame, and the legs of the lower shell are connected with The upper plane of the frame is connected, and the bottom of the lower casing is provided with an annular groove with an upward notch; a discharge port is arranged on the bottom surface of the annular groove of the lower casing.

The grinding disc includes a disc seat, a lining plate, a moving cone, a retaining ring, a scraper frame and a scraper plate, and the grinding disc is located above the annular groove in the lower casing and the output thrust disc of the main reducer; the disc seat It is a rotating body, and the inner concave surface of the upper part of the disc base is fixed with a plurality of wear-resistant lining plates with low inside and high outside. The wear-resistant lining plates surround a disc-shaped grinding track, and the lower part of the disc base passes through the bottom of the lower shell. The annular hole enclosed by the annular groove, the bottom surface of the lower part of the disc seat is fixedly connected with the output thrust disc of the main reducer; the movable cone is located on the upper side of the disc seat, and is fixedly connected with the outer convex surface of the upper part of the disc seat. The movable cone is integral or divided. Body type, the cone angle of the moving cone is 30°-60°, and the surface is compounded with a wear-resistant lining. The retaining ring is located on the upper plane of the moving cone and connected with the moving cone; the scraper is located on the upper part of the disc seat Below the lower plane, and fixedly connected with the disc base, the plurality of scraper plates are connected with the scraper frame; the feeder is located above the grinding disc.

Each of the grinding rollers is located above the grinding disc, and the inclination angle between the axial centerline of each grinding roller and the horizontal plane is not more than 12°, and each grinding roller is arranged at an equal angle and equidistant from each other on the horizontal plane; one end of the grinding rollers The grinding body roller cover is fixed, the grinding surface of the roller cover is arc-shaped, and the arc-shaped outer surface is compounded with a wear-resistant lining; the other end of the grinding roller is fixedly connected with the transmission arm; the grinding roller The total projected area on the grinding disc is 60-70% of the area of the grinding track;

The transmission arm is installed on the upper plane of the frame, and includes a rocker arm, a boom, a cross shaft, a bearing seat, a bearing and a thrust device, and the rocker arm and the boom are connected by a cross shaft and a pin, and the cross shaft The shaft is supported on the bearing seat by two bearings, and the bearing seat is connected with the upper plane of the frame and the legs of the lower housing as a whole. A part of the thrust device is fixed on one end surface of the horizontal shaft, and a part is fixed on one end of the bearing seat. end face;

The pressurizing device includes an oil cylinder, a pressurized base, a hydraulic system, an accumulator and a pipeline. The pressurizing device is located under the transmission arm, and the head earring of the oil cylinder passes through the pin shaft and the lower hole of the boom. connected, the cylinder body of the oil cylinder is connected with the pressurized base through a pin shaft, the pressurized base is located on the frame base, and is fixed on the concrete foundation through anchor bolts, and the hydraulic system is pressurized The oil circuit is connected with the rod cavity of the oil cylinder through the accumulator and the pipeline, and the oil circuit of the lifting roller is connected with the rodless cavity of the oil cylinder through the pipeline;

The limiting device is located on the outside of the boom and installed on the vertical plate inside the frame, and multiple sets of disc springs are arranged in the limiting device;

The upper casing includes a casing, a grinding roller door, a cover plate and a fixed cone. The casing is located above the lower casing, is cylindrical, and is connected with the lower casing. The casing is provided with a The grinding roller door can be turned in and out freely. The cover plate is located above the shell and connected with the shell to support the reverse baffle high-efficiency heater and feeder. The cover plate is provided with an outlet Tuyere 2: The fixed cone is set at the lower part of the upper shell and surrounds the movable cone of the grinding table. The fixed cone is split and its position can be adjusted up and down. The distance between the sections of each split fixed cone is 40mm-80mm. The grinding surface of the fixed cone is compounded with a wear-resistant lining.

In the main transmission device, the rotating speed of the grinding disc is controlled by adjusting the operating frequency of the main motor through a frequency converter; the height of the retaining ring is 5-40mm and adjustable, and the residence time of waste concrete sand powder on the grinding disc is controlled. Reach 30-60 seconds.

A method for using a sand powder roller mill for efficient preparation of waste concrete recycled sand powder, specifically comprising the following steps:

Step 1. Heating and feeding: Introduce hot air at 100°C to 300°C into the air inlet of the reverse baffle high-efficiency heater, and the crushed waste concrete sand-slurry particles enter the heating chamber from top to bottom In the shell, it is evenly distributed on the stepped grate plate of the bulk material, and the hot air is introduced from the hot blast furnace into the heating chamber shell from bottom to top, and the sand powder and hot air are between the stepped grate plate of the bulk material and the movable baffle plate It is X-shaped cross-reverse flow, rapidly heats the sand-slurry particles, evaporates the water on the surface of the particles, and dehydrates and embrittles the cement paste wrapped on the sand surface, resulting in cracks. Adjust the distance between the feeding pipe and the grinding disc. Regulate the throughput of sand powder and carry out continuous feeding;

Step 2. Crushing and stripping: start the main motor, the main motor drives the millstone to rotate through the main reducer, adjust the speed of the main motor and the millstone through the frequency converter, stop the adjustment when the millstone speed meets the requirements, and keep the millstone speed constant; The hydraulic oil cylinder of the pressing device pulls the lower end of the boom to drive the grinding roller to rotate, so that a squeezing zone and a peeling zone with a multi-dimensional force field reasonably distributed are formed between the grinding roller sleeve and the grinding disc liner;

The heated waste concrete sand-slurry particles fall on the center of the grinding disc, move to the edge of the grinding disc under the centrifugal force generated by the rotating grinding disc, and enter the grinding track to form a material layer; the waste concrete sand-slurry particles enter the sand-slurry stripping device, and the particles The group is selectively crushed by the extrusion, shearing and frictional multi-dimensional force fields of the grinding roller sleeve and the grinding disc liner. Due to the high hardness of the primary sand and the cement paste wrapped on the surface of the sand grains, it is dehydrated, embrittled and produced after heating. Cracks, by optimizing and controlling the thickness of the material layer, the hydraulic pressure of the grinding roller and the rotational speed of the grinding disc, using the speed difference generated by the layered movement of the particle group in the material layer and the differences in the hardness, brittleness and grindability of each component, the sand particles wrapped in the The cement paste on the surface is phase-separated and peeled off to form coarse sand (2.36-4.75mm), medium sand (1.18-2.36mm), fine sand (0.075-1.18mm) and fine powder (﹤0.075mm). Under the action of centrifugal force, the material continues to move to the edge of the grinding disc, and enters the grinding and shaping process;

Step 3. Grinding and shaping: the peeled coarse sand (2.36-4.75mm), medium sand (1.18-2.36mm), and fine sand (0.075-1.18mm) still contain a part of granular cement paste that has not been ground Grind into fine powder, and the surface of some sand particles is still covered with part of the cement paste. The movable cone and the fixed cone form a concentric grinding cavity. The concentric grinding cavity is divided into a wedge-shaped area and a parallel area. The wedge-shaped area has the smallest mesh The angle is 20°～22°, the vertical distance of the parallel zone is 10mm～35mm and can be adjusted; the material after selective crushing from the sand-slurry stripping device enters the concentric grinding cavity under the action of centrifugal force and gravity, and is subjected to The extrusion, shearing and friction of the moving cone rotating at a high speed (4 ~ 8m/s), and at the same time, the sand particles of different particle sizes are used as the grinding body to rub the sand-slurry and cement slurry again between the particles of the material layer, so that Part of the cement paste wrapped on the surface of the sand grains is ground off, and at the same time, the granular cement paste is ground into a fine powder; due to the mutual grinding between sand grains of different particle sizes, the protruding corners and edges on the sand grains are ground off, Realize sand shaping;

Step 4. Dispersion and discharge: The regenerated sand powder after peeling and shaping falls into the ring-shaped collection tank, and the clumped materials are loosened under the centrifugal impact of the rotating scraper, and the fine particles adhering to the surface of the sand particles are further removed. powder, and all discharged from the discharge port, and then through winnowing and screening, regenerated coarse sand (2.36 ~ 4.75mm), regenerated medium sand (1.18 ~ 2.36mm), regenerated fine sand (0.075 ~ 1.18mm) and Regenerated fine powder (﹤0.075mm), sand-slurry particles larger than 4.75mm continue to return to the sand powder roller mill for crushing-stripping.

The advantages of the present invention are:

1. The present invention effectively solves the problems of poor performance such as poor gradation, high water absorption and low activity of the recycled sand powder produced by the impact crusher preparation system based on the principle of non-selective single particle crushing. The sand powder roller mill of the present invention is designed based on the principle of selective material layer crushing under the action of a multidimensional force field. The waste concrete sand powder is heated to remove the moisture on the sand-slurry surface, and the cement paste wrapped on the sand surface Dehydration, embrittlement, and cracks; after entering the sand powder roller mill, by adjusting the material throughput in the mill, the speed of the milling table, the pressure of the roller mill, the height of the retaining ring, and at the same time adjusting the grinding gap between the movable cone and the fixed cone, etc., the sand-slurry The particles are subjected to multi-dimensional force fields such as extrusion, shearing, and friction in the material layer for many times, so that the sand and the slurry are peeled off, and at the same time, regenerated sand and fine powder are produced, and the sand-slurry peeling efficiency reaches more than 90%, which improves the recycling rate. Sand shaping effect, greatly reducing the amount of cement paste on the surface of recycled sand particles;

2. The invention adopts the principle of selective material layer crushing under the action of multi-dimensional force field. The energy efficiency utilization rate of the crushing and peeling of sand-slurry particles is higher than that of single particle impact crushing of ball mills, which can save energy consumption by 30-40%, and has obvious energy saving Effect;

3. The regenerated sand produced by the present invention has high apparent density, low water absorption, good sphericity, less microcracks, low crushing index value, and very little difference in physical properties from primary sand. The matching control system can meet the fineness modulus requirements of different engineering products and replace part of natural river sand; the fine powder produced by the present invention is provided to the regenerated micro powder activation preparation system in the next step to continue grinding to produce highly active regenerated micro powder. Replace some mineral admixtures;

4. The present invention can realize the intellectualization of production equipment, which is beneficial to large-scale production, reduces production energy consumption, and improves the economic benefits of the enterprise; the present invention has a fully enclosed structure and micro-negative pressure operation, and there is no dust in the production process;

5. The products produced by the present invention are of high quality, and can realize high cost-effective utilization of waste concrete recycled sand powder, which is conducive to improving the comprehensive utilization rate of renewable resources, and is conducive to improving the performance of recycled sand powder ready-mixed mortar, recycled sand powder concrete and products. Good for project quality. The invention has excellent promotion value.

Description of drawings

Fig. 1 is an axial side view of a sand powder roller mill provided by an embodiment of the present invention.

Fig. 2 is a top view of the sand powder roller mill provided by the embodiment of the present invention.

Fig. 3 is a schematic structural view of a sand powder roller mill provided by an embodiment of the present invention.

Fig. 4 is a schematic diagram of the structure of the grinding disc of the sand powder roller mill provided by the embodiment of the present invention.

Fig. 5 is a schematic structural diagram of the transmission arm of the sand powder roller mill provided by the embodiment of the present invention.

Fig. 6 is a schematic structural diagram of a heating and feeding device for waste concrete sand-slurry particles provided by an embodiment of the present invention.

Fig. 7 is a partially enlarged view of the structure of the waste concrete sand-slurry particle stripping device and the grinding device provided by the embodiment of the present invention.

Fig. 8 is an enlarged schematic view of the breaking and discharging structure provided by the embodiment of the present invention.

detailed description

In order to make the object, technical solution and advantages of the present invention more clear, the present invention will be further described in detail in conjunction with the following embodiments and accompanying drawings.

In the description of the present invention, the "connection", "connection", "combination", "composition", "composite", and "enclosure" that need to be explained should be understood in a broad sense, for example, it can be a fixed connection or a flexible connection. Detachable connection; it can be mechanical connection or electrical connection; it can be direct connection or indirect connection through an intermediary, and it can be the internal communication of two parts. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention according to specific situations.

In the description of the present invention, the waste concrete sand powder that needs to be explained is the sand-slurry particles with a particle size of less than 10 mm produced by crushing and sorting waste concrete blocks, and the components contain hardened cement mortar.

In the present invention, when the comprehensive moisture content of waste concrete sand powder is greater than 2.5%, hot air needs to be passed in for heating, and when it is less than 2.5%, hot air may not be passed in.

In the present invention, waste concrete sand powder is strictly forbidden to contain ferrous impurities such as steel bars, iron nuggets, alloy steel, etc., which will not be described in detail in the embodiments.

Example 1

Referring to Figures 1-8, a sand powder roller mill for efficient preparation of waste concrete recycled sand powder includes waste concrete sand-slurry particle heating and feeding device 100, waste concrete sand-slurry particle stripping and shaping mechanism 200.

The waste concrete sand-slurry particle heating and feeding device 100 is located above the upper shell of the sand powder roller mill and connected to the upper cover of the upper shell, including a reverse baffle high-efficiency heater 110 and a feeder 120, The reverse baffle high-efficiency heater 110 is located above the feeder 120 and connected by a flange, and the feeder 120 is located inside the sand powder roller mill and above the grinding disc;

The reverse baffle high-efficiency heater 110 includes a heating chamber 111, a bulk material stepped grate plate 112, a movable baffle 113 and an insulating layer 114; the top of the heating chamber 111 shell is provided with a feeding port 115 and Air outlet one 116, the bottom is provided with a heated material collecting hopper, and the middle part is provided with an air inlet 117 that presents a certain angle with the horizontal plane. X"-shaped distribution; the plurality of bulk material stepped grate plates 112 are evenly arranged from top to bottom below the feeding port and close to the air inlet side of the shell, and each bulk material stepped grate plate and the horizontal plane present a certain angle. The method is connected to the housing through a flange; the set of movable baffles 113 is arranged below the air outlet, and a plurality of baffles are evenly distributed from top to bottom and integrated with the side plates on both sides. Each baffle has a certain angle with the horizontal plane, and the inclination direction is opposite to the bulk material ladder grate plate, and one-to-one corresponds to an angle of 75°~105°. The side plates on both sides are connected to multiple sets of horizontal grooves on the shell through bolts. The holes are connected; the insulation layer 114 is laid outside the heating chamber;

The feeder 120 includes a feeding pipe 121, a feeding pipe 122 and an adjusting bolt 123; the feeding pipe 121 is arranged below the heating chamber collecting hopper and connected by a flange; the feeding pipe 122 It is set on the lower part of the feeding pipe and connected with the flange through the multi-piece adjusting bolts 123 .

The waste concrete sand-slurry particle stripping and shaping mechanism 200 structurally includes an integral base 210, a main transmission device 220, a frame and a lower casing 230, a grinding disc 240, a grinding roller 250, a transmission arm 260, and a pressurizing device 270 , limit device 280, upper housing 290;

The integral base 210 is a steel structure, including the main reducer base 211 and the frame base 212, two of which are connected by bolts or welded as a whole; the integral base 210 is located on a concrete foundation, and uses anchor bolts Buried in the foundation hole grouting fixed. The setting of the overall base 210 improves the stability of the equipment during operation;

The main transmission device 220 includes a main motor base 221 , a main motor 222 , a coupling 223 , a main speed reducer 224 and a frequency converter 225 . The main motor base 221 is located on the concrete foundation, and is fixed by grouting in the foundation hole with anchor bolts; the main motor 222 is installed on the main motor base through bolt connection, and the output shaft of the main motor 222 is in the horizontal direction The main reducer 224 is located on the base 211 of the main reducer, and the vertical output thrust plate of the main reducer 224 passes through the lower plane of the grinding disc 240 through a coupling. Blue connection; the frequency converter 225 is connected with the main motor through a cable, and the frequency conversion of the main motor 222 is adjustable. Both the main motor 222 and the main reducer 224 are provided with a lubrication system;

The frame and the lower casing 230 are steel structural parts, including at least three frames 231, the lower casing 232 and the discharge port 233. The frame is located on the frame base 212 and fixed by anchor bolts On the concrete foundation; the lower shell 232 is located on the upper plane of the frame, and is connected to the upper plane of the frame 231 through the legs of the lower shell. Groove; the discharge port 233 is arranged on the bottom surface of the annular groove of the lower shell; a composite wear-resistant liner is laid in the annular groove;

The grinding disc 240 includes a disc seat 241, a lining plate 242, a moving cone 243, a retaining ring 244, a scraper frame 245 and a scraper plate 246, and the grinding disc is located in the annular groove of the lower casing 232 and the main reducer 224 Above the output thrust disc; the disc seat 241 is a rotating body, and the inner concave surface of the upper part of the disc seat 241 is fixed with a plurality of wear-resistant liners 242, which are low inside and high outside, and the wear-resistant liner 242 surrounds a disc-shaped grinding track, the lower part of the disc seat 241 passes through the annular hole enclosed by the annular groove of the lower casing, and the bottom surface of the lower part of the disc seat 241 is fixedly connected with the output thrust disc of the main reducer 224; the moving cone 243 is located on the disc seat 241 The upper side is fixedly connected with the outer convex flange of the upper part of the disc seat 241. The movable cone 243 is integral or split. The cone angle of the movable cone 243 is 30°-60°. The ring 244 is located on the upper plane of the movable cone 243, and is connected with the movable cone 243; the scraper frame 245 is located below the lower plane of the upper part of the disk seat 241, and is fixedly connected with the disk seat 241, and the plurality of scraper plates 246 is connected with the scraper frame 245, and the impact surface between the scraper and the material is designed with a composite wear-resistant steel plate to prolong its service life;

Each of the grinding rollers 250 is located above the grinding disc 240, and the inclination angle between the axial center line of each grinding roller 250 and the horizontal plane is not more than 12°, and each grinding roller is arranged at an equal angle and equidistant from each other on the horizontal plane; One end of the roller 250 is fixed with a grinding body roller sleeve 251, the grinding surface of the roller sleeve 251 is arc-shaped, and the arc-shaped outer surface is compounded with a wear-resistant lining, which can be welded online with a wear-resistant welding wire; The other end of the roller 250 is fixedly connected with the transmission arm 260;

Each of the transmission arms 260 is installed on the upper plane of the frame 231, including a rocking arm 261, a boom 262, a cross shaft 263, a bearing seat 264, a bearing 265, a thrust device 266, and the rocking arm 261 and the boom 262 is connected with a column pin through a horizontal shaft 263, and the horizontal shaft 263 is supported on a bearing seat 264 through two bearings 265, and the bearing seat 264 is connected with the upper plane of the frame 231 and the legs of the lower housing 232 as a whole, so that A part of the thrust device 266 is fixed on an end surface of the transverse shaft 263 , and a part is fixed on an end surface of the bearing seat 264 . The lower part of the movable arm 262 is connected with the oil cylinder 271 through a pin shaft; the sand powder roller mill of this embodiment adopts a rocker turning mechanism, and the grinding roller can be turned out of the mill for maintenance;

Each of the pressurizing devices 270 includes an oil cylinder 271, a press base 272, a hydraulic system 273, an accumulator 274 and a pipeline. The upper earring is connected with the lower hole of the boom 262 through the pin shaft, and the cylinder body of the oil cylinder 271 is connected with the pressurized base 272 through the pin shaft, and the pressurized base 272 is located on the frame base 212, and the The foot bolts are fixed on the concrete foundation, the pressurized oil circuit of the hydraulic system 273 is connected with the rod cavity of the oil cylinder 271 through the accumulator 274 and the pipeline, and the roller lifting oil circuit is connected with the rodless cavity of the oil cylinder 271 through the pipeline, which can realize the Loading and lifting of grinding rollers;

Each of the limiting devices 280 is located outside the boom 262 and installed on the inner vertical plate of the frame 231. There are multiple groups of disc springs arranged in the limiting device for adjusting the gap between the grinding roller and the grinding disc;

The upper casing 290 includes a casing 291, a grinding roller door 292, a cover plate 293 and a fixed cone 294. The casing 291 is located above the lower casing 232 and is cylindrical, and is connected to the lower casing 232 through a flange. connection, the shell 291 has a grinding roller door 292, so that the grinding roll can be turned in and out freely, the cover plate 293 is located above the shell 291, connected with the shell 291 through a flange, and supports the reverse Baffle the high-efficiency heater 110 and the feeder 120. The cover plate 293 is provided with an air outlet 295; Cone 294 is a split type, its position can be adjusted up and down, the distance between the sections of each split fixed cone is 40mm ~ 80mm, which is conducive to the discharge of unbreakable iron impurities mixed in; the fixed cone 294 is compounded with wear-resistant lining.

Example 2

Referring to Figures 1 to 8, when the present invention is working, if the comprehensive moisture content of the waste concrete sand powder is greater than 2.5%, the air inlet 117 of the reverse baffle high-efficiency heater 110 is fed with hot air at 100°C to 300°C, and the mixed materials are crushed and removed. The waste concrete sand powder with iron impurities in it enters the heating chamber 111 from top to bottom, and is evenly distributed on the bulk material stepped grate plate 112, and hot air is introduced from the hot blast stove into the heating chamber 111 from bottom to top. In the heating chamber 111, the sand powder and the hot air flow in an "X" shape crossed and reversed between the bulk material stepped grate plate 112 and the movable baffle plate 113. The distance between the bulk material stepped grate plate 112 and the movable baffle plate 113 is adjustable, which not only ensures the heating effect of the sand powder, but also ensures the smooth flow of the sand powder.

In the present invention, when the main transmission device 220 is working, the rotating speed of the grinding disc 240 is controlled by adjusting the operating frequency of the main motor 222 through the frequency converter 225; at the same time, the height of the retaining ring 244 is adjusted to control the retention of waste concrete sand powder on the grinding track of the grinding disc The time reaches 30-60 seconds, so as to ensure the effect of sand-slurry stripping.

In the present invention, the waste concrete sand-slurry particle stripping and shaping mechanism 200 functionally includes a sand-slurry stripping device 201 and a sand-slurry grinding device 202; the preparation of waste concrete recycled sand powder is mainly completed by the sand-slurry stripping device 201, The sand-slurry grinding device 202 plays the role of auxiliary stripping and shaping;

The sand-slurry stripping device 201 comprises a grinding disc 240 and at least three grinding rollers 250. The inner concave surface of the upper part of the grinding disc 240 is covered with a plurality of wear-resistant liners with low inside and high outside, and surrounds a disc-shaped grinding track. The radius of the inner surface of the track is R ₁ ; each grinding roller 250 is equipped with a tire-shaped wear-resistant roller sleeve 251, the grinding surface of the roller sleeve 251 is arc-shaped, and the radius of the arc-shaped outer surface is R ₂ ; the radius R ₁ of the inner surface of the grinding track is greater than the roller sleeve The radius R ₂ of the arc-shaped outer surface, the distance between the extension line of the connecting line of the two arc centers and the intersection point of the two arcs is a minimum gap, the minimum gap is located at the upper part of the climbing section of the grinding track, the minimum gap L=10-25mm, the minimum The design of the position and size of the gap is conducive to avoid excessive vibration and stop when the material layer is too thin. At the same time, it can apply efficient and stable grinding roller pressure to improve the peeling efficiency of sand-slurry particles; grinding roller 250 The total projected area on the grinding disc 240 is 60-70% of the area of the grinding track. The increase of the projected area can make the sand-slurry particles be subjected to multi-dimensional force fields in the material layer for many times, which is beneficial to improve the sand-slurry interaction. Peeling efficiency; the hydraulic loading force of each grinding roller 250 is provided by the transmission arm 260 and the pressurized oil cylinder 271, and the hydraulic loading force is equal in magnitude and adjustable. Reasonable control of the hydraulic pressure of the grinding roller can realize sand-slurry peeling, and at the same time Meet the requirements of stable, safe and economical operation of the mill, the hydraulic pressure of the grinding roller is low, the stripping efficiency is low, the hydraulic pressure of the grinding roller is high, and the sand is easy to be crushed; the minimum gap between each grinding roller sleeve 251 and the grinding disc liner 242 is set for the first time 5-10mm, the limit is adjusted by the limit device 280 to avoid direct contact between the grinding roller and the liner and strong vibration;

The sand-slurry grinding device 202 includes a moving cone 243 and a set of fixed cones 294 . The movable cone 243 is located on the upper side of the disc seat 241, and the cone angle of the movable cone 243 is 30° to 60°; the fixed cone 294 is located at the lower part of the upper casing 290 and surrounds the upper movable cone 243 of the grinding disc. The fixed cone 294 is a split type. The position can be adjusted up and down, and the distance between the sections of each split fixed cone is 40mm~80mm, which is beneficial to discharge the mixed unbreakable iron impurities; the moving cone and the fixed cone form a concentric grinding cavity, and the concentric grinding cavity is divided It is a wedge-shaped area and a parallel area. The minimum meshing angle of the wedge-shaped area is 20°~22°, which is conducive to the smooth entry of sand-slurry particles into the wedge-shaped area to form a stable material layer; the vertical distance of the parallel area is 10mm~35mm, and the length of the parallel area is 60mm~ 200mm, the size of the gap is adjustable, set a reasonable gap and the length of the parallel zone, through the regulation of the speed of the grinding disc, the efficient peeling of sand-slurry particles is realized, and the cement slurry is ground into fine powder.

In the present invention, the grinding chamber of the sand powder roller mill is surrounded by the lower casing 232, the grinding disc 240, the upper casing 290 and the reverse baffle high-efficiency heater 110 to form a fully enclosed structure, and the top of the upper casing cover plate 293 is provided with two air outlets. 295, so that a slight negative pressure is formed in the grinding chamber, no dust overflows, which meets the requirements of green production; the bottom of the lower shell 232 is set as an annular groove with the notch upward, and the bottom surface of the annular groove is provided with a discharge port 233 and a scraper rack 245 is located in the annular groove with the notch upwards, and is connected with the grinding disc as a whole. A plurality of scraper plates 246 are connected with the scraper frame 245, and the material cakes from the grinding device 202 are crushed under the centrifugal impact of the rotating scraper plates. The material is loosened, and the fine powder adhering to the surface of the sand is further removed, and all of it is discharged from the discharge port 233.

Example 3

Referring to Figures 1-8, a method for using a sand roller mill for efficient preparation of recycled sand powder from waste concrete comprises the following steps:

Step 1, heating and feeding: when the present invention is working, if the comprehensive moisture content of waste concrete sand powder is greater than 2.5%, the air inlet 117 of the reverse baffle high-efficiency heater 110 is fed with hot air at 100°C to 300°C, and the crushed Waste concrete sand-slurry particles enter the heating chamber 111 from top to bottom, and are evenly distributed on the bulk material ladder grate plate 112. Hot air is introduced from the hot blast stove into the heating chamber 111 from bottom to top, and the sand The powder and hot air flow in an "X" cross-reverse direction between the bulk material ladder grate plate 112 and the movable baffle plate 113, rapidly heating the sand-slurry particles, improving the heat exchange efficiency of the sand-slurry particles, and evaporating the surface of the particles moisture, and dehydrate and embrittle the cement paste wrapped on the sand surface, resulting in cracks. Adjust the distance between the feeding pipe 122 and the grinding disc 240 to regulate the throughput of the sand powder and perform continuous feeding.

Step 2, crushing and peeling: when the present invention is working, start the main motor 222, the main motor drives the millstone to rotate through the main reducer 224, adjust the speed of the main motor and the millstone 240 through the frequency converter 225, and stop the adjustment when the millstone speed reaches the requirement , to keep the disc rotation speed constant. The lower end of the boom 262 is pulled by the hydraulic cylinder 271 of the grinding roller pressurizing device 270, and the grinding roller 250 is driven to rotate, so that a squeeze zone with a multi-dimensional force field reasonably distributed between the grinding roller sleeve 251 and the grinding disc liner 242 is formed and peeled off. Extrusion zone, the gap between the curved surface of the disc and the roller is large and the linear velocity is equal, and the material is mainly affected by the extrusion force; the peeling zone - the gap between the curved surface of the disc and the roller is small and the difference in linear velocity is getting larger and larger. The material layer is not only affected by extrusion force, but also by shear force and friction; the extrusion zone provides a dense and stable material layer for the peeling zone. The heated waste concrete sand-slurry particles fall on the center of the grinding disc 240, and move to the edge of the grinding disc under the action of the centrifugal force generated by the rotation of the grinding disc driven by the main motor 222, and enter the grinding track to form a material layer that is conducive to the peeling of the sand-slurry. The waste concrete sand-slurry particles enter the sand-slurry stripping device 210, and the material layer under the action of the hydraulic pressure generated by the oil cylinder is subjected to the multi-dimensional force fields such as extrusion, shearing, and friction of the grinding roller sleeve 251 and the grinding disc liner 242 Selective crushing is carried out. Due to the high hardness of the primary sand and the cement paste wrapped on the surface of the sand grains after heating, it dehydrates, becomes embrittled and produces cracks. By optimizing the control of the thickness of the material layer, the grinding pressure of the grinding roller 250 and the rotation speed of the grinding disc 240, the material is used Due to the speed difference between particles in the layer and the difference in physical properties such as hardness, brittleness and grindability of each component, the cement paste wrapped on the surface of the sand particles is separated and peeled off to form coarse sand (2.36 ~ 4.75mm ), medium sand (1.18-2.36mm), fine sand (0.075-1.18mm) and fine powder (﹤0.075mm). At the same time, through the regulation of the multi-dimensional force field, the damage to the grain shape of the sand grains, the generation of micro-cracks and the possibility of further crushing are reduced. The stripped material continues to move to the edge of the grinding disc under the action of centrifugal force, and enters into the grinding device 202 .

Step 3. Grinding and shaping: the peeled coarse sand (2.36-4.75mm), medium sand (1.18-2.36mm), and fine sand (0.075-1.18mm) contain a part of granular cement paste that has not been ground into a fine powder, and the surface of some sand grains is still covered with part of the cement paste. In the present invention, the sand-slurry grinding device includes a moving cone 243 and a set of fixed cones 294 . The movable cone 243 rotates with the disk seat 241, and the fixed cone 294 surrounds the movable cone on the grinding table. The movable cone and the fixed cone form a concentric grinding cavity. The concentric grinding cavity is divided into a wedge-shaped area and a parallel area. The wedge-shaped area has a minimum meshing angle 20°～22°, the vertical distance of the parallel zone is 10mm～35mm and can be adjusted. The material after selective crushing from the sand-slurry stripping device enters the concentric grinding cavity under the action of centrifugal force and gravity. By setting a reasonable gap between the movable cone and the fixed cone, the length of the parallel zone and adjusting the rotational speed of the grinding disc, the concentric grinding can be achieved. The material layer in the cavity is squeezed, sheared and frictioned by the moving cone 243 rotating at a medium speed (4-8m/s), and at the same time, sand particles of different particle sizes are used as grinding bodies to grind sand-slurry and cement paste. The friction between the particles of the material layer is carried out again, so that part of the cement paste wrapped on the surface of the sand grains is ground away, and at the same time, the granular cement paste is ground into a fine powder. Due to the mutual grinding between sand particles of different particle sizes, the more prominent corners and edges on the sand particles are worn away, so as to realize the shaping of the sand particles and improve the performance of the recycled sand.

Step 4, breaking up and discharging: in operation of the present invention, the regenerated sand powder after stripping and shaping falls into the ring-shaped collecting tank, and the clumped materials are loosened under the centrifugal impact of the rotating scraper 246, and further removed The fine powder adhering to the surface of the sand grains is all discharged from the discharge port 233 and enters the next process. The next process is through winnowing and screening to sort out regenerated coarse sand (2.36-4.75mm), regenerated medium sand (1.18-2.36mm), regenerated fine sand (0.075-1.18mm) and regenerated fine powder (﹤0.075mm ), the sand-slurry particles larger than 4.75mm continue to return to the sand powder roller mill for crushing-stripping.

Summary of the principle of the present invention: the present invention is aimed at the physical and chemical properties of the various components in the waste concrete sand powder of different regions and ages, and the differences in physical properties such as hardness and grindability caused by the residual cement slurry on the surface of the recycled sand. From the perspective of effective separation of components of waste concrete sand powder, according to the bond strength of the sand-slurry interface, and based on the principle of selective material layer crushing under the action of a multi-dimensional force field, heating-feeding, crushing-peeling, grinding-shaping, grinding A sand powder roller mill for efficient preparation of waste concrete high-quality recycled sand powder designed by the method of dispersing and discharging.

Table 1 is the contrast of the present invention and each content of traditional equipment:

Table 2 is the comparison of the regenerated sand produced after the grinding of C40 of the present invention and the basic performance of natural sand:

The listed effects are shown in Tables 1 and 2. According to Table 1, it can be seen that the present invention achieves good results and better solves the disadvantages of poor performance of waste concrete sand powder prepared by traditional equipment. According to Table 2, it can be seen that compared with natural sand, the regenerated sand prepared by the present invention has higher water absorption rate, and other indicators such as apparent density, bulk density and porosity are not much different from natural sand. Bulk density is even better than natural sand, reaching the purpose of the invention.

The basic principles, main features and advantages of the present invention have been shown and described above, and those skilled in the art should understand that the present invention is not limited by the above-mentioned embodiments, and what described in the above-mentioned embodiments and description is only to illustrate the present invention In principle, under the premise of not departing from the spirit and scope of the present invention, simple modifications and replacements by those skilled in the art are within the protection scope of the present invention.

Claims (2)

1. The utility model provides a waste concrete regeneration sand powder high efficiency preparation is with sand powder roller mill which characterized in that: comprises a waste concrete sand-slurry particle heating and feeding device and a waste concrete sand-slurry particle stripping and shaping mechanism; the waste concrete sand-slurry particle heating and feeding device heats sand-slurry particles before grinding and continuously feeds by regulating and controlling the throughput of sand powder; the waste concrete sand-slurry particle stripping and shaping mechanism selectively crushes material layers of the heated waste concrete sand-slurry particle groups, phase splitting and stripping the cement slurry wrapped on the surface of sand particles, grinding the granular cement slurry into fine powder, grinding the protruded edges and corners of the sand particles, and screening to sort out regenerated coarse sand, regenerated medium sand, regenerated fine sand and regenerated fine powder;

the waste concrete sand-slurry particle heating and feeding device comprises a reverse baffling efficient heater and a feeder, wherein the reverse baffling efficient heater is positioned above the feeder and is connected with the feeder through a flange; the reverse baffling efficient heater comprises a heating chamber shell, a bulk material stepped grate plate, a movable baffle plate and a heat insulation layer; the top of the heating chamber shell is provided with a feeding port and a first air outlet, the bottom of the heating chamber shell is provided with a material collecting hopper, the middle of the heating chamber shell is provided with an inclined air inlet, and two connecting lines of the feeding port and the material collecting hopper and the centers of the air inlet and the first air outlet are distributed in an X shape; the bulk material stepped grate plates are uniformly arranged below the feeding port and close to the side of the air inlet of the heating chamber shell from top to bottom, and each bulk material stepped grate plate forms a certain included angle with the horizontal plane and is connected to the heating chamber shell by adopting an insertion method; the movable baffle plate is arranged below the air outlet, a plurality of baffle plates are uniformly distributed from top to bottom and are integrated with the side plates at two sides, each baffle plate forms a certain included angle with the horizontal plane, the inclined direction of each baffle plate is opposite to that of the bulk material stepped grate plate, the baffle plates are in one-to-one correspondence to form included angles of 75-105 degrees, and the side plates at two sides are connected with a plurality of groups of horizontal groove-shaped holes in the heating chamber shell through bolts; the heat-insulating layer is laid outside the heating chamber shell; the feeder comprises a feeding pipe, a discharging pipe and an adjusting bolt; the feeding pipe is arranged below the collecting hopper of the heating chamber shell and is connected with the collecting hopper through a flange; the blanking pipe is sleeved at the lower part of the feeding pipe and is connected with the flange through a plurality of adjusting bolts;

the waste concrete sand-slurry particle stripping and shaping mechanism comprises an integral base, a main transmission device, a frame, a lower shell, a grinding disc, a plurality of grinding rollers, a transmission arm, a pressurizing device, a limiting device and an upper shell;

the integral base comprises a main speed reducer base and a rack base, and the main speed reducer base and the rack base are connected or welded into a whole in pairs through bolts; the integral base is positioned on a concrete foundation and is embedded into a foundation hole by adopting foundation bolts to be fixed by grouting; the main transmission device comprises a main motor base, a main motor, a coupler, a main speed reducer and a frequency converter, wherein the main motor base is positioned on a concrete foundation and is embedded in a foundation hole by adopting a foundation bolt for grouting and fixing; the main motor is arranged on the main motor base, and the output shaft of the main motor is axially connected with the input shaft of the main speed reducer through the coupler in the horizontal direction; the main speed reducer is positioned on a main speed reducer base, and an output thrust disc in the vertical direction of the main speed reducer is connected with the lower plane of the grinding disc through a flange; the frequency converter is connected with the main motor through a cable;

the number of the racks is at least three, the racks are positioned on the rack base and fixed on the concrete foundation through foundation bolts; the lower shell is positioned on the upper plane of the frame and is connected with the upper plane of the frame through lower shell supporting legs, and an annular groove with an upward notch is formed in the bottom edge of the lower shell; a discharge hole is formed in the bottom surface of the annular groove of the lower shell;

the grinding disc comprises a disc seat, a lining plate, a moving cone, a material blocking ring, a material scraping frame and a material scraping plate, and is positioned above the annular groove in the lower shell and the output thrust disc of the main speed reducer; the disc seat is a rotating body, a plurality of wear-resistant lining plates with low inside and high outside are fixed on the inner concave surface of the upper part of the disc seat, the wear-resistant lining plates surround to form a disc-shaped grinding track, the lower part of the disc seat penetrates through an annular hole surrounded by an annular groove of the lower shell, and the bottom surface of the lower part of the disc seat is fixedly connected with an output thrust disc of the main speed reducer; the movable cone is positioned on the side surface of the upper part of the disc seat and fixedly connected with the outer convex surface of the upper part of the disc seat, the movable cone is integrated or split, the conical angle of the movable cone is 30-60 degrees, the surface of the movable cone is compounded with a wear-resistant lining, and the stop ring is positioned on the upper plane of the movable cone and connected with the movable cone; the scraping frame is positioned below the lower plane of the upper part of the disc seat and is fixedly connected with the disc seat, and the scraping plates are connected with the scraping frame; the feeder is positioned above the grinding disc;

each grinding roller is positioned above the grinding disc, the inclination angle of the axial center line of each grinding roller and the horizontal plane is not more than 12 degrees, and each grinding roller is arranged on the horizontal plane at equal angles and intervals; a grinding body roller sleeve is fixed at one end of the grinding roller, the grinding surface of the roller sleeve is in a circular arc shape, and a wear-resistant lining is compounded on the outer surface of the circular arc shape; the other end of the grinding roller is fixedly connected with the transmission arm; the total projection area of the grinding rollers on the grinding disc is 60 to 70 percent of the area of the grinding track; the transmission arm is arranged on the upper plane of the rack and comprises a rocker arm, a movable arm, a cross shaft, a bearing seat, a bearing and a thrust device, wherein the rocker arm and the movable arm are connected through the cross shaft and a pin, the cross shaft is supported on the bearing seat through 2 bearings, the bearing seat is connected with the upper plane of the rack and a support leg of the lower shell into a whole, one part of the thrust device is fixed on one end face of the cross shaft, and the other part of the thrust device is fixed on one end face of the bearing seat; the pressurizing device comprises an oil cylinder, a pressurizing base, a hydraulic system, an energy accumulator and a pipeline, the pressurizing device is positioned below the transmission arm, a lug ring at the head part of the oil cylinder is connected with a lower hole of the movable arm through a pin shaft, the cylinder body of the oil cylinder is connected with the pressurizing base through a pin shaft, the pressurizing base is positioned on the frame base and fixed on a concrete foundation through anchor bolts, a pressurizing oil path of the hydraulic system is connected with a rod cavity of the oil cylinder through the energy accumulator and the pipeline, and an oil path of the lifting roller is connected with a rodless cavity of the oil cylinder through the pipeline;

the limiting device is positioned on the outer side of the movable arm and is arranged on a vertical plate in the rack, and a plurality of groups of disc springs are arranged in the limiting device; the upper shell comprises a shell, a grinding roller door, a cover plate and a fixed cone, the shell is positioned above the lower shell, is cylindrical and is connected with the lower shell, the shell is provided with the grinding roller door for the grinding roller to freely turn in and out, the cover plate is positioned above the shell and is connected with the shell to support the reverse deflection efficient heater and the feeder, and the cover plate is provided with a second air outlet; the fixed cone is arranged at the lower part of the upper shell and surrounds the periphery of the movable cone of the grinding disc, the fixed cone is split, the position of the fixed cone is adjustable up and down, the distance between the fixed cone sections of each split body ranges from 40mm to 80mm, and the grinding surface of the fixed cone is compounded with a wear-resistant lining;

in the main transmission device, the rotating speed of the grinding disc is controlled by adjusting the working frequency of the main motor through a frequency converter; the height of the material blocking ring is 5 to 40mm and is adjustable, and the retention time of the waste concrete sand powder on the grinding disc is controlled to be 30 to 60 seconds.

2. The use method of the sand powder roller mill for efficiently preparing the waste concrete regenerated sand powder, according to claim 1, is characterized by comprising the following steps: the method specifically comprises the following steps: step one, heating and feeding: introducing hot air at 100-300 ℃ into an air inlet of the reverse baffling efficient heater, introducing crushed waste concrete sand-slurry particles into the heating chamber shell from top to bottom, uniformly distributing the crushed waste concrete sand-slurry particles on the bulk material stepped grate plate, introducing the hot air into the hot air furnace from bottom to top, introducing the hot air into the heating chamber shell, enabling sand powder and the hot air to flow in an X-shaped crossed reverse direction between the bulk material stepped grate plate and the movable baffle plate, rapidly heating the ground sand-slurry particles, evaporating the surface moisture of the particles, dehydrating and embrittling cement slurry wrapped on the surface of the sand to generate cracks, adjusting the distance between a discharging pipe and a grinding disc to adjust the throughput of the sand powder, and continuously feeding the sand powder; step two, crushing and stripping: starting a main motor, driving the grinding disc to rotate through a main speed reducer, adjusting the rotating speed of the main motor and the rotating speed of the grinding disc through a frequency converter, stopping adjustment when the rotating speed of the grinding disc meets the requirement, and keeping the rotating speed of the grinding disc constant; the lower end of the movable arm is pulled by a hydraulic oil cylinder of the grinding roller pressurizing device to drive the grinding roller to rotate, so that a squeezing area and a stripping area which are reasonably distributed in a multi-dimensional force field are formed between a grinding roller sleeve and a grinding disc lining plate; the heated waste concrete mortar-slurry particles fall at the center of the grinding disc, move towards the edge of the grinding disc under the action of centrifugal force generated by the rotary grinding disc and enter a grinding track to form a material layer; waste concrete sand-slurry particles enter a sand-slurry stripping device, particle groups are selectively crushed under the actions of extruding, shearing and rubbing a multidimensional force field by a grinding roller sleeve and a grinding disc lining plate, and as the original sand is high in hardness and cement slurry wrapped on the surface of sand particles is heated, the cement slurry is dehydrated, embrittled and cracked, the cement slurry wrapped on the surface of the sand particles is subjected to phase splitting and stripping by optimally regulating and controlling the thickness of a material layer, the hydraulic pressure of a grinding roller and the rotating speed of a grinding disc by utilizing the speed difference generated during layered movement of the particle groups in the material layer and the hardness, brittleness and grindability physical property difference of each component to form coarse sand, medium sand, fine sand and fine powder, the stripped material continuously moves to the edge of the grinding disc under the action of centrifugal force, and enters a grinding and shaping process; step three, grinding and shaping: the stripped coarse sand, medium sand and fine sand still contain a part of granular cement slurry which is not ground into fine powder, the surfaces of some sand grains still wrap part of the cement slurry, the movable cone and the fixed cone form a concentric grinding cavity, the concentric grinding cavity is divided into a wedge-shaped area and a parallel area, the minimum meshing angle of the wedge-shaped area is 20-22 degrees, and the vertical distance of the parallel area is 10mm-35mm and is adjustable; the materials after being selectively crushed from the sand-slurry stripping device enter a concentric grinding cavity under the action of centrifugal force and gravity, are extruded, sheared and subjected to the action of friction force by a moving cone rotating at a medium speed, and meanwhile, sand grains with different grain sizes are used as grinding bodies to carry out inter-grain friction on the sand-slurry and the cement slurry again, so that part of cement slurry wrapped on the surfaces of the sand grains is ground off, and meanwhile, the granular cement slurry is ground into fine powder; because the sand grains with different grain sizes are rubbed with each other, the protruded edges and corners on the sand grains are ground off, and the sand grains are shaped; step four, scattering and discharging: the stripped and shaped regenerated sand powder falls into an annular collecting groove, agglomerated materials are loosened under the centrifugal impact action of a rotary scraper, fine powder adhered to the surface of sand grains is further removed and is completely discharged from a discharge port, then the regenerated coarse sand, the regenerated medium sand, the regenerated fine sand and the regenerated fine powder are sorted by winnowing and screening, and sand-slurry particles larger than 4.75mm are continuously ground and stripped by a sand-powder roller mill.

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