CN115445741A - A method for producing machine-made sand with high yield from rock waste - Google Patents

Abstract

The invention discloses a method for preparing machine-made sand with high yield of rock waste. Using rock waste as the main raw material, a dry-wet combined process flow of "adjustable soil removal process-multi-stage segmental crushing and screening-full product shaping and re-screening-wet wheel bucket washing and fine sand recovery" is proposed to optimize the mechanism Improve the quality of sand products and improve process production efficiency. The present invention combines a vertical impact breaker with a grinding machine to make the finished sand more reasonable in gradation and lower in fineness modulus. The new sand washing and fine sand recovery integrated machine is used as the sand washing and fine sand recovery device, which can The finished aggregate with low fineness modulus can be obtained in a higher yield. In addition, the process requires less water, and the water can be recycled. At the same time, the mud cake can be used as a raw material for the brick factory.

Description

A method for producing machine-made sand with high yield from rock waste

technical field

The invention relates to the field of sand making, in particular to a method for preparing machine-made sand with high yield by using rock waste.

Background technique

In recent years, my country's demand for construction sand has grown rapidly, and natural river sand, as a non-renewable ground material resource in a short period of time, is increasingly scarce. With the shortage of natural river sand market supply and rising prices, the promotion and application of machine-made sand as fine aggregate has become the main direction of the development of mixed soil engineering. Manufactured sand refers to rock particles with a particle size of less than 4.75 mm, which are produced through soil removal, mining, mechanical crushing, and screening, but does not include particles of soft rocks and weathered rocks. Rock waste is the waste discharged by mining enterprises under certain technical and economic conditions, but at the same time it is a potential secondary resource and can be used as a raw material for the production of machine-made sand.

The production of high-quality machine-made sand has high requirements for ore, equipment and production management. Traditional production processes mainly include dry sand making, wet sand making and semi-dry sand making. The wet process crushing operation adopts water shower pre-wetting to suppress dust, and the screening operation is washed with water, which consumes a lot of water and muddy matter, and the sewage treatment and muddy matter storage occupy a large area, but the surface of the sand and gravel is clean and the appearance is good. The crushing and screening operations of the dry process need to be sealed and the bag filter is used to solve the dust problem. The comprehensive utilization of stone powder is high, but the raw materials need to strictly control the content of soil and organic matter and the surface of sand and gravel aggregates. The semi-dry process is similar to the wet process. No water is added to the crushing and screening operation, but the pre-screening operation and the final product are washed with water, which reduces the water consumption of the full wet process.

In the specific production process, the preparation of machine-made sand from hard rock materials such as granite usually requires processes such as soil removal, crushing, shaping, and screening. In the early stripping stage of aggregate mines, there may be more soil in the raw materials mined; some aggregate mines may also contain more soil in the mine rock stratum, and soil removal is required when entering the production system, and sieves can be used points (dry method) or water drench (wet method). Due to the hardness of rocks such as granite, strong abrasiveness, and the large particle size span of the original stone, the crushing process usually adopts coarse, medium, and fine multi-stage crushing methods. The main crushing equipment includes: jaw crusher, cone crusher, vertical shaft impact Crusher, ball mill, double rotor sand making machine, vertical mill sand making machine, etc. After crushing, the particle shape is often poor, and there are too many needle-like particles, so it needs to be shaped frequently. Among them, the vertical shaft impact crusher has a unique "rock-on-rock" principle, which can simultaneously crush, pulverize and shape materials, and is the most commonly used shaping equipment. In order to better reduce incomplete crushing and excessive crushing, and make full use of materials of different sizes, more screening systems should be set up in the production process to effectively screen the materials entering the next treatment process. Commonly used screening equipment includes: circular vibrating screen, three-axis elliptical horizontal vibrating screen, air screening machine, etc. In addition, for the control of the stone powder content in the product, the dry sand making process can adopt the screening method, while the wet sand making process can adopt the sand washing process. In the sand washing process, excessive loss of fine sand should be avoided, and dehydration treatment should be supplemented.

At present, due to defects in the process of most production lines, the performance indicators of the finished machine-made sand products are far from the requirements of the national and industry standards, mainly reflected in the large clay content of the aggregate and its poor adaptability to external additives; Poor roundness, poor coagulation workability; unreasonable gradation, fineness modulus, stone powder content is not up to standard, etc. For example, some enterprises produce washed machine-made sand with a lack of fine particles, poor particle gradation, and poor particle shape. It is often necessary to adjust the concrete mix ratio with natural medium sand or fine sand to obtain better working performance, resulting in a replacement rate of machine-made sand. not tall. In addition, the equipment configuration of some production lines is unreasonable, and the particle size distribution of the discharge port is "more at both ends and less in the middle". On the one hand, the crushing of coarse materials is not complete, and the circulation in the process is large; The recovery rate of large and fine sand is low, resulting in low production efficiency of finished sand and large amount of tailings. Chinese patent CN112439530A discloses the name: a production line of high-quality granite machine-made sandstone aggregate and its technological process. This technology puts forward the concept of "more screening and less breaking" and sets up multi-stage screening process to ensure the high quality of finished aggregates. The whole line is equipped with high-precision weighing and intelligent conveying system to realize the automatic control of the production line operation. The disadvantage of this technology is that a single vertical impact crusher is used in the crushing and shaping unit, resulting in a large amount of circulation in the process, a large output of stone powder, and low production efficiency. Chinese patent CN112452502A discloses the name: a fine-quality basalt machine-made sandstone aggregate production line and its technological process. This technology adopts a dry-wet combination process to realize the recovery of dust. Although the sewage circulation system is added to the technical process, water washing and screening methods are used in many places in the process, resulting in large water demand and high pressure for sewage treatment; in addition, the sand washing recovery unit is not reasonable enough, the recovery rate of fine sand is low and the installation Occupies a large area.

Contents of the invention

The purpose of the present invention is to overcome the shortcomings of the traditional technology and provide a method for preparing machine-made sand with high yield from rock waste.

The present invention uses rock waste as the main raw material, and proposes a dry-wet combined process flow of "adjustable soil removal process-multi-stage segmental crushing and screening-full product shaping and re-screening-wet wheel bucket washing and fine sand recovery", with Optimize the quality of finished machine-made sand and improve process production efficiency.

The technical scheme that the present invention adopts is as follows:

A method for preparing machine-made sand with a high yield of rock waste, comprising the following steps:

1) The feeder receives the ore, sorts the ore according to the different particle sizes into the oversize of the feeder and the undersize of the feeder, and the oversize of the feeder enters the coarse crusher through the one-way belt conveyor for coarse crushing. Crushed, the sieved material of the feeder enters the soil removal sieve through the one-way belt conveyor;

Wherein, the particle size of the oversize of the feeder is greater than 200mm (150mm), and the particle size of the undersize of the feeder is less than 200mm (150mm);

2) The soil removal sieve sorts the material under the sieve of the feeder into the upper material of the soil removal sieve and the lower material of the soil removal sieve according to different particle sizes, and the upper material of the soil removal sieve enters the pre-screen through the one-way belt conveyor, The sieve under the soil removal sieve is transported as spoil to the mine dump for stockpiling;

The coarse crusher coarsely crushes the material on the sieve of the feeder and enters the pre-screen through the one-way belt conveyor;

Wherein, the particle size of the material on the soil removal sieve is greater than 10 mm, and the particle size of the material under the soil removal sieve is less than 10 mm;

3) The materials entering the pre-sieve are sorted into one-layer sieve feeding, second-layer sieve feeding and second-layer sieve discharge according to different particle sizes, and the first-layer sieve feeding enters through a one-way belt conveyor Secondary crushing buffer silo, the upper material sieve of the second-layer sieve enters the buffer silo for fine crushing and shaping through the one-way belt conveyor, and the unloading material of the second-layer sieve enters the buffer silo for shaping sand making through the one-way belt conveyor;

Suspended iron removers are installed on each one-way belt conveyor that pre-screens and transports materials outward, and hoisted electric vibrating feeders are installed at the bottom of all transfer buffer silos in the production line.

4) The secondary crushing buffer silo is discharged through the electric vibrating feeder and fed to the secondary crusher through the one-way belt conveyor. The output of the secondary crushing machine enters the classifying screen through the one-way belt conveyor, and the classifying screen sorts the materials It is divided into grading sieve loading and grading sieve discharging. The grading sieve feeding is returned to the secondary crusher through the one-way belt conveyor, and the grading sieve discharge is sent to the buffer silo for fine crushing and shaping through the one-way belt conveyor;

5) The buffer bin for fine crushing and shaping is discharged through the electric vibrating feeder and fed to the fine crushing and shaping machine through the one-way belt conveyor. The output of the fine crushing and shaping machine enters the finished coarse aggregate screen through the one-way belt conveyor; The finished product sieve sorts the materials into one layer of sieve, two layers of sieve, three layers of sieve and three layers of sieve according to different particle sizes. The first layer of sieve enters the 20-31.5 mm finished aggregate silo, the second layer sieve feeds into the 10-20mm finished aggregate bin, the third layer sieve feeds into the 4.75-10mm finished aggregate bin, and the third layer sieve discharges into the shaping through the one-way belt conveyor Buffer silo for sand making;

Among them, the hoppers of the first layer of sieve feeding, the second layer of sieve feeding, and the third layer of sieve feeding are connected with the two-way belt conveyor, and one end is respectively connected with 20-31.5mm finished aggregate, 10-20mm finished aggregate, 4.75 -10mm finished aggregate silo is connected, and the other end is connected with the feed end of the buffer silo for fine crushing and shaping. Tape scales are installed in the direction of the 10mm finished aggregate silo, the outlets of the 20-31.5mm finished aggregate silo, the 10-20mm finished aggregate silo, and the 4.75-10mm finished aggregate silo are opposite to the inlet of the transshipment truck. The car electronic scale is installed at the bottom of the truck;

6) The buffer bin for shaping sand making is discharged through the electric vibration feeder and fed to the shaping sand making machine through the one-way belt conveyor, and the output of the shaping sand making machine enters the finished fine aggregate screen through the one-way belt conveyor , the fine aggregate finished sieve sorts the materials according to different particle sizes into one-layer sieve feeding, second-layer sieve feeding, and second-layer sieve discharging; the first-layer sieve feeding is returned to shaping by a one-way belt conveyor Buffer silo for sand making, the second-layer sieve feeds the material into the high-fineness modulus 0-4.75mm finished aggregate bin or grinder, the grinder grinds the material and then enters the integrated sand washing and fine sand recovery machine, the second-layer sieve The material enters the integrated sand washing and fine sand recycling machine through the one-way belt conveyor;

7) The materials in the sand washing and fine sand recovery integrated machine are washed and fine sand recycled to obtain finished aggregates with a fineness modulus of 0-4.75mm. The details are as follows: The sand washing and fine sand recovery integrated machine consists of wheel bucket sand washing machine, The fine sand recovery cyclone, high-frequency vibrating dewatering screen and feed pump are composed. The material entering the sand washing and fine sand recovery integrated machine is rinsed with water, and the sand-containing slurry formed flows into the wheel bucket sand washing machine for scrubbing, and the wheel bucket The overflow of the sand washing machine enters the pump pool under the dewatering screen, and is pumped by the slurry pump to the special fine sand recovery cyclone. The sand with a larger specific gravity moves downward centrifugally along the outer ring of the sorting space, and is discharged through the sand outlet; The mud with a small specific gravity is discharged from the upper overflow pipe; the sand settling products and the coarse sand scooped up by the wheel bucket sand washing machine enter the high-frequency vibrating dewatering screen for dehydration, and finally the wet sand with a certain amount of water is piled up by a one-way belt conveyor and stored in low fineness. Degree modulus 0-4.75mm finished aggregate silo, the overflow product is flocculated, concentrated and precipitated and then filtered with a filter press, the overflow from the thickener and the filtrate from the filter press enter the circulating pool of the factory area, and the mud cake is stacked by a one-way belt conveyor Temporary stockpiles exist.

Beneficial effects of the present invention:

1. In the sand making process, the combined sand making process of vertical impact breaking and grinding machine is adopted. The vertical impact crusher is mainly used for sand making, supplemented by grinding sand making such as rod mills and vertical mills as adjustments, and the two complement each other. Compared with the grinding machine, the vertical shaft impact crusher has the advantages of smaller volume, simpler foundation and higher efficiency, but its sand making is not complete, the circulation volume in the process is large, the fineness modulus of the finished sand is larger, and the particles are thicker, which is easy to The disadvantages of producing more coarse sand and stone powder, and less intermediate-grade particles; although the grinding machine-made sand is easy to adjust and stable in quality, it has the disadvantages of low output, large investment, and high energy consumption. The experimental test and application prove that the finished sand is blended from vertical impact crushed sand, grinder crushed sand and some <3mm silt removal under the inspection sieve. The gradation is the most reasonable and the fineness modulus is more suitable.

2. The new sand washing and fine sand recovery integrated machine is used as the sand washing and fine sand recovery device. The fine aggregate finished sieve residue and the ground high-fineness modulus 0-4.75mm finished aggregate contain a lot of stone powder. After sand washing and fine sand recovery, the low-fineness modulus can be obtained in a higher yield. Finished aggregate. The sand-containing slurry of the machine-made sand flows into the wheel bucket sand washing machine for scrubbing. The overflow of the sand washing machine enters the pump pool under the dewatering screen, and is pumped to the cyclone by the slurry pump. Under a certain feeding pressure, the fluid in the swirling flow Centrifugal movement inside the device. Due to the action of the centrifugal force field, the fine sand particles in the fluid accelerate the sedimentation, which strengthens the separation process. The sand with a larger specific gravity moves downward centrifugally along the outer ring of the sorting space, and is discharged through the grit chamber; the mud with a smaller specific gravity is discharged from the upper overflow pipe. The sand settling product and the coarse sand picked up by the wheel bucket sand washing machine enter the high-frequency vibrating dewatering screen for dehydration to form a mixed sand product. The overflow product is concentrated by the concentration tank and then pumped to the filter press. The overflow from the concentrator and the filter press filtrate enter the circulating pool of the factory area, and are reused without being discharged. The process requires little water, and the water can be recycled, and at the same time, the mud cake can be used as raw material for the brick factory.

Description of drawings

Fig. 1 is the production process flowchart of the present invention.

detailed description

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

The invention includes a production line for producing machine-made sand with high yield from rock waste, the production line includes a raw material bin, a feeder, a rough breaker, a desilting screen, a mud pile, a pre-screen, a secondary crusher, a classifying screen, Fine crushing and shaping machine, finished product sieve, finished aggregate bin, shaping sand making machine, grading screen, grinding machine, sand washing and fine sand recovery integrated machine, sewage thickener, compressor, various conveyors and dust collecting air pipes and other equipment and accessories .

A method for preparing machine-made sand with a high yield of rock waste, using the above-mentioned production line, comprising the following steps:

1) Coarse crushing and soil removal (mud)

The mined ore is transported to the raw material warehouse by a dump truck, and then the ore is fed into the coarse crusher or the soil removal screen by a feeder. Among them, the feeder is preferably a bar vibrating feeder, and a flap valve is installed in the lower chute to flexibly adjust whether to enter the soil removal operation according to the soil content of the raw ore mining; the bar spacing is adjusted between 150mm-200mm. Materials that are larger than the distance between the rods enter the coarse crusher through the one-way belt conveyor for coarse crushing, and materials that are smaller than the distance between the rods enter the one-way belt conveyor through the chute with a flap valve and are sent to the soil removal screen. The primary crusher is preferably a jaw crusher. The soil removal screen is preferably a vibrating screen, with a screen hole of 10mm. The material on the screen larger than 10mm is fed into the pre-screen by a one-way belt conveyor, and the material smaller than 10mm is transported as spoil to the mine dump for storage. If there is no need to remove soil, the material whose bar vibrating feeder is smaller than the bar spacing is directly discharged and merged with the jaw crusher and enters the pre-screen.

2) Pre-screening

The material enters the pre-screen through the discharge port of the coarse crusher through the one-way belt conveyor. The pre-screening is preferably double-layer circular vibrating pre-screening. The material on the first layer of the sieve enters the medium crushing buffer silo through the one-way belt conveyor, and the material on the second layer of the sieve enters the fine crushing and shaping through the one-way belt conveyor. In the buffer silo, the remaining material of the second-layer sieve enters the buffer silo for sand making through the one-way belt conveyor. In addition, suspended iron removers are installed on each one-way belt conveyor that conveys materials from the circular vibrating pre-screen, and suspended electric vibrating feeders are installed at the bottom of all transfer buffer bins in the production line.

3) medium crushing

The secondary crushing buffer silo is discharged through the electric vibrating feeder and fed to the secondary crushing machine through the one-way belt conveyor. The secondary crusher is preferably a single/multi-cylinder hydraulic cone crusher. The output of the secondary crusher enters the classifying screen through the one-way belt conveyor. The grading sieve is preferably a circular vibrating grading sieve. The material on the grading sieve returns to the secondary crusher through the one-way belt conveyor, and the under-screen material enters the buffer bin for fine crushing and shaping through the one-way belt conveyor.

4) Finely crushed and shaped

The buffer bin for fine crushing and shaping is discharged through the electric vibrating feeder and fed to the fine crushing and shaping machine through the one-way belt conveyor. The fine crushing and shaping machine is preferably a vertical shaft impact crushing and shaping machine. The output of the shaping machine enters the finished coarse aggregate screen through the one-way belt conveyor.

5) Coarse aggregate screening

The output of the fine crushing and shaping machine enters the finished coarse aggregate screen through the one-way belt conveyor. The finished screen is preferably a three-layer three-axis elliptical horizontal vibrating screen. The first to third layer sieve feeding and discharging hoppers are connected to the two-way belt conveyor, and one end is respectively connected to the 20-31.5mm, 10-20mm, and 4.75-10mm finished aggregate bins. , the other end is connected with the feed end of the buffer silo for fine crushing and shaping, and the three-layer sieve sieve surplus hopper is connected with the buffer silo for sand making through the connection of the one-way belt conveyor. In addition, the three two-way belt conveyors are equipped with belt scales in the direction of 20-31.5mm finished aggregate bin, 10-20mm finished aggregate bin and 4.75-10mm finished aggregate bin, 20-31.5mm finished aggregate bin, 10-20mm The finished aggregate silo and the outlet of the 4.75-10mm finished aggregate silo are directly opposite to the inlet of the container of the transfer truck, and the bottom of the transfer truck is equipped with a car electronic scale.

6) Shaping sand making

The shaping sand making process is mainly completed in the sand making building. The sand making building includes a buffer silo for shaping sand making, a shaping sand making machine, a finished fine aggregate screen, a grinder, a sand washing and fine sand recovery integrated machine, and a transmission device. The buffer bin for shaping sand making is discharged through the electric vibrating feeder and fed to the shaping sand making machine through the one-way belt conveyor. Shaping sand making machine is preferably vertical shaft impact crusher. The output of the sand making machine enters the finished fine aggregate screen through the one-way belt conveyor. The fine aggregate finished screen is preferably a double-layer three-axis elliptical horizontal vibrating screen. The material on the first layer of the sieve is returned to the buffer silo for sand making through the one-way belt conveyor, and the material on the second layer of the sieve is fed by the hopper and the two-way belt conveyor. Connected, one end is connected to the high-fineness modulus 0-4.75mm finished aggregate bin, the other end is connected to the feed end of the grinder, and the remaining material from the second-layer sieve enters the sand washing and fine sand recovery through the one-way belt conveyor One machine. The discharge hopper of the grinder is connected with the all-in-one sand washing and fine sand recycling machine through a one-way belt conveyor. The mill is preferably a rod mill or a vertical mill. In addition, tape scales are installed on the belt conveyors that transport finished products in the sand making building. The high-fineness modulus 0-4.75mm finished aggregate bin is directly opposite to the feed port of the transfer truck. The bottom of the transfer truck is equipped with a car electronic scale.

7) Sand washing fine sand recovery

The sand washing and fine sand recovery machine is a new type of sand washing and fine sand recovery integrated machine, which is composed of a wheel bucket sand washing machine, a special fine sand recovery cyclone, a high-frequency vibrating dewatering screen and a feeding pump. The machine-made sand is rinsed with water, and the sand-containing slurry formed flows into the wheel bucket sand washing machine for scrubbing. The overflow of the sand washing machine enters the pump pool under the dewatering screen, and is pumped to the cyclone by the slurry pump. The sand with a larger specific gravity moves downward centrifugally along the outer ring of the sorting space, and is discharged through the grit chamber; the mud with a smaller specific gravity is discharged from the upper overflow pipe. The sand settling products and the coarse sand picked up by the wheel bucket sand washing machine enter the high-frequency vibrating dewatering screen for dehydration, and finally the wet sand with a certain amount of water is piled up by the one-way belt conveyor and stored in the finished aggregate bin with a low fineness modulus of 0-4.75mm. After the overflow product is flocculated, concentrated and precipitated, it is filtered with a filter press, and the overflow from the thickener and the filter press filtrate enter the circulating pool of the plant. The mud cake is stored in a temporary storage yard by a one-way belt conveyor.

Claims (8)

1. A method for preparing sand by utilizing a rock waste high-yield preparation machine is characterized by comprising the following steps:

1) The feeding machine receives the ore, the ore is separated into feeding machine oversize products and feeding machine undersize products according to different particle sizes, the feeding machine oversize products enter the coarse crusher through the one-way rubber belt conveyor to be coarsely crushed, and the feeding machine undersize products enter the soil removal sieve through the one-way rubber belt conveyor;

2) The soil removing screen separates undersize of the feeding machine into oversize and undersize of the soil removing screen according to different particle sizes, the oversize of the soil removing screen enters a pre-screen through a one-way rubber belt conveyor, and the undersize of the soil removing screen is transported to a mine waste dump for storage as waste soil;

coarse crushing the oversize products of the feeder by a coarse crusher, and then feeding the crushed products into a pre-screening machine through a one-way rubber belt conveyor;

3) Materials entering a pre-screening device are sorted into a first-layer screen feeding material, a second-layer screen feeding material and a second-layer screen discharging material according to different particle sizes, the first-layer screen feeding material enters a middle-crushing buffer bin through a one-way rubber belt conveyor, the second-layer screen feeding material enters a buffer bin for fine crushing and shaping through a one-way belt conveyor, and the second-layer screen discharging material enters a buffer bin for shaping and sand making through a one-way rubber belt conveyor;

4) The medium crushing buffer bin discharges materials through an electric vibration feeder and feeds the materials to a medium crusher through a one-way rubber belt conveyor, the discharged materials of the medium crusher enter a grading sieve through the one-way rubber belt conveyor, the grading sieve separates the materials into oversize materials of the grading sieve and undersize materials of the grading sieve, the oversize materials of the grading sieve return to the medium crusher through the one-way rubber belt conveyor, and the undersize materials of the grading sieve enter the buffer bin for fine crushing and shaping through the one-way rubber belt conveyor;

5) The fine crushing and shaping buffer bin discharges materials through an electric vibration feeder and feeds the materials to a fine crushing and shaping machine through a one-way rubber belt conveyor, the fine crushing and shaping machine discharges materials through the one-way rubber belt conveyor and enters a coarse aggregate finished product sieve, the coarse aggregate finished product sieve separates the materials into a first-layer sieve material, a second-layer sieve material, a third-layer sieve material and a third-layer sieve material according to different particle sizes, the first-layer sieve material enters a 20-31.5mm finished product aggregate bin, the second-layer sieve material enters a 10-20mm finished product aggregate bin, the third-layer sieve material enters a 4.75-10mm finished product aggregate bin, and the third-layer sieve material enters a shaping sand making buffer bin through the one-way rubber belt conveyor;

6) The buffer bin for shaping and sand making discharges through an electric vibration feeder and feeds the materials to a shaping and sand making machine through a one-way rubber belt conveyor, the discharged materials of the shaping and sand making machine enter a fine aggregate finished product sieve through the one-way rubber belt conveyor, and the fine aggregate finished product sieve sorts the materials into a first-layer sieve material, a second-layer sieve material and a second-layer sieve material according to different particle sizes;

feeding the material on the first-layer sieve back to a buffer bin for shaping and sand making through a one-way rubber belt conveyor, feeding the material on the second-layer sieve into a finished aggregate bin or a grinding machine with the high fineness modulus of 0-4.75mm, grinding the material by the grinding machine, feeding the ground material into a sand washing and fine sand recycling integrated machine, and feeding the material on the second-layer sieve into the sand washing and fine sand recycling integrated machine through the one-way rubber belt conveyor; 7) And (3) washing sand and recovering fine sand from the materials in the sand washing and fine sand recovering integrated machine to obtain finished aggregate with the fineness modulus of 0-4.75 mm.

2. The method for preparing the sand by the rock waste high-yield preparation machine according to the claim 1, wherein in the step 1), the particle size of the oversize material of the feeding machine is more than 200mm, and the particle size of the undersize material of the feeding machine is less than 200mm.

3. The method for preparing sand by using rock wastes in a high-yield machine according to claim 1, characterized in that in the step 1), the particle size of oversize products of the feeding machine is more than 150mm, and the particle size of undersize products of the feeding machine is less than 150mm.

4. The method for preparing sand by using rock waste in a high-yield preparation machine as claimed in claim 1, wherein in the step 2), the particle size of the oversize of the earth removing sieve is more than 10mm, and the particle size of the undersize of the earth removing sieve is less than 10mm.

5. The method as claimed in claim 1, wherein in step 3), each unidirectional tape conveyor that is used to transport materials in advance and sieve outwards is equipped with a suspended iron remover, and the bottoms of all the transfer buffer bins of the production line are equipped with a suspended electric vibration feeder.

6. The method as claimed in claim 1, wherein in step 5), the hopper for feeding the first layer screen, the second layer screen and the third layer screen is connected to a bidirectional belt conveyor, one end of the hopper is connected to the 20-31.5mm finished aggregate bin, the 10-20mm finished aggregate bin and the 4.75-10mm finished aggregate bin, and the other end of the hopper is connected to the feeding end of the buffer bin for fine crushing and shaping.

7. The method as claimed in claim 6, wherein the three bi-directional belt conveyors are respectively provided with a belt scale in the directions of the 20-31.5mm finished product silo, the 10-20mm finished product silo and the 4.75-10mm finished product silo, the 20-31.5mm finished product silo, the 10-20mm finished product silo and the 4.75-10mm finished product silo are opposite to the feeding port of the container of the transfer truck, and the bottom of the transfer truck is provided with an electronic scale.

8. The method for preparing sand by utilizing rock wastes in a high-yield manner according to claim 1, wherein the step 7) comprises the following steps: the sand washing and fine sand recycling integrated machine consists of a bucket wheel sand washing machine, a special fine sand recycling cyclone, a high-frequency vibration dewatering screen and a feeding pump, wherein materials entering the sand washing and fine sand recycling integrated machine are subjected to water leaching, formed sand-containing slurry automatically flows into the bucket wheel sand washing machine to be scrubbed, the bucket wheel sand washing machine overflows into a pump pond below a screen of the dewatering screen, and is pumped to the special fine sand recycling cyclone through a slurry pump, and sand with high specific gravity centrifugally moves downwards along the outer ring of the sorting space and is discharged through a sand setting port; discharging the mud with lower specific gravity from an upper overflow pipe; the settled sand product and coarse sand fished by a wheel bucket sand washer enter a high-frequency vibration dewatering screen together for dewatering, finally, wet sand containing certain moisture is stacked in a finished aggregate bin with a low fineness modulus of 0-4.75mm by adopting a one-way rubber belt conveyor, an overflow product is filtered by a filter press after being flocculated, concentrated and precipitated, overflow liquid of the concentrator and filtrate of the filter press enter a plant circulating water pool, and mud cakes are stacked in a temporary storage yard by adopting the one-way rubber belt conveyor.

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