A sandstone processing system and method

Abstract

The application provides a sandstone processing system and method, which comprises a coarse crushing workshop, a medium and fine crushing workshop and a first screening workshop connected in sequence, the medium and fine crushing workshop and the first screening workshop form a closed loop, a drainage material screening workshop, a second screening workshop and a flushing screening workshop are connected to a discharge port of the first screening workshop, a sand making workshop and a pea stone screening workshop are connected to a discharge port of the second screening workshop, the discharge port of the sand making workshop and the second screening workshop form a closed loop, the discharge port of the sand making workshop and the discharge port of the second screening workshop are connected to the drainage material screening workshop, and a sand washing and fine sand recycling all-in-one machine is arranged in the second screening workshop. The application can meet the demand of different finished products, realize production according to the variety and proportion of the required aggregate in different periods of the whole construction of a project, and comprehensively consider the production process of asphalt concrete aggregate. The content of stone powder and the water content of the finished sand are uniform and stable, and the product quality is stable.

Description

Technical Field

[0001] This invention belongs to the field of pumped storage and hydroelectric aggregate technology, specifically relating to an aggregate processing system and method. Background Technology

[0002] Due to the high quality requirements for concrete aggregates in pumped storage and hydropower projects, particularly regarding mud content, dust coating, flaky and needle-like particle content, and fineness modulus, the aggregate system needs to produce three types of coarse aggregates (40mm-80mm), medium aggregates (20mm-40mm), and small aggregates (5mm-20mm), as well as normal sand (<5mm), subbase material (0mm-80mm), drainage material (5mm-80mm), and asphalt concrete aggregates. This results in a wide variety of aggregate types. Throughout the construction process, the types and proportions of aggregates will fluctuate significantly at different times due to various reasons. Therefore, the process design must include appropriate solutions to address these issues. Thus, finding a suitable aggregate processing technology that meets the requirements of such projects is imperative. Summary of the Invention

[0003] The purpose of this invention is to provide a sand and gravel processing system that overcomes the aforementioned technical problems existing in the prior art.

[0004] The purpose of this invention is to provide a sand and gravel processing method, wherein coarse crushing is carried out using a jaw crusher in an open circuit; medium crushing is carried out using an impact crusher in an open circuit; medium and fine crushing is carried out using an impact crusher and a first screening unit in a closed circuit; the first screening unit produces bedding material, drainage material, large stones, and medium stones; and sand making is carried out using a high-pressure roller mill and a second screening unit in a closed circuit; the second screening unit produces small stones, pebbles, and sand.

[0005] Therefore, the technical solution provided by the present invention is as follows:

[0006] A sand and gravel processing system includes a coarse crushing workshop, a medium and fine crushing workshop, and a first screening workshop connected in sequence. The medium and fine crushing workshop and the first screening workshop form a closed loop. The discharge port of the first screening workshop is connected to a drainage material screening workshop, a second screening workshop, and a washing screening workshop.

[0007] The discharge port of the second screening workshop is connected to the sand making workshop and the pebbles screening workshop. The discharge port of the sand making workshop and the second screening workshop form a closed loop. The discharge ports of the sand making workshop and the second screening workshop are both connected to the drainage material screening workshop. The second screening workshop is equipped with an integrated sand washing and fine sand recovery machine.

[0008] It also includes a pre-screening workshop, which is connected to the coarse crushing workshop by the same feeder. The discharge port of the pre-screening workshop is connected to a waste soil shed and a semi-finished product stockpile. The discharge port of the coarse crushing workshop is connected to the semi-finished product stockpile. Below the semi-finished product stockpile is a discharge corridor connected to the medium and fine crushing workshop.

[0009] The coarse crushing workshop is equipped with a jaw crusher, the medium and fine crushing workshop is equipped with an impact crusher, and the sand making workshop is equipped with a high-pressure double roller mill and / or a vertical shaft impact crusher.

[0010] The pre-screening workshop is equipped with a circular vibrating screen, which includes a 60mm screen and a 10mm screen arranged from top to bottom.

[0011] The first screening workshop is equipped with a second circular vibrating screen, which includes an 80mm screen, a 40mm screen and a 20mm screen arranged from top to bottom.

[0012] The second screening workshop is equipped with a circular vibrating screen three, which includes a 10mm screen, a 5mm screen and a 3mm screen arranged from top to bottom;

[0013] The drainage material screening workshop is equipped with a circular vibrating screen four. The screen mesh diameter of the circular vibrating screen four is 40mm or 20mm from top to bottom, or can be adjusted to the required mesh diameter of 5mm.

[0014] The washing and screening workshop is equipped with a circular vibrating screen five, which includes a 40mm screen and a 5mm screen arranged from top to bottom.

[0015] The pebbles screening workshop is equipped with a circular vibrating screen six, the mesh size of which is adjustable.

[0016] The feeder is a bar vibrating feeder, and the semi-finished product storage area is a point-stacking cone-shaped stack.

[0017] It also includes a wastewater treatment system, which comprises an integrated sand washing and fine sand recovery machine, a wastewater collection tank, a thickening tank, a return water tank, and a buffer mixing tank. The wastewater discharged from the integrated sand washing and fine sand recovery machine enters the wastewater collection tank through a pipe channel. The wastewater collection tank is connected to the thickening tank through a slurry pump. The thickening tank is equipped with an overflow trough at the top and a sludge hopper at the bottom. The sludge hopper is connected to the buffer mixing tank through a slurry pump.

[0018] A method for processing sand and gravel, employing a sand and gravel processing system, includes the following steps:

[0019] Step 1) The feeder separates the raw material larger than 150mm into the coarse crushing workshop for crushing. The material smaller than 150mm is conveyed to the pre-screening workshop by a belt conveyor. After screening, the material larger than 10mm and the coarse crushed material are conveyed to the semi-finished material stockpile by a belt conveyor. The material smaller than 10mm is sent to the waste soil stockpile.

[0020] Step 2) The semi-finished product is conveyed to the medium and fine crushing silo and enters the medium and fine crushing workshop for medium crushing. The medium crushed material is conveyed to the first screening workshop by a belt conveyor. The aggregates larger than 80mm and some of the aggregates 20-80mm screened out in the first screening workshop are sent to the medium and fine crushing workshop for fine crushing by a belt conveyor. The crushed material is then conveyed to the first screening workshop by a belt conveyor for closed-loop circulation.

[0021] Step 3) The 20mm-40mm and 40mm-80mm aggregates screened out in the first screening workshop enter the washing and screening workshop, where they are screened to obtain 40mm-80mm large stone aggregates and 20mm-40mm medium stone aggregates. The 0mm-20mm aggregates enter the second screening workshop.

[0022] The remaining 0mm-20mm, 20mm-40mm, and 40mm-80mm materials are mixed in proportion on a conveyor belt and then sent to the drainage material screening workshop for screening. Some of the 0mm-80mm mixed material is sent to the subbase material stockpile; the remaining part is sent to the drainage material screening workshop for screening. Some of the 20mm-80mm and all of the material smaller than 5mm are sent to the subbase material stockpile after being screened in the drainage material screening workshop, and the 5-80mm mixed material is sent to the drainage material stockpile.

[0023] Step 4) Some of the 5-20mm small stones screened out in the second screening workshop are stored in the finished product stockpile, and some of the 5-20mm stones are sent to the pebbles screening workshop for the production of pebbles; the remaining 5-20mm small stones and some 3-5mm materials are sent to the sand making workshop for sand making and shaping, and then enter the sand washing and fine sand recovery integrated machine in the second screening workshop to remove mud and powder to obtain finished sand; considering the insufficient sand ratio of the bedding material, some of the finished sand is mixed by a belt conveyor and then sent to the bedding material stockpile, and the remaining finished sand is sent to the finished product stockpile.

[0024] When it is necessary to produce asphalt concrete aggregate, the screen mesh sizes in the second screening workshop, from top to bottom, are 9.5mm, 4.75mm, and 2.36mm, while the screen mesh sizes in the pebbles screening workshop, from top to bottom, are 19mm and 16mm.

[0025] In step 4), the wastewater generated after the sand washing and fine sand recovery integrated machine in the second screening workshop removes mud and powder is introduced into the wastewater collection tank through a pipe channel. The wastewater in the tank is then pumped into the thickening tank for concentration by a slurry pump. During the concentration process, chemicals are added to accelerate the coagulation and sedimentation of solid particles in the mud in the thickening tank, thereby achieving solid-liquid separation.

[0026] The clear water in the upper layer of the thickening tank flows into the return water pool through the overflow trough and is recycled for material washing; the high-concentration slurry after coagulation in the lower layer accumulates in the sludge hopper at the bottom of the tank, and is then pumped into the buffer mixing tank for buffering, and then pumped to the filter press workshop for pressing and drying. The clear water after pressing enters the return water pool, and the sludge cake waste is transported out by truck for disposal.

[0027] The beneficial effects of this invention are:

[0028] In the sand and gravel production process, this invention uses a jaw crusher for coarse crushing, which has advantages such as simple structure, light weight, easy installation and maintenance, reliable operation, convenient discharge port adjustment, and less likelihood of material jamming. For medium and fine crushing, an impact crusher is used, which, considering the characteristics of limestone lithology, offers advantages such as high crushing ratio and good particle shape. The semi-finished material after coarse crushing is first crushed in the medium crusher and then screened in the first screening stage, which helps to ensure the particle shape of large stones. The fine crushing and the first screening stage form a closed circuit, producing subbase material and drainage material from the first screening stage, which helps to ensure the continuity of the subbase material gradation. The sand making process uses a high-pressure roller mill, which has the advantages of controllable fineness modulus and low stone powder production. Combined with the second screening stage, the closed-circuit wet production process effectively removes mud and controls powder.

[0029] This invention employs a wet production process. The main finished materials of the system include: subbase material (0mm-80mm) and drainage material (5mm-80mm); concrete aggregates of 40mm-80mm, 20mm-40mm, 5mm-20mm, and <5mm; pebbles for shotcrete and anchoring (5mm-13mm pebbles); fine aggregates of 0.075mm-2.36mm and coarse aggregates of 2.36mm-19mm (reserved) required for asphalt concrete. This invention can meet the needs of different finished materials, enabling production according to the required aggregate types and proportions at different stages of the entire construction project. It also comprehensively considers the production process of asphalt concrete aggregates. The stone powder content and moisture content in the finished sand are uniform and stable, resulting in consistent product quality. Attached Figure Description

[0030] Figure 1 This is a flowchart illustrating the present invention.

[0031] In the diagram: 1. Coarse crushing workshop; 2. Pre-screening workshop; 3. Medium and fine crushing workshop; 4. First screening workshop; 5. Drainage material screening workshop; 6. Second screening workshop; 7. Sand making workshop; 8. Washing screening workshop; 9. Pebble screening workshop; 10. Waste soil shed; 11. Semi-finished material pile; 12. Medium and fine crushing silo; 13. Feeder. Detailed Implementation

[0032] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0033] Exemplary embodiments of the present invention will now be described with reference to the accompanying drawings. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to fully and completely disclose the invention and to fully convey its scope to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the drawings is not intended to limit the invention. In the drawings, the same units / elements are referred to by the same reference numerals.

[0034] Unless otherwise stated, the terms used herein (including technical terms) have their common meaning as understood by one of ordinary skill in the art. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood to have a meaning consistent with the context of their relevant field, and not to be interpreted as having an idealized or overly formal meaning.

[0035] Example 1

[0036] This invention provides a sand and gravel processing system, such as Figure 1 As shown, it includes a coarse crushing workshop 1, a medium and fine crushing workshop 3, and a first screening workshop 4 connected in sequence. The medium and fine crushing workshop 3 and the first screening workshop 4 form a closed loop. The discharge port of the first screening workshop 4 is connected to a drainage material screening workshop 5, a second screening workshop 6, and a washing screening workshop 8.

[0037] The discharge port of the second screening workshop 6 is connected to the sand making workshop 7 and the pebbles screening workshop 9. The discharge port of the sand making workshop 7 and the second screening workshop 6 form a closed loop. The discharge ports of the sand making workshop 7 and the second screening workshop 6 are both connected to the drainage material screening workshop 5. The second screening workshop 6 is equipped with an integrated sand washing and fine sand recovery machine.

[0038] This invention produces aggregates through a coarse crushing workshop 1 and a medium and fine crushing workshop 3. Fine crushing utilizes a closed-loop production process involving a crusher and a first screening unit. The first screening workshop 4 produces subbase material, large stones, and medium stones. Sand making utilizes a closed-loop production process involving a sand making workshop 7 and a second screening unit. The second screening workshop 6 produces small stones and sand. To adjust the fineness modulus of the sand, a portion of the 3mm-5mm coarse sand is returned to a high-pressure roller mill for shaping. The high-pressure roller mill-made sand is mixed with the process sand (<3mm), and after desliming and powdering by a sand washing and fine sand recovery device, it enters the sand stockpile. This invention allows for the production of aggregates according to the required types and proportions at different stages of the entire construction project.

[0039] Example 2

[0040] Based on Embodiment 1, this embodiment provides a sand and gravel processing system, which also includes a pre-screening workshop 2. The pre-screening workshop 2 and the coarse crushing workshop 1 are connected by the same feeder 13. The discharge port of the pre-screening workshop 2 is connected to a waste soil shed 10 and a semi-finished product stockpile 11. The discharge port of the coarse crushing workshop 1 is connected to the semi-finished product stockpile 11. The semi-finished product stockpile 11 is provided with a discharge corridor connected to the medium and fine crushing workshop 3.

[0041] The raw materials are sourced from the quarry's block stone, and controlled blasting combined with mechanical crushing is used to ensure that the excavated stone particle size is below 800mm. The raw materials are transported by dump trucks to the unloading platform and then unloaded into the primary crushing workshop 1.

[0042] The primary crushing process employs an open-circuit production method. In this embodiment, the primary crushing workshop 1 is equipped with two heavy-duty bar vibrating feeders 13 and two crushers. Raw materials larger than 150mm are separated by the bar feeders 13 and fed into the crushers for further crushing. The semi-finished material is conveyed by a conveyor belt to the semi-finished material stockpile 11 for storage; materials smaller than 150mm are conveyed by a conveyor belt to the soil removal and screening workshop. The soil removal and screening workshop is equipped with one circular vibrating screen with screen apertures of 60×60mm and 20×20mm. After screening, materials larger than 20mm and the primary crushed material are conveyed by a conveyor belt to the semi-finished material stockpile 11 for storage, while materials smaller than 20mm enter the waste soil shed 10. When the raw material is relatively clean, it may not need to enter the soil removal and screening workshop and can be directly conveyed to the semi-finished material stockpile 11 for storage via a conveyor belt.

[0043] Example 3

[0044] Based on Example 1, this example provides a sand and gravel processing system, wherein the coarse crushing workshop 1 is equipped with a jaw crusher, the medium and fine crushing workshop 3 is equipped with an impact crusher, and the sand making workshop 7 is equipped with a high-pressure double roller mill.

[0045] Jaw crushers are chosen for coarse crushing due to their simple structure, light weight, ease of installation and maintenance, reliable operation, convenient discharge port adjustment, and resistance to material jamming. Impact crushers are used for medium and fine crushing, offering advantages such as high crushing ratio and good particle shape, specifically tailored to the characteristics of limestone. High-pressure double-roll mills are characterized by good product particle shape, high sand production rate, low stone powder output, and the ability to produce stone powder using wet methods.

[0046] The two-stage crushing process of "jaw crusher + impact crusher + double roller crushing" is actually a three-stage crushing process of "jaw crusher + medium crushing impact crusher + fine crushing impact crusher + double roller crushing" (two impact crushers are arranged in the same workshop): the jaw crusher and medium crushing impact crusher are produced in open circuit. The continuous crushing process is conducive to shaping coarse aggregate, reducing the content of needle-like and flaky materials and reducing the closed-circuit circulation volume of the first screening workshop 4.

[0047] Example 4

[0048] Based on Example 2, this example provides a sand and gravel processing system. The pre-screening workshop 2 is equipped with a circular vibrating screen, which includes a 60mm screen and a 10mm screen arranged from top to bottom.

[0049] The first screening workshop 4 is equipped with a circular vibrating screen 2, which includes an 80mm screen, a 40mm screen and a 20mm screen arranged from top to bottom;

[0050] The second screening workshop 6 is equipped with a circular vibrating screen 3, which includes a 10mm screen, a 5mm screen and a 3mm screen arranged from top to bottom;

[0051] The drainage material screening workshop 5 is equipped with a circular vibrating screen four. The screen mesh diameter of the circular vibrating screen four is 40mm or 20mm from top to bottom, or can be adjusted to the required mesh diameter of 5mm.

[0052] The washing and screening workshop 8 is equipped with a circular vibrating screen five, which includes a 40mm screen and a 5mm screen arranged from top to bottom.

[0053] The pebbles screening workshop 9 is equipped with a circular vibrating screen six, the mesh size of which is adjustable. In this embodiment, it is 13mm.

[0054] In this embodiment, the medium and fine crushing workshop 3 is equipped with two impact crushers. The crushed material is conveyed to the first screening workshop 4 via a belt conveyor. The aggregate larger than 80mm and some of the 20-80mm aggregates screened out in the first screening workshop 4 are conveyed back to the medium and fine crushing workshop 3 via a belt conveyor for further crushing. The crushed material is then conveyed back to the first screening workshop 4 via a belt conveyor for closed-loop circulation. The first screening workshop 4 is equipped with four heavy-duty circular vibrating screens with screen opening sizes of 80mm×80mm, 40mm×40mm, and 20mm×20mm, respectively. The mixed material crushed in the medium and fine crushing workshop 3 is conveyed to the first screening workshop 4 via a belt conveyor. After screening, the material larger than 80mm and some of the 20-80mm aggregates are conveyed back to the medium and fine crushing regulating hopper for cyclic crushing (the ratio is adjustable).

[0055] To save production costs, after the jaw crusher + medium crusher impact crusher + fine crusher impact crusher, the material and drainage material are produced after screening in the first screening workshop 4. Before the first screening workshop 4 (inclusive), dry production is adopted (without water washing).

[0056] The washing and screening workshop 8 is equipped with one circular vibrating screen 5. After washing and screening, large and medium stones are conveyed to the finished product stockpile via conveyor belt. 0-80mm bedding material is conveyed to the bedding material stockpile via conveyor belt. The drainage material screening workshop 5 is equipped with one circular vibrating screen 4. 5-80mm stones are screened and conveyed to the drainage material stockpile. The undersize material smaller than 5mm is mixed into the bedding material stockpile via conveyor belt. The remaining 5-20mm and some 3-5mm materials enter the sand making workshop 7 for sand making and shaping. A high-pressure roller mill is installed to produce manufactured sand. Manufactured sand smaller than 5mm enters the sand washing and fine sand recovery device for desliming and de-dusting, with some becoming finished sand. The remaining portion is conveyed to the bedding material stockpile via conveyor belt to replenish the bedding material. The high-pressure roller mill is suitable for dry or wet sand and gravel production lines, featuring high yield, low powder production, and shaping function for coarse sand.

[0057] The second screening workshop 6 uses a wet process. It is equipped with two circular vibrating screens (3), with screen opening sizes of 10mm×10mm, 5mm×5mm, and 3mm×3mm respectively. Two 50t / h integrated sand washing and fine sand recovery machines are located at the bottom. Some 5-20mm small stones are stockpiled in the finished product pile. The pebbles screening workshop 9 has one circular vibrating screen (6), partly used for pebbles production. The remaining 5-20mm and some 3-5mm materials enter the sand making workshop (7), where a high-pressure roller mill produces manufactured sand. Manufactured sand smaller than 5mm enters the sand washing and fine sand recovery device for desliming and powdering, with some becoming finished sand and the remainder being conveyed to the bedding material via a conveyor belt to replenish the bedding material. 5-9.5mm and 9.5-20mm stones can be flexibly mixed with the second screen in a closed-circuit sand making process to adjust the particle size distribution.

[0058] To control the mud content and stone powder content of the sand, the mixture of small stones and finished sand is washed and screened in the No. 6 screen of the second screening workshop, which is a wet production process and the fine sand is recycled; in order to control the stone powder content of the aggregate, a circular vibrating screen is set up to wash the finished large stones and medium stones before entering the finished material silo.

[0059] like Figure 1 As shown, the finished materials produced by this invention include: subbase material (0mm~80mm) and drainage material (5mm~80mm); concrete aggregates of 40mm~80mm, 20mm~40mm, 5mm~20mm, and <5mm; pebbles for shotcrete and anchoring (5mm~13mm pebbles); fine aggregates of 0.075mm~2.36mm and coarse aggregates of 2.36mm~19mm (reserved) required for asphalt concrete. This invention can meet the needs of different finished materials, enabling production according to the required aggregate types and proportions at different stages of the entire construction project. It also comprehensively considers the production process of asphalt concrete aggregates. The stone powder content and moisture content in the finished sand are uniform and stable, resulting in consistent product quality.

[0060] Example 5

[0061] Based on Example 2, this example provides a sand and gravel processing system, wherein the feeder 13 is a bar vibrating feeder 13, and the semi-finished product storage area is a point-stacking cone-shaped material storage area.

[0062] The raw material is limestone or limestone interbedded with sandstone. The raw material particle size is required to be no greater than 800mm, and raw materials with a high mud content are not allowed to enter the sand and gravel processing system. The raw material larger than 150mm is separated by bar feeder 13 and enters the primary crushing workshop 1 for crushing.

[0063] The semi-finished product storage area is a point-piled cone-shaped material pile, with a corridor underneath the pile for material discharge, which transports the semi-finished products to the medium and fine crushing workshop 3.

[0064] Example 6

[0065] Based on Example 1, this example provides a sand and gravel processing system, which also includes a wastewater treatment system. The wastewater treatment system includes an integrated sand washing and fine sand recovery machine, a wastewater collection tank, a thickening tank, a return water tank, and a buffer mixing tank. The wastewater discharged from the integrated sand washing and fine sand recovery machine enters the wastewater collection tank through a pipe channel. The wastewater collection tank is connected to the thickening tank through a slurry pump. The thickening tank is provided with an overflow trough at the top and a sludge hopper at the bottom. The sludge hopper is connected to the buffer mixing tank through the slurry pump.

[0066] The second screening workshop 6 and the washing and screening workshop 8 are the main sources of wastewater, with a high concentration of suspended solids. In the second screening workshop 6, a sand washing and fine sand recovery machine is used to remove and recover coarse particles from the sand and gravel wastewater, thereby reducing the suspended solids concentration. The wastewater from the upstream production is introduced into a wastewater collection tank through a pipe channel. The wastewater in the tank is then pumped into a thickening tank for concentration. During the concentration process, chemicals are added to accelerate the coagulation and sedimentation of solid particles in the thickening tank, achieving solid-liquid separation. The clear water from the upper layer of the thickening tank flows into a return water tank through an overflow channel and is recycled for material washing. The high-concentration slurry from the lower layer accumulates in a sludge hopper at the bottom of the tank. It is then pumped into a buffer mixing tank for buffering, and then pumped to the filter press workshop for filtration and drying. The clear water after filtration enters the return water tank, while the sludge cake waste is transported by truck for disposal.

[0067] Example 7

[0068] This embodiment provides a method for processing sand and gravel, such as Figure 1 As shown, it includes the following steps:

[0069] Step 1) Feeder 13 separates the raw material larger than 150mm into the coarse crushing workshop 1 for crushing. The material smaller than 150mm is conveyed to the pre-screening workshop 2 by a belt conveyor. After screening, the material larger than 20mm and the coarse crushed material are conveyed to the semi-finished product stockpile 11 by a belt conveyor for storage. The material smaller than 20mm is sent to the waste soil stockpile.

[0070] Step 2) The semi-finished product is conveyed to the medium and fine crushing silo 12 and enters the medium and fine crushing workshop 3 for medium crushing. The medium crushed material is conveyed to the first screening workshop 4 by a belt conveyor. The aggregates larger than 80mm and some of the aggregates 20-80mm screened out by the first screening workshop 4 enter the medium and fine crushing workshop 3 for crushing by a belt conveyor. The crushed material is conveyed to the first screening workshop 4 by a belt conveyor for closed-loop circulation.

[0071] Step 3) The 20mm-40mm and 40mm-80mm aggregates screened out in the first screening workshop 4 enter the washing and screening workshop 8, where they are screened to obtain 40mm-80mm large stone aggregates and 20mm-40mm medium stone aggregates. Some 0mm-20mm aggregates enter the second screening workshop 6.

[0072] The remaining 0mm-20mm, 20mm-40mm, and 40mm-80mm materials are mixed in proportion on a conveyor belt and then sent to the drainage material screening workshop for screening. Some of the 0mm-80mm mixed material is sent to the subbase material stockpile; the remaining part is sent to the drainage material screening workshop for screening. Some of the 20mm-80mm and all of the material smaller than 5mm are sent to the subbase material stockpile after being screened in the drainage material screening workshop, and the 5-80mm mixed material is sent to the drainage material stockpile.

[0073] Step 4) Some of the 5-20mm small stones screened out in the second screening workshop 6 are stored in the finished product stockpile, and some of the 5-20mm stones are sent to the pebbles screening workshop 9 for the production of pebbles; the remaining 5-20mm small stones and some 3-5mm materials are sent to the sand making workshop 7 for sand making and shaping, and then sent to the sand washing and fine sand recovery integrated machine in the second screening workshop 6 to remove mud and powder to obtain finished sand; considering the insufficient sand ratio of the bedding material, some of the finished sand is mixed by a belt conveyor and sent to the bedding material stockpile, and the remaining finished sand is sent to the finished product stockpile.

[0074] Since the sand ratio of the subbase material is 30-45%, the sand ratio of the subbase material obtained by this invention does not meet the requirements. Therefore, some of the finished sand is supplemented by a conveyor belt to increase the required sand ratio of the subbase material: some 0-80mm sand enters the drainage material screening workshop. After screening, <5mm and some 40-80mm or 20-80mm sand enter the subbase material stockpile to obtain the drainage material gradation.

[0075] The raw material source for this invention is limestone or limestone interbedded with sandstone aggregate. The raw material particle size must not exceed 800mm, and raw materials with high mud content are not allowed to enter the sand and gravel processing system. The sand and gravel processing system adopts a wet production process. The main finished materials of the system include: subbase material (0mm~80mm) and drainage material (5mm~80mm); concrete aggregates of 40mm~80mm, 20mm~40mm, 5mm~20mm, and <5mm; pea gravel for shotcrete and anchoring (5mm~13mm pea gravel); fine aggregate of 0.075mm~2.36mm required for asphalt concrete; and coarse aggregate of 2.36mm~19mm (reserved). The aggregate process flow is determined as: "jaw crusher + impact crusher + roller crusher".

[0076] Example 8

[0077] Based on Example 7, this example provides a sand and gravel processing method. When it is necessary to produce asphalt concrete aggregate, the screen mesh diameters of the second screening workshop 6 from top to bottom are 9.5mm, 4.75mm and 2.36mm, and the screen mesh diameters of the pebbles screening workshop 9 from top to bottom are 19mm and 16mm.

[0078] This invention takes into account the production process of asphalt concrete aggregates.

[0079] In step 4), the wastewater generated after the sand washing and fine sand recovery integrated machine in the second screening workshop 6 removes mud and powder is introduced into the wastewater collection tank through the pipe channel. The wastewater in the tank is then pumped into the thickening tank for concentration by the slurry pump. During the concentration process, chemical treatment is carried out. The chemical accelerates the coagulation and sedimentation of the solid particles of mud in the thickening tank, so as to achieve solid-liquid separation.

[0080] The clear water in the upper layer of the thickening tank flows into the return water pool through the overflow trough and is recycled for material washing; the high-concentration slurry after coagulation in the lower layer accumulates in the sludge hopper at the bottom of the tank, and is then pumped into the buffer mixing tank for buffering, and then pumped to the filter press workshop for pressing and drying. The clear water after pressing enters the return water pool, and the sludge cake waste is transported out by truck for disposal.

[0081] Based on the characteristics of product specifications, gradation requirements, varying lithology of raw materials, and large demand for finished sand, this invention's main process flow is: "two-stage crushing + two-stage screening + high-pressure roller mill sand making and shaping." The advantages of this process are its simplicity and good finished particle shape. After on-site blasting, the material source interlayer contains a significant amount of mud and flaky aggregates. To reduce the content of needle-like and flaky aggregates and considering the small demand for large stones, a continuous crushing process is adopted to improve the yield and quality of the finished material. Before entering the finished material silo, a circular vibrating screen is installed to wash the finished large and medium stones. To control the mud and stone powder content in the sand, a 6-screening unit in the second screening workshop washes and screens the mixture of small stones and finished sand, and recovers the fine sand. To ensure the required sand quantity, excess small stones and some coarse sand are fed into a high-pressure roller mill for sand making and fineness modulus adjustment.

[0082] The above examples are merely illustrative of the present invention and do not constitute a limitation on the scope of protection of the present invention. All designs that are the same as or similar to the present invention are within the scope of protection of the present invention.

Claims

1. A grit processing system, characterized by: The first screening workshop is used for screening part of 20mm-40mm and 40mm-80mm aggregate into the washing screening workshop to obtain large stone and medium stone products, and the remaining 0mm-80mm mixture is sent to the drainage material screening workshop; the drainage material screening workshop is used for separating 5-80mm mixture into drainage material, and mixing materials less than 5mm and part of 20mm-80mm materials into cushion material; The discharge outlet of the first screening workshop is also communicated with the second screening workshop, the discharge outlet of the second screening workshop is communicated with the sand making workshop and the pea stone screening workshop, the sand making workshop is provided with a high-pressure counter-roller crusher and / or a vertical shaft impact crusher, and the discharge outlet of the sand making workshop and the second screening workshop form a closed loop, the second screening workshop is used for screening part of 5-20mm small stones as products, part of 5-20mm into the pea stone screening workshop to produce pea stone material, and the remaining 5-20mm and part of 3-5mm material is sent to the sand making workshop for sand shaping; The discharge outlet of the sand making workshop and the second screening workshop form a closed loop, the discharge outlet of the sand making workshop and the discharge outlet of the second screening workshop are both communicated with the drainage material screening workshop, and the second screening workshop is provided with a sand washing and fine sand recycling all-in-one machine, which is used for removing mud and powder from the incoming material of the sand making workshop and part of the incoming material of the first screening workshop to obtain finished sand. The pre-screening workshop is communicated with the coarse crushing workshop through the same feeder, the discharge outlet of the pre-screening workshop is communicated with a waste soil material shed and a semi-finished product pile, the discharge outlet of the coarse crushing workshop is communicated with the semi-finished product pile, and a discharge corridor communicated with the medium and fine crushing workshop is arranged below the semi-finished product pile.

2. A sand processing system according to claim 1, characterized in that: The coarse crushing workshop is provided with a jaw crusher, and the medium and fine crushing workshop is provided with a counterattack crusher.

3. A sand processing system according to claim 1, characterized in that: The pre-screening workshop is provided with a circular vibrating screen one, which comprises 60mm and 10mm screen meshes arranged from top to bottom; 4. A sand processing system according to claim 2, characterized in that: The first screening workshop is provided with a circular vibrating screen two, which comprises 80mm, 40mm and 20mm screen meshes arranged from top to bottom; The second screening workshop is provided with a circular vibrating screen three, which comprises 10mm, 5mm and 3mm screen meshes arranged from top to bottom; The drainage material screening workshop is provided with a circular vibrating screen four, and the screen mesh aperture of the circular vibrating screen four is 40mm or 20mm or adjusted to the required aperture or 5mm; The washing screening workshop is provided with a circular vibrating screen five, which comprises 40mm and 5mm screen meshes arranged from top to bottom; The pea stone screening workshop is provided with a circular vibrating screen six, and the screen mesh aperture of the circular vibrating screen six is adjustable. The feeder is a bar vibrating feeder, and the semi-finished product pile is a point pile conical pile.

5. A sand processing system as claimed in claim 2, characterized in that: ​ 6. A sand processing system according to any one of claims 1-5, characterized in that: The wastewater treatment system comprises a sand washing and fine sand recycling all-in-one machine, a wastewater collecting tank, a thickening tank, a backwater tank and a buffer mixing tank, wastewater discharged from the sand washing and fine sand recycling all-in-one machine enters the wastewater collecting tank through a pipe groove, the wastewater collecting tank is communicated with the thickening tank through a slurry pump, an overflow tank is arranged at the upper portion of the thickening tank, a sludge collecting hopper is arranged at the bottom of the thickening tank, and the sludge collecting hopper is communicated with the buffer mixing tank through a slurry pump.

7. A method of processing sand and gravel using the sand and gravel processing system according to any one of claims 1 to 6, characterized in that: The method comprises the following steps: Step 1) A feeding machine divides the raw material larger than 150 mm into a coarse crushing workshop for crushing, and the material smaller than 150 mm is conveyed to a pre-screening workshop by a belt conveyor, the material larger than 10 mm after screening and the material after coarse crushing are conveyed to a semi-finished product stockpile by a belt conveyor, and the material smaller than 10 mm is put into a waste pile; Step 2) The semi-finished product is conveyed to a medium and fine crushing bin, crushed in a medium and fine crushing workshop, and conveyed to a first screening workshop by a belt conveyor; the material larger than 80 mm and part of the material of 20-80 mm screened in the first screening workshop is crushed in the medium and fine crushing workshop for fine crushing, and the crushed material is conveyed to the first screening workshop for closed-circuit circulation; Step 3) Part of the material of 20-40 mm and 40-80 mm screened in the first screening workshop is put into a washing and screening workshop, 40-80 mm large stone aggregate and 20-40 mm medium stone aggregate are obtained by screening, and part of 0-20 mm is put into a second screening workshop; The remaining 0-20 mm, 20-40 mm and 40-80 mm material screened is mixed on the belt conveyor according to a proportion, put into a drainage material screening workshop, part of 0-80 mm mixed material is put into a cushion material stockpile, and the remaining part is screened in the drainage material screening workshop, part of 20-80 mm and all of the material smaller than 5 mm is put into the cushion material stockpile after being screened in the drainage material screening workshop, and 5-80 mm mixed material is put into a drainage material stockpile; Step 4) Part of 5-20 mm small stone screened in the second screening workshop is put into a finished product stockpile, part of 5-20 mm is put into a pea stone screening workshop for producing pea stone material, the remaining 5-20 mm small stone and part of 3-5 mm material are put into a sand making workshop for sand making and shaping, and then the sand after mud removal and powder removal in the washing and fine sand recycling all-in-one machine in the second screening workshop is obtained; part of the finished product sand is mixed and then put into the cushion material stockpile, and the remaining finished product sand is put into the finished product stockpile.

8. A method of processing sand and gravel according to claim 7, characterized in that: When asphalt concrete aggregate needs to be produced, the screen mesh aperture of the second screening workshop from top to bottom is 9.5 mm, 4.75 mm and 2.36 mm, and the screen mesh aperture of the pea stone screening workshop from top to bottom is 19 mm and 16 mm.

9. A method of processing sand and gravel according to claim 7, characterized in that: Step 4) The wastewater produced after the washing and fine sand recycling all-in-one machine in the second screening workshop removes mud and powder is introduced into a wastewater collecting tank through a pipe groove, the wastewater in the tank is pumped into a thickening tank through a slurry pump for concentration, and a medicament is added for treatment in the concentration process, the medicament accelerates the coagulation and precipitation of the solid particles in the slurry in the thickening tank, and solid-liquid separation is realized; The clear water on the top of the thickener flows into the backwater pool through the overflow tank and is recycled for material washing; the high-concentration slurry condensed on the bottom of the thickener accumulates in the sludge accumulator at the center of the bottom, enters the buffer mixing pool through the slurry pump for buffering, and is then sent to the filter press workshop through the slurry pump for pressure filtration and drying. The clear water after pressure filtration enters the backwater pool, and the mud cake waste is transported out by a vehicle for disposal.

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