Dry-method machine-made sand and modified superfine limestone powder integrated production process

Abstract

The invention discloses an integrated production process of dry-method machine-made sand and modified superfine limestone powder, which comprises the following steps: carrying out coarse crushing, intermediate crushing, shaping sand making, winnowing, washing and wet mixing on raw materials, carrying out secondary fine selection on the winnowed and screened stone powder, separating the roughed stone powder by taking 0.045 mm as a boundary, returning part of the material with the particle size of more than 0.045 mm to finished product machine-made sand through a conveying belt, and carrying out secondary fine selection on the part of the material with the particle size of more than 0.045 mm to obtain the modified superfine limestone powder with the particle size of more than 0.045 mm. Mixing with the mixture as a machine-made sand finished product to be piled up; stone powder with the particle size being smaller than or equal to 0.045 mm is stored into a powder tank through a lifting machine and serves as a raw material of the modified superfine limestone powder. According to the process, the limestone powder is properly treated while high-quality aggregate is produced, comprehensive utilization of resources is perfectly realized in cooperation with an application scheme of a developed modified superfine limestone powder product, environmental pollution is avoided, safety risks are reduced, and great economic benefits are brought to enterprises; the use of the modified superfine limestone powder product can stimulate and drive the development of the building material industry.

Description

Technical Field

[0001] The invention relates to the technical field of sand and gravel production, and in particular to an integrated production process for dry-process machine-made sand and modified ultrafine limestone powder. Background Art

[0002] At present, domestic artificial sand production lines mostly adopt dry production, through a multi-stage and multi-segment crushing process to improve the particle shape and size of the product, and finally use different forms of powder selection equipment to complete the control of the stone powder content in the artificial sand.

[0003] Due to the different raw material tastes of each company, the raw materials will change to a certain extent during the production process. In addition, the production equipment levels and process routes of each company are uneven, resulting in a huge difference in the appearance of machine-made sand and stone powder products and poor quality stability.

[0004] Since the entire market has limited capacity to absorb ordinary stone powder, the proper handling of stone powder during the production process is an issue that needs to be urgently addressed. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the existing defects and provide an integrated production process of dry machine-made sand and modified ultrafine limestone powder, which can effectively solve the problems in the background technology.

[0006] To achieve the above object, the present invention provides the following technical solution: a dry process for producing machine-made sand and modified ultrafine limestone powder, comprising the following steps:

[0007] Step 1: Coarse crushing: The raw materials mined from the mine are controlled to have a particle size of ≤800mm and transported to the crushing pit of the production line by dump trucks. A vibrating feeder is installed under the pit to transport the raw materials to the jaw crusher to process the materials into a particle size of ≤200mm and enter the semi-finished product yard.

[0008] Step 2: Secondary crushing: The materials on the semi-finished product yard are conveyed to the impact crusher through the cage belt below for secondary crushing. After inspection and screening, the particle size of the materials is controlled to be 5mm-45mm and enters the 45mm transfer bin for standby use.

[0009] Step 3: Shaping. The material enters the vertical shaft impact crusher from the 45mm transfer bin through the vibrating feeder for shaping, and then enters the screening equipment for classification through the conveyor belt. After classification, the finished material with a particle size of more than 5mm is washed and dehydrated and then stored according to different specifications, realizing the preparation of fine coarse aggregate.

[0010] Step 4: Air separation and mixing. The materials with particle size ≤ 5mm are sent to the sand separator and mud washer via a conveyor belt. The machine-made sand products after being selected by the sand separator and mud washer are mixed and then put into the finished product yard, waiting for shipment.

[0011] Step 5: Stone powder selection. The stone powder selected by the sand selection machine and mud washing machine is selected twice, and the coarse stone powder is separated at a boundary of 0.045mm. The material with a particle size of more than 0.045mm is returned to the finished machine-made sand through the conveyor belt and mixed with it as the finished machine-made sand for storage; the stone powder with a particle size of ≤0.045mm is stored in the powder tank through the elevator as the raw material for modified ultrafine limestone powder.

[0012] Step 6: Preparation of modified ultrafine limestone powder. Stone powder with a particle size of ≤0.045mm is measured by screw conveyor, and modified materials and powdered admixtures are added and stirred for 6 minutes. The finished product after stirring is transported to the finished powder tank by the elevator and waits for shipment.

[0013] As a preferred technical solution of the present invention, in the step one, the vibrating feeder is equipped with mud removal grate bars, which can separate the material with a particle size of ≤60mm in the material, and this part of the raw material is screened for the second time, and the material with a particle size of >12mm is recycled, and the screened material is used as backfill for the foundation or road base.

[0014] As a preferred technical solution of the present invention, in the step 2, the part of the material with a particle size of more than 45 mm is crushed again, and the part with a particle size of ≤5 mm enters the mud washer.

[0015] As a preferred technical solution of the present invention, in step four, the mud washer and the sand separator both use high-pressure air as the powder selection power. By adjusting the air volume, not only the stone powder content in the machine-made sand can be controlled, but also the sand fineness modulus can be adjusted.

[0016] As a preferred technical solution of the present invention, in step five, an O-type powder concentrator is used to concentrating the stone powder screened out by the sand concentrator and the mud washer.

[0017] As a preferred technical solution of the present invention, in the step three, when the raw materials are not completely desludged, the system washes the materials after air separation in the mud washer twice, and after the dehydration and fine sand recovery process, mixes them with the products of the sand separator and enters the yard, which can effectively solve the quality risks caused by the instability of raw materials.

[0018] Compared with the prior art, the beneficial effects of the present invention are: the stone powder is properly processed while producing high-quality aggregates, and the application scheme of the modified ultrafine limestone powder product developed by us is combined with the perfect realization of the comprehensive utilization of resources, avoiding environmental pollution, reducing safety risks, and bringing greater economic benefits to enterprises. The use of modified ultrafine limestone powder products will stimulate and drive the development of the building materials industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a flow chart of the coarse crushing process of the present invention;

[0020] Figure 2 This is a flow chart of the crushing process in the present invention;

[0021] Figure 3 It is a partial flow chart of the shaping sand making process of the present invention;

[0022] Figure 4 It is a partial second flow chart of the shaping sand making process of the present invention;

[0023] Figure 5 The present invention is a flow chart of the admixture production process. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] See also Figure 1-5 The present invention provides a technical solution: a dry process for producing machine-made sand and modified ultrafine limestone powder, comprising the following steps:

[0026] Step 1: Coarse crushing. The raw materials mined from the mine are controlled to have a particle size of ≤800mm and transported to the crushing pit of the production line by dump trucks. A vibrating feeder is installed under the pit to transport the raw materials to the jaw crusher for processing into materials with a particle size of ≤200mm and then enter the semi-finished product yard. The vibrating feeder is equipped with mud removal grates, which can separate materials with a particle size of ≤60mm. This part of the raw materials is then screened for the second time, and materials with a particle size of >12mm are recycled. The screened materials are used as backfill for the foundation or road base.

[0027] Step 2: Secondary crushing: The materials on the semi-finished product yard are conveyed to the impact crusher through the cage belt below for secondary crushing. After inspection and screening, the particle size of the materials is controlled to be 5mm-45mm and enter the 45mm transfer bin for standby use. The part of the material with a particle size of >45mm is crushed again, and the part ≤5mm enters the mud washer.

[0028] Step 3: Shaping. The material is shaped by the vertical shaft impact crusher after passing through the vibrating feeder from the 45mm transfer bin, and then enters the screening equipment for classification through the conveyor belt. The finished products with a particle size of more than 5mm are graded and stored as finished products according to different specifications after two processes of washing and dehydration, realizing the preparation of fine coarse aggregate. When the raw materials are not completely desludged, the system will wash the materials after air separation in the mud washer twice, and after dehydration and fine sand recovery processes, they will be mixed with the products of the sand separator and then enter the yard, which can effectively solve the quality risks caused by the instability of raw materials.

[0029] Step 4: Air separation and mixing. Materials with a particle size of ≤5mm are sent to the sand selection machine via a conveyor belt. The machine-made sand products from the sand selection machine and mud washing machine are mixed and wetted before entering the finished product yard, waiting for shipment. The mud washing machine and sand selection machine both use high-pressure air as the powder selection power. By adjusting the air volume, not only can the stone powder content in the machine-made sand be controlled, but also the sand fineness modulus can be adjusted.

[0030] Step 5: Stone powder selection. The stone powder selected by the sand selection machine and the mud washing machine is selected by the O-type powder selection machine for secondary selection. After the secondary selection, the coarse stone powder is separated by 0.045mm. The material with a particle size of more than 0.045mm is returned to the finished machine-made sand through the conveyor belt and mixed with it as the finished machine-made sand for storage; the stone powder with a particle size of ≤0.045mm is stored in the powder tank through the elevator as the raw material for modified ultrafine limestone powder.

[0031] Step 6: Preparation of modified ultrafine limestone powder. The stone powder with a particle size of ≤0.045mm is measured by screw conveyor, and other modified materials are added and stirred. The finished product after stirring is transported to the finished powder tank by the elevator and waits for shipment.

[0032] Using ultrafine limestone powder as a carrier, it is mixed with a certain proportion of active mineral admixtures for concrete and surfactants to obtain modified ultrafine limestone powder, which can replace high-quality fly ash and mineral powder, fill the grading defects of powder in concrete, reduce the hydration heat of cement, and become the most excellent admixture in concrete. It is convenient and economical to use in concrete, and its improvement effect is particularly obvious for large volume and high-grade concrete.

[0033] Modified ultrafine limestone powder used in concrete can improve its working performance, mechanical properties and durability, significantly reduce cement consumption, directly reduce carbon emissions from the source, save concrete mix costs, and improve concrete construction efficiency. It can be applied to different operating methods and different grades of concrete, and has a very broad market demand.

[0034] Modified ultrafine limestone powder can help construction and construction units to quickly open up the market in the field of construction projects. Taking the lining shotcrete in tunnel construction as an example, the addition of modified ultrafine limestone powder can improve the working performance, mechanical properties and durability of concrete, while significantly reducing the amount of cement in tunnel concrete and solving the quality defects of fly ash, increasing the workability and viscosity of concrete, reducing the rebound rate of shotcrete, improving work efficiency, reducing construction costs, and creating good economic benefits for the enterprise.

[0035] Modified ultrafine limestone powder can also significantly reduce the amount of cement used, directly reducing carbon emissions from the source. While improving the working performance, mechanical properties and durability of tunnel concrete, it can significantly reduce the amount of cement used in shotcrete and the rebound rate of shotcrete. It can significantly reduce the construction cost of shotcrete from both the mix ratio level and the rebound rate level, and significantly reduce the carbon emissions of tunnel concrete.

[0036] The production system can also automatically recover and adjust some of the surplus aggregate products and process them into scarce varieties, perfectly solving the pressure caused by product inventory.

[0037] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An integrated production process for dry-process machine-made sand and modified ultrafine limestone powder, characterized in that: The following steps are involved: Step 1: Coarse crushing: The raw materials mined from the mine are controlled to have a particle size of ≤800mm and transported to the crushing pit of the production line by dump trucks. A vibrating feeder is installed under the pit to transport the raw materials to the jaw crusher to process the materials into a particle size of ≤200mm and enter the semi-finished product yard. Step 2: Secondary crushing: The materials on the semi-finished product yard are conveyed to the impact crusher through the cage belt below for secondary crushing. After inspection and screening, the particle size of the materials is controlled to be 5mm-45mm and enters the 45mm transfer bin for standby use. Step 3: Shaping. The material enters the vertical shaft impact crusher from the 45mm transfer bin through the vibrating feeder for shaping, and then enters the screening equipment for classification through the conveyor belt. After classification, the finished material with a particle size of more than 5mm is washed and dehydrated and then stored according to different specifications, realizing the preparation of fine coarse aggregate. Step 4: Air separation and mixing. The materials with particle size ≤ 5mm are sent to the sand separator and mud washer via a conveyor belt. The machine-made sand products after being selected by the sand separator and mud washer are mixed and then put into the finished product yard, waiting for shipment. Step 5: Stone powder selection. The stone powder selected by the sand selection machine and mud washing machine is selected twice, and the coarse stone powder is separated at a boundary of 0.045mm. The material with a particle size of more than 0.045mm is returned to the finished machine-made sand through the conveyor belt and mixed with it as the finished machine-made sand for storage; the stone powder with a particle size of ≤0.045mm is stored in the powder tank through the elevator as the raw material for modified ultrafine limestone powder. Step 6: Preparation of modified ultrafine limestone powder. Stone powder with a particle size of ≤0.045mm is measured by screw conveyor, and modified materials and powdered admixtures are added and stirred for 6 minutes. The finished product after stirring is transported to the finished powder tank by the elevator and waits for shipment.

2. The integrated production process of dry-process machine-made sand and modified ultrafine limestone powder according to claim 1, characterized in that: In the step 1, the vibrating feeder is equipped with mud removal grates, which can separate the materials with a particle size of ≤60mm. This part of the raw materials is screened for the second time, and the materials with a particle size of >12mm are recycled. The screened materials are used as backfill for the foundation or the road base.

3. The integrated production process of dry-process machine-made sand and modified ultrafine limestone powder according to claim 1 is characterized in that: In the step 2, the part of the material with a particle size of more than 45 mm is crushed again, and the part with a particle size of ≤5 mm enters the mud washer.

4. The integrated production process of dry-process machine-made sand and modified ultrafine limestone powder according to claim 1 is characterized in that: In the step 4, the mud washer and the sand separator both use high-pressure air as the powder selection power. By adjusting the air volume, not only the stone powder content in the machine-made sand is controlled, but also the sand fineness modulus is adjusted.

5. The integrated production process of dry-process machine-made sand and modified ultrafine limestone powder according to claim 1, characterized in that: In the step 5, an O-type powder concentrator is used to select the stone powder screened out by the sand concentrator and the mud washer.

6. The integrated production process of dry-process machine-made sand and modified ultrafine limestone powder according to claim 1, characterized in that: In the step three, when the raw materials are not completely desludged, the system will wash the materials after air separation in the mud washer twice, and after the dehydration and fine sand recovery process, mix them with the products of the sand separator and enter the yard to solve the quality risks caused by the instability of raw materials.

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