Dry-breaking and wet-screening sand-making process for weathered rocks

Abstract

The invention provides a weathered rock dry breaking and wet screening sand making process. The process comprises the following steps: collecting and obtaining raw stones; dividing the raw rocks into N types of weathered rocks; the method comprises the following steps: selecting characteristic indexes and corresponding rated parameters G, selecting crushers of corresponding types according to the rated parameters G, metering to obtain characteristic index numerical values Sn of various types of weathered rocks, selecting share coefficients Kn for various types of weathered rocks, and mixing corresponding parts by mass of weathered rocks according to the share coefficients Kn to obtain mixed stone; and crushing the mixed stone, mixing with water, desliming, and dehydrating to obtain the finished sand. By adopting the technical scheme provided by the invention, weathered rocks with different hardness are matched and mixed together for crushing, so that the homogenization degree of raw materials is improved, overload operation of the crusher is avoided, the production safety is guaranteed, and the service life of the crusher is prolonged.

Description

A dry crushing and wet screening process for sand making from weathered rock Technical Field

[0001] This invention belongs to the field of sand making technology, and in particular relates to a dry crushing and wet screening process for sand making from weathered rock. Background Technology

[0002] The manufactured sand process generally includes steps such as rock crushing, desliming, sand washing, and screening. Sand is an important building material required for construction projects. During the manufactured sand process, dust pollution is easily generated, and the moisture content of the raw materials needs to be increased. However, when the moisture content is high, the crusher cavity is prone to clogging when preparing sand with a particle size of less than 5mm. This requires continuous shutdown of the crusher for cleaning, which reduces production efficiency.

[0003] In the prior art, patent document with publication number "CN112676026A" discloses a dry crushing and wet screening sand making process, which includes the following steps in sequence: crushing, water mixing, and fine aggregate screening: after the sand and water are mixed, they are discharged from the hopper and screened in the fine aggregate screening equipment. The sand-water mixture at the bottom of the fine aggregate screening equipment enters the sand washing machine, which washes the sand-powder-water mixture. After the sand is dewatered by the dewatering screen, it enters the finished sand conveyor belt. The water-sand mixture is classified into 0.5mm sand-powder-water mixture on the first screen of the high-frequency screen of the fine aggregate screening equipment. The aggregate entering the subsequent screens of the sand washing machine is basically >0.5mm particles with poor viscosity, which avoids clogging the screen. By adopting the above technical solution, the sand classification and dewatering treatment are well achieved.

[0004] However, there are many types of rocks in nature, and most of them have undergone a long weathering process to become weathered rocks. According to the degree of weathering, weathered rocks are divided into five types: unweathered rocks, slightly weathered rocks, moderately weathered rocks, strongly weathered rocks, and completely weathered rocks. The appearance and morphology of different types of weathered rocks are different, and their hardness is also completely different. Among them, unweathered rocks, slightly weathered rocks, and moderately weathered rocks are difficult to crush due to their high hardness, while strongly weathered rocks and completely weathered rocks are easier to crush due to their low hardness. Therefore, in the crushing process of manufactured sand, if the crusher only crushes a single type of weathered rock, it is easy to cause the crusher to operate under overload for a long time, which is not conducive to production safety and will also affect the service life of the crusher. Summary of the Invention

[0005] To solve the above-mentioned technical problems, the present invention provides a process for dry crushing and wet screening of weathered rock to produce sand.

[0006] The present invention is achieved through the following technical solutions.

[0007] This invention provides a dry crushing and wet screening sand making process for weathered rock, comprising the following steps: Step 1: Collecting and obtaining raw stone; Step 2: Based on morphological characteristics, classifying the raw stone obtained in Step 1 into N types of weathered rock according to the degree of weathering; Step 3: Selecting characteristic indicators and corresponding rated parameters G according to requirements, then selecting the appropriate type of crusher according to the rated parameters G, and then measuring the corresponding characteristic indicators of each type of weathered rock in Step 2 to obtain the characteristic indicator values ​​Sn for each type of weathered rock, and then selecting the share coefficient Kn for each type of weathered rock, where n is a positive integer and n=1,2,...,N, and making... , Then, according to the proportion coefficient Kn, select the corresponding mass fraction of the weathered rock of the corresponding type, and mix them evenly to obtain mixed stone; Step 4: Put the mixed stone from Step 3 into a crusher for crushing to obtain mixed crushed stone with a particle size smaller than the design threshold; Step 5: Add water to the mixed crushed stone from Step 4 and mix evenly to obtain mixed slurry; Step 6: Send the mixed slurry from Step 5 into a desliming screen to remove the mud and obtain mixed sand soup; Step 7: Send the mixed sand soup from Step 6 into a dewatering screen to remove the water and obtain finished sand.

[0008] The types of weathered rocks mentioned in step two include unweathered rocks, slightly weathered rocks, moderately weathered rocks, strongly weathered rocks, and completely weathered rocks.

[0009] The characteristic index mentioned in step three is compressive strength, and the rated parameter G = 80 MPa.

[0010] The characteristic index mentioned in step three is the crushing index, and the rated parameter G=20%.

[0011] The crusher mentioned in step three is a vertical shaft impact crusher.

[0012] Step 3, measuring the corresponding characteristic indicators of various types of weathered rocks, means: randomly selecting at least three test stones from the corresponding type of weathered rocks, measuring them separately, and using the calculated arithmetic mean as the characteristic indicator value Sn of that type of weathered rock.

[0013] The design threshold mentioned in step four is 20mm.

[0014] In step five, the mass ratio of the mixed crushed stone to water is 700:3 to 900:3.

[0015] In step six, the mesh size of the desliming screen is less than 40 mm.

[0016] The weathered rock dry crushing and wet screening sand making process also includes the following steps: the mixed sand soup is sent into a sand washing machine to wash away impurities, and then step seven is carried out.

[0017] The beneficial effects of this invention are as follows: By adopting the technical solution of this invention, weathered rocks are classified according to their degree of weathering, and weathered rocks of different hardness are combined and mixed together for crushing, which improves the homogenization of raw materials and avoids the crusher from overloading unweathered rocks, slightly weathered rocks, and moderately weathered rocks. This is beneficial to improving the fineness of sand, ensuring production safety, and extending the service life of the crusher. Attached Figure Description

[0018] Figure 1 is a process flow diagram of the present invention. Detailed Implementation

[0019] The technical solution of the present invention is further described below, but the scope of protection is not limited to what is described.

[0020] As shown in Figure 1, this invention provides a dry crushing and wet screening sand making process for weathered rock, comprising the following steps: Step 1: Collecting and obtaining raw stone; Step 2: Based on morphological characteristics, classifying the raw stone obtained in Step 1 into N types of weathered rock according to the degree of weathering; Step 3: Selecting characteristic indicators and corresponding rated parameters G according to requirements, then selecting the appropriate type of crusher according to the rated parameters G, and then measuring the corresponding characteristic indicators of each type of weathered rock in Step 2, obtaining the characteristic indicator values ​​Sn of each type of weathered rock, and then selecting the share coefficient Kn for each type of weathered rock, where n is a positive integer and n=1,2,...,N, and making... , Then, according to the proportion coefficient Kn, select the corresponding mass fraction of the weathered rock of the corresponding type, and mix them evenly to obtain mixed stone; Step 4: Put the mixed stone from Step 3 into a crusher for crushing to obtain mixed crushed stone with a particle size smaller than the design threshold; Step 5: Add water to the mixed crushed stone from Step 4 and mix evenly to obtain mixed slurry; Step 6: Send the mixed slurry from Step 5 into a desliming screen to remove the mud and obtain mixed sand soup; Step 7: Send the mixed sand soup from Step 6 into a dewatering screen to remove the water and obtain finished sand.

[0021] By adopting the technical solution of this invention, weathered rocks are classified according to their degree of weathering, and weathered rocks of different hardness are combined and mixed together for crushing. This improves the homogenization of raw materials and avoids overloading the crusher with unweathered, slightly weathered, and moderately weathered rocks. This not only helps to improve the fineness of sand, but also ensures production safety and extends the service life of the crusher.

[0022] Specifically, the weathered rock types mentioned in step two include unweathered rock, slightly weathered rock, moderately weathered rock, strongly weathered rock, and completely weathered rock. Preferably, the characteristic index mentioned in step three is compressive strength, with a rated parameter G = 80 MPa. The characteristic index mentioned in step three is crushing index, with a rated parameter G = 20%. The crusher mentioned in step three is a vertical shaft impact crusher. Measuring the corresponding characteristic indexes of various types of weathered rock in step three refers to: randomly selecting at least three test stones from the corresponding type of weathered rock, measuring them separately, and then using the calculated arithmetic mean as the characteristic index value Sn for that type of weathered rock.

[0023] For example, according to the relevant provisions on compressive strength in the standard "Construction Gravel and Crushed Stone" (GB / T14685-2022), the crushing capacity of the crusher must be less than 80 MPa for the rock's compressive strength. The collected raw stones are divided into two categories: slightly weathered rock and moderately weathered rock. The average compressive strength of moderately weathered rock is 66.54 MPa, and the average compressive strength of slightly weathered rock is 91.6 MPa. Based on the rated parameter G=80 MPa, when the blending ratio of moderately weathered rock to slightly weathered rock is set at 49:51, This meets the crushing capacity requirements of the crusher and also avoids the crusher operating under overload conditions for a long time.

[0024] For example, according to the crushing index requirements in the standard "Construction Gravel and Crushed Stone" (GB / T14685-2022), the crushing capacity of the crusher must be less than 20% for the crushing index. The collected raw stone is divided into two categories: slightly weathered rock and moderately weathered rock. The average crushing index for moderately weathered rock is 29%, and the average crushing index for slightly weathered rock is 8.7%. Based on the rated parameter G=20%, when the blending ratio of moderately weathered rock to slightly weathered rock is set at 55.7:44.3, This meets the crushing capacity requirements of the crusher and avoids the crusher operating under overload conditions for a long time. In addition, the design threshold mentioned in step four is 20mm. In step five, the mass ratio of the mixed crushed stone to water is 700:3 to 90. The weathered rock dry crushing and wet screening sand making process also includes the following steps: sending the mixed sand soup into a sand washing machine to wash and remove impurities, and then proceeding to step seven.

Claims

1. A process for dry crushing and wet screening of weathered rock to produce sand, characterized in that: Includes the following steps: Step 1: Collect raw stones; Step 2: Based on morphological characteristics, classify the raw stones from Step 1 into N types of weathered rocks according to their degree of weathering; Step 3: Select characteristic indicators and corresponding rated parameters G according to requirements, then select the appropriate type of crusher based on the rated parameters G, and then measure the corresponding characteristic indicators of each type of weathered rock from Step 2, obtaining the characteristic indicator values ​​Sn for each type of weathered rock. Then, select a share coefficient Kn for each type of weathered rock, where n is a positive integer and n = 1, 2, ..., N, and make... ， Then, according to the proportion coefficient Kn, select the corresponding mass fraction of the weathered rock of the corresponding type, and mix them evenly to obtain mixed stone; Step 4: Put the mixed stone from Step 3 into a crusher for crushing to obtain mixed crushed stone with a particle size smaller than the design threshold; Step 5: Add water to the mixed crushed stone from Step 4 and mix evenly to obtain mixed slurry; Step 6: Send the mixed slurry from Step 5 into a desliming screen to remove the mud and obtain mixed sand soup; Step 7: Send the mixed sand soup from Step 6 into a dewatering screen to remove the water and obtain finished sand.

2. The weathered rock dry crushing and wet screening sand making process as described in claim 1, characterized in that: The types of weathered rocks mentioned in step two include unweathered rocks, slightly weathered rocks, moderately weathered rocks, strongly weathered rocks, and completely weathered rocks.

3. The weathered rock dry crushing and wet screening sand making process as described in claim 1, characterized in that: The characteristic index mentioned in step three is compressive strength, and the rated parameter G = 80 MPa.

4. The weathered rock dry crushing and wet screening sand making process as described in claim 1, characterized in that: The characteristic index mentioned in step three is the crushing index, and the rated parameter G=20%.

5. The weathered rock dry crushing and wet screening sand making process as described in claim 1, characterized in that: The crusher mentioned in step three is a vertical shaft impact crusher.

6. The weathered rock dry crushing and wet screening sand making process as described in claim 1, characterized in that: Step 3, measuring the corresponding characteristic indicators of various types of weathered rocks, means: randomly selecting at least three test stones from the corresponding type of weathered rocks, measuring them separately, and then using the calculated arithmetic mean as the characteristic indicator value Sn of that type of weathered rock.

7. The weathered rock dry crushing and wet screening sand making process as described in claim 1, characterized in that: The design threshold mentioned in step four is 20mm.

8. The weathered rock dry crushing and wet screening sand making process as described in claim 1, characterized in that: In step five, the mass ratio of the mixed crushed stone to water is 700:3 to 900:

3.

9. The weathered rock dry crushing and wet screening sand making process as described in claim 1, characterized in that: In step six, the mesh size of the desliming screen is less than 40 mm.

10. The weathered rock dry crushing and wet screening sand making process as described in claim 1, characterized in that: The weathered rock dry crushing and wet screening sand making process also includes the following steps: the mixed sand soup is sent into a sand washing machine to wash away impurities, and then step seven is carried out.

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