Production method of copper-doped tailing pavement base material

Abstract

The invention belongs to the technical field of copper tailing resource recycling, and particularly relates to a production method of a copper-doped tailing pavement base material. The method comprises the following steps: S1, grading, determining the blending proportion of the copper tailings and aggregates with various particle sizes, preparing 5-10kg of the copper tailing-doped pavement base material according to the blending proportion, uniformly mixing for 2-3min, sieving the uniformly mixed mixture to remove the aggregates, taking the copper tailings at the bottom of the sieve, and measuring the water content of the copper tailings, so as to obtain the copper tailing-doped pavement base material; calculating the water adding amount when the copper-doped tailing pavement base material is mixed; and putting the copper tailings, the aggregates with various particle sizes and the cement into a mixing station, mixing for 20-25 seconds, adding the calculated water addition amount, and mixing for 10-15 seconds to prepare the copper-doped tailing pavement base material. According to the invention, the addition amount of water is scientifically and effectively controlled so as to ensure that the copper-doped tailing pavement base material has good performance.

Description

Technical Field

[0001] The present invention belongs to the field of comprehensive utilization of copper tailings resources, and particularly relates to a production method of a pavement base course material mixed with copper tailings. Background Art

[0002] Copper tailings refer to the solid waste remaining after the beneficiation process of mines mainly engaged in copper ore resources exploitation, where the useful components in the ore are screened out. Usually, more than 98% of the components in copper ore become tailings after extraction, and the stacking of copper tailings requires land occupation, affecting the normal production and use of mining enterprises.

[0003] Semi-rigid base course materials have high early strength, good plate properties, and strong stress diffusion ability. Currently, semi-rigid materials are basically used for the existing pavement base courses; the composition and mechanical properties of copper tailings are similar to those of sand and gravel, and it has the potential to replace natural aggregates. Preparing semi-rigid materials from copper tailings for use as pavement base courses is a good way to use copper tailings with high value. When using copper tailings as aggregate for pavement base courses, a pressure filtration process is required to dehydrate the copper tailings. At present, the water content of the dehydrated copper tailings is 12 - 16%, and it is mixed with natural aggregates to prepare a pavement base course material mixed with copper tailings.

[0004] In the current design and construction specifications of pavement base course materials, the compaction test method is used to determine the optimum water content of the base course materials, and according to the water content of the raw materials, the blending method is used to determine the water addition amount during the production and preparation of pavement base course materials. For natural aggregates, their water content is generally very low and usually negligible, and the water addition amount is the optimum water content. However, the water content of copper tailings is 12 - 16%. If the blending method is used, when the copper tailings content reaches more than 25%, there will be a situation where the water addition amount is very small or no water needs to be added. In fact, after the copper tailings are mixed with the aggregates, the water in the copper tailings cannot make the surfaces of the copper tailings and the aggregates have the same water film thickness, and the surface of the aggregates cannot form a wetting effect, thus unable to undergo an effective chemical reaction with cement, resulting in the unqualified strength of the pavement base course material mixed with copper tailings. Summary of the Invention

[0005] In order to overcome the above defects in the prior art, the present invention provides a production method of a pavement base course material mixed with copper tailings. The present invention scientifically and effectively controls the water addition amount to ensure that the pavement base course material mixed with copper tailings has good performance.

[0006] To achieve the above object, the present invention adopts the following technical solutions: A production method of a pavement base course material mixed with copper tailings, the specific steps are as follows: S1. Through gradation synthesis, determine the mixing ratio of copper tailings and aggregates of each particle size. Prepare 5 - 10 kg of pavement base materials mixed with copper tailings according to the mixing ratio, mix evenly for 2 - 3 minutes, then screen the evenly mixed mixture to remove the aggregates, take the copper tailings at the bottom of the screen, and measure its moisture content P h , calculate the water addition amount during the mixing of pavement base materials mixed with copper tailings. The water addition amount calculation formula is as follows: ; ; ; ; ; In the formula: SA w ——Specific surface area of copper tailings, m 2 / kg; ρ w ——Dry density of copper tailings, g / cm 3 ; r w ——Average particle size of copper tailings, mm; u p ——Average water film thickness of pavement base materials mixed with copper tailings under the optimum moisture content state, um; P z ——Optimum moisture content determined by the compaction test of pavement base materials mixed with copper tailings, %; ρ s ——Density of water, g / cm 3 ; SA1——Specific surface area of aggregates with a particle size of 20 - 30 mm, m 2 / kg; P1——Proportion of aggregates with a particle size of 20 - 30 mm in pavement base materials mixed with copper tailings, %; SA2——Specific surface area of aggregates with a particle size of 10 - 20 mm, m 2 / kg; P2——Proportion of aggregates with a particle size of 10 - 20 mm in pavement base materials mixed with copper tailings, %; SA3——Specific surface area of aggregates with a particle size of 5 - 10 mm, m 2 / kg; P3——Proportion of aggregates with a particle size of 5 - 10 mm in pavement base materials mixed with copper tailings, %; SA4——Specific surface area of aggregates with a particle size of 3 - 5 mm, m 2 / kg; P4——Proportion of aggregates with a particle size of 3 - 5 mm in pavement base materials mixed with copper tailings, %; P w —— Proportion of copper tailings in the road base material mixed with copper tailings, %; SA s —— Specific surface area of cement, m 2 / kg; P s —— Proportion of cement in the road base material mixed with copper tailings, %; u z —— After the water in the copper tailings is transferred to the aggregate, the thickness of the water film on the surface of the aggregate, um; ɑ —— Water transfer coefficient on the surface of copper tailings after mixing; P ws —— Moisture content of copper tailings, %; P j —— Water addition amount during mixing of the road base material mixed with copper tailings, %; u g —— Thickness of the water film on the surface of copper tailings in the natural undried state, um; S2. Put the copper tailings, aggregates of each particle size, and cement into the mixing station and mix for 20 - 25 s, then add the calculated water addition amount and mix for 10 - 15 s to prepare the road base material mixed with copper tailings.

[0007] Preferably, in step S1, before uniformly mixing the road base material mixed with copper tailings, dry the copper tailings in an oven, measure the moisture content P ws of the copper tailings, screen the aggregates of each particle size and the dried copper tailings to determine the particle size composition of each raw material, and conduct gradation synthesis to determine the mixing ratio of the aggregates of each particle size and the copper tailings, and determine the cement proportion P s in the road base material mixed with copper tailings and the optimum moisture content P z .

[0008] Preferably, in step S1, the method for measuring the specific surface area of the aggregates of each particle size is as follows: Weigh 500 - 1000 g of the aggregates, after filtering the weighed aggregates by soaking in alcohol, place them in a sealed container and centrifuge for 2 - 3 min, and place absorbent paper at the bottom of the container; weigh the mass of the centrifuged aggregates; then dry and weigh the mass of the dried aggregates, and calculate the specific surface area of the aggregates according to the thickness of the alcohol film on the surface of the aggregates and the volume of the adsorbed alcohol.

[0009] Preferably, the specific surface area of the aggregates is calculated according to the following formula: ; In the formula: SA —— Specific surface area of the aggregates, m 2 / kg; m s —— Mass of the aggregates after centrifugal rotation after soaking in alcohol, g; mg —— Mass of the aggregate after drying, g; m k —— Mass of the aggregate during sampling, g; μ j —— Thickness of the alcohol film, um; ρ j —— Density of alcohol, g / cm 3 。

[0010] Preferably, in step S1, the copper tailings are equivalent to spheres, and the calculation formula for the thickness of the water film on the surface of the copper tailings in the natural undried state is as follows: ; ; In the formula: r w —— Average particle size of the copper tailings, mm; r i —— Sieve hole size, mm; r i+1 —— Sieve hole size of the previous grade of the i-th grade, mm; Q i —— Screen residue of the copper tailings on the sieve of, %; u g —— Thickness of the water film on the surface of the copper tailings in the natural undried state, um; P ws —— Moisture content of the copper tailings, %; ρ w —— Density of the dried copper tailings, g / cm 3 ; ρ s —— Density of water, g / cm 3 。

[0011] Preferably, in step S1, after the copper tailings are uniformly mixed with aggregates of various particle sizes, the water transfer coefficient on the surface of the copper tailings is calculated according to the following formula: ; In the formula: ɑ —— Water transfer coefficient on the surface of the copper tailings after mixing; P h —— Moisture content of the copper tailings after being uniformly mixed with aggregates of various particle sizes, %; P ws —— Moisture content of the copper tailings, %。

[0012] Preferably, the particle size of the copper tailings ≤ 2.36 mm.

[0013] Preferably, the thickness of the alcohol film is 10 - 16 μm, and the soaking time of each particle size aggregate in alcohol is ≥ 12 h.

[0014] Preferably, the cement proportion P in the copper tailings incorporated pavement base material s is 3.0% - 4.5%; the specific surface area of the cement is 350 - 400 m 2 / kg.

[0015] Preferably, each particle size aggregate is an aggregate with a particle size of 20 - 30 mm, an aggregate with a particle size of 10 - 20 mm, an aggregate with a particle size of 5 - 10 mm, and an aggregate with a particle size of 3 - 5 mm.

[0016] The advantages of the present invention are as follows: (1) Through a microscopic perspective, the present invention analyzes the change in the water film thickness on the surfaces of copper tailings and aggregates during the mixing process of water transfer, and enables the surfaces of copper tailings, each particle size aggregate, and cement to finally reach the state of the most water film thickness. According to the change in the water film thickness on the surfaces of copper tailings and aggregates after part of the water in the copper tailings is transferred to the aggregates, the water addition amount during the mixing process is calculated, thereby providing a scientific and effective method for determining the water addition amount of the copper tailings incorporated pavement base material.

[0017] (2) According to the mixing ratio result of the copper tailings incorporated pavement base material, the present invention prepares a mixture of copper tailings and aggregates, accurately simulates the water transfer process during the mixing process of copper tailings and aggregates, and proposes a calculation method for the water transfer coefficient during the mixing process of copper tailings, ensuring the calculation accuracy of the water addition amount in the production preparation of the copper tailings incorporated pavement base material and guaranteeing the material performance.

[0018] (3) During the mixing process of copper tailings and aggregates in the present invention, part of the water in the copper tailings is transferred to the aggregates. Considering the water film thickness on the surfaces of the transferred copper tailings and aggregates, with the average water film thickness on the surfaces of cement, aggregates, and copper tailings in the optimal moisture content state as the target value, the water addition amount during the mixing process is calculated, enabling the surfaces of various raw materials to reach the optimal water wetting state, which is beneficial to the interaction between various raw materials and gives full play to better performance. Specific embodiments

[0019] A production method for a copper tailings incorporated pavement base material includes the following steps: S1. Sampling the copper tailings and measuring its moisture content P ws is 13.6%, the water density is taken as 1 g / cm 3 , drying the copper tailings, and the density of the dried copper tailings ρ w is 2.71 g / cm 3, the sieving of the dried copper tailings, aggregates with a particle size of 20 - 30 mm, aggregates with a particle size of 10 - 20 mm, aggregates with a particle size of 5 - 10 mm, and aggregates with a particle size of 3 - 5 mm was carried out, and the results are shown in Table 1 below: Table 1 ;

[0020] S2. Perform gradation synthesis. The gradation synthesis results of copper tailings, aggregates with a particle size of 20 - 30 mm, aggregates with a particle size of 10 - 20 mm, aggregates with a particle size of 5 - 10 mm, and aggregates with a particle size of 3 - 5 mm are shown in Table 2 below: Table 2 Blending ratio ; S3. According to the method of "Test Regulations for Inorganic Binding Material Stabilized Materials in Highway Engineering" (JTG 3441), carry out mix proportion design tests to determine the cement ratio P s , the optimum moisture content P z , and the maximum dry density are shown in Table 3 below: Table 3 ;

[0022] S4. Weigh the aggregates with a particle size of 20 - 30 mm, aggregates with a particle size of 10 - 20 mm, aggregates with a particle size of 5 - 10 mm, and aggregates with a particle size of 3 - 5 mm respectively. After immersing the four kinds of aggregates in alcohol for 15 h and filtering, centrifuge them in a closed container for 2 - 3 min in turn. There is absorbent paper at the bottom of the container, and weigh the mass of each centrifuged sample; then dry them and weigh the mass of each dried aggregate. According to the alcohol film thickness and the adsorbed alcohol volume on the surface of each aggregate, the alcohol film thickness μ j Take 14 um, alcohol density ρ j Take 0.789 g / cm³, and calculate the specific surface area of each aggregate according to the following formula. The results are shown in Table 4 below: ; Table 4 ;

[0023] S5. Equivalent the copper tailings to spheres, and calculate the surface water film thickness u g of the copper tailings in the natural state and the undried state according to the following formula: = 0.31 mm; = 19 um; S6. According to the proportion of 30% copper tailings, 15% aggregates with a particle size of 20 - 30 mm, 23% aggregates with a particle size of 10 - 20 mm, 26% aggregates with a particle size of 5 - 10 mm, and 6% aggregates with a particle size of 3 - 5 mm, prepare 8 kg of the road base material mixed with copper tailings and mix evenly for 2 - 3 minutes. Then, sieve the evenly mixed mixture through a sieve with a sieve hole size of 2.36 mm, take the copper tailings at the bottom of the sieve, and measure its moisture content to be 9.6%. Calculate the water transfer coefficient of the copper tailings according to the following formula: = 0.31; S7. Under the requirement of controlling the surface water film thickness of aggregates and cement at the optimum moisture content of the road base material mixed with copper tailings, the specific surface area of cement is 360 m 2 / kg. During the mixing process of copper tailings with aggregates with a particle size of 20 - 30 mm, 10 - 20 mm, 5 - 10 mm, and 3 - 5 mm, part of the water is transferred to the aggregates with a particle size of 20 - 30 mm, 10 - 20 mm, 5 - 10 mm, and 3 - 5 mm. Calculate the water addition amount during the mixing of the road base material mixed with copper tailings according to the following formula: = 7.14 m 2 / kg; = 2.63 um; = 0.87 um; = 2.55%; ;

[0024] S8. According to the results of the mix design, add 30% copper tailings, 15% aggregates with a particle size of 20 - 30 mm, 23% aggregates with a particle size of 10 - 20 mm, 26% aggregates with a particle size of 5 - 10 mm, 6% aggregates with a particle size of 3 - 5 mm, and 3.5% cement into the mixing station and mix for 23 s, then add 2.55% water and mix for 12 s to prepare the road base material mixed with copper tailings. Construct the mixed road subbase material and test the constructed road as shown in Table 5 below. The results meet the specification requirements.

[0025] Table 5 Test Results of the Road Base Material Mixed with Copper Tailings after Construction ;

[0026] The above is only a preferred embodiment of the present invention, and it is not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A production method of a copper-doped tailings road base material, characterized in that, The specific steps are as follows: S1. Through gradation synthesis, determine the blending ratio of copper tailings and aggregates of each particle size. Prepare 5 - 10 kg of pavement base materials with copper tailings according to the blending ratio, mix evenly for 2 - 3 min, then sieve the evenly mixed mixture to remove the aggregates, take the copper tailings at the bottom of the sieve, measure its moisture content, and calculate the water addition amount during the mixing of the pavement base materials with copper tailings. The water addition amount calculation formula is as follows: ； ； ； ； ； In the formula: SA w —— Specific surface area of copper tailings, m 2 / kg; ρ w —— Dry density of copper tailings, g / cm 3 ; r w ——Average particle size of copper tailings, mm; u p ——Average water film thickness of the road base material mixed with copper tailings under the optimal moisture content state, um; P z —— Optimum moisture content determined by compaction test of copper-doped tailings roadbase material, %; ρ s —— density of water, g / cm 3 ; SA1——Specific surface area of aggregate with a particle size of 20 - 30 mm, m 2 / kg; P1—the proportion of aggregates with a particle size of 20 - 30 mm in the pavement base materials with copper tailings, %; SA2——Specific surface area of aggregates with a particle size of 10 - 20 mm, m 2 / kg; P2—the proportion of aggregates with a particle size of 10 - 20 mm in the pavement base materials with copper tailings, %; SA3—Specific surface area of aggregate with a particle size of 5 - 10 mm, m 2 / kg; P3—the proportion of aggregates with a particle size of 5 - 10 mm in the pavement base materials with copper tailings, %; SA4 —— Specific surface area of aggregate with a particle size of 3 - 5 mm, m 2 / kg; P4—the proportion of aggregates with a particle size of 3 - 5 mm in the pavement base materials with copper tailings, %; P w —— Proportion of copper tailings in the base course material of the copper tailings admixed road surface, %; SA s —— Specific surface area of cement, m 2 / kg; P s —— Cement proportion in copper-tailings-incorporated pavement base course materials, %; u z —— the thickness of the water film on the surface of the aggregate after the water in the copper tailings is transferred to the aggregate, μm; ɑ—the surface water transfer coefficient of copper tailings after mixing; P ws —— Moisture content of copper tailings, %; P j —— Water addition during mixing of copper-doped tailings pavement base course materials, %; u g —— Thickness of the water film on the surface of copper tailings in the natural undried state, um; S2. Put the copper tailings, aggregates of each particle size, and cement into the mixing station and mix for 20 - 25 s, then add the calculated water addition amount and mix for 10 - 15 s to prepare the pavement base materials with copper tailings.

2. The production method of a copper-doped tailings road base material according to claim 1, characterized in that, In step S1, before evenly mixing the pavement base materials with copper tailings, dry the copper tailings in an oven, measure the moisture content of the copper tailings, sieve the aggregates of each particle size and the dried copper tailings to determine the particle size composition of each raw material, and conduct gradation synthesis to determine the blending ratio of aggregates of each particle size and copper tailings. And according to relevant mix design tests, determine the cement ratio and the optimum moisture content in the pavement base materials with copper tailings.

3. A production method of a copper-doped tailings road base material according to claim 1, characterized in that In step S1, the method for measuring the specific surface area of aggregates of each particle size is as follows: Weigh 500 - 1000 g of aggregates, filter the weighed aggregates after soaking them in alcohol, place them in a sealed container and centrifuge for 2 - 3 min, with absorbent paper placed at the bottom of the container; weigh the mass of the aggregates after centrifugation; then dry and weigh the mass of the dried aggregates, and calculate the specific surface area of the aggregates according to the alcohol film thickness on the surface of the aggregates and the volume of adsorbed alcohol.

4. The production method of a copper-doped tailings pavement base course material according to claim 3, characterized in that, The specific surface area of the aggregates is calculated according to the following formula: ； In the formula: SA - Specific surface area of the aggregate, m 2 / kg; m s —— Mass of the aggregate after alcohol immersion and centrifugal rotation, g; m g —— Mass of the aggregate after drying, g; m k —— Mass of the aggregate during sampling, g; μ j —— Thickness of alcohol film, um; ρ j —— Density of alcohol, g / cm 3 .

5. A production method of a copper-doped tailings road base material according to claim 2, characterized in that, In step S1, the calculation formula for the surface water film thickness of copper tailings in the natural undried state is as follows: ； ； In the formula: r w ——Average particle size of copper tailings, mm; r i —— Screen hole size, mm; r i+1 —— Screen hole size of the previous gear of the i-th gear, mm; Q i —— Screen residue of copper tailings with sieve aperture , %; u g —— Thickness of the water film on the surface of copper tailings in the natural undried state, um; P ws —— Water content of copper tailings, %; ρ w ——Density of dried copper tailings, g / cm 3 ; ρ s —— Density of water, g / cm 3 。 6. The production method of a copper-doped tailings road base material according to claim 1, wherein, In step S1, after evenly mixing the copper tailings and aggregates of each particle size, the surface water transfer coefficient of copper tailings is calculated according to the following formula: ； In the formula: ɑ—the surface water transfer coefficient of copper tailings after mixing; P h —— moisture content of copper tailings, %, after being evenly mixed with aggregates of each particle size; P ws —— moisture content of copper tailings, % 7. A production method of a copper-doped tailings pavement base material according to claim 1, characterized in that: The particle size of the copper tailings ≤ 2.36 mm.

8. A production method of a copper-doped tailings road base material according to claim 3, characterized in that: The alcohol film thickness is 10 - 16 um, and the soaking time of aggregates of each particle size in alcohol is ≥ 12 h.

9. A production method of a copper-doped tailings pavement base material according to claim 1 or 2, characterized in that: The proportion of cement in the copper-doped tailings pavement base material is 3.0% - 4.5%; the specific surface area of the cement is 350 - 400 m 2 / kg.

10. A production method of a copper-doped tailings pavement base course material according to claim 1, characterized in that: The aggregates of each particle size are aggregates with a particle size of 20 - 30 mm, 10 - 20 mm, 5 - 10 mm, and 3 - 5 mm.

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