Engineering muck resource utilization method based on water washing treatment

Abstract

The invention discloses an engineering muck resource utilization method based on water washing treatment, which comprises the following steps: testing the fineness modulus of waste muck in a factory, trying to calculate the fineness modulus of coarse sand and fine sand which are mixed according to different proportions, and establishing a raw material blending ratio comparison table; the current batch of waste residue soil serves as first raw material sand, the fineness modulus of the first raw material sand is detected, and if the first raw material sand is fine sand, coarse sand needs to be blended; if the sand is coarse sand, fine sand needs to be blended; if the fineness modulus standard range is within the fineness modulus standard range, blending is not needed; if blending is needed, nearby coarse sand / fine sand is selected as second raw material sand, the specific fineness modulus of the second raw material sand is measured, the ratio of the first raw material sand to the second raw material sand is determined according to a raw material blending ratio comparison table, and the first raw material sand and the second raw material sand are jointly used as washing sand production line raw materials; if not, the raw material is first raw material sand; measuring the silt content of the raw materials, and adjusting equipment to proper parameters; the raw materials are put into a production line according to the determined proportion, and water washing treatment is started. According to the method, the waste residue soil treatment efficiency and the qualified rate of finished products are improved, and high universality is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of utilization of construction waste, and in particular relates to a method for resource utilization of construction waste based on water washing treatment. Background Art

[0002] Excavation projects such as river dredging and subway shield tunneling will produce a large amount of slag with a high sand content. These slag, as waste material from excavation projects, can be used to produce fine aggregate for construction projects after sand washing and mud reduction treatment, thus realizing the resource utilization of waste earth and stone.

[0003] In the prior art, a water-washing sand system is usually used to clean and treat high-sand-content slag. Due to geological differences at different locations during the excavation process, the fineness modulus and mud content of the excavated waste slag may be quite different. During the processing, when the fineness modulus of the raw sand (slag with high sand content) is greatly different from the conventional value range, the finished sand produced by the existing sand washing production line and sand washing process is difficult to meet the requirements of the construction sand specification. The unqualified finished product after the first treatment needs to be accurately mixed with other raw materials of fineness modulus and then put into the water washing production line for secondary cleaning, which wastes time, manpower and material resources, has low production efficiency and low product qualification rate. In addition, when the mud content of the raw sand exceeds the conventional range, the parameters originally set for the equipment in the sand washing production line cannot meet the needs of the normal production and operation of the sand washing line. It is necessary to continuously observe and test the quality of the finished sand manually and frequently adjust the parameters of the sand washing equipment. In this case, the sand washing effect mainly depends on the experience and professional level of the operator, which may lead to a large quality error of the finished sand, and it is necessary to rework and re-wash, which seriously affects the production efficiency and product quality of the sand washing line.

[0004] In summary, there is an urgent need for a treatment process for waste soil with a wide range of fineness modulus and mud content, so as to improve the treatment efficiency of waste soil, save costs and ensure the quality of the finished products. Summary of the invention

[0005] The present invention is made to solve the above-mentioned problems, and its purpose is to provide a method for resource utilization of construction waste based on water washing treatment.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A method for resource utilization of construction waste based on water washing treatment, comprising:

[0008] Step S1: predetermine the standard range of fineness modulus according to industry specifications and production requirements, take the waste soil with a fineness modulus lower than the standard range as fine sand, and take the waste soil with a fineness modulus higher than the standard range as coarse sand, take multiple samples of the waste soil to be processed in the factory to perform fineness modulus tests, calculate the fineness modulus of the coarse sand samples and the fine sand samples after mixing in different proportions, and establish a raw material blending ratio comparison table;

[0009] Step S2: taking a batch of waste soil to be washed as the first raw material sand, sampling the first raw material sand for fineness modulus detection, if the first raw material sand is fine sand, it needs to be blended with coarse sand; if the first raw material sand is coarse sand, it needs to be blended with fine sand; if the fineness modulus of the first raw material sand is within the standard range of fineness modulus, it does not need to be blended;

[0010] Step S3: If the first raw sand needs to be blended with coarse sand / fine sand, select coarse sand / fine sand near the water-washed sand production line as the second raw sand, sample and measure the specific fineness modulus of the second raw sand, and determine the ratio of the first raw sand and the second raw sand with reference to the raw material blending ratio comparison table, and use the first raw sand and the second raw sand together as the raw materials of the water-washed sand production line; if the first raw sand does not need to be blended, the first raw sand accounts for 100% of the ratio of the raw materials of the water-washed sand production line;

[0011] Step S4: sampling and measuring the mud content of the raw materials of the water-washed sand production line, and adjusting the water-washed sand production line equipment to appropriate parameters according to the mud content of the raw materials;

[0012] Step S5: Add raw materials into the water-washed sand production line according to the ratio determined in step S3, and start water washing;

[0013] Step S6: Sampling and quality inspection are performed on the current batch of finished products obtained after water washing. If qualified, they are stored or transported out as fine aggregates; if water washing is required for the next batch of waste soil, the cycle is continued back to step S2.

[0014] Furthermore, in step S1, waste soil piled up in the factory is sampled at multiple different locations to determine the fineness modulus, the fineness modulus of the coarse sand samples and the fine sand samples after mixing in different proportions is calculated, verified through experiments, and the results of the calculation and experiments are statistically analyzed. According to the fineness modulus after mixing and the proportion of coarse and fine sand in the blending process, combined with actual production conditions and needs, the optimal ratio is determined, and a raw material blending ratio comparison table is established. The raw material blending ratio comparison table lists the fineness modulus ranges of several fine sands, the fineness modulus ranges of several coarse sands, and the fineness modulus ranges of coarse sand in each fineness modulus range and fine sand in each fineness modulus range after mixing in the preferred ratio.

[0015] Furthermore, in step S1, when measuring the fineness modulus, the sample is first dried in a high-temperature oven, and then a particle size test is performed to measure the cumulative sieve residue percentage of each level of sieve, and the fineness modulus is calculated according to the following formula:

[0016] (1)

[0017] Where M x is the fineness modulus, A1, A2, A3, A4, A5, and A6 are the cumulative percentages of the 1st to 6th levels, and the corresponding mesh specifications are 4.75mm, 2.36mm, 1.18mm, 0.60mm, 0.30mm, and 0.15mm respectively;

[0018] Based on the data obtained from the particle size test, the cumulative sieve residue percentage after mixing coarse sand and fine sand is calculated according to the following formula:

[0019] (2)

[0020] In the formula, A i is the cumulative percentage of the i-th grade residue after blending; M1 and M2 are the blending mass of coarse sand and fine sand respectively, in g; n is the blending ratio of fine sand to coarse sand; m 1i 、m 2i are the sieve masses of coarse sand and fine sand in the particle size test at the i-th level, in g;

[0021] The cumulative percentage of screen residues at each level after the coarse and fine sands are mixed is calculated according to formula (2), and the fineness modulus after the coarse and fine sands are mixed is calculated by substituting it into formula (1).

[0022] Preferably, the drying temperature of the high temperature oven is 105±5°C.

[0023] Further, in step S4, if the raw material includes the first raw material sand and the second raw material sand, samples are taken from each of them respectively, and after mixing and stirring them in proportion and evenly, the mud content thereof is determined as the raw material mud content; if the raw material is only the first raw material sand, the mud content of the first raw material sand is sampled and determined as the raw material mud content.

[0024] Furthermore, in step S4, the mud content of the raw material is determined by a water washing method: the sample is placed in water, the mud is separated by stirring, settling and filtering, then dried and weighed, and finally the mud content percentage of the sample is calculated.

[0025] Further, in step S4, the parameters of the water-washed sand production line equipment adjusted according to the mud content of the raw materials include the motor operating frequency of the flat conveyor belt at the bottom of the screening feeder 1,

[0026] When the mud content of the raw material is less than 10%, the motor operating frequency of the flat conveyor belt is set between 18Hz-20Hz; when the mud content of the raw material is in the range of 10%-20%, the motor operating frequency of the flat conveyor belt is set between 16Hz-18Hz; when the mud content of the raw material is in the range of 20%-30%, the motor operating frequency of the flat conveyor belt is set between 15Hz-16Hz.

[0027] Furthermore, the sand washing pump used for conveying clean water to the unrinsed pipe in the water-washed sand production line is a variable frequency sand washing pump;

[0028] In step S4, the parameters of the water-washing sand production line equipment adjusted according to the mud content of the raw materials include the operating frequency of the sand washing pump,

[0029] When the mud content of the raw material is less than 10%, the operating frequency of the sand washing pump is set to 38Hz; when the mud content of the raw material is in the range of 10%-20%, the operating frequency of the sand washing pump is set to 40Hz; when the mud content of the raw material is in the range of 20%-30%, the operating frequency of the sand washing pump is set to 42Hz.

[0030] Furthermore, in step S5, if the raw materials are first raw sand and second raw sand, when feeding, the first raw sand and second raw sand of different coarseness are alternately added into the silo of the screening feeder by a loader in multiple times.

[0031] Furthermore, in step S6, the sampling quality inspection of the finished product after the water washing treatment includes fineness modulus inspection and mud content inspection.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. The method for resource utilization of construction waste soil based on water washing treatment of the present invention improves the qualified rate of finished products by pre-blending the first raw material sand with a larger or smaller fineness modulus before water washing, avoids repeated water washing, greatly improves the treatment efficiency of waste soil, and is applicable to batches of waste soil with large differences in fineness modulus in the factory, thereby improving the universality of the water washing treatment process.

[0034] 2. The method for resource utilization of construction waste based on water washing treatment of the present invention measures the mud content of the raw materials in advance before water washing, and adjusts the equipment operating parameters specifically based on the mud content of each batch of raw materials. There is no need for operators to repeatedly debug based on experience, which can improve the stability of production line operation, ensure the quality of finished products, and improve production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic diagram of the connection relationship of the water-washed sand production line;

[0036] Figure 2 This is a flow chart of the resource utilization method of construction waste based on water washing treatment.

[0037] Figure Number:

[0038] 1-screening feeder, 2-drum screen, 3-bucket wheel sand washing machine, 4-cyclone separator, 5-vibration dewatering screen, 6-liquid separation tank, 7-sand washing pump, 8-concentration tank, 9-finished sand storage area. DETAILED DESCRIPTION

[0039] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the following embodiments and the accompanying drawings specifically illustrate the method for resource utilization of construction waste based on water washing treatment of the present invention.

[0040] Example 1

[0041] like Figure 1 As shown, the water-washed sand production line generally mainly includes a screening feeder 1, a drum screen 2, several bucket wheel sand washers 3, a cyclone separator 4, a vibrating dewatering screen 5, a liquid separation tank 6 and a control cabinet and other equipment. The screening feeder 1 is arranged at the front end of the production line, including a grille, a silo arranged at the bottom of the grille and a conveyor belt at the bottom of the silo. The grille can screen out larger stone impurities. The conveyor belt includes a flat conveyor belt and an inclined conveyor belt connected to the tail end of the flat conveyor belt. The end of the inclined conveyor belt is connected to the drum screen 2. The drum screen 2 includes a drum structure, a multi-layer screen and a gravel conveyor belt. The screen is used to screen stones, gravel and sand. A rinse pipe is provided above the side of the screen. The clean water in the rinse pipe is supplied by a sand washing pump 7, which can flush and rinse the mud-sand mixture to achieve the purpose of mud removal. The gravel conveyor belt at the end of the drum screen 2 is connected to the bucket wheel sand washer 3. The number of bucket wheel sand washers 3 is set according to needs. Multiple bucket wheel sand washers 3 can be connected in series in sequence to perform multi-stage sand washing to enhance the sand washing effect. Figure 1There are two bucket wheel sand washers 3. The bucket wheel sand washer 3 is provided with a leaching pipe, an impeller and a sand washing tank. The impeller is arranged on a disc rotated by an electric drive. A screen and a sand storage tank are arranged inside the impeller. A mud overflow port is arranged on the side of the sand washing tank. The liquid separation tank 6 is arranged on one side of the production line, including a multi-stage sedimentation tank. The cyclone separator unit 4 receives the mud and sand mixture overflowing from the bucket wheel sand washer 3, separates the mud and a small amount of fine sand, and the mud enters the liquid separation tank 6 for precipitation and is then collected in the concentration tank 8, while the fine sand enters the vibrating dewatering screen 5 together with the semi-finished sand (containing a small amount of mud) output after leaching by the bucket wheel sand washer; the vibrating dewatering screen 5 is arranged at the end of the water-washed sand production line, including a driving motor, a vibration spring, a steel frame, a dewatering screen and a leaching pipe. The upper part of the steel frame is connected to the dewatering screen, and the lower part is connected to the vibration spring. Fine sand and semi-finished sand are mixed at the vibrating dewatering screen 5 and washed again, then dehydrated and output to obtain finished sand, i.e. fine aggregate for construction projects, which is transported to the finished sand storage area 9 after passing the test. The control cabinet is set in the control room next to the sand washing production line, and is electrically connected to the screening feeder 1, drum screen 2, bucket wheel sand washing machine 3, cyclone separator 4, vibrating dewatering screen 5, sand washing pump 7 and other equipment, and can adjust the operating parameters of the equipment.

[0042] like Figure 2 As shown, the present invention provides a method for resource utilization of construction waste based on water washing treatment, comprising:

[0043] Step S1: predetermine the standard range of fineness modulus according to industry specifications and production requirements, take the waste soil with a fineness modulus lower than the standard range as fine sand, and take the waste soil with a fineness modulus higher than the standard range as coarse sand, take multiple samples of waste soil with high sand content to be processed in the factory to conduct fineness modulus tests, calculate the fineness modulus of coarse sand samples and fine sand samples mixed in different proportions, and establish a raw material blending ratio comparison table;

[0044] Step S2: taking a batch of waste soil to be washed as the first raw material sand, sampling the first raw material sand for fineness modulus detection, if the current first raw material sand is fine sand with a fineness modulus lower than the standard range of fineness modulus, it is necessary to blend with coarse sand; if the current first raw material sand is coarse sand with a fineness modulus higher than the standard range of fineness modulus, it is necessary to blend with fine sand; if the current first raw material sand has a fineness modulus within the standard range of fineness modulus, it is not necessary to blend;

[0045] Step S3: If the first raw sand needs to be blended with coarse sand / fine sand, select coarse sand / fine sand near the water-washed sand production line as the second raw sand, sample and measure the specific fineness modulus of the second raw sand, and determine the ratio of the first raw sand and the second raw sand with reference to the raw material blending ratio comparison table, and use the first raw sand and the second raw sand together as the raw materials of the water-washed sand production line; if the first raw sand does not need to be blended, the first raw sand accounts for 100% of the ratio of the raw materials of the water-washed sand production line;

[0046] Step S4: sampling and measuring the mud content of the raw materials of the water-washed sand production line, and adjusting the water-washed sand production line equipment to appropriate parameters according to the mud content;

[0047] Step S5: adding raw materials, i.e., the first raw material sand or the first raw material sand and the second raw material sand in a corresponding ratio, into the water-washing sand production line according to the ratio determined in step S3, and starting water washing;

[0048] Step S6: Sampling and quality inspection are performed on the current batch of finished products obtained after water washing. If qualified, they are stored or transported out as fine aggregates; if water washing is required for the next batch of waste soil, the cycle is continued back to step S2.

[0049] Furthermore, in step S1, waste soil piled up in the factory is sampled at multiple different locations to determine the fineness modulus, waste soil with a fineness modulus lower than the standard range of fineness modulus is taken as fine sand, and waste soil with a fineness modulus higher than the standard range of fineness modulus is taken as coarse sand, and the fineness modulus of coarse sand samples and fine sand samples mixed in different proportions is calculated, verified by experiments, and statistical analysis is performed on the results of the calculations and experiments. According to the fineness modulus after mixing and the proportion of coarse and fine sand in the blending process, combined with actual production conditions and needs, the preferred ratio is determined, and a raw material blending ratio comparison table is established. Specifically, the raw material blending ratio comparison table lists the fineness modulus intervals of several fine sands, the fineness modulus intervals of several coarse sands, and the fineness modulus ranges after the coarse sand in each fineness modulus interval and the fine sand in each fineness modulus interval are mixed in the preferred ratio, providing a ratio reference for each batch of waste soil that is subsequently washed.

[0050] Furthermore, in step S1, step S2 and step S3, when measuring the fineness modulus, the sample is first dried in a high-temperature oven, and then a particle size test is performed to measure the cumulative sieve residue percentage of each level of sieve, and the fineness modulus is calculated according to the following formula:

[0051] (1)

[0052] Where M x is the fineness modulus, A1, A2, A3, A4, A5 and A6 are the cumulative sieve residue percentages of the 1st to 6th levels, and the corresponding sieve hole specifications are 4.75mm, 2.36mm, 1.18mm, 0.60mm, 0.30mm and 0.15mm respectively.

[0053] In the process of measuring the fineness modulus, the high temperature oven drying temperature is preferably 105±5°C, which can achieve rapid drying of the sample and improve test efficiency.

[0054] Furthermore, in step S1, based on the data measured by the particle size test, the cumulative sieve residue percentage after the coarse sand and fine sand are mixed is calculated according to the following formula:

[0055] (2)

[0056] In the formula, A i is the cumulative percentage of the i-th grade residue after blending; M1 and M2 are the blending mass of coarse sand and fine sand respectively, in g; n is the blending ratio of fine sand to coarse sand; m 1i 、m 2i They are respectively the sieved masses of coarse sand and fine sand at the i-th level in the particle size test, in g.

[0057] Then, the cumulative percentage of each level of screen residue after the coarse and fine sands are mixed is calculated according to formula (2). Similarly, the fineness modulus after the coarse and fine sands are mixed can be calculated using formula (1).

[0058] After performing multiple ratio calculations on multiple groups of different coarse and fine sand combinations, the calculation results can be further verified through indoor tests. After statistical analysis of the calculation and experimental results, based on comprehensive consideration of production needs, on-site raw material conditions and other factors, the appropriate raw material coarse and fine sand fineness modulus range and the suitable ratio of coarse and fine sand combinations with different fineness moduli are determined, a raw material blending ratio comparison table is established, and the corresponding expected fineness modulus after mixing according to the ratio is listed for reference. After the water washing ratio table is established, the subsequent water washing treatment of each batch of waste slag soil in the factory can basically refer to the data in the table to determine the ratio, which can improve the qualified rate of finished sand after a single water washing, avoid repeated water washing, and effectively improve the efficiency of using waste slag soil to produce fine aggregate, while saving manpower, material and time costs and improving resource utilization.

[0059] Furthermore, in steps S2 and S3, the fineness modulus of the first raw sand is compared with the standard range of fineness modulus. If the fineness modulus of the current first raw sand exceeds the standard range of fineness modulus, it is necessary to mix coarse sand or fine sand accordingly. The operator can first visually judge the waste soil available for mixing on site based on experience, select waste soil with a coarseness that roughly meets the requirements as the second raw sand, and then sample and measure the specific fineness modulus of the second raw sand. Refer to the raw material blending ratio comparison table to determine the ratio of the first raw sand to the second raw sand, and use the first raw sand and the second raw sand together as the raw materials for the washed sand production line. If the fineness modulus of the current first raw sand is within the standard range of fineness modulus, there is no need to mix coarse sand or fine sand separately, and the first raw sand accounts for 100% of the raw material ratio of the washed sand production line.

[0060] Furthermore, in step S4, if the raw material includes the first raw material sand and the second raw material sand, the two are sampled respectively, mixed in proportion and stirred evenly, and the mud content thereof is determined as the raw material mud content. If the raw material is only the first raw material sand, the mud content of the first raw material sand is sampled and determined as the raw material mud content. The raw material mud content can be determined by traditional methods, such as a water washing method: the sample is placed in water, and impurities such as soil are separated by stirring, settling, filtering and other steps, and then dried and weighed, and finally the mud content percentage of the sample is calculated.

[0061] Further, in step S4, the parameters of the water-washed sand production line equipment adjusted according to the mud content of the raw materials include the motor operating frequency of the flat conveyor belt. Specifically, the rated power of the flat conveyor belt motor is 11KW. When the mud content of the raw materials is less than 10%, the motor operating frequency of the flat conveyor belt is set between 18Hz-20Hz; when the mud content of the raw materials is in the range of 10%-20%, the motor operating frequency of the flat conveyor belt is set between 16Hz-18Hz; when the mud content of the raw materials is in the range of 20%-30%, the motor operating frequency of the flat conveyor belt is set between 15Hz-16Hz. According to the mud content of the raw materials, a lower flat conveyor belt motor operating frequency is set when the mud content is large, and a higher flat conveyor belt motor operating frequency is set when the mud content is small, which can control the feed amount of the raw materials, thereby achieving the comprehensive production goals of ensuring the quality of sand washing when the mud content is large and ensuring the efficiency of sand washing when the mud content is small.

[0062] Furthermore, the sand washing pump 7 ( Figure 1 ) is a variable frequency sand washing pump, and the rated power of the motor of the sand washing pump 7 is 22KW. In step S4, the water-washing sand production line equipment parameters adjusted according to the mud content of the raw material also include the operating frequency of the sand washing pump 7. When the mud content of the raw material is less than 10%, the operating frequency of the sand washing pump 7 is set to 38Hz; when the mud content of the raw material is in the range of 10%-20%, the operating frequency of the sand washing pump 7 is set to 40Hz; when the mud content of the raw material is in the range of 20%-30%, the operating frequency of the sand washing pump 7 is set to 42Hz. By controlling the operating frequency of the variable frequency sand washing pump 7, the overall water output of the leaching pipe can be adjusted, and different flushing volumes and flushing processes are set for raw materials with different mud contents, which can ensure the comprehensive benefits of sand washing effect and energy consumption balance.

[0063] Furthermore, in step S5, if the raw materials are first raw sand and second raw sand, when feeding, the first raw sand and second raw sand of different coarseness are added alternately into the hopper of the screening feeder 1 by a loader in multiple times, so that the coarse and fine sands are mixed more evenly in the screening feeder 1.

[0064] Furthermore, in step S6, the current batch of finished products obtained after the water washing process is sampled for quality inspection to confirm that the parameters such as fineness modulus and mud content meet the requirements to ensure the quality of the finished sand (fine aggregate). If the water-washed sand production line needs to wash the next batch of waste soil, it returns to step S2 to continue the cycle.

[0065] Example 2

[0066] On the basis of Example 1, this example further describes in detail the process of establishing the raw material blending ratio comparison table in step S1 in combination with specific numerical values.

[0067] First, the fineness modulus standard range set in this embodiment is 2.3-3.0 (Class I sand), and multiple samples of high-sand content waste soil to be treated in the factory are taken for fineness modulus testing. The waste soil with a fineness modulus lower than the fineness modulus standard range is regarded as fine sand, and the waste soil with a fineness modulus higher than the fineness modulus standard range is regarded as coarse sand. The particle size test data of the two samples are recorded as shown in Table 1 below:

[0068] Table 1 Particle size test data

[0069]

[0070] Substituting the values ​​of the sieve residue percentage of each level of sieve measured in the particle size test into formula 1 for calculation, the fineness modulus of sample 1 is calculated to be 3.25, which is higher than the standard range of fineness modulus and is coarse sand; the fineness modulus of sample 2 is 2.12, which is lower than the standard range of fineness modulus and is fine sand.

[0071] The fineness modulus of coarse sand and fine sand mixed in different proportions was calculated, and the results are shown in Table 2 below:

[0072] Table 2 Blending results

[0073]

[0074] Substituting the cumulative sieve residue percentages, sieve mass and blending mass of coarse sand and fine sand in Table 1 into Formula 2 for calculation, the cumulative sieve residue percentages of mixed raw material sand at the corresponding blending ratio can be obtained. Formula 1 can be used to further calculate the corresponding fineness modulus according to the cumulative sieve residue percentages of mixed raw material sand at each level. As shown in Table 2, if the fine sand of sample 2 is blended with the coarse sand of sample 1 at a ratio of 1:1, the fineness modulus of the mixed sand is calculated to be 2.62; if the fine sand of sample 2 is blended with the coarse sand of sample 1 at a ratio of 1:2, the fineness modulus of the mixed sand is calculated to be 2.83; if the fine sand of sample 2 is blended with the coarse sand of sample 1 at a ratio of 1:3, the fineness modulus of the mixed sand is calculated to be 2.98.

[0075] By analogy, we can continue to perform ratio calculations on other samples with different fineness modulus according to the above process to obtain sufficient sample data. In order to verify the reliability of the calculation results, we can further conduct indoor tests and production line trial production.

[0076] When establishing a raw material blending ratio comparison table, the preferred ratio is determined based on the actual coarseness of the waste soil to be washed and treated in the factory and the amount of waste soil of different coarsenesses.

[0077] Example 3

[0078] On the basis of Example 1 and Example 2, this example further describes in detail the process of determining the ratio of the first raw material sand and the second raw material sand in step S3 in combination with specific numerical values.

[0079] The raw material blending ratio comparison table referred to in this embodiment is shown in Table 3 below:

[0080] Table 3 Comparison table of raw material blending ratios

[0081]

[0082] In this embodiment, the fineness modulus of the first raw material sand is measured to be 3.25, which is higher than the standard range of fineness modulus 2.3-3.0, and needs to be blended with fine sand.

[0083] The operator selects a batch of fine sands that can be used for blending on site, and samples and measures the specific fineness modulus thereof. In this embodiment, in order to more fully demonstrate the reliability of this method, two fine sands with different fineness moduli shown in Table 4 below are used for illustration.

[0084] Table 4 Results of coarse and fine sand mixing ratio

[0085]

[0086] As shown in Table 4, the fineness modulus of coarse sand (first raw material sand) is 3.25, which is within the range of 3.2-3.3 in Table 3; if the fine sand taken nearby is "fine sand 1", the fineness modulus of fine sand 1 is 2.12 after test, which is within the range of 2.0-2.2 in Table 3, then the ratio of fine sand to coarse sand can be selected as 1:2 according to Table 3, and the fineness modulus after calculation and experimental verification is 2.89, which is within the standard range of fineness modulus. If the fine sand taken nearby is "fine sand 2", the fineness modulus of fine sand 2 is 2.48 after test, which is within the range of 2.2-2.5 in Table 3, so the ratio of fine sand to coarse sand is selected as 1:1 according to Table 3, and the fineness modulus after calculation and experimental verification is 2.86, which is within the standard range of fineness modulus. It can be seen that blending waste soil of different coarseness and fineness according to the raw material blending ratio comparison table before water washing treatment can make the fineness modulus of the raw materials entering the water-washed sand production line meet the standard range, improve the qualified rate of the finished product, avoid repeated water washing, reduce costs, and improve the resource utilization rate of waste soil.

[0087] Example 4

[0088] This embodiment further illustrates the setting standards for appropriate parameters of the water-washed sand production line equipment in step S4 of embodiment 1.

[0089] The water-washed sand production line was used for production tests. The types and specifications of the equipment used in the test were the same as those of most water-washed sand production lines in this field. The rated power of the flat conveyor belt motor was 11KW, and the rated power of the sand washing pump 7 motor was 22KW.

[0090] The following experiment is conducted by controlling variables to explore the influence of the motor operating frequency of the flat conveyor belt and the motor operating frequency of the sand washing pump on the mud content of the finished product.

[0091] First, the frequency of the sand washing pump is controlled to be constant, and the frequency of the flat conveyor belt is set to different values, and the same batch of waste soil (same raw material mud content) is washed with water. For example, the raw material mud content is 9.27%, the sand washing pump frequency is set to 38hz, and the flat conveyor belt frequencies are 14hz, 16hz, 18hz, 20hz, 21hz, and 22hz, respectively. After the water washing treatment, samples are taken to measure the mud content of the finished product. The results are shown in Table 5 below:

[0092] Table 5 Effect of flat conveyor belt frequency on mud content of finished products

[0093]

[0094] Based on the test results, taking into account the sand washing effect, fine sand efficiency and equipment operating energy consumption, when the mud content of the first raw sand is less than 10%, it is more appropriate to set the motor operating frequency of the flat conveyor belt between 18Hz-20Hz.

[0095] Continue to use raw materials with different mud contents to conduct experiments on controlled variables in the above manner. Similarly, it can be obtained that: when the mud content of the raw materials is in the range of 10%-20%, it is more appropriate to set the motor operating frequency of the flat conveyor belt between 16Hz-18Hz; when the mud content of the raw materials is in the range of 20%-30%, it is more appropriate to set the motor operating frequency of the flat conveyor belt between 15Hz-16Hz.

[0096] According to the above method, the frequency of the flat conveyor belt is controlled to remain unchanged, the frequency of the sand washing pump is set to different values, a batch of waste soil (same raw material mud content) is washed with water, the mud content of the finished product is measured, and then the raw materials with different mud contents are further used to test the control variables. By the same token, it can be obtained that: when the mud content of the raw material is less than 10%, it is more appropriate to set the operating frequency of the sand washing pump 7 to 38Hz; when the mud content of the raw material is in the range of 10%-20%, it is more appropriate to set the operating frequency of the sand washing pump 7 to 40Hz; when the mud content of the raw material is in the range of 20%-30%, it is more appropriate to set the operating frequency of the sand washing pump 7 to 42Hz.

[0097] The standard range of raw material mud content based on which the parameters of the water-washed sand production line equipment are adjusted in this embodiment is obtained through a large number of experiments and summaries, and comprehensively considers the sand washing effect, fine sand efficiency and equipment operation energy consumption. It has good universality and practicality, and can be directly applied to most water-washed sand production lines or provide a reference for parameter setting of production line equipment.

[0098] In summary, the method for resource utilization of construction waste soil based on water washing treatment of the present invention can be applied to waste soil with a wide range of variations in fineness modulus and mud content, achieves high-efficiency water washing treatment, improves the qualified rate of finished products, avoids repeated water washing, ensures the quality of the output finished products, and at the same time improves the universality of the resource utilization method based on water washing treatment for different waste soils.

[0099] The above-mentioned embodiments are preferred examples of the present invention and are not intended to limit the protection scope of the present invention.

Claims

1. A method for resource utilization of construction waste based on water washing treatment, characterized in that: include: Step S1: predetermine the standard range of fineness modulus according to industry specifications and production requirements, take the waste soil with a fineness modulus lower than the standard range as fine sand, and take the waste soil with a fineness modulus higher than the standard range as coarse sand, take multiple samples of the waste soil to be processed in the factory to perform fineness modulus tests, calculate the fineness modulus of the coarse sand samples and the fine sand samples after mixing in different proportions, and establish a raw material blending ratio comparison table; Step S2: taking a batch of waste soil to be washed as the first raw material sand, sampling the first raw material sand for fineness modulus detection, if the first raw material sand is fine sand, it needs to be blended with coarse sand; if the first raw material sand is coarse sand, it needs to be blended with fine sand; if the fineness modulus of the first raw material sand is within the standard range of fineness modulus, it does not need to be blended; Step S3: If the first raw sand needs to be blended with coarse sand / fine sand, coarse sand / fine sand near the water-washed sand production line is selected as the second raw sand, and the specific fineness modulus of the second raw sand is measured by sampling, and the ratio of the first raw sand and the second raw sand is determined by referring to the raw material blending ratio comparison table, and the first raw sand and the second raw sand are used together as raw materials for the water-washed sand production line; if the first raw sand does not need to be blended, the first raw sand accounts for 100% of the ratio of the raw materials of the water-washed sand production line; Step S4: sampling and measuring the mud content of the raw materials of the water-washed sand production line, and adjusting the water-washed sand production line equipment to appropriate parameters according to the mud content of the raw materials; Step S5: Add raw materials into the water-washed sand production line according to the ratio determined in step S3, and start water washing; Step S6: Sampling and quality inspection are performed on the current batch of finished products obtained after water washing. If qualified, they are stored or transported out as fine aggregates; if water washing is required for the next batch of waste soil, the cycle is returned to step S2 to continue.

2. The method for recycling construction waste soil based on water washing treatment according to claim 1 is characterized in that: In the step S1, waste soil piled up in the factory is sampled at multiple different locations to determine the fineness modulus, the fineness modulus of coarse sand samples and fine sand samples after mixing in different proportions is calculated, verified through experiments, and statistically analyzed on the results of the calculation and experiments. According to the fineness modulus after mixing and the proportion of coarse and fine sand in the blending process, combined with actual production conditions and needs, the preferred ratio is determined, and the raw material blending ratio comparison table is established. The raw material blending ratio comparison table lists the fineness modulus ranges of several fine sands, the fineness modulus ranges of several coarse sands, and the fineness modulus ranges of coarse sand in each fineness modulus range and fine sand in each fineness modulus range after mixing in the preferred ratio.

3. The method for recycling construction waste soil based on water washing treatment according to claim 2 is characterized in that: In step S1, when measuring the fineness modulus, the sample is first dried in a high-temperature oven, and then a particle size test is performed to measure the cumulative sieve residue percentage of each level of sieve, and the fineness modulus is calculated according to the following formula: （1） Where M x is the fineness modulus, A1, A2, A3, A4, A5, and A6 are the cumulative percentages of the 1st to 6th levels, and the corresponding mesh specifications are 4.75mm, 2.36mm, 1.18mm, 0.60mm, 0.30mm, and 0.15mm respectively; Based on the data obtained from the particle size test, the cumulative sieve residue percentage after mixing coarse sand and fine sand is calculated according to the following formula: （2） In the formula, A i is the cumulative percentage of the i-th grade residue after blending; M1 and M2 are the blending mass of coarse sand and fine sand, respectively, in g; n is the mixing ratio of fine sand to coarse sand; m 1i 、m 2i are the sieve masses of coarse sand and fine sand in the particle size test at the i-th level, in g; The cumulative percentage of screen residues at each level after the coarse and fine sands are mixed is calculated according to formula (2), and the fineness modulus after the coarse and fine sands are mixed is calculated by substituting it into formula (1).

4. The method for recycling construction waste soil based on water washing treatment according to claim 3 is characterized in that: The drying temperature of the high temperature oven is 105±5°C.

5. The method for recycling construction waste soil based on water washing treatment according to claim 1 is characterized in that: In step S4, if the raw material includes the first raw material sand and the second raw material sand, samples are taken from the two respectively, mixed in proportion and stirred evenly, and then the mud content thereof is determined as the raw material mud content; if the raw material is only the first raw material sand, the mud content of the first raw material sand is sampled and determined as the raw material mud content.

6. The method for recycling construction waste soil based on water washing treatment according to claim 1 is characterized in that: In step S4, the mud content of the raw material is determined by a water washing method: the sample is placed in water, the mud is separated by stirring, settling and filtering, then dried and weighed, and finally the mud content percentage of the sample is calculated.

7. The method for recycling construction waste soil based on water washing treatment according to claim 1 is characterized in that: In step S4, the parameters of the water-washed sand production line equipment adjusted according to the mud content of the raw materials include the operating frequency of the motor of the flat conveyor belt at the bottom of the screening feeder, When the mud content of the raw material is less than 10%, the motor operating frequency of the flat conveyor belt is set between 18Hz-20Hz; when the mud content of the raw material is in the range of 10%-20%, the motor operating frequency of the flat conveyor belt is set between 16Hz-18Hz; when the mud content of the raw material is in the range of 20%-30%, the motor operating frequency of the flat conveyor belt is set between 15Hz-16Hz.

8. The method for recycling construction waste soil based on water washing treatment according to claim 1 is characterized in that: The sand washing pump used for conveying clean water to the unwashed pipe in the water-washed sand production line is a variable frequency sand washing pump; In step S4, the parameters of the water-washed sand production line equipment adjusted according to the mud content of the raw materials include the operating frequency of the sand washing pump, When the mud content of the raw material is less than 10%, the operating frequency of the sand washing pump is set to 38Hz; when the mud content of the raw material is in the range of 10%-20%, the operating frequency of the sand washing pump is set to 40Hz; when the mud content of the raw material is in the range of 20%-30%, the operating frequency of the sand washing pump is set to 42Hz.

9. The method for recycling construction waste soil based on water washing treatment according to claim 1 is characterized in that: In step S5, if the raw materials are first raw sand and second raw sand, when feeding, the first raw sand and second raw sand of different coarseness are alternately added into the silo of the screening feeder by a loader in multiple times.

10. The method for recycling construction waste soil based on water washing treatment according to claim 1 is characterized in that: In step S6, the sampling quality inspection of the finished product after water washing includes fineness modulus detection and mud content detection.

Images