Device for simulating environmental influence of ardealite-based test piece under rainfall condition

Abstract

The utility model discloses a device for simulating the environmental influence of an ardealite-based test piece under a rainfall condition, which comprises a collecting mechanism, a dripping mechanism and a detecting mechanism, and the collecting mechanism comprises an overflow water container, a test piece container, a conduit and a seepage water container; the dripping mechanism comprises a water conveying pipe and a water conveying driving part; the detection mechanism is used for detecting the content of soluble phosphorus, fluorine and heavy metal impurities in water collected by the overflow water container and the seepage water container. The device and the method for simulating the environmental influence of the ardealite-based test piece under the rainfall condition, provided by the utility model, have the beneficial effects that the erosion of rainwater to the ardealite-based test piece can be simulated, and overflow water and seepage water generated after the ardealite-based test piece is simulated to be scoured and eroded by raindrops are extracted; the soluble impurity leaching amount of the ardealite-based test piece can be conveniently detected through the detection mechanism, so that the influence of an ardealite product on the environment can be evaluated.

Description

Technical Field

[0001] The utility model relates to the technical field of environmental impact of phosphogypsum-based products, in particular to a device and method for simulating the environmental impact of a phosphogypsum-based specimen under precipitation conditions. Background Art

[0002] Phosphogypsum (PG), a byproduct of the phosphating industry, is produced in large quantities and contains soluble phosphorus, fluorine, and small amounts of heavy metal impurities, which can pollute the environment. While heavy metal impurities are effectively solidified in a persulfurized system, the higher concentrations of soluble phosphorus and fluorine compared to other impurities necessitate systematic leaching evaluation before the product can be put into practical use.

[0003] The environmental assessment of phosphogypsum is to detect the content of toxic and harmful impurities by dissolving soluble impurities in phosphogypsum or its products in the external water environment.

[0004] Standard leaching tests are primarily divided into two categories. One uses pure water as the leaching agent to simulate the leaching of hazardous components from solid waste into the environment by surface or groundwater, consistent with the standard HJ557-2010, "Toxicity Leaching Method for Solid Waste and Horizontal Oscillation Method." The other is a standard leaching method test, using acid as the leaching agent to simulate the leaching of waste into the environment under the influence of acidic precipitation or leachate. These include the sulfuric acid and nitric acid method, as per the standard HJ / T 299-2007, "Toxicity Leaching Method for Solid Waste," and the acetic acid buffer solution method, as per HJ / T 300-2007, "Toxicity Leaching Method for Solid Waste." The US standard TCLP method is similar to the acetic buffer solution method.

[0005] The above methods all only sample by leaching phosphogypsum, which can evaluate the environmental impact of underwater phosphogypsum in natural environments. However, for phosphogypsum located on the ground, soluble substances are generally only leached out during rainfall, and rainfall has a certain amount of kinetic energy, which has a certain corrosive effect on the surface of the phosphogypsum. Current testing methods cannot simulate this usage condition. Utility Model Content

[0006] The purpose of the present invention is to overcome the above-mentioned technical deficiencies and to propose a device and method for simulating the environmental impact of phosphogypsum-based specimens under precipitation conditions, which is used to simulate the impact of rainfall erosion on the ground of phosphogypsum under precipitation conditions, causing soluble impurities to dissolve into the outside world and on the external environment.

[0007] In order to achieve the above technical purpose, the present invention adopts the following technical solutions:

[0008] The utility model provides a device for simulating the environmental impact of phosphogypsum-based specimens under precipitation conditions, comprising:

[0009] a collecting mechanism comprising an overflow water container, a test container, a conduit, and a permeated water container, wherein the test container is disposed in the overflow water container, a leakage hole is formed on the bottom surface of the test container, and the leakage hole is connected to the permeated water container via the conduit;

[0010] a water dripping mechanism, the water dripping mechanism comprising a water pipe and a water delivery driver, the outlet end of the water pipe being vertically arranged and located directly above the specimen container, the water delivery driver being used to deliver water to the inlet of the water pipe; and

[0011] The detection mechanism is used to detect the content of soluble phosphorus, fluorine and heavy metal impurities in the water collected by the overflow water container and the seepage water container.

[0012] In some embodiments, a water hole cooperating with the water leakage hole is opened on the conduit, the water hole is communicated with the water leakage hole, and a filter is provided in the conduit.

[0013] In some embodiments, the filter is a cotton core that is spread throughout the interior of the catheter.

[0014] In some embodiments, the conduit is square.

[0015] In some embodiments, the water delivery drive component includes a water source container and a water pump, the inlet of the water pump is connected to the water source container, and the outlet of the water pump is connected to the inlet end of the water delivery pipe.

[0016] In some embodiments, the water delivery drive further includes a water inlet pipe, one end of which is connected to the water source container, and the other end of which is connected to the inlet of the water pump.

[0017] In some embodiments, the water pump is a peristaltic pump.

[0018] In some embodiments, the dripping mechanism further includes a wind shielding pipe, which is arranged between the outlet of the water pipe and the specimen container.

[0019] In some embodiments, an overflow gap is provided on the upper edge of the specimen container.

[0020] In some embodiments, two symmetrical holes are opened on the side wall of the overflow water container, and the two ends of the conduit are respectively embedded in the two symmetrical holes, and the gap between the symmetrical holes and the conduit is filled with sealant.

[0021] Compared with the prior art, the device and method provided by the present invention for simulating the environmental impact of phosphogypsum-based specimens under precipitation conditions have the following beneficial effects:

[0022] (1) It can simulate the erosion of rainwater on phosphogypsum-based specimens, extract the overflow water and permeate water generated after the simulated raindrops erode the phosphogypsum-based specimens, and facilitate the measurement of the amount of soluble impurities leached from the phosphogypsum-based specimens by the testing agency to evaluate the impact of phosphogypsum products on the environment;

[0023] (2) By setting up overflow water containers, specimen containers, conduits and seepage water containers, the overflow water and seepage water generated by raindrops eroding the phosphogypsum-based specimens can be collected separately, making it easier to study the environmental impacts caused by the overflow water and seepage water of phosphogypsum products. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic structural diagram of an apparatus for simulating environmental impacts on phosphogypsum-based specimens under precipitation conditions provided by one embodiment of the present invention;

[0025] Figure 2 yes Figure 1 Schematic diagram of the structure of the specimen container and the conduit;

[0026] Figure 3 yes Figure 2 Schematic diagram of the three-dimensional structure of the specimen container;

[0027] Figure 4 It is the corresponding relationship between the diameter of a raindrop and its terminal falling velocity;

[0028] Figure 5 is the linear relationship between raindrop number density and rainfall intensity;

[0029] Figure 6 is the correspondence between the average diameter of raindrops and rainfall intensity;

[0030] Figure 7 is the diurnal variation of summer precipitation at the destination;

[0031] Figure 8 It is a curve that simulates the relationship between the falling speed of raindrops and the falling time;

[0032] Explanation of the accompanying reference numerals: 1-collecting mechanism, 11-overflow water container, 12-test piece container, 121-leakage hole, 122-overflow gap, 13-conduit, 131-water hole, 132-filter element, 14-permeated water container, 2-drip mechanism, 21-water pipe, 211-water outlet, 22-water drive element, 221-water source container, 222-water pump, 223-water inlet pipe, 23-wind shield pipe, 3-phosphogypsum-based specimen. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0034] In order to simulate the impact of rainfall erosion on the ground of phosphogypsum, which causes soluble impurities to dissolve into the outside world and thus has an impact on the external environment, the utility model provides a device for simulating the environmental impact of phosphogypsum-based specimens under precipitation conditions, which can simulate the environmental impact of phosphogypsum-based specimens under precipitation conditions.

[0035] See also Figure 1 , Figure 1 This is a structural schematic diagram of an apparatus for simulating the environmental impact of phosphogypsum-based specimens under precipitation conditions in one embodiment of the present invention. The apparatus for simulating the environmental impact of phosphogypsum-based specimens under precipitation conditions includes a collecting mechanism 1, a dripping mechanism 2 and a detection mechanism (not shown).

[0036] See also Figure 1 and Figure 2 The collecting mechanism 1 includes an overflow water container 11, a specimen container 12, a conduit 13, and a permeated water container 14. The specimen container 12 is used to place the phosphogypsum-based specimen 3. The specimen container 12 is arranged in the overflow water container 11. A water leakage hole 121 is opened on the bottom surface of the specimen container 12. The water leakage hole 121 is connected to the permeated water container 14 via the conduit 13.

[0037] The dripping mechanism 2 includes a water pipe 21 and a water driving member 22. The outlet end of the water pipe 21 is vertically arranged and located directly above the specimen container 12. The water driving member 22 is used to deliver water to the inlet of the water pipe 21.

[0038] The detection mechanism is used to detect the content of soluble phosphorus, fluorine and heavy metal impurities in the water collected by the overflow water container 11 and the permeated water container 14.

[0039] In one embodiment, see Figure 1 and Figure 2 The conduit 13 is provided with a water hole 131 that matches the water leakage hole 121. The water hole 131 is communicated with the water leakage hole 121. A filter 132 is provided in the conduit 13. In this embodiment, the conduit 13 is square, and the filter 132 is a cotton core that is spread all over the inside of the conduit 13. The filter 132 can block solid particles and prevent solid particles from entering the permeated water container 14 through the conduit 13.

[0040] In one embodiment, see Figure 1-Figure 3An overflow notch 122 is provided on the upper edge of the test container 12 , so that when the test container 12 is full of water, the water will flow from the overflow notch 122 into the overflow water container 11 below.

[0041] In one embodiment, see Figure 1 The water delivery drive 22 includes a water source container 221 and a water pump 222. The inlet of the water pump 222 is connected to the water source container 221, and the outlet of the water pump 222 is connected to the inlet of the water delivery pipe 21. During use, the water pump 222 is turned on to pump water from the water source container 221 into the water delivery pipe 21, where it drips onto the upper surface of the phosphogypsum-based specimen 3 below. In this embodiment, the water pump 222 is a peristaltic pump.

[0042] In one embodiment, see Figure 1 The dripping mechanism 2 further includes a windshield 23, which is disposed between the outlet of the water pipe 21 and the specimen container 12. In this embodiment, by providing the windshield 23, when water drips from the outlet of the water pipe 21, it will pass through the windshield 23, thereby shielding the water droplets from the wind and preventing them from being disturbed by external airflow and deflecting laterally.

[0043] In one embodiment, see Figure 1 The water delivery drive component 22 also includes a water inlet pipe 223 , one end of the water inlet pipe 223 is connected to the water source container 221 , and the other end of the water inlet pipe 223 is connected to the inlet of the water pump 222 .

[0044] The method for using the device for simulating the environmental impact of phosphogypsum-based specimens under precipitation conditions provided by the utility model comprises the following steps:

[0045] S1. Set the experimental parameters according to the rainfall characteristics of the destination, and then assemble the device according to the set parameters;

[0046] S2. Fill the water source container 221 with water, and place a phosphogypsum-based specimen 3 in the specimen container 12, with the upper surface of the phosphogypsum-based specimen 3 higher than the lowest point of the upper edge of the specimen container 12; the edges of the contact surface between the phosphogypsum-based specimen 3 and the inner bottom surface of the specimen container 12 may be sealed;

[0047] S3. Start the water delivery driver 22, which injects a preset flow of water into the inlet of the water delivery pipe 21. The water drips from the outlet of the water delivery pipe 21 onto the upper surface of the phosphogypsum-based specimen 3, simulating the erosion of the phosphogypsum-based specimen 3 by precipitation. A portion of the water penetrates into the phosphogypsum-based specimen 3 and is then discharged from the leak hole 121 into the conduit 13. The water then enters the permeated water container 14 through the conduit 13. The remaining portion of the water flows from the surface of the phosphogypsum-based specimen 3 into the specimen container 12. When the specimen container 12 is full of water, the water overflows into the overflow water container 11 below. After simulating the first preset time, the water delivery driver 22 is closed for the second preset time.

[0048] S4. Repeat step S3 several times according to the frequency of heavy rainfall at the destination, with the number of repetitions being equal to the frequency of heavy rainfall at the destination;

[0049] S5. Detecting the content of soluble phosphorus, fluorine and heavy metal impurities in the water collected by the overflow water container 11 and the infiltration water container 14 through a detection mechanism. Judging whether the content of soluble phosphorus, fluorine and heavy metal impurities in the water flowing into ponds, streams, rivers and lakes after rainwater erodes the phosphogypsum products is excessive by judging the content of soluble phosphorus, fluorine and heavy metal impurities in the water collected by the overflow water container 11. If the content is excessive, it indicates that the water flowing into ponds, streams, rivers and lakes after rainwater erodes the phosphogypsum products has a great impact on the environment. Judging whether the content of soluble phosphorus, fluorine and heavy metal impurities in the water collected by the infiltration water container 14 is excessive by judging the content of soluble phosphorus, fluorine and heavy metal impurities in the water infiltrating into the ground after rainwater erodes the phosphogypsum products. If the content is excessive, it indicates that the water infiltrating into the ground after rainwater erodes the phosphogypsum products has a great impact on the environment.

[0050] In step S1, the method for setting the experimental parameters according to the rainfall characteristics of the destination includes the following steps:

[0051] S11. Obtain the frequency of heavy rainfall and the rainfall intensity B at the destination over a period of time, determine a threshold value D0 of the raindrop diameter at the destination based on the rainfall intensity B, and obtain the outlet diameter of the water pipe based on the threshold value D0 of the raindrop diameter at the destination;

[0052] The step S11 specifically includes the following steps:

[0053] S111. Obtain the frequency and intensity of heavy rainfall at the destination within a period of time.

[0054] S112. Obtain a functional relationship between precipitation intensity and raindrop diameter, and determine a threshold value D0 of the raindrop diameter at the destination based on the functional relationship between precipitation intensity and raindrop diameter and the precipitation intensity B at the destination. The functional relationship between precipitation intensity and raindrop diameter can be obtained from relevant literature and will not be described in detail in this utility model.

[0055] S113. Determine, through experiments, the relationship between the outlet diameter of the water pipe and the diameter of simulated raindrops flowing out of the outlet of the water pipe;

[0056] S114. Determine the outlet diameter of the water pipe based on the relationship between the outlet diameter of the water pipe and the diameter of the simulated raindrops flowing out of the outlet of the water pipe, so that the diameter of the simulated raindrops flowing out of the outlet of the water pipe is equal to the threshold value D0 of the raindrop diameter at the destination.

[0057] S12. Obtain the area of the upper surface of the phosphogypsum-based specimen, and calculate the water pipe flow rate Q based on the precipitation intensity B at the destination, the area of the upper surface of the phosphogypsum-based specimen, and the water outlet diameter of the water pipe;

[0058] S13. Determine the height difference between the outlet of the water pipe and the upper surface of the phosphogypsum-based specimen based on the threshold value D0 of the raindrop diameter at the destination, the outlet diameter of the water pipe, and the flow rate Q of the water pipe.

[0059] The step S13 specifically includes the following steps:

[0060] S131. Calculate the mass and initial velocity of the simulated raindrops based on the water outlet diameter and the water flow rate Q of the water pipe;

[0061] Among them, the method for calculating the mass of simulated raindrops according to the outlet diameter of the water pipe is:

[0062] The diameter of the simulated raindrop is obtained according to the outlet diameter of the water pipe;

[0063] The simulated raindrops are assumed to be spheres, and the mass of each simulated raindrop is calculated by substituting the density of water and the diameter of the simulated raindrops according to the volume formula of the sphere and the density-volume-mass formula.

[0064] Among them, the method for calculating the initial velocity of simulated raindrops based on the outlet diameter and flow rate of the water pipe is:

[0065] According to the diameter of the water pipe outlet, the area of the water pipe outlet is obtained;

[0066] The initial velocity of the simulated raindrops is obtained according to the flow rate of the water pipe and the area of the water pipe outlet.

[0067] S132, calculating the falling speed vm of the raindrop when it hits the ground based on the threshold value D0 of the raindrop diameter at the destination;

[0068] S133. The formula for the resistance a raindrop encounters during its fall is: F = 1 / 2CρSv 2 , where F is the drag, C is the air resistance coefficient, ρ is the air density, S is the frontal area of the object, which can be obtained based on the diameter of the simulated raindrop, and v is the relative speed between the raindrop and the air;

[0069] S134. Let the acceleration of the simulated raindrop falling be a. Then, during the process of the simulated raindrop falling, its acceleration satisfies the following formula:

[0070] ma=mg-1 / 2CρSv 2 ,

[0071] Among them, m is the mass of the simulated raindrop, g is the acceleration of gravity, C is the air resistance coefficient, ρ is the air density, S is the windward area of the object, which can be obtained according to the diameter of the simulated raindrop, and v is the relative motion speed between the raindrop and the air;

[0072] S135. Let C*ρ*S=k, and we can get the acceleration formula:

[0073]

[0074] Where t is the falling time of the simulated raindrop;

[0075] Since raindrops fall to the ground at a uniform or nearly uniform speed, when v = vm, a = 0. Substituting this into the above formula, we can find the value of k when the raindrop falls to the ground, k0;

[0076] S136. Substituting k0, the mass m0 of the simulated raindrop, and the initial velocity v0 of the simulated raindrop into the acceleration formula, the formula for the falling time and falling velocity of the simulated raindrop can be obtained as follows:

[0077]

[0078] Where g is the acceleration due to gravity and E is a constant;

[0079] S137. Based on the formula for the simulated raindrop's falling time and falling velocity, a curve is plotted showing the relationship between the simulated raindrop's falling time and falling velocity. A threshold value v1 for the simulated raindrop's falling velocity is selected. The curve is then integrated to calculate a threshold value h1 for the simulated raindrop's falling height. The height difference H between the water pipe's outlet and the top surface of the phosphogypsum-based specimen is then set to H ≥ h1. In other words, the height difference between the water pipe's outlet and the top surface of the phosphogypsum-based specimen must be no less than the threshold value for the simulated raindrop's falling height.

[0080] In order to better understand the present invention, the implementation process of the present invention is described in detail below in conjunction with a specific implementation case. The main purpose of the present invention is to extract overflow water and infiltration water generated after simulated raindrops scour and erode phosphogypsum-based specimens in a simulated precipitation environment, so as to facilitate the measurement of the amount of soluble impurities leached from the phosphogypsum-based specimens in subsequent work to evaluate the impact of phosphogypsum products on the environment.

[0081] (1) Control of natural environmental variables

[0082] In the natural environment, rainfall is the most direct indicator of rainfall intensity. It refers to the depth of liquid or solid water that falls from the sky and accumulates on a horizontal surface without evaporation, infiltration, or loss, measured in millimeters. According to GBT 28592-2012, rainfall is categorized into seven levels: trace rainfall (scattered light rain), light rain, moderate rain, heavy rain, torrential rain, heavy rainstorm, and extremely heavy rainstorm. See Table 1 for the specific classification.

[0083] Table 1: Rainfall classification standards

[0084]

[0085] The amount of rainfall and the speed of raindrops falling cannot be determined in advance. On the one hand, raindrops are accelerated by gravity from a certain height in the air, and on the other hand, they are also affected by air resistance. These two forces together determine that raindrops begin to fall at a constant speed after falling to a certain height. The two forces work in the following way:

[0086] G=mg

[0087] F=1 / 2CρSv 2

[0088] Where: G - gravity, unit: N; m - mass, unit: kg; g - acceleration due to gravity, unit: N / kg, approximately 9.8 N / kg; F - drag, unit: N; C - air drag coefficient, approximately 0.45; ρ - air density, dry air is approximately 1.3 kg / m 3 ; S-the windward area of the object, unit: m 2 ; v-the relative speed between raindrops and air, unit: m / s.

[0089] The above two aspects are self-generated variables controlled by the natural environment. Among them, rainfall is easier to simulate in an experimental environment, while the speed of raindrops falling is more difficult to control.

[0090] Since the research object is a phosphogypsum-based specimen, the research goal is to simulate the amount of harmful ions dissolved by natural rainfall on the specimen surface. Therefore, the control of raindrop velocity is changed to control momentum, which can better measure the intensity of precipitation on the specimen. The momentum of raindrops is calculated according to the formula p = mvkg·m / s 3 , which is determined by both the mass of the raindrop and the speed of the raindrop.

[0091] According to previous studies, there is a good correspondence between the diameter of raindrops and their final falling velocity. Therefore, the final momentum of naturally falling raindrops can be obtained based on this curve, which becomes a reference indicator for experimental control. Later, scholars used the PARISVEL laser raindrop spectrometer to measure the raindrop particle size, calculate the falling velocity of raindrops, and correct the curve to make the result more accurate. The fitting diagram is shown below. Figure 4 shown.

[0092] Raindrop distribution density is a variable that can be affected by both rainfall amount and raindrop volume. Previous studies have found that the raindrop number density and rainfall intensity show a good linear relationship, such as Figure 5 There is also a corresponding functional relationship between the average diameter of raindrops and rainfall intensity, as shown in Figure 6 shown.

[0093] (2) Constructing a simulation test device

[0094] Reference Figures 1 to 3 The simulation test device includes a collecting mechanism 1, a dripping mechanism 2 and a detecting mechanism. The specific structures and principles of the collecting mechanism 1, the dripping mechanism 2 and the detecting mechanism have been described in detail above and will not be repeated here.

[0095] (3) Experimental parameter setting

[0096] According to the above variable analysis, and under the experimental conditions of a closed container with no wind, the variables that need to be controlled in the experiment are reduced to two aspects: (1) rainfall intensity and (2) raindrop terminal momentum.

[0097] However, under experimental conditions, since the diameter of the water outlet 211 of the water pipe 21 is determined, the simulated raindrop volume can also be determined, and then the rainfall intensity and raindrop velocity are determined, and the final momentum of the raindrop is controlled by the raindrop velocity and the initial velocity of the water outlet 211.

[0098] The method for setting the experimental parameters includes the following steps:

[0099] a. Destination research

[0100] from Figure 4 It can be seen that the speed v of a raindrop falling to the ground is a function of the diameter D of the raindrop, as shown by Figure 6 It can be seen that the average value of raindrop diameter D is a function of precipitation intensity B.

[0101] Then, we took a location in central my country as our destination. Heavy rainfall in this area has a distinct seasonal distribution, decreasing in summer, spring, and autumn. It primarily occurs in the afternoon and evening, lasting for about an hour. Spatially, it is dense in the east and west, and sparse in the center. Current standards define short-term heavy rainfall as 20 mm or more per hour.

[0102] The frequency of heavy rainfall at the destinations from 2008 to 2017 was counted, and the results are shown in Table 2.

[0103] Table 2: Frequency of heavy rainfall in the destinations from 2008 to 2017

[0104]

[0105] Table 2 shows that heavy rainfall is frequent in summer, which is a key area that needs to be studied. Some scholars have studied the diurnal variation of summer rainfall in this area, such as Figure 7 The diurnal variation of precipitation in this region is very obvious. The daily variation curve of cumulative precipitation is mainly bimodal, showing the characteristics of a semi-diurnal cycle. The peak precipitation occurs at 08:00 and 17:00, and the precipitation levels in these two periods are comparable.

[0106] From the above two pieces of information, it can be concluded that the average daily heavy rainfall in the region in summer can be roughly divided into two periods, with a peak interval of about 10 hours and each duration of about 6 hours. The cumulative precipitation in each period can be roughly calculated to be 100 mm, which can be characterized as a heavy rain according to Table 1. In order to simulate the heavy rainfall environment, the 14-year average precipitation is used as the standard, and each 100 mm precipitation is set to be completed within 1 hour to meet the numerical requirements of heavy rainfall and simulate the extreme environment. Therefore, in this experiment, the simulated precipitation intensity Bm is set to 100 mm / h. Figure 6 , set the raindrop diameter threshold D0 to 3mm.

[0107] b. Calculate the flow rate and diameter of the water pipe

[0108] (1) Total container type and capacity setting

[0109] Since phosphogypsum-based specimens are typically 40mm square, the diameter of the overflow water container is set to 200mm. A hole is opened in the side of the overflow water container and a conduit is placed. After the conduit is installed, the joint between the side opening and the conduit is sealed.

[0110] Experiments have determined that due to surface tension and friction, if the diameter d of the water outlet 211 and the water pipe 21 is set to 1 mm, the simulated raindrop diameter D1 is approximately 3 mm. Of course, under certain experimental conditions, the diameter d of the water outlet 211 of the water pipe 21 can be adjusted as needed, and the simulated raindrop diameter D1 can be set to 2.7 mm, 2.8 mm, or 2.9 mm.

[0111] Based on the simulated precipitation intensity Bm = 100 mm / h determined in step a, and reflecting it as water falling on the upper surface of the phosphogypsum-based specimen, the total precipitation in one hour is 4*4*10 = 160 mL. The water pipe flow rate Q is then 160 / 60 = 2.67 mL / min.

[0112] Calculate the corresponding flow rate Q of the water pipe 41 based on the area of the upper surface of the test piece and the simulated precipitation intensity Bm;

[0113] c. Calculate the mass and initial velocity of simulated raindrops

[0114] According to the flow formula v=Q / S, substituting the diameter d=1 mm of the water outlet 211 of the water pipe 21 and the flow rate Q=2.67 mL / min of the water pipe 21, the initial velocity v0 of the simulated raindrop is calculated to be 0.0567 m / s.

[0115] The simulated raindrops are approximately regarded as spheres, and according to the volume formula of a sphere, V = 4 / 3πr 3 , density volume mass formula m = Vρ, substitute the density of water and the diameter of the simulated raindrop D1 = 3mm, and calculate the mass of each simulated raindrop m = 1.413*10- 6 kg,

[0116] d. Setting the final momentum of simulated raindrops

[0117] Reference Figure 6 , we know that the falling speed v of a raindrop with a diameter of 3mm is about 9m / s, so v=9m / s.

[0118] The formula for the resistance a raindrop encounters during its fall is: F = 1 / 2CρSv 2 , where F is the resistance, C is the air resistance coefficient, ρ is the air density, S is the windward area of the object, and v is the relative speed between the raindrop and the air.

[0119] Let the falling acceleration of the raindrop be a. Then, during the falling process, its acceleration satisfies the following formula: ma=mg-1 / 2CρSv 2 ,

[0120] Since raindrops are not rigid bodies, the frontal area S is unknown during the falling process, and the air resistance coefficient is not constant. We can set C*ρ*S=k, where k is unknown. The acceleration formula is:

[0121]

[0122] Because a raindrop will reach a constant speed of 9m / s after falling to a certain height, a=0 at this time, and the raindrop falls at a constant speed, so the H value can be set higher than this height. Substituting the two values of v=9m / s and a=0 into the above acceleration formula, we can calculate k=0.34*10- 6 ,

[0123] The acceleration formula of the raindrop falling process is used to simulate the falling process of raindrops, and k = 0.34*10- 6 , the mass of simulated raindrops m = 1.413*10- 6 Substituting kg and the initial velocity of the simulated raindrop v0 = 0.0567 m / s, the acceleration of gravity g = 9.8 N / kg into the acceleration formula, the formula for the falling time and falling velocity of the simulated raindrop can be obtained:

[0124]

[0125] Use Origin software to draw a curve of the relationship between the falling speed v of simulated raindrops and the falling time t, such as Figure 8 shown.

[0126] Since the function relationship describes the threshold, it takes infinite time when v approaches 9m / s, so when the final velocity threshold v1 is set to 7m / s, Figure 8 Integrating the curve shown above yields a practically feasible height threshold h1 = 9.15 m. When the accuracy of simulated raindrop terminal momentum approaches 90%, setting H ≥ 9.15 m effectively controls the final momentum of raindrops. Alternatively, the final velocity threshold v1 can be set to 8 m / s, 6.5 m / s, and so on, depending on the actual situation.

[0127] In the above experimental parameter method, due to the different climatic conditions in different destinations, the selected simulated precipitation intensity Bm and raindrop diameter threshold D0 will vary from place to place. For example, in the arid northwest region of my country, the simulated precipitation intensity Bm value may be 30mm / h, and the raindrop diameter threshold D0 may be 2mm. In the coastal areas of southern my country, the simulated precipitation intensity Bm value may be 150mm / h.

[0128] (IV) Experimental simulation

[0129] In the simulation experiment of the present invention, the natural precipitation erosion simulation method includes the following steps:

[0130] (1) Fill a water source container with water and place a phosphogypsum-based specimen in the specimen container so that the upper surface of the phosphogypsum-based specimen is higher than the lowest point of the upper edge of the specimen container;

[0131] (2) Start the water pump and pump the water in the water source container out of the water outlet of the water pipe and drop it on the upper surface of the phosphogypsum-based specimen to simulate the erosion of precipitation on the phosphogypsum-based specimen. After 1 hour of simulation, turn off the water pump and continue for 10 hours;

[0132] (3) Repeat step S2 several times based on the heavy rainfall frequency of the destination surveyed in step a;

[0133] (4) Collect the water in the overflow water container and the water in the seepage water container respectively. The water in the overflow water container can simulate the water flowing into ponds, streams, rivers, and lakes after rainwater erodes the phosphogypsum products, and the water in the seepage water container can simulate the water seeping into the ground after rainwater erodes the phosphogypsum products.

[0134] Since the natural precipitation point is random, a fully simulated site would require a sufficiently large area, which is not in line with the purpose of this experiment. Therefore, the precipitation mode is set to a single-point precipitation mode, and the single-point water drop position is changed at a specified interval to better control the precipitation amount and simulated raindrop momentum. Therefore, the upper surface of the phosphogypsum-based specimen is divided into multiple simulation areas. In step (3), the phosphogypsum-based specimen is moved horizontally before each repetition of step (2), and each simulation area on the phosphogypsum-based specimen is tested in turn.

[0135] In a preferred embodiment of the present invention, the upper surface of the phosphogypsum-based specimen is square, and the upper surface is equally divided into four simulation areas. Each time step (2) is performed, only one of the simulation areas is tested.

[0136] The filter element 132 can be a cotton core, or a material such as sand that can be permeated by water. The cross section of the conduit 13 can be square, circular, oval, etc. The conduit 13 can be a closed tube or a slotted tube with a C-shape cross section.

[0137] Reference Figures 1 to 3 In a preferred embodiment of the present invention, the cross section of the conduit 13 is square, and the interior of the conduit 13 is filled with cotton cores. The conduit 13 is embedded in the overflow water container 11 through symmetrical holes, and the symmetrical holes are sealed. The conduit 13 has two functions: (1) supporting the specimen container 12; (2) a water leakage hole 121 is provided on the bottom surface of the specimen container 12, and a water through hole 131 corresponding to the water leakage hole 121 is provided on the upper part of the conduit 13. After the water at the bottom of the specimen container 12 enters the interior of the conduit 13 through the water leakage hole 121 and the water through hole 131, it seeps through the cotton core and drips into the permeation water container 14.

[0138] Preferably, an overflow notch 122 is provided on the upper edge of the specimen container 12 , and the overflow notch 122 is the lowest point of the upper edge of the specimen container 12 .

[0139] The beneficial effects of the technical solution provided by the utility model include:

[0140] (1) It can simulate the erosion of rainwater on phosphogypsum-based specimens, extract the overflow water and permeate water generated after the simulated raindrops erode the phosphogypsum-based specimens, and facilitate the measurement of the amount of soluble impurities leached from the phosphogypsum-based specimens by the testing agency to evaluate the impact of phosphogypsum products on the environment;

[0141] (2) By setting up overflow water containers, specimen containers, conduits and seepage water containers, the overflow water and seepage water generated by raindrops eroding the phosphogypsum-based specimens can be collected separately, making it easier to study the environmental impacts caused by the overflow water and seepage water of phosphogypsum products.

[0142] The specific embodiments of the present invention described above do not limit the scope of protection of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A device for simulating the environmental impact of phosphogypsum-based specimens under precipitation conditions, characterized in that: include: a collecting mechanism comprising an overflow water container, a test container, a conduit, and a permeated water container, wherein the test container is disposed in the overflow water container, a leakage hole is formed on the bottom surface of the test container, and the leakage hole is connected to the permeated water container via the conduit; a water dripping mechanism, the water dripping mechanism comprising a water pipe and a water delivery driver, the outlet end of the water pipe being vertically arranged and located directly above the specimen container, the water delivery driver being used to deliver water to the inlet of the water pipe; and The detection mechanism is used to detect the content of soluble phosphorus, fluorine and heavy metal impurities in the water collected by the overflow water container and the seepage water container.

2. The device for simulating the environmental impact of phosphogypsum-based specimens under precipitation conditions according to claim 1, characterized in that: A water hole matching the water leakage hole is provided on the conduit, the water hole is communicated with the water leakage hole, and a filter is provided in the conduit.

3. The device for simulating the environmental impact of phosphogypsum-based specimens under precipitation conditions according to claim 2, characterized in that: The filter element is a cotton core that is spread all over the inside of the catheter.

4. The device for simulating the environmental impact of phosphogypsum-based specimens under precipitation conditions according to claim 1, characterized in that: The conduit is square in shape.

5. The device for simulating the environmental impact of phosphogypsum-based specimens under precipitation conditions according to claim 1, characterized in that: The water delivery drive component includes a water source container and a water pump. The inlet of the water pump is connected to the water source container, and the outlet of the water pump is connected to the inlet end of the water delivery pipe.

6. The device for simulating the environmental impact of phosphogypsum-based specimens under precipitation conditions according to claim 5, characterized in that: The water delivery drive component further includes a water inlet pipe, one end of which is connected to the water source container, and the other end of which is connected to the inlet of the water pump.

7. The device for simulating the environmental impact of phosphogypsum-based specimens under precipitation conditions according to claim 5, characterized in that: The water pump is a peristaltic pump.

8. The device for simulating the environmental impact of phosphogypsum-based specimens under precipitation conditions according to claim 1, characterized in that: The dripping mechanism further includes a wind shielding pipe, which is arranged between the outlet of the water delivery pipe and the specimen container.

9. The device for simulating the environmental impact of phosphogypsum-based specimens under precipitation conditions according to claim 1, characterized in that: An overflow notch is provided on the upper edge of the test piece container.

10. The device for simulating the environmental impact of phosphogypsum-based specimens under precipitation conditions according to claim 1, characterized in that: Two symmetrical holes are provided on the side wall of the overflow water container, and the two ends of the conduit are respectively embedded in the two symmetrical holes, and the gap between the symmetrical holes and the conduit is filled with sealant.

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