Method for measuring evaporation coefficient of dripping system

Abstract

The invention relates to a method for measuring the evaporation coefficient of a dripping system, and solves the problem that the evaporation coefficient of the dripping system is directly measured by a proper method at present. The method is completed by using a measuring device, and the measuring device comprises a water retaining tank, a drop-leaching net composed of drop-leaching pipes, a water collecting tank, a water storage tank, ore, a water pump and a submersible pump. The water pump is an adjustable pump controlled by a frequency converter and can adjust flow and pressure, liquid level meters are installed on the water collecting tank and the water storage tank, a flow meter and a pressure meter are installed between the water pump and the dripping pipe, and the water collecting tank is communicated with the water storage tank. According to the invention, the dripping operation of the dripping pipeline is simulated in a laboratory, the ore layer with a certain thickness simulates the ore heap, and the evaporation coefficient is measured under the same wind speed, temperature and humidity as the field production condition, so that the measured evaporation coefficient of the dripping system is more reasonable.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of hydrometallurgy, in particular to a method for determining evaporation coefficient of drip irrigation system. BACKGROUND

[0002] Currently, the heap leaching operation of copper uses drip irrigation system, the surface of the ore heap has a plurality of drip irrigation pipes, the drip irrigation pipes keep a certain distance from each other, the drip irrigation holes on the drip irrigation pipes uniformly sprinkle the solution on the surface of the ore heap, the solution penetrates through the whole heap from top to bottom, and flows out of the heap to the solution pool. When the copper concentration of the solution reaches the requirement, the solution is pumped into the extraction workshop; when the copper concentration is lower than the requirement, it continues to return to the drip irrigation operation, as shown in the formula. Figure 1

[0003] The bottom of the heap is paved with an impermeable membrane, and has a 1‰ slope to facilitate the solution to flow to the outlet of the heap and finally to the solution pool. After the ore heap is completed, the amount of ore is determined by the collection side, and the total amount of metal into the heap is determined by the ore sample test data; when the drip irrigation starts, the copper in the ore heap will be leached out every time the solution circulates; the longer the drip irrigation time, the higher the leached copper, and the higher the leaching rate; the leached copper amount needs to be calculated in production to track the leaching of the heap.

[0004] The formula for calculating the daily leached copper amount is: Daily leached copper amount ΔM = copper content of lower heap solution M1 - copper content of upper heap solution M2 M1 = amount of upper heap solution Copper concentration C1 of upper heap solution; wherein V1 can be determined by the flow meter at the outlet of the pump, and C1 can be determined by regular sample test; M2 = amount of lower heap solution Copper concentration C2 of lower heap solution; wherein C2 can be determined by regular sample test, and the amount of lower heap solution cannot be directly determined due to the large area of the bottom of the heap.

[0005] In actual production process, in order to determine ΔM, it is usually assumed that the amount of lower heap solution V2 = the amount of upper heap solution (100%-coefficient a), and the coefficient a (%) is the evaporation coefficient of the drip irrigation system. Currently, the evaporation coefficient is an empirical data, which is usually 3%-4%.

[0006] The length of the drip irrigation pipe is usually about 100m, and the heap is a permanent heap with a large amount of ore below, so there is no suitable method for direct measurement. SUMMARY

[0007] The purpose of the present application is to design a method for determining the evaporation coefficient of the drip irrigation system, which provides a technical basis for the daily copper production of the heap in the heap leaching production.

[0008] The present application is realized by the following technical solutions: ​A method for determining the evaporation coefficient of a drip irrigation system includes a water baffle, a nozzle, a water collection tank, a water storage tank, ore, a water pump, and a submersible pump; the water pump is a frequency converter-controlled adjustable pump, which can adjust the flow rate and pressure so that the nozzle inlet pressure and flow rate are consistent with the actual production conditions; The bottom of the water-retaining tank is lined with ore of P80=50mm particle size, with a thickness of not less than 30cm. It should be rinsed for 1-2 hours beforehand to remove fine particles and prevent clogging of pipes and equipment. After rinsing, it should be dried. The spray nozzles are a drip net composed of dripping pipes, which are laid directly on the ore surface. There are four dripping pipes in total, connected to DN25 pipes on both sides. The spacing between the dripping pipes is 0.5m, and each pipe is 3.8m long. Each dripping pipe has seven drip holes spaced 0.5m apart. The dimensions of the water-retaining tank are: length, width, and height not less than... m; During the operation of the drip irrigation pipe, the water flows naturally from the bottom slope of the water retainer into the water collection tank. When the water level in the water collection tank rises to half of its capacity, the system automatically starts the submersible pump and pumps the water back into the storage tank. This process is controlled by the liquid level sensor to achieve automatic judgment and start / stop. Measurement method: Before the experiment begins, fill the water tank to the upper limit of the level gauge, record the initial level, turn on the valve and water pump to start the drip irrigation pipe, and adjust the water pump operating parameters to keep the pressure and flow rate at the drip irrigation pipe outlet consistent with the production. Water filling stage: The entire water filling stage of the equipment shall last for no less than 1 hour to ensure the stability of the system. After the water filling stage is completed, the water pump, submersible pump and valve shall be turned off in sequence, and the liquid level of the water storage tank and the water collection tank shall be recorded at this time to provide reference data for subsequent evaporation calculation. The measurement phase includes the following steps: 1) Environmental Setup: To simulate a natural evaporation environment, electric heating plates were arranged around the water-blocking tank, and a temperature control system was used to stably maintain the temperature of the test area within ±2℃ of the annual average temperature of the production site. Simultaneously, an adjustable-speed fan was installed above the water-blocking tank, maintaining the wind speed at the annual average wind speed of the site. The humidity of the entire test area was adjusted to closely approximate the actual site parameters. Real-time data on ambient temperature, humidity, and wind speed were continuously monitored and recorded by installed sensors to ensure the controllability of external variables during the test and to closely approximate the actual site conditions. 2) After completing the environmental setup, restart the water pump, valves, and submersible pump, adjust the water pump operating parameters to ensure that the pressure and flow rate at the drip outlet are consistent with production, and start timing; 3) Closely monitor changes in liquid level and environmental parameters to ensure a stable and reliable test process. The test should be conducted for a considerable period of time until the liquid level in the storage tank changes significantly. 4) Repeat steps 1-3) at least three times to ensure the repeatability and representativeness of the results. For each test, the initial and final liquid levels of the water collection tank and storage tank, the running time of the drip pipe, the pressure, the ambient temperature, humidity and wind speed parameters should be fully recorded. The evaporation rate E is calculated based on the change in the water level in the storage tank, using the following formula:

[0009] In the formula, V I , V F The liquid volumes before and after the test are shown in the water collection tank and water storage tank, respectively. The formula for calculating the evaporation coefficient is: a=E / V In the formula: a is the evaporation coefficient, E is the measured evaporation amount, and V is the cumulative amount of solution passing through the drip tube, which is equal to the average flow rate measured by the flow meter. Test duration.

[0010] An apparatus for determining the evaporation coefficient of a drip irrigation system includes a water-blocking tank, a drip irrigation net composed of dripping pipes, a water collection tank, a water storage tank, ore, a water pump, and a submersible pump; the water pump is an adjustable pump controlled by a frequency converter, which can adjust the flow rate and pressure; level gauges are installed on the water collection tank and the water storage tank; a flow meter and a pressure gauge are installed between the water pump and the dripping pipes; and the water collection tank and the water storage tank are connected.

[0011] This invention simulates drip irrigation operations in a laboratory using a drip irrigation pipeline and a layer of ore of a certain thickness to simulate an ore pile. Under the same wind speed, temperature, and humidity conditions as on-site production, the evaporation coefficient is measured, making the measured evaporation coefficient of the drip irrigation system more reasonable. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of surface dripping in the stockpile. Figure 2 A schematic diagram of the spray trajectory of the solution dripping on the stockpile; Figure 3 This is a schematic diagram of the evaporation measuring device used in this invention; Figure 4 This is a schematic diagram of a drip irrigation system. Detailed Implementation

[0013] Factors affecting the evaporation coefficient 'a' include humidity, temperature, wind speed, and droplet size (specific surface area). The drip trajectory of the solution dripping on the stockpile is as follows: Figure 2As shown in the diagram: The ore is typically secondary crushed ore with a particle size P80 = 50mm; individual drip irrigation pipes are laid directly on the surface of the ore pile, with drip holes spaced approximately 30cm apart; the number of drip irrigation pipes on the pile surface depends on the pile area, the spacing between drip holes on the pipes is generally 50cm, and the length of a single drip irrigation pipe is equal to the width of the pile, generally not exceeding 100m. The solution seeps out from the drip holes of the drip irrigation pipe in droplets, wetting and diffusing within the ore surface area, forming a diffusion cone.

[0014] Evaporation of the solution during heap leaching consists of two parts: 1) evaporation occurs as the solution droplets move through the air; 2) evaporation also occurs after the solution droplets wet the ore surface due to temperature, wind speed, and air humidity. The evaporation coefficient is the sum of the two evaporation losses and the total amount of solution leached from the dripping pipe.

[0015] Evaporation measuring device such as Figure 3 As shown in the figure: 1) The bottom of the water tank is covered with ore (not shown in the figure), with a particle size P80=50mm and a thickness of not less than 30cm. It should be rinsed for 1-2 hours in advance to remove fine particles and prevent clogging of pipes and equipment. After rinsing, it should be dried; 2) The nozzles are drip nets composed of drip pipes (such as...). Figure 4 As shown), the drip irrigation pipes are laid directly on the ore surface, totaling 4 drip irrigation pipes. Each drip irrigation pipe is connected to a DN25 pipe on both sides, with a spacing of 0.5m between pipes. Each pipe is 3.8m long and has 7 drip holes spaced 0.5m apart. 3) Dimensions of the water-retaining tank: length, width, height... m (the water tank in the above figure needs to be redrawn), can be enlarged appropriately if experimental conditions permit.

[0016] The water pump is a frequency converter-controlled adjustable pump, allowing for adjustments to flow rate and pressure to ensure that the inlet pressure and flow rate of the drip irrigation pipe match actual production conditions. During drip irrigation operation, water flows naturally from the bottom slope of the baffle tank into the collection tank. When the water level in the collection tank rises to half its capacity, the system automatically starts the submersible pump and pumps the water back into the storage tank. This process is controlled by a level sensor for automatic detection and start / stop.

[0017] Before starting the experiment, fill the water tank to the upper limit of the level gauge and record the initial level. Turn on the valves and water pump to start the drip irrigation system, and adjust the water pump operating parameters to keep the pressure and flow rate at the drip irrigation outlet consistent with the production settings.

[0018] Water filling phase: The entire water filling phase should last no less than 1 hour to ensure system stability. After the water filling phase is complete, sequentially shut off the water pump, submersible pump, and valves. Finally, record the liquid levels in the storage tank and collection tank at this point to provide baseline data for subsequent evaporation calculations.

[0019] Measurement phase: 1) Environmental Setup: To simulate a natural evaporation environment, electric heating plates were arranged around the water-blocking tank, and a temperature control system was used to stably maintain the temperature of the test area within ±2℃ of the annual average temperature of the production site. Simultaneously, an adjustable-speed fan was installed above the water-blocking tank, maintaining the wind speed at the annual average wind speed of the site. The humidity of the entire test area was adjusted to closely approximate the actual site parameters. Real-time data on ambient temperature, humidity, and wind speed were continuously monitored and recorded by installed sensors to ensure the controllability of external variables during the test and to closely approximate the actual site conditions.

[0020] 2) After completing the environmental setup, restart the water pump, valves and submersible pump, adjust the water pump operating parameters to keep the pressure and flow rate at the drip outlet consistent with production, and start timing.

[0021] 3) Close monitoring of liquid level and environmental parameters is necessary to ensure a stable and reliable test process. Due to the small evaporation coefficient, the system water volume is unlikely to change significantly in a short period of time. Therefore, the test should be conducted for a considerable period until a significant change occurs in the water level in the storage tank.

[0022] This test should be repeated at least three times to ensure the repeatability and representativeness of the results. For each test, the initial and final liquid levels of the collection tank and storage tank, the drip irrigation time, pressure, ambient temperature, humidity, and wind speed should be recorded in detail.

[0023] The evaporation rate E is calculated based on the changes in the liquid level of the water collection tank and storage tank, using the following formula:

[0024] In the formula, V I , V F The figures represent the liquid volumes before and after the test in the water collection tank and water storage tank, respectively.

[0025] The formula for calculating the evaporation coefficient is: a=E / V In the formula: a is the evaporation coefficient, E is the measured evaporation amount, and V is the cumulative amount of solution passing through the drip tube (equal to the average flow rate measured by the flow meter). (Test time).

[0026] By adjusting factors such as temperature, wind speed, and humidity, the spray evaporation coefficient can be measured for different seasons, which can better guide on-site production management.

[0027] This invention has the following characteristics: 1. Evaporation measuring device: 1) Adjustable water pump to ensure that the working pressure and flow rate of the dripping pipe are consistent with the on-site production; 2) The bottom of the water collection tank is laid with ore of the same particle size as the ore produced by heap leaching, and the ore is washed and dried in advance.

[0028] 2. Fill the system with water before the test to reduce the impact of system components and ore washing water on the test results.

[0029] 3. By adjusting factors such as temperature, wind speed, and humidity, the test environment is made consistent with the heap leaching production conditions.

[0030] 4. Other measures ensure that the testing environment and conditions are consistent with those of heap leaching production.

[0031] 5. By adjusting factors such as temperature, wind speed, and humidity, the drip evaporation coefficient can be measured for different seasons, which can better guide on-site production management.

Claims

1. A method of determining the evaporation coefficient of a drip irrigation system, characterized in that: It comprises a water baffle tank, a shower head, a water collecting tank, a water storage tank, ore, a water pump and a submersible pump; the water pump is a variable frequency controlled adjustable pump, the flow and pressure of which can be adjusted, so that the inlet pressure and flow of the shower head are consistent with the actual production; The bottom of the water baffle tank is paved with ore with a particle size P80=50mm and a thickness of not less than 30cm, and is washed in advance for 1-2h to remove fine particles and prevent the pipeline and equipment from being blocked, and is dried after washing; Water baffle box size: length, width and height not less than m; During the operation of the drip irrigation pipe, water flows from the bottom slope of the water baffle tank into the water collecting tank naturally, when the water level in the water collecting tank rises to half of its capacity, the system automatically starts the submersible pump and draws water back into the water storage tank, and the process is controlled by the liquid level sensor to realize automatic judgment and start-stop; Determination method: Before the experiment, water is injected into the water storage tank to the upper limit scale of the liquid level meter, the initial liquid level record is made, the valve and the water pump are opened, the drip irrigation pipe is operated, and the operation parameters of the water pump are adjusted to keep the pressure and flow at the outlet of the drip irrigation pipe consistent with the production; The water filling stage: the duration of the water filling stage of the entire device is not less than 1 hour to ensure the stability of the system state, after the completion of the water filling stage, the water pump, the submersible pump and the valve are closed in turn, and the liquid levels of the water storage tank and the water collecting tank at this time are recorded to provide reference data for subsequent evaporation calculation; The determination stage includes the following steps: 1) Environmental setting: in order to simulate the natural evaporation environment, electric heating plates are arranged around the water baffle tank, and the temperature control system is used to stably control the temperature of the test area at the average temperature of the production site ±2℃; at the same time, an adjustable speed fan is arranged above the water baffle tank, and the wind speed is kept at the average wind speed of the site; the air humidity of the entire test area is adjusted to approach the site parameters. The real-time data of environmental temperature, humidity and wind speed are continuously monitored and recorded by the installed sensors to ensure the controllability of external variables during the test and to approach the actual situation of the site as much as possible; 2) After completing the environmental setting, the water pump, valve and submersible pump are reopened, the operation parameters of the water pump are adjusted to keep the pressure and flow at the outlet of the drip irrigation pipe consistent with the production, and the timing is started; 3) Pay close attention to the changes of liquid level and environmental parameters to ensure the stability and reliability of the test process, and the test time should be kept for a long time until the liquid level of the water storage tank changes obviously; 4) Steps 1-3 are repeated not less than three times to ensure the repeatability and representativeness of the results, and the initial and final liquid levels of the water collecting tank and the water storage tank, the operation time of the drip irrigation pipe, the pressure, the environmental temperature, the humidity and the wind speed parameters are recorded; The evaporation coefficient calculation formula is: wherein V I , V F V1 and V2 are the liquid volumes before and after the test, respectively. a=E / V ​ where: a is the evaporation coefficient, E is the measured evaporation, V is the cumulative volume of solution passed through the drip irrigation pipe, equal to the average flow measured by the flow meter Test time.

2. The method of determining the evaporation coefficient of a drip irrigation system according to claim 1, characterized in that: The method is completed by using a device for determining the evaporation coefficient of the drip irrigation system, the device comprises a water blocking tank, a drip irrigation pipe, a drip irrigation net, a water collecting tank, a water storage tank, ores, a water pump and a submersible pump; the water pump is a variable frequency controller adjustable pump, the flow and pressure can be adjusted, liquid level meters are installed on the water collecting tank and the water storage tank, flow meters and pressure gauges are installed between the water pump and the drip irrigation pipe, and the water collecting tank and the water storage tank are communicated.

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