Lime milk automatic preparation method and system

Abstract

The invention relates to an automatic lime milk preparation method and system, and belongs to the field of mineral separation process automation. The automatic lime milk preparation system comprises a lime milk preparation device, a lime milk grinding and filtering device, a lime milk concentration measurement and control device, a lime milk conveying and storage control device and a control system, under the control of the control system, the automatic control of preparing the lime milk from the quick lime is realized. According to the automatic lime milk preparation method, lime milk preparation is achieved through cooperative work of multiple control modules, and a quick lime feeding automatic control module, a lime milk preparation system equipment interlocking control module, a quick lime water adding lime milk preparation automatic control module and a mixed medium supplementing and lime milk grinding and deslagging automatic control module are included. A lime milk concentration detection and automatic control module; and a lime milk conveying and storage automatic control module. According to the invention, the automation level of lime milk preparation and the preparation precision of lime milk can be improved.

Description

Technical Field

[0001] This invention relates to an automatic lime slurry preparation method and system, which is particularly suitable for the automatic preparation of lime slurry using quicklime in mineral processing, and belongs to the field of mineral processing automation technology. Background Technology

[0002] Lime is a commonly used mineral processing reagent in flotation production, widely used in both metallic and non-metallic minerals. The core role of lime in flotation is to adjust the pH of the pulp and act as an inhibitor. Lime can neutralize acidic substances in the pulp, making it alkaline, which is beneficial for the adsorption and reaction of certain flotation reagents. Lime also has an inhibitory effect, increasing the hydrophilicity of minerals and thus inhibiting their flotation. In short, by appropriately adding lime, the pH of the pulp can be altered, thereby improving the effectiveness of flotation reagents and increasing flotation efficiency.

[0003] In its invention patent "Automatic Lime Slurry Preparation Equipment Based on Weighing, ZL201010597424.2", the applicant innovatively provided a new method and device for automatically preparing lime slurry using lime powder, based on the then-current requirements of lime slurry production processes. While using lime powder to prepare lime slurry was an early method employed in mineral processing, it has been gradually replaced by direct preparation of lime slurry using quicklime due to its high production costs, significant dust generation, and severe pollution.

[0004] Currently, the preparation of lime slurry using quicklime and water in mineral processing is mainly done manually. While this method is simple, easy to implement, low-cost, and produces little dust, it also has some drawbacks, primarily: (a) Manual preparation of lime slurry requires multiple workers and is labor-intensive; (b) The concentration of the prepared lime slurry is unstable, affecting the accuracy of subsequent lime slurry additions and thus impacting production indicators; (c) Quicklime carries a large amount of stone residue that remains in the lime tank, requiring manual cleaning, which is labor-intensive; (d) The prepared lime slurry contains a large amount of lime particles and slag, easily causing valve and pipeline blockages, requiring production shutdowns for manual unblocking, affecting the normal operation of flotation; (e) The stones and slag carried by the quicklime require site storage, occupying significant storage space and causing environmental pollution. Due to these problems, the existing lime slurry preparation and addition process suffers from high failure rates and poor accuracy, thus affecting the technical indicators and economic benefits of mineral processing. Summary of the Invention

[0005] To overcome the shortcomings of existing lime slurry preparation methods in mineral processing, this invention provides an automated lime slurry preparation method and system, including both an automated lime slurry preparation method and an automated lime slurry preparation system. This invention plays a positive role in improving the automation level of lime slurry preparation, increasing the accuracy of lime slurry preparation, reducing labor and labor intensity, reducing the discharge of waste rock and slag, and lowering steel ball consumption and lime slurry production costs.

[0006] Based on the characteristics of the current mineral processing technology of preparing lime slurry using quicklime and the problems existing in the current process, this invention further innovates the technical methods and equipment system on the basis of the invention patent that has been granted (application number ZL201010597424.2, patent name "Weighing-type Automatic Lime Slurry Preparation Equipment").

[0007] The overall technical concept of this invention is as follows: Quicklime storage, lime slurry preparation, and lime output are achieved through the control of a lime trough equipped with a screw conveyor and elevator, suitable for quicklime with large particle size and containing stones. Grinding and slag removal of the lime slurry prevents lime agglomeration and ensures lime slurry with the required fineness. Concentration detection and water addition control of the lime slurry ensure lime slurry meets the process concentration and fineness requirements. The lime slurry is then transported to a storage tank to provide sufficient lime slurry for flotation production. A matching automatic control method is proposed, forming an automatic control method and equipment system suitable for preparing lime slurry using quicklime. This system is applicable not only to the automatic preparation of lime slurry in mineral processing but also to other similar production processes. The stones entrained in the quicklime are used as auxiliary grinding media, gradually consumed during grinding, thus eliminating the need for manual cleaning of the stones and turning waste into utilization.

[0008] The technical solution of this invention is as follows: This invention provides an automatic lime slurry preparation system, including a lime slurry preparation device, a lime slurry grinding and filtering device, a lime slurry concentration measurement and control device, a lime slurry conveying and storage control device, and a control system. The lime slurry preparation device, lime slurry grinding and filtering device, lime slurry concentration measurement and control device, and lime slurry conveying and storage control device are connected sequentially, and under the control of the control system, automatic control of preparing lime slurry from quicklime is achieved.

[0009] The lime slurry preparation device includes a frequency converter 2, an electric regulating valve 3, an electromagnetic flow meter 4, a semi-circular lime trough 5, a feed inlet 6, an array of nozzles 7, a spiral 8, a spiral lift 9, a geared motor 24, and a chute 25.

[0010] The semi-circular lime trough 5 is used to store quicklime and is semi-cylindrical in shape with a sloping installation.

[0011] The spiral 8 is driven by a geared motor 24 and is used to push and output lime forward. It has a single spiral structure and is installed inside the semi-circular lime trough 5. Its upper end is connected to the geared motor 24 and is mounted on a rotating shaft, and its lower end is connected to a spiral lift 9. The height of the spiral 8 is controlled by the spiral lift 9. The speed of the spiral 8 is adjusted by controlling the geared motor 24 through the frequency converter 2.

[0012] The electric regulating valve 3, electromagnetic flow meter 4, and array nozzle 7 are connected in sequence to control the flow rate of the spray water. The flow rate of the spray water is adjusted by adjusting the opening of the electric regulating valve 3. The flow rate of the spray water is detected by the electromagnetic flow meter 4. The array nozzle 7 is equipped with multiple nozzles and is installed at the lower end of the semi-circular lime trough 5 for lime spraying.

[0013] The chute 25 is used to transport lime from the semi-circular lime trough 5 to the small ball mill 10.

[0014] The technical solution for the lime slurry grinding and filtering device is as follows: A lime slurry grinding and filtering device includes a small ball mill 10, a vibrating screen 11, and a slag receiving cart 12. The lime slurry is ground finely by the small ball mill 10. The small ball mill 10 uses small steel balls and stones carried by quicklime as grinding media, turning waste stones into usable material, reducing the consumption of small steel balls and avoiding the accumulation of large amounts of stones. The small ball mill 10 is installed at an angle, with the outlet slightly lower than the inlet. The lime slurry output from the small ball mill 10 enters the vibrating screen 11. Through vibration, the lime slurry and slag are fully separated, preventing screen clogging. Qualified lime slurry enters the concentration measuring container 14, while the slag enters the slag receiving cart 12.

[0015] The technical solution of the lime slurry concentration measurement and control device is as follows: A lime slurry concentration measurement and control device includes a solenoid valve 13, a concentration measuring container 14, a force sensor 15, a concentration measuring ultrasonic level gauge 16, a concentration measuring stirrer 17, and a force sensor signal transmitter 18.

[0016] The concentration measuring container 14 is used to buffer lime slurry and measure and control its concentration, ensuring that the concentration of lime slurry prepared each time is qualified. The concentration measuring container 14 is installed below the vibrating screen 11 to receive the lime slurry output from the vibrating screen 11; the amount of water added is adjusted by controlling the on / off state of the solenoid valve 13 to control the concentration of the lime slurry; the force sensor 15 is used to measure the total weight of the concentration measuring container 14, and its signal is amplified and conditioned by the force sensor signal transmitter 18; the concentration measuring ultrasonic level gauge 16 is used to measure the lime slurry level in the concentration measuring container 14; the concentration signal and level signal are transmitted to the control system 1 for lime slurry concentration calculation and concentration and level control.

[0017] The concentration measuring stirrer 17 is used to prevent lime slurry from settling, and multiple sets of blades are set in sections on its rotating shaft to ensure that the lime slurry will not settle and the liquid surface is flat when the rotation speed is slow, so as to facilitate accurate detection of the lime slurry level.

[0018] The technical solution of the lime slurry conveying and storage control device includes: a pipe flexible connector adapter 19, a small slurry pump 20, a lime slurry storage tank 21, a storage tank agitator 22, and a storage tank ultrasonic level gauge 23. The small slurry pump 20 conveys lime slurry from the concentration measuring container 14 to the lime slurry storage tank 21. The small slurry pump 20 is installed below the lime slurry storage tank 21. The pipe flexible connector adapter 19 connects the output pipe of the concentration measuring container 14 and the input pipe of the small slurry pump 20 to reduce the influence of external factors on the force sensor 15 measurement. The lime slurry storage tank 21 is installed at a relatively high position so that the lime slurry has a high flow rate during gravity flow, thus avoiding pipe blockage. The shaft of the storage tank agitator 22 is segmented with multiple sets of blades, which can keep the lime slurry from settling and maintain a flat liquid surface at slow speeds, thereby improving the liquid level detection accuracy of the lime slurry storage tank 21.

[0019] The technical solution of the control system includes a touch screen computer, a programmable logic controller (PLC), AC contactors, circuit breakers, protective electrical appliances, a control cabinet, and peripheral circuits. The control system enables the power supply, distribution, control, and management of all equipment in the lime slurry preparation system.

[0020] An automatic method for preparing lime slurry, the method comprising:

[0021] Automatic control of quicklime feeding is achieved through an automatic quicklime feeding control module.

[0022] The interlocking control of the lime slurry preparation system equipment is achieved through the lime slurry preparation system equipment interlocking control module;

[0023] Automatic control of quicklime-water-lime-slurry preparation is achieved through an automatic control module.

[0024] Automatic control of mixing media replenishment and lime slurry grinding and slag removal is achieved through an automatic control module for mixing media replenishment and lime slurry grinding and slag removal.

[0025] The lime slurry concentration is detected and automatically controlled using a lime slurry concentration detection and automatic control module.

[0026] The automatic control of lime slurry conveying and storage is achieved through an automatic control module for lime slurry conveying and storage.

[0027] Through the coordinated work of all the modules mentioned above, the automatic control of lime slurry preparation is achieved.

[0028] The working steps of the interlocking control module of the lime slurry preparation system equipment include:

[0029] Step S11: Upon receiving the master start command, an audible and visual alert is issued, and after a delay, the relevant equipment is started in the order from back to front of the process. Upon receiving the master start command from the control system, an audible and visual alert is first issued, followed by a delay of several minutes, and then the system equipment is started sequentially from back to front of the process.

[0030] Step S12: Upon receiving the general stop command, the system stops the relevant equipment sequentially from beginning to end according to the process after a delay. The general stop command is divided into an emergency stop command and a normal stop command. When an emergency stop command is received, the system immediately stops all equipment; when a normal stop command is received, the system stops the equipment sequentially from beginning to end. If the lime slurry preparation is not yet complete, the system waits until the lime slurry preparation is finished before stopping all equipment. If subsequent flotation production is in progress, the storage tank agitator 22 will remain running until manually stopped.

[0031] Step S13: Start or stop the screw conveyor and screw jack according to the feeding control command. After receiving the start feeding control command, the system starts or stops the screw 8, screw jack 9 and geared motor 24 according to the system control requirements.

[0032] Step S14: Start or stop the lime slurry preparation device according to the equipment control command for lime slurry preparation. After receiving the equipment control command for lime slurry preparation, the system starts or stops the screw conveyor 8 and the screw elevator 9 and turns the spray water on or off as needed.

[0033] Step S15: Start or stop the grinding and filtering device according to the control command of the lime slurry grinding and filtering equipment. After receiving the control command of the lime slurry grinding and filtering equipment, the system starts or stops the small ball mill 10 and the vibrating screen 11 according to the control requirements.

[0034] Step S16: Start or stop the lime slurry concentration measurement and control device according to the lime slurry concentration measurement and control command. After receiving the lime slurry concentration measurement and control command, the system starts or stops the concentration measuring stirrer 17 and solenoid valve 13 according to control requirements.

[0035] Step S17: Start or stop the lime slurry conveying and storage control device according to the lime slurry conveying and storage control command. After receiving the lime slurry conveying and storage control command, the system starts or stops the small slurry pump 20 and the storage tank agitator 22 according to control needs.

[0036] The automatic control module for quicklime feeding has the following operating steps:

[0037] Step S21: Adjust the screw height and screw speed to the required values. The screw height of the screw 8 is adjusted to the required value by the screw jack 9, and the screw speed of the screw 8 is adjusted to the required value by the frequency converter 2. These two required values ​​are obtained by debugging the control system in advance.

[0038] Step S22: Quicklime is fed into the semi-circular lime trough through the feed inlet, and is transported and stacked by the rotation of a screw. After the quicklime is fed into the semi-circular lime trough 5 through the feed inlet, it is transported forward by the rotation of the screw, thereby realizing the stacking of quicklime in the semi-circular lime trough 5.

[0039] Step S23: Control the thickness of the quicklime pile by adjusting the height of the screw. During the quicklime handling process, the screw 8 is slowly raised by the screw jack 9 to achieve quicklime piles of different thicknesses, so that the quicklime fills the semi-circular lime trough 5.

[0040] Step S24: Determine the load on the screw based on the current value of the screw motor, and adjust the height of the screw accordingly. The deeper the screw 8 is embedded in the lime, the greater the motor current of the screw 8, and vice versa. Adjust the height of the screw 8 based on the motor current of the screw 8.

[0041] Step S25: Quicklime is piled into the semi-circular lime trough from bottom to top until the conveying and piling are completed. By gradually raising the screw 8, quicklime is piled into the semi-circular lime trough 5 from the bottom to the top of the screw 8 until the quicklime input from the feed inlet 6 is completely piled up.

[0042] The automatic control module for preparing lime slurry by adding water to quicklime includes the following steps:

[0043] Step S31: Control the spray water flow rate to the set value and start the screw conveyor to output lime. The control loop consisting of electric regulating valve 3, electromagnetic flow meter 4 and PID controller controls the spray water flow rate within the set value range, and the lime is output from the semi-circular lime tank 5 by the rotation of screw 8.

[0044] Step S32: The lime output flow rate is controlled by adjusting the screw speed and screw height. The lime output flow rate is related to the screw speed and height of the screw 8; the higher the screw speed, the greater the flow rate, and the lower the screw height, the greater the output flow rate, and vice versa. The control system automatically adjusts the screw speed and screw height according to control requirements.

[0045] Step S33: Adjust the output lime and spray water flow rates according to the lime slurry concentration and flow rate in the concentration measuring container, and control them within the upper and lower limits. When the dry lime mass flow rate and lime slurry concentration are greater than the upper limit, reduce the screw speed to reduce the lime output flow rate; when the dry lime mass flow rate and lime slurry concentration are less than the lower limit, increase the screw speed to increase the lime output flow rate; when increasing the screw speed cannot output enough dry lime, gradually reduce the screw height to increase the lime output flow rate; when the lime slurry concentration is too low, automatically reduce the spray water flow rate until the lime output flow rate meets the requirements, and at the same time adjust the spray water flow rate to the normal value.

[0046] Step S34: Control the lime slurry concentration in the concentration measuring container within a certain range above the process requirement value. To facilitate subsequent control of the lime slurry concentration, it is necessary to first control the lime slurry concentration in the concentration measuring container 14 within a certain range above the process requirement value to ensure that the lime slurry concentration does not fall below the process requirement value when there are large fluctuations in the process.

[0047] Step S35: Upon receiving the command to stop lime slurry preparation, the lime slurry preparation is stopped. When the system receives the command to stop lime slurry preparation, it immediately stops the rotation of screw 8 and screw elevator 9, and shuts off the spray water, thereby stopping the lime slurry preparation.

[0048] The automatic control module for adding mixed media and grinding and removing slag from lime slurry includes the following working steps:

[0049] Step S41: Using the current value of the small ball mill as a reference, add small steel balls from the inlet of the small ball mill until the current reaches the empirical value. The current value of the small ball mill 10 is related to its load. Since the load of the small ball mill 10 is mainly composed of small steel balls, the current value is primarily determined by the load of small steel balls. Using the current value of the small ball mill 10 as a reference, add small steel balls from the inlet of the small ball mill 10 until the current value reaches the empirical value. Based on the characteristic that the current value of the small ball mill corresponds to its load in a single peak value, a gradual addition of small steel balls is adopted to maintain the load of the small ball mill 10 at an appropriate position before the peak value.

[0050] Step S42: The grinding media consists mainly of small steel balls, supplemented by stones embedded in the lime, for grinding lime slurry. Since the stones embedded in the quicklime are random, when adding small steel balls to the small ball mill 10, ensure that the loading of small steel balls is slightly higher than the minimum limit, thereby forming a grinding media state with small steel balls as the main component and stones embedded in the lime as the supplement, for grinding lime slurry.

[0051] Step S43: Calculate the amount of small steel balls to be added based on the running time of the small ball mill, and simultaneously refer to the current of the small ball mill to add small steel balls. The small steel balls are continuously worn and consumed during the grinding process, requiring continuous, timed replenishment. Calculate the amount of small steel balls to be added within the timed interval and add them accordingly. The more small steel balls added, the higher the current value. When the current value reaches a certain value, stop adding small steel balls.

[0052] Step S44: Based on the average current value and its trend over a period of time, determine and control the load status of the small ball mill. Since the load on the small ball mill varies, obtain a data sequence of the average current value and its trend over a period of time, and use this as a basis to determine and control the load status of the small ball mill. When the load becomes excessive, stop lime slurry preparation and resume lime slurry preparation after it returns to normal.

[0053] Step S45: The lime slurry is filtered by a vibrating screen. The underside of the screen is the qualified product, and the overside is the slag. The slag slides into the slag receiving cart due to vibration. Vibrating screen 11 is used to filter the lime slurry. The underside of the screen is the qualified lime slurry, and the overside is the slag. The slag slides into the slag receiving cart 12 due to vibration. The slag receiving cart 12 can be lifted to a designated location by a crane in the plant and then manually pushed open for processing.

[0054] The working steps of the lime slurry concentration detection and automatic control module include:

[0055] Step S51: The concentration measuring stirrer is used to stir at low speed to keep the lime slurry in suspension and maintain a flat liquid surface for accurate level measurement. The stirring shaft of the concentration measuring stirrer 17 is equipped with multiple sets of blades, which can keep the lime slurry in suspension and the liquid surface flat under low-speed stirring to facilitate accurate level measurement in the concentration measuring container 14.

[0056] Step S52: Detect the liquid level in the concentration measuring container using an ultrasonic level gauge and the total weight of the concentration measuring container using a force sensor. Detect the liquid level in the concentration measuring container 14 using an ultrasonic level gauge 16 installed above the concentration measuring container 14 and the total weight of the concentration measuring container 14 using a force sensor 15 installed below the concentration measuring container 14. Subtract the gross weight from the total weight to obtain the weight of the lime slurry.

[0057] Step S53: Calculate the lime slurry concentration in the concentration measurement container using a mathematical model. The mathematical model for calculating the lime slurry concentration is as follows:

[0058]

[0059] In the formula, p is the percentage concentration, d0 is the density of water, δ is the density of dry lime, and K v N is the volume index. L0The A / D value of the level signal when the concentration measurement container is emptied, N L K is the current A / D value of the concentration measurement container's level signal. w N is the weight coefficient. w0 The weight signal A / D value of N when the concentration measurement container 14 is emptied. w The current weight signal A / D value of the concentration measurement container 14.

[0060] Step S54: Calculate the volumetric flow rate of the lime slurry and the mass flow rate of the dry lime based on the liquid level, concentration, and density of the lime slurry in the concentration measuring container. Calculate the dry lime flow rate and the volumetric flow rate of the lime slurry based on the liquid level change in the concentration measuring container 14 over a period of time and the current concentration. Let the liquid level change in the concentration measuring container 14 over time T be ΔL, the current concentration of the lime slurry be p, and the current density be d, then the volumetric flow rate Q of the lime slurry output from the semi-circular lime tank 5 is... v And the mass flow rate Q of converting lime slurry to dry lime. m The calculation formula is:

[0061] Volumetric flow rate Q v Calculation formula: Q v =K Q ΔL / T

[0062] Mass flow rate Q m Calculation formula: Q m =Q v dp

[0063] Step S55: Calculate the upper limit of the liquid level corresponding to the current lime slurry concentration. When the liquid level reaches the upper limit, issue a lime slurry stop preparation command. Calculate the amount of dry lime required to prepare one batch of lime slurry and the upper limit of the liquid level in the concentration measuring container 14 based on the lime slurry process concentration and the volume of the concentration measuring container 14. When the measured liquid level reaches the upper limit, issue a stop lime slurry preparation command and a stop lime slurry grinding and filtering command.

[0064] Step S56: Stop lime slurry preparation. Using pulse control of the water replenishment solenoid valve, gradually control the lime slurry concentration to the required process value, while simultaneously issuing a slurry pump delivery command. Upon receiving the stop lime slurry preparation command, the system immediately stops preparation, waits for several minutes until the prepared lime slurry has completely flowed into the concentration measuring container 14, and then uses the method of sequentially opening the solenoid valve 13 to adjust the lime slurry concentration to the required process value. When the concentration error is less than 0.5%, stop water replenishment, completing the preparation of this lime slurry concentration, and simultaneously issue a slurry pump delivery command. The formula for calculating the opening time of solenoid valve 13 is:

[0065]

[0066] In the formula, t is the opening time of the solenoid valve, and ps The required lime slurry concentration is given by p, where p is the current lime slurry concentration, Kq is the flow coefficient of the solenoid valve, and K... w N is the weight coefficient. w0 The weight signal A / D value of N when the concentration measurement container 14 is emptied. w The current weight signal A / D value of the concentration measurement container 14.

[0067] The automatic control module for conveying and storing lime slurry includes the following operating steps:

[0068] Step S61: Start the small slurry pump to deliver qualified lime slurry to the lime slurry storage tank, and simultaneously run the storage tank agitator. After receiving the command to start the small slurry pump, the system immediately starts the small slurry pump 20 to deliver lime slurry to the lime slurry storage tank 21, and simultaneously runs the storage tank agitator 22. If flotation production is ongoing, the storage tank agitator will remain running.

[0069] Step S62: After the weight change of the concentration measuring container is less than the threshold for a period of time, stop the operation of the small slurry pump and the concentration measuring agitator. The weight of the concentration measuring container 14 decreases continuously as lime slurry is transported. When the weight change of the concentration measuring container 14 is less than the threshold, it indicates that the lime slurry in the concentration measuring container 14 has been emptied. After a delay, a command to stop lime slurry concentration measurement and control is issued.

[0070] Step S63: Detect the liquid level in the lime slurry storage tank using an ultrasonic level gauge. The liquid level in the lime slurry storage tank 21 is detected using an ultrasonic level gauge 23 installed above the lime slurry storage tank 21.

[0071] Step S64: When the liquid level in the lime slurry storage tank is higher than the upper limit, a command to stop lime slurry preparation is issued. When the liquid level in the lime slurry storage tank 21 is higher than the upper limit, the system issues a command to stop lime slurry preparation.

[0072] Step S65: When the liquid level in the lime slurry storage tank is below the lower limit, a command to start lime slurry preparation is issued. When the liquid level in the lime slurry storage tank 21 is below the lower limit, the system issues a command to start lime slurry preparation.

[0073] Based on the technology of the invention patent application number ZL201010597424.2, entitled "Automatic Weighing Lime Slurry Preparation Equipment", this invention further innovates the technical methods and equipment system according to the current process characteristics of using quicklime to prepare lime slurry in mineral processing: It designs a device with quicklime storage, lime slurry preparation, and lime output functions, especially suitable for large pieces of quicklime and situations involving large stones; by grinding and removing slag from the lime slurry, it avoids lime clumping and obtains lime slurry with qualified fineness; by detecting the concentration of the lime slurry and controlling water addition, it obtains lime slurry that meets the process concentration and fineness requirements; and it transports the lime slurry to a storage tank to provide sufficient lime slurry for flotation production. To achieve automatic control of the designed lime slurry preparation equipment system, a corresponding automatic control method is proposed, forming an automatic control method and equipment system suitable for preparing lime slurry using quicklime. This system is applicable not only to the automatic preparation of lime slurry in mineral processing but also to other similar production processes. It enables fully automatic control of the entire lime slurry preparation process, from feeding, mixing, grinding, filtering, concentration measurement, concentration control, transportation to storage. Furthermore, it utilizes the stones entrained in the quicklime as auxiliary grinding media, which are gradually consumed during grinding, eliminating the need for manual removal of these stones and turning waste into resources. This invention plays a positive role in improving the automation level of lime slurry preparation, increasing the accuracy of lime slurry preparation, reducing labor and labor intensity, reducing the discharge of waste rock and slag, and lowering steel ball consumption and lime slurry production costs.

[0074] This invention provides an automatic lime slurry preparation method and system, including an automatic lime slurry preparation method and an automatic lime slurry preparation system. The invention automatically adjusts the height of the screw to pile quicklime fed from the inlet to various positions in the lime trough; it controls the output flow rate of lime by adjusting the screw's rotation speed and height; it controls the concentration of the lime slurry output from the lime trough within a required range by controlling the output lime flow rate and the spray water flow rate; and it uses the screw's pushing action to output lime along with stones from the bottom of the lime trough to a small ball mill; utilizing small steel balls and stones as... The lime slurry is ground using a small ball mill as the grinding medium to reduce steel ball consumption and avoid the discharge of stones. A vibrating screen filters the lime slurry to remove slag and obtain lime slurry of the required fineness. A concentration measuring container serves as a buffer for the lime slurry and a device for detecting concentration and flow rate. Water is added to adjust the slurry concentration, keeping it within the required range. A small slurry pump transports the lime slurry to a storage tank. The lime slurry level in the storage tank is monitored; lime slurry preparation is stopped when the level exceeds the upper limit, and resumed when the level falls below the lower limit. The entire lime slurry preparation process is automated under the control of the system.

[0075] The beneficial effects of this invention are:

[0076] (1) The automatic control of the lime milk preparation process from feeding, mixing, grinding, filtering, concentration measurement, concentration control, conveying to storage has a positive effect on reducing the cost of lime milk preparation and reducing labor and labor intensity of workers.

[0077] (2) By grinding, removing slag and precisely controlling the concentration of lime milk, the concentration and fineness of lime milk are ensured to meet the process requirements, which provides favorable conditions for the precise control, stabilization and optimization of mineral processing production indicators for subsequent flotation production.

[0078] (3) Using the stones carried by lime as auxiliary grinding media not only turns waste into useful material, but also reduces the wear and tear of steel balls and the emission of waste. Attached Figure Description

[0079] Figure 1 This is the overall control flowchart of the present invention;

[0080] Figure 2 This is a system structure and control flowchart of the present invention;

[0081] Figure 3 This is a side view of the lime milk preparation apparatus of the present invention;

[0082] Figure 4 This is a flowchart of the equipment interlock control of the lime slurry preparation system of the present invention;

[0083] Figure 5 This is a flowchart of the quicklime feeding control of the present invention;

[0084] Figure 6 This is a flowchart of the lime milk preparation control process of the present invention;

[0085] Figure 7 This is a flowchart of the grinding, media replenishment and filtration control process of the present invention;

[0086] Figure 8 This is a flowchart of the lime slurry concentration detection and control method of the present invention;

[0087] Figure 9 This is a flowchart of the lime slurry conveying, storage and interlocking control of the present invention.

[0088] Figure 1-9Labels for each item: 1-Control system, 2-Frequency converter, 3-Electric regulating valve, 4-Electromagnetic flow meter, 5-Semi-circular lime trough, 6-Inlet, 7-Array nozzle, 8-Screw, 9-Screw jack, 10-Small ball mill, 11-Vibrating screen, 12-Slag receiving trolley, 13-Solenoid valve, 14-Concentration measuring container, 15-Force sensor, 16-Concentration measuring ultrasonic level gauge, 17-Concentration measuring agitator, 18-Force sensor signal transmitter, 19-Pipeline flexible connector adapter, 20-Small slurry pump, 21-Lime slurry storage tank, 22-Storage tank agitator, 23-Storage tank ultrasonic level gauge, 24-Geared motor, 25-Chutter. Detailed Implementation

[0089] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0090] Example 1: As Figures 1-9 As shown, a certain ore processing plant processes lead-zinc ore with a capacity of 2000 t / d using a flotation process. Lime is used as a depressant. The process requirements for lime addition in flotation production are: 1.2 kg of dry lime per ton of ore, a lime slurry concentration of 25%, and a lime slurry storage volume sufficient for 8-16 hours of flotation production. Additionally, the quicklime used by the processing plant to prepare the lime slurry contains a significant amount of lumps, with the largest lumps reaching 100 mm in size.

[0091] To meet the requirements for the use conditions and production process of lime slurry in flotation production, this embodiment provides an automatic lime slurry preparation method and system, including an automatic lime slurry preparation method and an automatic lime slurry preparation system.

[0092] This embodiment provides an automatic lime slurry preparation method and system, including an automatic lime slurry preparation method and an automatic lime slurry preparation system. The invention automatically adjusts the height of the screw to pile the quicklime fed from the inlet to various positions in the lime trough; it controls the output flow rate of the lime by adjusting the screw's rotation speed and height; it controls the concentration of the lime slurry output from the lime trough within the required range by controlling the output lime flow rate and the spray water flow rate; and it uses the screw's pushing action to output the lime along with stones from the bottom of the lime trough to a small ball mill; utilizing small steel balls and stones as... The lime slurry is ground using a small ball mill as the grinding medium to reduce steel ball consumption and avoid the discharge of stones. A vibrating screen filters the lime slurry to remove slag and obtain lime slurry of the required fineness. A concentration measuring container serves as a buffer for the lime slurry and a device for detecting concentration and flow rate. Water is added to adjust the slurry concentration, keeping it within the required range. A small slurry pump transports the lime slurry to a storage tank. The lime slurry level in the storage tank is monitored; lime slurry preparation is stopped when the level exceeds the upper limit, and resumed when the level falls below the lower limit. The entire lime slurry preparation process is automated under the control of the system.

[0093] The automatic lime slurry preparation system described in this embodiment includes a lime slurry preparation device, a lime slurry grinding and filtering device, a lime slurry concentration measurement and control device, a lime slurry conveying and storage control device, and a control system. The lime slurry preparation device, lime slurry grinding and filtering device, lime slurry concentration measurement and control device, and lime slurry conveying and storage control device are connected sequentially. Under the control of the control system, the automatic preparation of lime slurry from quicklime is achieved.

[0094] The technical solution of the lime milk preparation device is as follows: A lime milk preparation device includes a frequency converter 2, an electric regulating valve 3, an electromagnetic flow meter 4, a semi-circular lime trough 5, a feed inlet 6, an array of nozzles 7, a spiral 8, a spiral lift 9, a geared motor 24, and a chute 25.

[0095] The design and selection of various components of the lime slurry preparation device in this embodiment are as follows: Frequency converter 2: 3kW power, 380VAC voltage; Electric regulating valve 3: DN25 diameter, V-type ball valve, stainless steel material, 220VAC power supply, 4-20mA input signal; Electromagnetic flowmeter 4: DN25 diameter, rubber lining, stainless steel electrode, integrated type, 220VAC power supply, 4-20mA output signal; Semi-circular lime trough 5: 2000mm diameter, 4000mm length; Inlet 6: Length 600mm, Width 800mm, Height 800mm, Inner chute slope 45°; Array nozzle 7: Nozzle diameter 150mm, 5 in total; Spiral 8: Diameter 1600mm; Spiral jack 9: Power 0.75KW, Reduction ratio 40, Stroke 1300mm; Gear motor 24: Power 2.2kw, Power supply 380VAC, Reduction ratio 50; Chute 25: Width 300mm, Height 200mm, Length should be sufficient to connect with the feed inlet of the small ball mill 10.

[0096] In this embodiment, the semi-circular lime trough 5 is used to store quicklime. It is semi-cylindrical in shape and installed on a slope with an angle of about 10°. The spiral 8 is used to push and output quicklime. It is a single spiral structure and is installed inside the semi-circular lime trough 5. Its upper end is connected to the reduction motor 24 and installed on the rotating shaft. Its lower end is connected to the spiral lift 9. The speed of the spiral 8 is adjusted by the frequency converter 2, and the lifting and lowering of the spiral 8 is controlled by the spiral lift 9. The electric regulating valve 3, the electromagnetic flow meter 4, and the array nozzle 7 are connected in sequence to control the flow rate of the spray water. The array nozzle 7 is installed at the lower end of the semi-circular lime trough 5 and is used to spray water at various positions at the lower end of the semi-circular lime trough 5.

[0097] The technical solution of the lime slurry grinding and filtering device in this embodiment is as follows: A lime slurry grinding and filtering device includes a small ball mill 10, a vibrating screen 11, and a slag receiving cart 12. The lime slurry is ground finely by the small ball mill 10. The small ball mill 10 uses small steel balls and stones carried by quicklime as grinding media, turning waste stones into usable materials, thereby reducing the consumption of small steel balls and avoiding the accumulation of large amounts of stones. The small ball mill 10 is installed at an angle, with the outlet slightly lower than the inlet. The lime slurry output from the small ball mill 10 enters the vibrating screen 11. Through vibration, the lime slurry and slag are fully separated and the screen is prevented from clogging. Qualified lime slurry enters the concentration measuring container 14, and the slag enters the slag receiving cart 12.

[0098] The design and selection of each component of the lime slurry grinding and filtering device in this embodiment are as follows: Small ball mill 10: diameter * length = 900mm * 1600mm, power 7.5kw, voltage 380VAC, small steel ball diameter 30mm; Vibrating screen 11: working mode is linear, screen mesh 40 mesh, power 0.75kw, voltage 380VAC, length * width = 600mm * 500mm; Slag receiving trolley 12: length * width * height = 800mm * 600mm * 600mm.

[0099] In this embodiment, a small ball mill 10 is used to grind the lime slurry, thoroughly pulverizing it for subsequent production use. The small ball mill 10 uses small steel balls and stones carried by the quicklime as grinding media, turning previously waste stones into usable material. This not only reduces the consumption of small steel balls but also reduces the amount of stone piled up during production. The small ball mill 10 is installed at an angle, with the discharge port slightly lower than the feed port at an angle of approximately 5°. The lime slurry output from the small ball mill 10 enters a vibrating screen 11. The vibration eliminates screen blockage, allowing qualified lime slurry to flow out from under the screen, while the slag slides from the screen onto a slag collection cart 12. The slag collection cart 12 can be manually pushed or transported by a workshop starter.

[0100] The technical solution of the lime slurry concentration measurement and control device is as follows: A lime slurry concentration measurement and control device includes a solenoid valve 13, a concentration measuring container 14, a force sensor 15, a concentration measuring ultrasonic level gauge 16, a concentration measuring stirrer 17, and a force sensor signal transmitter 18.

[0101] The components of the lime slurry concentration measurement and control device in this embodiment are designed and selected as follows: Solenoid valve 13: diameter DN25, voltage 220VAC; Concentration measuring container 14: diameter 800mm, height 1500mm; Force sensor 15: force range 0-1000kg, output signal 0-14mV; Concentration measuring ultrasonic level gauge 16: measuring range 0-2000mm, power supply 220VAC, output signal 4-20mA; Concentration measuring stirrer 17: power 0.25kw, voltage 380VAC, speed 60r / min, with 4 sets of blades; Force sensor signal transmitter 18: input signal 0-14mV, power supply voltage 24VDC, output signal 4-20mA.

[0102] In this embodiment, the concentration measuring container 14 is used to buffer lime slurry and measure and control its concentration to ensure that the concentration of lime slurry prepared each time is qualified. The concentration measuring container 14 is installed below the vibrating screen 11 and receives the lime slurry output from the vibrating screen 11; the amount of water added is adjusted by the on / off control of the solenoid valve 13 to control the concentration of lime slurry; the force sensor 15 is used to measure the total weight of the concentration measuring container 14, and its signal is amplified and conditioned by the force sensor signal transmitter 18; the concentration measuring ultrasonic level gauge 16 is used to measure the lime slurry level in the concentration measuring container 14; the concentration signal and the level signal are transmitted to the control system 1 for lime slurry concentration calculation and concentration and level control.

[0103] The concentration measuring stirrer 17 is used to prevent lime slurry from settling, and five sets of blades are arranged in sections on its rotating shaft to ensure that the lime slurry will not settle and the liquid surface is flat when the rotation speed is slow, so as to facilitate accurate detection of the lime slurry level.

[0104] The technical solution of the lime slurry conveying and storage control device described in this embodiment is as follows: it includes a pipe flexible connector adapter 19, a small slurry pump 20, a lime slurry storage tank 21, a storage tank agitator 22, and a storage tank ultrasonic level gauge 23. The small slurry pump 20 conveys lime slurry from the concentration measuring container 14 to the lime slurry storage tank 21. The small slurry pump 20 is installed approximately 300mm below the bottom of the lime slurry storage tank 21. The pipe flexible connector adapter 19 connects the output pipe of the concentration measuring container 14 and the input pipe of the small slurry pump 20 to reduce the influence of external factors on the force sensor 15 measurement. The lime slurry storage tank 21 is installed at a relatively high position, approximately 2m above the concentration measuring container 14, so that the lime slurry has a high flow rate during gravity flow, thereby avoiding pipe blockage. The shaft of the storage tank agitator 22 is segmented with 6 sets of blades, which can keep the lime slurry from settling and maintain a flat liquid surface at slow speeds, thereby improving the liquid level detection accuracy of the lime slurry storage tank 21.

[0105] The components of the lime slurry conveying and storage control device in this embodiment are designed and selected as follows: Pipe flexible connector adapter 19: diameter 30mm, length 150mm, silicone material; Small slurry pump 20: power 1.1kw, speed 2660r / min, voltage 380VAC; Lime slurry storage tank 21: diameter 1300mm, height 2200mm; Storage tank agitator 22: 5 sets of blades, speed 75r / min, power 0.75kw, voltage 380VAC; Storage tank ultrasonic level gauge 23: measuring range 0-3000mm, power supply voltage 24VDC, output signal 4-20mA.

[0106] The technical solution of the control system includes a touch screen computer, a programmable logic controller (PLC), AC contactors, circuit breakers, protective electrical appliances, a control cabinet, and peripheral circuits. The control system enables the power supply, distribution, control, and management of all equipment in the lime slurry preparation system.

[0107] The main components of the control system in this embodiment are designed and selected as follows: Touch screen computer: CPU I54200, 4G memory, 100G hard disk, 15.6-inch capacitive touch screen; Programmable controller S7-1200, DI 24 points, DO 24 points, AI 8-channel 16-bit resolution, AO 4-channel 12-bit resolution; AC contactors: 30A for small ball mill, 20A for spiral, 10A for other motor equipment; Circuit breakers and protective electrical appliances are configured according to the control system design; Control cabinet height * width * thickness = 2000 * 800 * 400; Peripheral circuits are equipped with electrical materials and connections according to the needs of the control system.

[0108] An automatic method for preparing lime slurry, the method comprising:

[0109] Automatic control of quicklime feeding is achieved through an automatic quicklime feeding control module.

[0110] The interlocking control of the lime slurry preparation system equipment is achieved through the lime slurry preparation system equipment interlocking control module;

[0111] Automatic control of quicklime-water-lime-slurry preparation is achieved through an automatic control module.

[0112] Automatic control of mixing media replenishment and lime slurry grinding and slag removal is achieved through an automatic control module for mixing media replenishment and lime slurry grinding and slag removal.

[0113] The lime slurry concentration is detected and automatically controlled using a lime slurry concentration detection and automatic control module.

[0114] The automatic control of lime slurry conveying and storage is achieved through an automatic control module for lime slurry conveying and storage.

[0115] Through the coordinated work of all the modules mentioned above, the automatic control of lime slurry preparation is achieved.

[0116] The working steps of the interlocking control module of the lime slurry preparation system equipment include:

[0117] Step S11: Upon receiving the master start command, an audible and visual alert is activated, and after a delay, the relevant equipment is started in the order from back to front according to the process flow. Upon receiving the master start command from the control system, the electric bell will sound first, followed by a flashing alarm. After a 3-minute delay, the system equipment will be started sequentially from back to front according to the process flow. The equipment start-up sequence is: storage tank agitator 22 → concentration measuring agitator 17 → vibrating screen 11 → small ball mill 10 → screw jack 9 → screw conveyor 8.

[0118] Step S12: Upon receiving the general stop command, the system stops the relevant equipment sequentially from beginning to end according to the process after a delay. The general stop command is divided into an emergency stop command and a normal stop command. When an emergency stop command is received, the system immediately stops all equipment; when a normal stop command is received, the system stops the equipment sequentially from beginning to end. If the lime slurry preparation is not yet complete, the system waits until the lime slurry preparation is finished before stopping all equipment. If subsequent flotation production is in progress, the storage tank agitator 22 will remain running until manually stopped. The equipment stop sequence is: screw conveyor 8 → screw jack 9 → small ball mill 10 → vibrating screen 11 → concentration measuring agitator 17 → storage tank agitator 22.

[0119] Step S13: Start or stop the screw conveyor and screw jack according to the feeding control command. After receiving the control command to start feeding, the system starts or stops the screw 8, screw jack 9 and geared motor 24 according to the system control requirements. The screw 8 is driven by the geared motor 24.

[0120] Step S14: Start or stop the lime slurry preparation device according to the equipment control command for lime slurry preparation. After receiving the equipment control command for lime slurry preparation, the system starts or stops the screw conveyor 8 and the screw elevator 9 and turns the spray water on or off as needed.

[0121] Step S15: Start or stop the grinding and filtering device according to the control command of the lime slurry grinding and filtering equipment. After receiving the control command of the lime slurry grinding and filtering equipment, the system starts or stops the small ball mill 10 and the vibrating screen 11 according to the control requirements.

[0122] Step S16: Start or stop the lime slurry concentration measurement and control device according to the lime slurry concentration measurement and control command. After receiving the lime slurry concentration measurement and control command, the system starts or stops the concentration measuring stirrer 17 and solenoid valve 13 according to control requirements.

[0123] Step S17: Start or stop the lime slurry conveying and storage control device according to the lime slurry conveying and storage control command. After receiving the lime slurry conveying and storage control command, the system starts or stops the small slurry pump 20 and the storage tank agitator 22 according to control needs.

[0124] The automatic control module for quicklime feeding has the following operating steps:

[0125] Step S21: Adjust the screw height and screw speed to the required values. The screw jack 9 is used to adjust the height of the screw 8 to the required value, and the frequency converter 2 is used to adjust the speed of the screw 8 to the required value. These two required values ​​are obtained through prior debugging of the control system. In this embodiment, the height of the screw 8 is adjusted so that its axis is parallel to the center line of the semi-circular lime trough, and the speed is adjusted to 18 r / min.

[0126] Step S22: Quicklime is fed into the semi-circular lime trough through the feed inlet, and is transported and stacked by the rotation of a screw. After the quicklime is fed into the semi-circular lime trough 5 through the feed inlet, it is transported forward by the rotation of the screw, thereby realizing the stacking of quicklime in the semi-circular lime trough 5.

[0127] Step S23: Control the thickness of the quicklime pile by adjusting the height of the screw. During the quicklime handling process, the screw 8 is slowly raised by the screw jack 9 to achieve quicklime piles of different thicknesses, so that the quicklime fills the semi-circular lime trough 5.

[0128] Step S24: Determine the load on the screw based on the current value of the screw motor, and adjust the height of the screw accordingly. The deeper the screw 8 is embedded in the lime, the greater the motor current of the screw 8, and vice versa. Adjust the height of the screw 8 based on the motor current of the screw 8.

[0129] Step S25: Quicklime is piled into the semi-circular lime trough from bottom to top until the conveying and piling are completed. By gradually raising the screw 8, quicklime is piled into the semi-circular lime trough 5 from the bottom to the top of the screw 8 until the quicklime input from the feed inlet 6 is completely piled up.

[0130] The automatic control module for preparing lime slurry by adding water to quicklime includes the following steps:

[0131] Step S31: Control the spray water flow rate to the set value and start the screw conveyor to output lime. The control loop consisting of electric regulating valve 3, electromagnetic flow meter 4 and PID controller controls the spray water flow rate within the set value range, and the lime is output from the semi-circular lime tank 5 by the rotation of screw 8.

[0132] Step S32: The lime output flow rate is controlled by adjusting the screw speed and screw height. The lime output flow rate is related to the screw speed and height of the screw 8; the higher the screw speed, the greater the flow rate, and the lower the screw height, the greater the output flow rate, and vice versa. The control system automatically adjusts the screw speed and screw height according to control requirements.

[0133] Step S33: Adjust the output lime and spray water flow rates according to the lime slurry concentration and flow rate in the concentration measuring container, and control them within the upper and lower limits. When the dry lime mass flow rate and lime slurry concentration are greater than the upper limit, reduce the screw speed to reduce the lime output flow rate; when the dry lime mass flow rate and lime slurry concentration are less than the lower limit, increase the screw speed to increase the lime output flow rate; when increasing the screw speed cannot output enough dry lime, gradually reduce the screw height to increase the lime output flow rate; when the lime slurry concentration is too low, automatically reduce the spray water flow rate until the lime output flow rate meets the requirements, and at the same time adjust the spray water flow rate to the normal value.

[0134] Step S34: Control the lime slurry concentration in the concentration measuring container within a certain range above the process requirement value. To facilitate subsequent control of the lime slurry concentration, it is essential to first control the lime slurry concentration in the concentration measuring container 14 within a certain range above the process requirement value. This ensures that the lime slurry concentration will not fall below the process requirement value when there are significant fluctuations in the process flow. In this embodiment, the process requirement value for the lime slurry concentration is 25%, and it is required to control the lime slurry concentration at approximately 30% during the lime slurry preparation process.

[0135] Step S35: Upon receiving the command to stop lime slurry preparation, the lime slurry preparation is stopped. When the system receives the command to stop lime slurry preparation, it immediately stops the rotation of screw 8 and screw elevator 9, and shuts off the spray water, thereby stopping the lime slurry preparation.

[0136] The automatic control module for adding mixed media and grinding and removing slag from lime slurry includes the following working steps:

[0137] Step S41: Using the current value of the small ball mill as a reference, add small steel balls from the inlet of the small ball mill until the current reaches the empirical value. The current value of the small ball mill 10 is related to its load. Since the load of the small ball mill 10 is mainly small steel balls, the current value is mainly determined by the load of small steel balls. Using the current value of the small ball mill 10 as a reference, add small steel balls from the inlet of the small ball mill 10 until the current value reaches the empirical value. In this embodiment, the empirical current value is 12.6A. Based on the characteristic that the current value of the small ball mill corresponds to its load in a single peak value manner, the method of gradually adding small steel balls is adopted to maintain the load of the small ball mill 10 at an appropriate position before the peak value.

[0138] Step S42: The grinding media consists mainly of small steel balls, supplemented by stones embedded in the lime, for grinding lime slurry. Since the stones embedded in the quicklime are random, when adding small steel balls to the small ball mill 10, ensure that the loading of small steel balls is slightly higher than the minimum limit, thereby forming a grinding media state with small steel balls as the main component and stones embedded in the lime as the supplement, for grinding lime slurry.

[0139] Step S43: Calculate the amount of small steel balls to be added based on the running time of the small ball mill, and simultaneously refer to the current of the small ball mill to add small steel balls. The small steel balls are continuously worn and consumed during the grinding process, requiring continuous, timed replenishment. Calculate the amount of small steel balls to be added within the timed interval and add them accordingly. The more small steel balls added, the higher the current value. When the current value reaches a certain value, the addition of small steel balls is stopped. In this embodiment, the relationship between the amount of small steel balls added and the running time is 0.65 kg / h, with replenishment once every 24 hours of operation.

[0140] Step S44: Based on the average current value and its trend over a period of time, determine and control the load status of the small ball mill. Since the load on the small ball mill varies, acquire a data sequence of the average current value and its trend over a period of time (e.g., 30 minutes), and use this data to determine and control the load status of the small ball mill. When the load becomes excessive, stop lime slurry preparation and resume lime slurry preparation after the load returns to normal.

[0141] Step S45: The lime slurry is filtered by a vibrating screen. The underside of the screen is the qualified product, and the overside is the slag. The slag slides into the slag receiving cart due to vibration. Vibrating screen 11 is used to filter the lime slurry. The underside of the screen is the qualified lime slurry, and the overside is the slag. The slag slides into the slag receiving cart 12 due to vibration. The slag receiving cart 12 can be lifted to a designated location by a crane in the plant and then manually pushed open for processing.

[0142] The working steps of the lime slurry concentration detection and automatic control module include:

[0143] Step S51: The concentration measuring stirrer is used to stir at low speed to keep the lime slurry in suspension and maintain a flat liquid surface for accurate level measurement. The stirring shaft of the concentration measuring stirrer 17 is equipped with multiple sets of blades, which can keep the lime slurry in suspension and the liquid surface flat under low-speed stirring to facilitate accurate level measurement in the concentration measuring container 14.

[0144] Step S52: Detect the liquid level in the concentration measuring container using an ultrasonic level gauge and the total weight of the concentration measuring container using a force sensor. Detect the liquid level in the concentration measuring container 14 using an ultrasonic level gauge 16 installed above the concentration measuring container 14 and the total weight of the concentration measuring container 14 using a force sensor 15 installed below the concentration measuring container 14. Subtract the gross weight from the total weight to obtain the weight of the lime slurry.

[0145] Step S53: Calculate the lime slurry concentration in the concentration measurement container using a mathematical model. The mathematical model for calculating the lime slurry concentration is as follows:

[0146]

[0147] In the formula, p is the percentage concentration, d0 is the density of water, δ is the density of dry lime, and K v N is the volume index. L0 The A / D value of the level signal when the concentration measurement container is emptied, N L K is the current A / D value of the concentration measurement container's level signal. w N is the weight coefficient. w0 The weight signal A / D value of N when the concentration measurement container 14 is emptied. w The current weight signal A / D value of the concentration measurement container 14.

[0148] In this embodiment, d0 is the density of water, which is 1 g / cm³. 3 δ represents the density of dry lime, taken as 3.2 g / cm³. 3 , K v The volume factor is set to 1.05; N L0 The A / D value of the level signal when the concentration measurement container is emptied is set to 12620; K w This is the weight coefficient, with a value of 0.0443.

[0149] Step S54: Calculate the volumetric flow rate of the lime slurry and the mass flow rate of the dry lime based on the liquid level, concentration, and density of the lime slurry in the concentration measuring container. Calculate the dry lime flow rate and the volumetric flow rate of the lime slurry based on the liquid level change in the concentration measuring container 14 over a period of time and the current concentration. Let the liquid level change in the concentration measuring container 14 over time T be ΔL, the current concentration of the lime slurry be p, and the current density be d, then the volumetric flow rate Q of the lime slurry output from the semi-circular lime tank 5 is... v And the mass flow rate Q of converting lime slurry to dry lime. m The calculation formula is:

[0150] Volumetric flow rate Q v Calculation formula: Q v =K Q ΔL / T

[0151] Mass flow rate Q m Calculation formula: Q m =Q v dp

[0152] In this embodiment, K Q It is 1.043.

[0153] Step S55: Calculate the upper limit of the liquid level corresponding to the current lime slurry concentration. When the liquid level reaches the upper limit, issue a lime slurry stop preparation command. Calculate the amount of dry lime required to prepare one batch of lime slurry and the upper limit of the liquid level in the concentration measuring container 14 based on the lime slurry process concentration and the volume of the concentration measuring container 14. When the measured liquid level reaches the upper limit, issue a stop lime slurry preparation command and a stop lime slurry grinding and filtering command.

[0154] Step S56: Stop lime slurry preparation. Using pulse control of the water replenishment solenoid valve, gradually control the lime slurry concentration to the required process value, while simultaneously issuing a slurry pump delivery command. Upon receiving the stop lime slurry preparation command, the system immediately stops preparation, waits 5 minutes, and after the prepared lime slurry has completely flowed into the concentration measuring container 14, uses the method of sequentially opening the solenoid valve 13 to adjust the lime slurry concentration to the required process value. When the concentration error is less than 0.5%, stop water replenishment, completing the lime slurry concentration preparation, and simultaneously issuing a slurry pump delivery command. The formula for calculating the opening time of solenoid valve 13 is:

[0155]

[0156] In the formula, t is the opening time of the solenoid valve, and p s The required lime slurry concentration is given by p, where p is the current lime slurry concentration, Kq is the flow coefficient of the solenoid valve, and K... w For the weight system, N w0 The weight signal A / D value of N when the concentration measurement container 14 is emptied. w The current weight signal A / D value of the concentration measurement container 14.

[0157] In this embodiment, p s It is 25%, Kq is 60.3, K w It is 0.0443.

[0158] The automatic control module for conveying and storing lime slurry includes the following operating steps:

[0159] Step S61: Start the small slurry pump to deliver qualified lime slurry to the lime slurry storage tank, and simultaneously run the storage tank agitator. After receiving the command to start the small slurry pump, the system immediately starts the small slurry pump 20 to deliver lime slurry to the lime slurry storage tank 21, and simultaneously runs the storage tank agitator 22. If flotation production is ongoing, the storage tank agitator will remain running.

[0160] Step S62: After the weight change of the concentration measuring container is less than the threshold for a period of time, stop the operation of the small slurry pump and the concentration measuring agitator. The weight of the concentration measuring container 14 decreases continuously as lime slurry is conveyed. When the weight change of the concentration measuring container 14 is less than the threshold (0.2 kg / min in this embodiment), it indicates that the lime slurry in the concentration measuring container 14 has been emptied. After a 3-minute delay, a command to stop the lime slurry concentration measurement and control is issued.

[0161] Step S63: Detect the liquid level in the lime slurry storage tank using an ultrasonic level gauge. The liquid level in the lime slurry storage tank 21 is detected using an ultrasonic level gauge 23 installed above the lime slurry storage tank 21.

[0162] Step S64: When the liquid level in the lime slurry storage tank is higher than the upper limit, a command to stop lime slurry preparation is issued. When the liquid level in the lime slurry storage tank 21 is higher than the upper limit, the system issues a command to stop lime slurry preparation.

[0163] Step S65: When the liquid level in the lime slurry storage tank is below the lower limit, a command to start lime slurry preparation is issued. When the liquid level in the lime slurry storage tank 21 is below the lower limit, the system issues a command to start lime slurry preparation.

[0164] The specific embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A lime milk automatic preparation system, characterized in that: The invention comprises a lime milk modulation device, a lime milk grinding and filtering device, a lime milk concentration measuring and control device, a lime milk conveying and storage control device, and a control system; the lime milk modulation device, the lime milk grinding and filtering device, the lime milk concentration measuring and control device, and the lime milk conveying and storage control device are connected in sequence, and under the control of the control system, automatic control of preparing lime milk from quicklime is realized.

2. The automatic lime milk preparation system according to claim 1, characterized in that: The lime milk modulation device comprises a frequency converter (2), an electric regulating valve (3), an electromagnetic flowmeter (4), a semicircular lime trough (5), a feed port (6), an array type spray head (7), a spiral (8), a spiral elevator (9), a reduction motor (24), and a chute (25); The semicircular lime trough (5) is used to store quicklime and is semi-cylindrical and installed in a sloped manner; The screw (8) is driven by a reduction motor (24) and is used to push and output lime forward. It is a single screw structure and is installed inside a semicircular lime trough (5). Its upper end is connected to the reduction motor (24) and installed on a rotating shaft, and its lower end is connected to a screw elevator (9). The height of the screw (8) is controlled by the screw elevator (9). The reduction motor (24) is controlled by a frequency converter (2), thereby adjusting the speed of the screw (8). The electric regulating valve (3), the electromagnetic flowmeter (4), and the array type spray head (7) are connected in sequence to control the flow rate of the spray water; the array type spray head (7) is provided with a plurality of spray heads and is installed at the lower end of the semicircular lime trough (5) to spray lime; The chute (25) is used to transport the lime output from the semicircular lime trough (5) to the small ball mill (10); The lime milk grinding and filtering device comprises a small ball mill (10), a vibrating screen (11), and a slag receiving cart (12); the lime milk is ground by the small ball mill (10) to be fully finely ground; the small ball mill (10) is installed in an inclined manner, and the outlet is slightly lower than the inlet; the lime milk output by the small ball mill (10) enters the vibrating screen (11), and through the vibration effect, the lime milk and the slag are fully separated and the screen is prevented from being blocked, and the qualified lime milk enters the concentration measuring container (14), and the slag enters the slag receiving cart (12).

3. The automatic lime milk preparation system according to claim 1, characterized in that: The lime milk concentration measurement and control device comprises a solenoid valve (13), a concentration measurement container (14), a force sensor (15), a concentration measurement ultrasonic level meter (16), a concentration measurement stirrer (17), and a force sensor signal transmitter (18); The concentration measuring container (14) is used to buffer the lime milk and measure and control the concentration of the lime milk to ensure that the concentration of the lime milk prepared each time is qualified; the concentration measuring container (14) is installed below the vibrating screen (11) to receive the lime milk output by the vibrating screen (11); the amount of added water is adjusted by the switch control of the electromagnetic valve (13) to control the concentration of the lime milk; the force sensor (15) is used to measure the total weight of the concentration measuring container (14), and its signal is amplified and conditioned by the force sensor signal transmitter (18); the concentration measuring ultrasonic level meter (16) is used to measure the lime milk liquid level of the concentration measuring container (14), and the concentration signal and liquid level signal are transmitted to the control system (1) for lime milk concentration calculation and concentration and liquid level control; the concentration measuring stirrer (17) is used to prevent the lime milk from settling, and a plurality of groups of blades are arranged in sections on its rotating shaft to ensure that the lime milk will not settle and the liquid surface is flat at a slow speed, so as to facilitate accurate detection of the lime milk liquid level; The lime milk conveying and storage control device comprises a pipeline flexible connection adapter (19), a small slurry pump (20), a lime milk storage barrel (21), a storage barrel agitator (22), and a storage barrel ultrasonic level meter (23); the lime milk is conveyed from the concentration measuring container (14) to the lime milk storage barrel (21) by the small slurry pump (20), and the installation position of the small slurry pump (20) is lower than the lime milk storage barrel (21); the pipeline flexible connection adapter (19) connects the output pipe of the concentration measuring container (14) and the input pipe of the small slurry pump (20) to reduce the influence of external factors on the measurement of the force sensor (15); the lime milk storage barrel (21) is installed at a high position so that the lime milk has a high flow rate during the self-flow process to avoid pipeline blockage; the rotating shaft of the storage barrel agitator (22) is segmented with multiple groups of blades, which can keep the lime milk from settling and the liquid surface flat at a slow rotation speed, thereby improving the liquid level detection accuracy of the lime milk storage barrel (21); The control system comprises a touch screen computer, a programmable controller, an AC contactor, a circuit breaker, a protective electrical appliance, a control cabinet, and a peripheral circuit; the control system is used to realize power supply, control, and management of the lime milk preparation system.

4. A method for automatically preparing lime milk, characterized in that: The method comprises: Automatic control of quicklime feeding is performed through the quicklime feeding automatic control module; The lime milk preparation system equipment interlocking control is performed through the lime milk preparation system equipment interlocking control module; Automatic control of adding quicklime and water to mix lime milk is performed through the quicklime and water mixing lime milk automatic control module; Automatic control of mixed medium addition and lime milk grinding and deslagging is performed through the mixed medium addition and lime milk grinding and deslagging automatic control module; The lime milk concentration detection and automatic control module is used to detect and automatically control the lime milk concentration; Automatic control of lime milk transportation and storage is performed through the lime milk transportation and storage automatic control module; All the modules mentioned above work together to achieve automatic control of lime milk preparation.

5. The automatic preparation method of lime milk according to claim 4, characterized in that: The working steps of the equipment interlocking control module of the lime milk preparation system include: Step S11: upon receiving the general start command, the system will give an audible and visual reminder, and start the related equipment in the order from the back to the front of the process after a delay; upon receiving the general start command of the control system, the system will first give a ringing and flashing warning, and after a delay of several minutes, the system equipment will be started in the order from the back to the front of the process; Step S12: After receiving the general stop command, the relevant equipment is stopped in sequence from the front to the back according to the process; the general stop command is divided into an emergency stop general command and a normal stop general command; when receiving the emergency stop command, the system immediately stops all equipment; when receiving the normal stop command, the system stops the equipment in sequence from the front to the back. If the preparation of lime milk has not been completed, all equipment will be stopped after the preparation of lime milk is completed. If subsequent flotation production is in progress, the storage bucket agitator (22) is in operation until it is manually stopped; Step S13: starting or stopping the screw (8) and the screw elevator (9) according to the feeding control instruction; after the system receives the feeding control instruction, it starts or stops the screw (8), the screw elevator (9) and the reduction motor (24) according to the system control requirements; Step S14: starting or stopping the lime milk modulation device according to the lime milk modulation device control instruction; after receiving the lime milk modulation device control instruction, the system starts or stops the screw (8), the screw elevator (9) and turns on or off the spray water according to the control requirements; Step S15: start or stop the grinding and filtering device according to the lime milk grinding and filtering device control instruction. After receiving the lime milk grinding and filtering device control instruction, the system starts or stops the small ball mill (10) and the vibrating screen (11) according to the control requirements; Step S16: Start or stop the lime milk concentration measurement and control device according to the lime milk concentration measurement and control instruction. After receiving the lime milk concentration measurement and control instruction, the system starts or stops the concentration measurement stirrer (17) and the solenoid valve (13) according to the control requirements; Step S17: starting or stopping the lime milk conveying and storage control device according to the lime milk conveying and storage control instruction; after receiving the lime milk conveying and storage control instruction, the system starts or stops the small slurry pump (20) and the storage bucket agitator (22) according to control requirements.

6. The automatic preparation method of lime milk according to claim 4, characterized in that: The working steps of the quicklime feeding automatic control module include: Step S21: adjusting the height and speed of the screw to desired values; adjusting the height of the screw (8) to the desired value by means of the screw elevator (9), and adjusting the speed of the screw (8) to the desired value by means of the frequency converter (2), wherein the two desired values ​​are obtained by debugging the control system in advance; Step S22: quicklime is fed from the feed port (6) into the semicircular lime trough (5), and the quicklime is transported and stacked by means of spiral rotation; after the quicklime is fed from the feed port (6) and falls into the semicircular lime trough (5), the quicklime is transported forward by means of spiral rotation, thereby realizing the stacking of the quicklime in the semicircular lime trough (5); Step S23: controlling the stacking thickness of the quicklime by adjusting the height of the spiral; during the quicklime transportation process, the spiral (8) is slowly lifted by the spiral elevator (9), thereby stacking quicklime of different thicknesses, so that the quicklime fills the semicircular lime trough (5); Step S24: judging the load of the screw according to the current value of the screw motor, and adjusting the height of the screw (8) according to the load; the deeper the screw (8) is embedded in the lime, the greater the motor current of the screw (8), and vice versa, and the height of the screw (8) is adjusted based on the motor current of the screw (8); Step S25: stacking the quicklime in the semicircular lime trough from bottom to top until the conveying and stacking are completed; by gradually lifting the control mode of the screw (8), stacking the quicklime in the semicircular lime trough (5) from the lower end to the upper end of the screw (8) until the quicklime input from the feed port (6) is stacked.

7. The automatic preparation method of lime milk according to claim 4, characterized in that: The working steps of the automatic control module for adding quicklime and water to prepare lime milk include: Step S31: the spray water flow rate is controlled within the set value, and the spiral is started to output lime; the spray water flow rate is controlled within the set value range through the control loop composed of the electric regulating valve (3), the electromagnetic flow meter (4) and the PID controller, and the lime is output from the semicircular lime trough (5) through the rotation of the spiral (8); Step S32: controlling the lime output flow rate by adjusting the spiral speed and spiral height; the lime output flow rate is related to the spiral speed and height of the spiral (8), the higher the spiral speed, the greater the flow rate, the smaller the spiral height, the greater the output flow rate, and vice versa; the control system automatically adjusts the spiral speed and spiral height according to control needs; Step S33: adjusting the output flow of lime and spray water according to the lime milk concentration and flow rate of the concentration measuring container and controlling them within the upper and lower limits; when the dry lime mass flow rate and the lime milk concentration are greater than the upper limit, reducing the spiral speed to reduce the lime output flow rate; when the dry lime mass flow rate and the lime milk concentration are less than the lower limit, increasing the spiral speed to increase the lime output flow rate; when increasing the spiral speed cannot output enough dry lime, gradually reducing the spiral height to increase the lime output flow rate; when the lime milk concentration is small, automatically reducing the spray water flow rate until the lime output flow rate meets the needs, and adjusting the spray water flow rate to a normal value; Step S34: controlling the concentration of the lime milk in the concentration measuring container to be within a certain range higher than the process requirement value; controlling the concentration of the lime milk in the concentration measuring container (14) to be within a certain range higher than the process requirement value, so as to ensure that the concentration of the lime milk will not be lower than the process requirement value when there is a large fluctuation in the process; Step S35: When receiving the instruction to stop lime milk modulation, lime milk modulation is stopped; when the system receives the instruction to stop lime milk modulation, the rotation of the spiral (8) and the spiral elevator (9) are immediately stopped, and the spraying water is turned off, thereby stopping lime milk modulation.

8. The automatic preparation method of lime milk according to claim 4, characterized in that: The working steps of the automatic control module for adding mixed medium and grinding and removing slag of lime milk include: Step S41: using the current value of the small ball mill (10) as a reference, adding small steel balls from the inlet of the small ball mill until the current reaches an empirical value; according to the characteristic that the current value of the small ball mill and its load are in a single peak corresponding relationship, a method of gradually adding small steel balls is adopted to keep the load of the small ball mill (10) at an appropriate position before the peak; Step S42: grinding the lime milk with small steel balls as the main grinding medium and stones carried by lime as the auxiliary grinding medium; when adding small steel balls to the small ball mill (10), the loading amount of small steel balls is ensured to be higher than the minimum position, so as to form a grinding medium state in which small steel balls are mainly used and stones carried by lime are auxiliary grinding medium, and the lime milk is ground; Step S43: Calculate the amount of small steel balls to be added based on the running time of the small ball mill and add the small steel balls with reference to the current of the small ball mill; stop adding the small steel balls when the current value reaches a certain value; Step S44: judging and controlling the load state of the small ball mill based on the average current value and its changing trend of the small ball mill over a period of time; obtaining a data sequence of the average current value and its changing trend of the small ball mill over a period of time, and judging and controlling the load state of the ball mill based on this; when the load state is too large, stopping the lime milk modulation, and waiting for it to return to normal before resuming the lime milk modulation; Step S45: The lime milk is filtered by a vibrating screen, and the lime milk below the screen is qualified products, and the lime milk above the screen is slag, which slides into the slag receiving cart due to the vibration; the lime milk is filtered by a vibrating screen (11), and the lime milk below the screen is qualified products, and the lime milk above the screen is slag, which slides into the slag receiving cart (12) due to the vibration, and the slag receiving cart (12) is lifted to a designated position by a crane in the factory building and then pushed open for processing manually.

9. The automatic preparation method of lime milk according to claim 4, characterized in that: The working steps of the lime milk concentration detection and automatic control module include: Step S51: The concentration measuring stirrer stirs at a low speed to keep the lime milk in a suspended state and keep the liquid surface flat so as to facilitate accurate liquid level measurement; a plurality of blades are arranged on the stirring shaft of the concentration measuring stirrer (17) to keep the lime milk in a suspended state and the liquid surface flat under low-speed stirring so as to facilitate accurate liquid level measurement of the concentration measuring container (14); Step S52: detecting the liquid level of the concentration measurement container by an ultrasonic level meter, and detecting the total weight of the concentration measurement container by a force sensor; detecting the liquid level of the concentration measurement container (14) by a concentration measurement ultrasonic level meter (16) installed above the concentration measurement container (14), and detecting the total weight of the concentration measurement container (14) by a force sensor (15) installed below the concentration measurement container (14), and subtracting the gross weight from the total weight to obtain the weight of the lime milk; Step S53: Calculate the lime milk concentration in the concentration measurement container by using a mathematical model; the mathematical model for calculating the lime milk concentration is: Where p is the percentage concentration, d0 is the density of water, δ is the density of dry lime, K v is the volume coefficient, N L0 N is the A / D value of the level signal when the concentration measurement container is empty. L K is the current A / D value of the level signal of the concentration measurement container, w is the weight coefficient, N w0 is the weight signal A / D value when the concentration measurement container 14 is emptied, N w is the current weight signal A / D value of the concentration measurement container 14; Step S54: Calculate the volume flow rate of lime milk and the mass flow rate of dry lime according to the liquid level, concentration and density of the lime milk in the concentration measuring container; Calculate the dry lime flow rate and the volume flow rate of lime milk according to the liquid level change of the concentration measuring container (14) within a period of time and the current concentration. Assuming that the liquid level change of the concentration measuring container (14) within a period of time T is ΔL, the current concentration of lime milk is p, and the current density is d, the volume flow rate Q of lime milk output from the semicircular lime trough (5) is v And the mass flow rate Q of lime milk converted into dry lime m The calculation formula is: Volume flow Q v Calculation formula: Q v =K Q ΔL / T; Mass flow Q m Calculation formula: Q m =Q v dp; Step S55: calculating the upper limit of the liquid level corresponding to the current lime milk concentration, and issuing a lime milk preparation stop instruction when the liquid level reaches the upper limit; calculating the amount of dry lime required for preparing one lime milk and the upper limit of the liquid level of the concentration measuring container (14) according to the lime milk process concentration and the volume of the concentration measuring container (14), and issuing a lime milk preparation stop instruction and a lime milk grinding and filtering stop instruction when the measured liquid level reaches the upper limit; Step S56: Stop the preparation of lime milk, and gradually control the concentration of lime milk to the process requirement value through pulse control of the water adding solenoid valve, and at the same time issue a slurry pump delivery instruction; the system immediately stops the preparation of lime milk according to the instruction to stop the preparation of lime milk, and waits for several minutes. After the prepared lime milk completely flows into the concentration measuring container (14), the concentration of lime milk is adjusted to the process requirement value by opening the solenoid valve (13) one by one. When the concentration error is less than 0.5%, stop adding water, complete the preparation of lime milk concentration, and at the same time issue a slurry pump delivery instruction; The calculation formula for the opening time of the solenoid valve (13) is: Where, t is the opening time of the solenoid valve, p s is the lime milk concentration required by the process, p is the current lime milk concentration, Kq is the flow coefficient of the solenoid valve, K w is the weight coefficient, N w0 is the weight signal A / D value when the concentration measurement container 14 is emptied, N w It is the current weight signal A / D value of the concentration measurement container 14.

10. The automatic preparation method of lime milk according to claim 4, characterized in that: The working steps of the lime milk conveying and storage automatic control module include: Step S61: start the small slurry pump to transport the qualified lime milk to the lime milk storage barrel, and run the storage barrel agitator at the same time; after receiving the instruction to start the small slurry pump, the system immediately starts the small slurry pump (20) to transport the lime milk to the lime milk storage barrel (21), and runs the storage barrel agitator (22); Step S62: when the weight change of the concentration measuring container is less than the threshold value for a period of time, the operation of the small slurry pump and the concentration measuring agitator is stopped; the weight of the concentration measuring container (14) decreases continuously with the transportation of the lime milk, and when the weight change of the concentration measuring container (14) is less than the threshold value, it indicates that the lime milk in the concentration measuring container (14) has been emptied, and after a delay of a period of time, an instruction to stop the lime milk concentration measurement and control is issued; Step S63: detecting the liquid level of the lime milk storage barrel by means of a storage barrel ultrasonic level meter; detecting the liquid level of the lime milk storage barrel (21) by means of a storage barrel ultrasonic level meter (23) installed above the lime milk storage barrel (21); Step S64: When the liquid level of the lime milk storage tank is higher than the upper limit, an instruction to stop lime milk preparation is issued; When the liquid level of the lime milk storage tank (21) is higher than the upper limit, the system issues an instruction to stop lime milk preparation; Step S65: When the liquid level of the lime milk storage tank is lower than the lower limit, an instruction to start lime milk preparation is issued; when the liquid level of the lime milk storage tank (21) is lower than the lower limit, the system issues an instruction to start lime milk preparation.

Images