A method for mineral flotation of full negative pressure regulation interface micro-nano bubble group

Abstract

The present application belongs to the technical field of mineral processing, and particularly relates to a method for controlling interface micro-nano bubble groups in the whole process of negative pressure for mineral flotation, comprising the following steps: S1, treating ore pulp with a flotation device and presetting influence parameters in a vacuum chamber; S2, repeating the operation of step S1 multiple times, controlling variables, and obtaining an empirical formula through experimental data fitting; S3, obtaining the best value Hx of the influence coefficient of the system at the maximum time through the empirical formula, and after determining the best values of all influence parameters through formula 2, using the best values of the key influence parameters as the working parameters of the flotation device to control flotation; a mathematical model directly connecting negative pressure and flotation recovery rate is established, which can quickly determine the influence parameters for different minerals and flotation reagents, and according to the mathematical model, the influence coefficient value of the best mineral recovery rate can be efficiently calculated, and the types of influence parameters are few, which is conducive to optimizing the flotation method.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of mineral processing, and particularly relates to a method for full-process negative pressure regulation of interface micro-nano bubble groups for mineral flotation. BACKGROUND

[0002] With the continuous trend of mineral resources being lean, fine and complex, it is difficult to effectively separate useful minerals and gangue minerals using conventional flotation methods. Flotation is a mineral processing process that separates solid minerals from water suspensions, i.e. ore slurries, according to the differences in the physical and chemical properties of the mineral surfaces. Foam flotation is widely used in industry, and its characteristic is that the target mineral selectively adheres to the flotation bubbles in the ore slurry and floats to the surface of the ore slurry, achieving the separation of useful minerals and gangue. In recent years, micro-nano bubbles have been applied to mineral flotation with good results, especially for complex and fine-grained mineral flotation.

[0003] Micro-nano bubbles are different from flotation bubbles. Micro-nano bubbles mainly change the properties of the mineral surface, promote the agglomeration of fine-grained minerals to increase the particle size, and increase the collision and adhesion probability between micro-nano bubbles and flotation bubbles. The diameter of micro-nano bubbles is micron or nanometer level. The diameter of flotation bubbles is usually millimeter level, and the main role is to make the mineral adhere to the surface of the bubble to form a mineralized bubble, which serves as a carrier for the mineral to float to the surface of the ore slurry to separate useful minerals and gangue minerals.

[0004] Micro-nano bubbles are mainly divided into bulk phase micro-nano bubbles and interface micro-nano bubbles. At present, the commonly used method for generating bulk phase micro-nano bubbles is hydrodynamic cavitation, also known as cavitation bubbles. Because the nucleation energy required for this bubble is high, the bubble nucleation pressure needs to be lower than the saturation vapor pressure, so the slurry flow rate usually needs to be more than 15 m / s. At this time, the phase change from liquid to gas occurs, which easily causes cavitation erosion and damages the equipment. At the same time, the process of generating this bubble only involves gas-liquid two phases, and there is a certain limitation in the interaction efficiency between the bubble and fine-grained minerals.

[0005] In the current technology, a Venturi tube type slurry conditioning device is used to generate interface micro-bubbles. However, because the throat diameter of the device is small, the slurry is prone to blockage. The depression amplitude needs to be determined by a large number of observations of the growth characteristics of micro-nano bubbles combined with mathematical models, and then the pipe diameter is adjusted. The process is relatively complex. At the same time, this method involves a complex fluid environment, and there are many parameters affecting the final flotation indicators, so it is difficult to optimize the performance of the equipment. On the other hand, this type of device can only apply negative pressure to the slurry conditioning part before flotation. SUMMARY

[0006] To solve the above problems, the present application provides a method for full-process negative pressure regulation of interface micro-nano bubble groups for mineral flotation.

[0007] The technical solution of this invention is: a method for controlling interfacial micro / nano bubble clusters under full negative pressure during mineral flotation, comprising the following steps:

[0008] S1. The slurry is processed using flotation equipment, and the operating parameters of the flotation equipment are preset. The flotation equipment includes a vacuum chamber and a flotation machine installed inside the vacuum chamber. The operating parameters include: the initial air pressure of the vacuum chamber, the pressure drop, the rotation speed of the flotation machine, the aeration rate, the flotation time, the stirring time, and the addition interval of mineral processing reagents. The pressure drop, the rotation speed of the flotation machine, the aeration rate, and the flotation time are taken as key influencing parameters.

[0009] S2. Repeat the flotation process in S1, treating the slurry with the flotation equipment, and adjust the key influencing parameters mentioned in S1 using the controlled variable method to obtain feedback data after flotation. Based on the feedback data, fit Equation 1:

[0010] ε=a1H 2 +a2H+a3

[0011] In the formula: ε is the flotation recovery rate, %; H is the system influence coefficient; a1, a2, and a3 are constants determined by fitting, which are affected by the mineral type and the type of flotation reagent;

[0012] S3. Obtain the optimal value Hx of the system influence coefficient H when ε is maximum using empirical formulas. Substitute Hx into the system influence coefficient calculation formula 2 to determine the optimal value of one of the key influence parameters. Repeat step S2 again, changing the key influence parameters as variables in turn, until the optimal values ​​of all key influence parameters are obtained. Then, use the optimal values ​​of each key influence parameter as the operating parameters of the flotation equipment for flotation control.

[0013] The formula for calculating the system influence coefficient is as follows:

[0014]

[0015] Where: H is the system influence coefficient, %; ΔP is the pressure drop, kPa; N is the flotation machine speed, r / s; Q is the aeration rate, m³ / s. 3 / min; T is the flotation time, in minutes.

[0016] Note: Based on the constant values ​​of a1, a2, and a3 obtained from the experimental fitting, the influencing factors are determined by the mineral type and the type of flotation reagent. It is necessary to repeat the operation of step S1 about 7 times. The obtained experimental data is then fitted with parameters to generate an empirical function. The fitted data obtained is very similar to the experimental data.

[0017] Further, the method for treating the ore pulp in the flotation device in step S1 is as follows: placing the ore pulp in the flotation device, controlling the pressure reduction range of the vacuum chamber to be 0-96 kPa, setting the stirring speed of the flotation machine to be 10-50 r / s, stirring the ore pulp, adding one or more ore-dressing reagents to the ore pulp after 1 min of stirring, and the interval time of each ore-dressing reagent is 1-6 min; after the reagent and the mineral are fully reacted, air is filled into the flotation machine, the air filling amount is controlled to be 0.05-0.4 m 3 / h, and then flotation is performed, and the duration of the flotation, i.e. the duration of scraping the bubbles, is 1-8 min.

[0018] It is explained that controlling the pressure reduction range of the vacuum chamber to be 0-96 kPa can ensure the generation of the interfacial micro-nano bubble group, controlling the stirring speed to be 10-50 r / s can ensure that the reagent is uniformly distributed in the ore pulp and fully reacts with the mineral, and can avoid problems such as bubble rupture and ore pulp overflow caused by too high stirring speed; the reagent adding mode can improve the flotation efficiency, reduce the reagent consumption, and maintain a suitable reagent concentration, and controlling the duration of the flotation to be 1-8 min has a direct impact on the flotation effect of the mineral. Too short time may cause the mineral and the reagent to fail to fully react, and too long time may cause oxidation of the easily-oxidized mineral, affecting the quality of the concentrate, and too long time also reduces the flotation efficiency, therefore, suitable flotation time can ensure the effective separation of the mineral and the quality of the bubble product.

[0019] Further, the target air pressure inside the vacuum chamber is between the saturated vapor pressure and the standard atmospheric pressure; the saturated vapor pressure in the vacuum chamber under normal temperature is 4 kPa.

[0020] It is explained that the interfacial micro-nano bubble is different from the common cavitation bubble, which is generated by the diffusion phenomenon caused by the difference in dissolved gas concentration, and has a lower bubble nucleation energy, so the bubble nucleation pressure is between the saturated vapor pressure and the normal pressure; the nucleation and growth involve solid, liquid and gas three phases, and compared with the cavitation bubble, it has the characteristics of high selectivity, controllability, bridging and low energy consumption.

[0021] Further, the ore-dressing reagent is one or more of a pH adjusting agent, a dispersant, a flocculant, an inhibitor, an activator, a collector, and a foaming agent.

[0022] Note: By adjusting the pH value of the ore pulp, the surface properties of the minerals are affected, so that they are in a suitable state for flotation; the main function of the dispersant is to improve the dispersibility of the reagent and the mineral, prevent the aggregation of the reagent and mineral particles, ensure that the reagent can be evenly distributed in the ore pulp, and improve the flotation efficiency; the flocculating agent is used to promote the formation of flocs of specific minerals, so that they can be more easily separated from the ore pulp during the flotation process; the depressor can reduce or prevent the interaction between the mineral and the collector, and is usually used to control those minerals that have good natural floatability or do not need to be floated; the activator can change the chemical composition of the mineral surface, eliminate the effect of the depressor, enhance the adsorption capacity of the mineral to the collector, and improve the floatability of the mineral; the collector can improve the hydrophobicity of the mineral surface, so that the mineral can float to the water surface; the frother is used to form stable foam in the ore pulp, which is conducive to the separation of minerals.

[0023] Further, the ore pulp is composed of minerals and water, and the minerals are one or more of sulfide ore, oxidized ore, non-metallic ore and coal.

[0024] Note: The use of interfacial micro-nano bubbles can expand the difference in hydrophobicity between minerals, improve the flotation efficiency of minerals, and promote the agglomeration of fine-grained minerals. This method is particularly suitable for poor and complex minerals such as sulfide ore, oxidized ore, non-metallic ore and coal. For such minerals, micro-bubble flotation not only improves the recovery rate and concentrate quality of the minerals, but also reduces the amount of reagent, thereby reducing environmental pollution.

[0025] Further, in the minerals, the mass fraction of minerals with a particle size of -0.074 mm is 60-100% of the total mineral mass, and the mass concentration of the ore pulp is 10-40%.

[0026] Note: The concentration and particle size of the ore pulp are directly related to the indicators in the mineral flotation process, such as mineral recovery rate and concentrate quality.

[0027] Further, a device for mineral flotation used in the method of controlling interfacial micro-nano bubble groups by full negative pressure in the whole process of mineral flotation, the flotation device includes a vacuum chamber, a flotation machine arranged inside the vacuum chamber, a flotation machine control system electrically connected to the flotation machine, a dosing system with one end extending out of the vacuum chamber and the other end arranged on the flotation machine, and a vacuum pump connected to the inside of the vacuum chamber through a pressure controller;

[0028] The flotation machine includes a body, a flotation tank arranged on the body, a stirring rod arranged inside the flotation tank, a rotor arranged at the bottom of the stirring rod, and a scraper arranged at the top of the flotation tank.

[0029] Description: The vacuum chamber is the core part of the device, and a negative pressure environment is created through the vacuum chamber, which is crucial for mineral flotation. In the negative pressure state, the hydrophobicity difference between the fine particles in the ore pulp is enlarged, and at the same time, the particle aggregation is promoted, which can better attach to the bubbles, thereby improving the flotation efficiency. Through the coordinated work of the flotation machine components, interface micro-nano bubbles are generated, which can effectively contact the surface of the mineral particles, enhance the hydrophobicity between the particles, and promote the particles to float to the surface, thereby realizing the effective separation of the minerals. The control system is responsible for monitoring and managing the entire flotation process, including the generation of flotation bubbles, the flow of ore pulp, and the addition of reagents, etc., to ensure that each link is coordinated to achieve the optimal flotation effect.

[0030] Further, the dosing system comprises a plurality of sub-units, each sub-unit comprising three sections of pipes connected from top to bottom, namely a first pipe, a second pipe and a third pipe, the top of the first pipe being provided with a dosing port, and the bottom of the first pipe being provided with a first valve, the bottom of the second pipe being provided with a second valve.

[0031] Description: Through the dosing system, necessary reagents such as foaming agent and collector can be added to the ore pulp without affecting the negative pressure environment inside the vacuum chamber, so as to adjust the chemical environment and physical state of the ore pulp, and the vacuum pump is responsible for maintaining the negative pressure environment inside the vacuum chamber, so that the interface micro-nano bubbles can effectively form on the surface of the minerals.

[0032] The beneficial effects of the present application are:

[0033] (1) A mathematical model directly linking negative pressure and flotation recovery rate is established, which can quickly determine the negative pressure parameters for different minerals and flotation reagents, avoid the influence of many factors in complex fluid environment, and efficiently calculate the influence coefficient value of the best mineral recovery rate according to the mathematical model, and the type of influence parameter is less, which is beneficial to optimize the flotation method, and the best flotation method is obtained by controlling the influence coefficient value.

[0034] (2) The full negative pressure flotation method adopted by the present application does not involve rapid flow of ore pulp, so there is no cavitation phenomenon, which avoids damage to the equipment. At the same time, the present application uses the method of direct vacuum extraction to generate interface micro-nano bubbles on the surface of the minerals, reduces the environmental pressure, makes the gas precipitate on the surface of the mineral solid in the form of extremely small bubbles, enlarges the wettability difference between the minerals, promotes the aggregation of fine particle minerals, and improves the collision and adhesion probability between the fine particle minerals and the flotation bubbles, thereby improving the mineral flotation efficiency and reducing the reagent consumption.

[0035] (3) The interface micro-nano bubble nucleation energy is low, the bubble nucleation pressure is between the saturated vapor pressure and the normal pressure, the bubbles can be directly generated on the solid surface, the generated bubbles can quickly and completely interact with the micro-fine particle minerals, the interaction efficiency is high, the pressure reduction range is between the normal pressure and the saturated vapor pressure, the whole process is under negative pressure in the process of slurry adjustment and flotation, the influence of the change from the negative pressure to the normal pressure on the interface bubble size is avoided, and the flotation efficiency is improved. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 is the work flow chart of mineral flotation in the experimental example 1 of the present application;

[0037] Figure 2 is the overall structure schematic diagram of the mineral flotation device used in the experimental example 1 of the present application;

[0038] Figure 3 is the structure schematic diagram of the dosing system in the experimental example 1 of the present application.

[0039] Wherein, 1-vacuum pump, 2-pressure controller, 3-vacuum chamber, 4-dosing system, 41-dosing port, 42-first pipeline, 43-first valve, 44-second pipeline, 45-second valve, 46-third pipeline, 5-flotation machine control system, 6-flotation machine, 7-flotation tank, 8-rotor, 9-stirring rod, 10-scraping plate. DETAILED DESCRIPTION

[0040] In order to further illustrate the manner of the present application and the effects achieved, the technical solutions of the present application will be clearly and completely described below in combination with experiments.

[0041] Example 1:

[0042] Butyl xanthate is used as a collector, starch is used as a pH regulator, water glass is used as an inhibitor, and No. 2 oil is used as a foaming agent, and the lead sulfide ore is enriched by adopting the direct flotation process. The main useful mineral in the ore is galena, a small amount of sphalerite, the lead element grade is 1.91%, the metallic minerals include magnetite and pyrite, and the gangue minerals are mainly silicate minerals such as quartz and calcite.

[0043] During the test, the ground ore slurry is added into the flotation tank 7 of the interface micro-nano bubble whole negative pressure flotation device, the vacuum chamber 3 is closed, and the absolute air tightness of the whole system is maintained; the stirring is started through the control system, and the vacuum pump 1 and the pressure controller 2 are used to quickly reduce the pressure in the vacuum chamber to the target pressure;

[0044] After stirring for 1 minute, lime, water glass, ethyl xanthate and No. 2 oil are added through the dosing system in sequence, and stirred for 1 min, 3 min, 3 min and 1 min respectively, at this time the pH of the ore slurry is 8, the dosages of the reagents are 300 g / t of water glass, 100 g / t of butyl xanthate, 10 g / t of2 After the drug fully acts, start the aeration and automatic scraper to begin the flotation; the flotation finally gets the galena concentrate and tailings, which are respectively dried, weighed, and tested for the Pb grade of galena in the concentrate, and the recovery rate is calculated. During the test, the steps remain unchanged except the pressure reduction range, rotation speed, aeration amount, and flotation time; the single variable test of the pressure reduction range, rotation speed, aeration amount, and flotation time is shown as follows:

[0045] 1. Optimal value determination of flotation time T:

[0046] Flotation time: 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0 min, pressure reduction range: 50 kPa, flotation machine 6 rotation speed: 30 r / s, aeration amount: 0.12 m 3 / h, and the obtained results are shown in Table 1.

[0047] Table 1 Mineral processing recovery rate and system influence coefficient results at different flotation times

[0048] T / min H Recovery / % 2.0 6617.91 56.10 2.5 6620.80 63.25 3.0 6623.41 66.42 3.5 6625.82 65.55 4.0 6628.05 64.30 4.5 6630.16 58.26 5.0 6632.14 54.32

[0049] H and ε in Table 1 are fitted by Matlab software, and the fitting relationship between H and ε is obtained as follows:

[0050] ε = -0.2228618H 2 + 2952.74567952H - 9,780,329.99, R 2 = 0.98, and the function fitting degree is good; wherein, R 2 is the function fitting goodness, and the value is between 0 and 1, and the closer to 1, the better the function fitting degree;

[0051] When ε is the maximum value, H x = 6624.61, H x is returned to formula 2, T x = 3.24 min, and the fitting value of ε is 66.48% at this time. According to the optimal flotation time, the flotation recovery rate is 66.40%, which indicates that the method has high accuracy.

[0052] 2. Optimal value determination of aeration amount Q:

[0053] Aeration amount: 0.06, 0.08, 0.10, 0.12, 0.14, 0.16, 0.18 m 3 / h, pressure reduction range: 50 kPa, flotation machine 6 rotation speed: 30 r / s, flotation time: 3.27 min, and the obtained results are shown in Table 2.

[0054] Table 2 Mineral processing recovery rate and system influence coefficient results at different aeration amounts

[0055] Q m3 / h H Recovery / % 0.06 6610.49 53.25 0.08 6615.81 62.53 0.10 6620.5 72.95 0.12 6624.73 80.32 0.14 6628.63 83.25 0.16 6632.26 81.32 0.18 6635.67 75.32

[0056] The H and ε in Table 2 are fitted by Matlab software, and the fitting relationship of H and ε is:

[0057] ε = -0.084762H 2 +1123.8169127H-3724936.18, R 2 = 0.96, and the function fitting degree is good;

[0058] When ε is the maximum value, H x = 6629.224, H x is returned to formula 2, Q x = 0.14m 3 / h is obtained, and the fitting value of ε is 80.73%. According to the optimal aeration amount, the flotation recovery is 81.47%, which shows that the method has high accuracy.

[0059] 3. The optimal value of the rotation speed N of the flotation machine 6 is determined:

[0060] The rotation speed of the flotation machine 6 is 20.00, 23.33, 26.67, 30.00, 33.33, 36.67, and 40.00 r / s, the pressure reduction amplitude is 50 kPa, the flotation time is 3.27 min, the aeration amount is 0.14m 3 / h, and the obtained results are shown in Table 3.

[0061] Table 3: Flotation recovery and system influence coefficient results at different rotation speeds

[0062] Speed r / s H Recovery / % 20.00 3022.39 65.33 23.33 4067.33 72.25 26.67 5269.42 75.44 30.00 6628.63 80.65 33.33 8144.98 84.37 36.67 9818.47 83.12 40.00 11649.1 77.28

[0063] The H and ε in Table 3 are fitted by Matlab software, and the fitting relationship of H and ε is:

[0064] ε = -0.0000006H 2 +0.01020006H+39.7566539, R 2 = 0.98, and the function fitting degree is good;

[0065] When ε is the maximum value, H x = 8500.05, H x is returned to formula 2, N x = 34.53 r / s, and the fitting value of ε is 83.11%. Since the rotation speed of the flotation machine 6 is a fixed level control, N is set to 34.60 r / s for testing, and the flotation recovery is 83.47%, which shows that the method has high accuracy.

[0066] 4. The optimal value of the pressure reduction amplitude ΔP is determined:

[0067] Depressurization amplitude: 30, 40, 50, 60, 70, 80, 90 kPa, flotation machine 6 rotation speed: 34.60 r / s, flotation time:

[0068] 3.27 min, air charge: 0.14 m 3 / h, the results are shown in Table 4.

[0069] Table 4 beneficiation recovery rate and system influence coefficient results of different depressurization amplitudes

[0070] Pressure drop kPa H Recovery / % 30 6778.15 68.32 40 7832.37 79.11 50 8762.4 85.68 60 9604.22 89.17 70 10379.2 90.06 80 11101.3 88.52 90 11780.1 85.65

[0071] The H and ε in Table 4 are fitted by Matlab software, and the fitting relationship between H and ε is obtained as follows:

[0072] ε = -0.00000183H2+0.03750805H-102.01136014, R2=0.99, the function fitting degree is good;

[0073] When ε is the maximum value, H x =10284.72, H x is returned to formula 2, and P x =68.25 kPa, and the fitting value of ε is 90.25% at this time. According to the optimal depressurization amplitude of 68.25 kPa, the flotation recovery rate is 90.47%, which shows that the method has high accuracy.

[0074] From the results of tests 1-4, the optimal values of ΔP, N, Q, and T are respectively: 68.25 kPa, 34.60 r / s, 0.14 m 3 / h, and 3.27 min.

[0075] The actual flotation of this parameter is obtained as follows:

[0076] ε1=90.47%;

[0077] The recovery rate calculated by formula 1 is:

[0078] ε2=90.25%;

[0079] Δε=|ε1-ε2|=0.22%;

[0080] As can be seen from the above, the predicted recovery rate obtained by formula 1 is very small compared with the actual flotation recovery rate, which shows that the flotation recovery rate can be better predicted by the formula, and then the parameters can be adjusted in time according to the actual demand.

[0081] The above embodiment is the preferred embodiment of the present application, but the embodiment of the present application is not limited by the above embodiment, and any change, modification, substitution, combination, simplification made without departing from the spirit and principle of the present application shall be equivalent replacement, and still belong to the protection scope of the technical solution of the present application.

[0082] Experimental Example 1: According to the process method of test 4 in the embodiment, a blank test of pressure reduction range is set, that is, the pressure reduction range is 0 kPa, N, Q, T are respectively: 34.60 r / s, 0.14 m 3 / h, 3.27 min. The rest of the experimental conditions remain unchanged for testing:

[0083] Flotation under normal pressure:

[0084] ε3=78.33%;

[0085] Δε=|ε1-ε3|=12.14%;

[0086] Therefore, the flotation with the pressure reduction range obtained by the method of the present application can greatly increase the mineral recovery rate.

[0087] Example 2: This embodiment describes the flotation equipment used in the mineral flotation method of Example 1, as shown in Figure 1 , 2 ,

[0088] The flotation equipment includes a vacuum chamber 3, a flotation machine 6 arranged inside the vacuum chamber 3, a flotation machine control system 5 electrically connected to the flotation machine 6, a dosing system 4 with one end extending out of the vacuum chamber 3 and the other end arranged on the flotation machine 6, and a vacuum pump 1 connected to the inside of the vacuum chamber 3 through a pressure controller 2;

[0089] The flotation machine 6 includes a body, a flotation tank 7 arranged on the body, a stirring rod 9 arranged inside the flotation tank 7, a rotor 8 arranged at the bottom of the stirring rod 9, and a scraper 10 movably arranged at the top of the flotation tank 7 through a mechanical arm;

[0090] The stirring rod 9 is hollow inside, a gas pump is arranged outside the vacuum chamber 3, and the stirring rod 9 is connected to the gas pump through a conduit inside for air charging of the ore pulp;

[0091] The stirring rod 9 is rotationally connected to the flotation tank 7 through a first rotary motor, a second rotary motor is arranged between the stirring rod 9 and the rotor 8, and the scraper 10 performs bubble scraping work on the ore pulp through a mechanical arm controlled by a motor;

[0092] As shown in Figure 2 , 3As shown, the dosing system 4 comprises a plurality of sub-units, each of which comprises three sections of pipes connected from top to bottom, namely a first pipe 42, a second pipe 44 and a third pipe 46, the top of the first pipe 42 is provided with a dosing port 41, and the bottom is provided with a first valve 43, the bottom of the second pipe 44 is provided with a second valve 45.

[0093] The device system also includes a power supply, a motor, the power supply, the motor, the first rotary motor, the second rotary motor, the mechanical arm, the vacuum pump 1, the pressure controller 2, the stirring rod 9, the rotor 8, the scraper 10, the conduit, and the air pump are all commercially available products, and will not be described here; the flotation machine 6 uses an XFDI single-tank flotation machine produced by Jilin Prospecting Machinery Factory.

[0094] The working principle of the device is as follows:

[0095] The ore pulp is added to the flotation tank 7, the vacuum chamber 3 is closed, the absolute air tightness of the entire system is maintained, the vacuum pump 1 and the pressure controller 2 are used to make the pressure in the vacuum chamber 3 reach the target value; then the control system 5 is used to start the motor that controls the rotation of the rotor 8 to stir the ore pulp, after a certain period of stirring, the dosing system 4 is used to add chemicals, and after the chemicals and minerals are fully reacted, air is filled and the automatic scraper 10 is used to scrape off the foam product. Repeating this step can obtain the recovery rate under the same amount of control of a single variable. Different system influence coefficient values are obtained through the relationship between the system parameters and the system influence coefficient of formula 2. Then, the flotation recovery rate and the system influence coefficient obtained by the control of a single variable test are fitted using Matlab software, to obtain the relationship between the system influence coefficient and the flotation recovery rate. The optimal system influence coefficient is calculated through the relationship between the system influence coefficient and the flotation recovery rate, and the extreme value of formula 1 is obtained, which is the optimal recovery rate, and the corresponding system influence coefficient is the optimal system influence coefficient; repeating the above steps can determine all the optimal system influence parameter values; then the optimal system influence parameter values are used for actual flotation to verify the accuracy of the fitting formula;

[0096] The specific dosing method is as follows: first, open the second valve 45 to make the second pipe 44 and the third pipe 46 in a vacuum state during the pressure reduction process of the vacuum chamber 3, then close the second valve 45, add the chemicals from the dosing port 41 into the first pipe 42, open the first valve 43 to make the chemicals enter the second pipe 44 under the pressure difference between the first pipe 42 and the second pipe 44, at this time the pressure in the second pipe 44 is normal pressure, then close the first valve 43, open the second valve 45, and then make the chemicals enter the flotation tank through the third pipe 46 under the pressure difference between the second pipe 44 and the third pipe 46.

[0097] Experimental Example 2: In terms of chemical consumption, the optimal parameters of the present application are compared with different amounts of chemicals under normal pressure, and the results are shown in Table 5.

[0098] Table 5 galena flotation concentrate recovery rate and reagent dosage under normal pressure and in the present application

[0099]

[0100]

[0101] As shown in Table 5, compared with the present application, when the dosage of xanthate is increased to 200 g / t under normal pressure flotation, the concentrate recovery rate is similar to that in the present application device, which shows that the dosage of collector can be reduced by half through the present application.

Claims

1. A full range of negative pressure regulation interface micro-nano bubble group method for mineral flotation, characterized by, The method comprises the following steps: S1, treating the ore pulp with a flotation device, and presetting the working parameters of the flotation device, wherein the flotation device comprises a vacuum chamber (3) and a flotation machine (6) arranged inside the vacuum chamber (3); the working parameters comprise: the initial air pressure of the vacuum chamber (3), the pressure reduction amplitude, the rotating speed of the flotation machine (6), the air charge, the flotation time, the stirring time, and the addition interval time of the beneficiation reagent; and the pressure reduction amplitude, the rotating speed of the flotation machine (6), the air charge, and the flotation time are taken as the key influencing parameters; S2, repeating the operation of treating the ore pulp with the flotation device in S1, and adjusting the key influencing parameters in S1 by the control variable method to obtain the feedback data after the flotation is completed, and fitting formula (1) based on the feedback data: ε = a1H 2 + a2H + a3 (1) In the formula, ε is the flotation recovery rate, %; H is the system influence coefficient; a1, a2, and a3 are constants determined by fitting, which are affected by the types of minerals and flotation reagents; S3, obtaining the optimal value Hx of the system influence coefficient H when the maximum ε is obtained by the empirical formula (1), substituting Hx into the system influence coefficient calculation formula (2) to determine the optimal value of one of the key influencing parameters, and repeating the operation of step S2 and sequentially replacing the key influencing parameters as variables until the optimal values of all the key influencing parameters are obtained, and then taking the optimal values of the key influencing parameters as the working parameters of the flotation device for flotation control: In the formula, the target air pressure inside the vacuum chamber (3) is between the saturated vapor pressure and the standard atmospheric pressure; and the saturated vapor pressure in the vacuum chamber (3) under normal temperature is 4 kPa. wherein: H is the system influence coefficient, %; ΔP is the pressure drop, kPa; N is the flotation machine (6) speed, r / s; Q is the aeration rate, m 3 / min; T is the flotation time, min.

2. A method for mineral flotation with full range of negative pressure regulated interface micro-nano bubble group according to claim 1, characterized in that, The method for treating the ore pulp in the flotation device in step S1 is as follows: placing the ore pulp in the flotation device, controlling the pressure reduction range of the vacuum chamber (3) to be 0-96 kPa, setting the stirring speed of the flotation machine (6) to be 10-50 r / s, stirring the ore pulp, adding one or more ore-dressing reagents to the ore pulp after 1 min of stirring, the interval time of each ore-dressing reagent being 1-6 min; after the reagent fully reacts with the mineral, air is filled into the flotation machine (6) at a controlled air filling amount of 0.05-0.4 m 3 / h, and then flotation is performed, the duration of the flotation, i.e. the duration of scraping the froth, being 1-8 min.

3. A method for mineral flotation with full range of negative pressure regulated interface micro-nano bubble group according to claim 2, characterized in that, The beneficiation reagent is one or more of a pH regulator, a dispersant, a flocculant, an inhibitor, an activator, a collector, and a foaming agent.

4. A method for mineral flotation with full range of negative pressure regulated interface micro-nano bubble group according to claim 2, characterized in that, The ore pulp is composed of minerals and water, and the minerals are one or more of sulfide ores, oxidized ores, non-metallic ores, and coal.

5. The method of claim 1, wherein the method is used for mineral flotation. In the minerals, the proportion of minerals with a particle size of -0.074 mm in the total mineral mass is 60-100%, and the mass concentration of the ore pulp is 10-40%.

6. A method for mineral flotation with full range of negative pressure regulated interface micro- and nano-bubble swarm as claimed in claim 5, wherein, The flotation device comprises a vacuum chamber (3), a flotation machine (6) arranged inside the vacuum chamber (3), a flotation machine control system (5) electrically connected to the flotation machine (6), a dosing system (4) with one end extending out of the vacuum chamber (3) and the other end arranged on the flotation machine (6), and a vacuum pump (1) connected to the inside of the vacuum chamber (3) through a pressure controller (2).

7. The device for mineral flotation according to any one of claims 1 to 6, characterized in that, The flotation machine (6) comprises a body, a flotation tank (7) arranged on the body, a stirring rod (9) arranged inside the flotation tank (7), a rotor (8) arranged at the bottom of the stirring rod (9), and a scraper (10) arranged at the top of the flotation tank (7). The dosing system (4) comprises a plurality of sub-units, each of which comprises three sections of pipelines connected from top to bottom, i.e., a first pipeline (42), a second pipeline (44), and a third pipeline (46); the first pipeline (42) is provided with a dosing port (41) at the top and a first valve (43) at the bottom; and the second pipeline (44) is provided with a second valve (45) at the bottom.

8. A device for mineral flotation used in the method of claim 7, wherein, ​

Images