1 flotation dynamics foundation
The rate of the flotation process can be determined by the rate at which the ore particles adhere to the bubbles. In terms of the interaction between particles, the flotation process is similar to the chemical process, so the flotation rate equation can also be analogized by the chemical rate equation. Its basic form is:
(1)
Where c is the concentration of the suspended mineral in the slurry at any given time; K is the rate constant; n is the number of flotation stages, and it is generally considered that the n value of the coarse-grained mineral is larger, while the n-value of the fine-grained mineral Smaller.
Later, with the concept of the material "variety", the researchers turned their attention to the change of the K value of the flotation rate constant. Since the flotation material is composed of different K value varieties, the species with larger flotation rate constants first float out, and the average K value of the remaining materials in the flotation machine gradually decreases with the extension of the flotation time. That is, the K value is a function of time.
At present, the theoretical model of flotation dynamics is basically based on the "collision adhesion theory." In recent years, with the most advanced high-speed photography technology and image technology, it has been observed that the collision, adsorption, desorption of bubbles and particles in the pulp system and the merger of bubbles and gas/particle combination in different chemical environments The process is possible. Therefore, the current flotation kinetics focuses on the mechanical properties of bubble hydration membrane under different influencing parameters, and finds the chemical condition parameters and hydrodynamic parameters to control the foam stability in the slurry system; and uses flotation to investigate the conventional conditions. And the flotation kinetics of minerals under the condition of special bubble hydration membrane properties, the relationship between bubble merger and enrichment process and flotation efficiency is studied. At the same time, the observed data are combined with modern mathematical, physical and fluid mechanics methods and numerical simulation (CFD) to simulate the influence of the mechanical properties of the bubble hydration membrane on the foam stability energy in the flotation system, thus determining the optimal flotation dynamics. A reasonable way to learn parameters.
Sun Wei, Hu Yuehua et al. explored a set of mature methods for observing the properties of bubbles in the slurry and the interaction between particles by means of high-speed cameras. It is believed that the phenomenon of particle aggregation during flotation is mainly derived from cavitation bubbles and gas. formation and bridging effect between the cell nuclei; the same time, each other bubbles and the particles under conditions to sphalerite as the research object, the dissolving amount of different levels of the drug, CO 2 slurry in the same manner, stirring intensity The action law and flotation behavior, it is believed that the addition of xanthate plays a role as a foaming agent in the flotation process. The dissolution of CO 2 promotes the aggregation of particles by forming cavitation bubbles and gas cores, and the appropriate stirring strength makes flotation The kinetic parameters were optimized to promote the whole flotation process. Based on this, a high-energy input agitating impeller was designed and proved to promote the aggregation and flotation of particles during flotation.
Z. Huang et al. directly observed the collision between bubbles and mineral particles by using high-speed camera, and analyzed the relationship between bubble rising speed, adsorption cap coverage and bubble trapping particle number. A new test method for discriminating bubble capture efficiency was proposed. It provides a new way to analyze the flotation dynamics from a microscopic perspective. Yan Hongjie and Sun Wei quantitatively described the microscopic processes of collision, adhesion and desorption of ore particles and bubbles, and established the transport equation of the float particles in the bubble and liquid phase during the flotation process. The average collision rate in the chamber CPT flotation column is 2.156×10 8 times (m 3 ·s), and the average collision probability under the corresponding flotation conditions is 0.017, the capture probability is 0.904, and the desorption probability is 0.097.
2 application of flotation kinetics
Flotation kinetics is also widely used in mineral processing practice. Firstly, the flotation dynamics utility model can be extracted from the ore dressing practice, and the applicability of the kinetic model can be judged by comparing the difference between the model simulation results and the actual field indicators. In order to guide the actual selection of the same type of minerals; secondly, according to the theory of flotation kinetics, the description of the mineral flotation behavior, the value of the flotation reagent used and the rationality of the beneficiation process are evaluated. Explain and give corresponding improvement schemes; finally, the dynamics of flotation equipment can guide the improvement of the internal and external environment of the flotation machine and the optimization design of the flotation machine.
We studied the kinetics of coal flotation sludge from the terms of granularity Emad Abkhoshk, who use fuzzy logic approach. It was found that at the 96.5% confidence level, the difference in particle size had a great influence on the flotation kinetic constant, while at the 95% confidence level, the particle size difference had little effect on the maximum recovery of the clean coal theory. Qiu Xianyang and Deng Haibo et al. studied the kinetics of the refining and flotation flotation of rhombohedrite, and studied the effects of temperature and sodium sulfide on the flotation recovery of rhombohedrite. Wangai Li et al., Salt Lake magnesium sulfate, potassium chloride were mixed Ore Flotation kinetics mixed flotation agent, the speed of application of discrete three-parameter model for floating two rate constants calculated with the residual rate floating chloride Change the timing of the change. Liping lead zinc copper sulfide ore flotation and dynamic analysis of the system, under optimum conditions selected flotation, mineral flotation test results on a single chalcopyrite, galena and sphalerite by fitting the Hehe. Qiu Xianhui studied the flotation kinetics of copper-zinc refractory sulfide ore, and studied the flotation kinetics of the high-efficiency chalcopyrite collector QP-O2 in the laboratory for rapid flotation of chalcopyrite. The results show that QP-O2 Flotation of chalcopyrite is significantly faster than sphalerite.
B. Rezai et al. first determined the surface roughness of ore in a quartz ore sample in Iran, and then investigated the surface roughness ( A ) and flotation of quartz ore samples of different size by batch scraping flotation test. The relationship between the rate constants ( K ). An Maoyan et al. used the coal quality analysis and screening test to study the floatability of low rank coals in view of the difficulty of low-rank coal flotation. Based on this, a low-rank coal flotation speed test was carried out to obtain a low-rank coal flotation rate model. Lijun Wang, who according to the basic principle of flotation kinetics, galena and pyrite flotation kinetics were analyzed, the overall balance of differentials flotation model based on the theory can simulate galena and pyrite In the flotation process, the correlation coefficient between the fitted value of the flotation recovery model and the experimental value averaged 0.999.
According to the flotation dynamics theory, the flotation behavior of specific minerals can be described, the value of the flotation reagent used and the rationality of the beneficiation process are evaluated and explained, and corresponding improvement schemes are given. Heinrich Schubert studied the influence of turbulence caused by impeller rotation on various parameters of flotation kinetics and its variation law. It was found that the optimal separation efficiency of coarse-grained and fine-grained particles was achieved under different impeller input power conditions. of. For the coarse-grained impeller, the input power of the impeller can be just dispersed, and for the fine-grained grade, the ratio of the impeller input power to the slurry dynamic viscosity should be as high as possible. Therefore, when processing minerals with a wide range of particle sizes, the coarse and fine fractions are treated separately to achieve the best separation effect.
Li Yan, Hu Yuehua et al. studied the flotation behavior of kaolinite with different fractions by using modified Hallimond tube combined with electrolytic flotation method. Through the data analysis, the flotation rate constant K and the multiple regression models of these factors were established. Regression equations and regression coefficients were tested for significance. It is found that for different grades of kaolinite, the electrolytic flotation rate increases with the increase of current intensity; when the current intensity is the same, the flotation rate of fine particles is larger at the cathode with smaller pore size, while the coarse particles are in the pore diameter. The flotation rate is large at large cathodes; there is a significant linear correlation between the flotation rate constant K and these factors.
Yu Yang Chuan according to basic principles such as flotation kinetics, right, dynamics of scheelite and wolframite fluorite flotation analyzed. The results show that the k value of the flotation rate constant is constantly changing during the flotation process. The conditioning agent citric acid significantly increases the difference between the mineral floating speeds.
Qiu Tingsheng et al. studied the flotation kinetics of chalcopyrite and sphalerite in the collector QPJD2 system through pure mineral flotation kinetics experiments. Studies have shown that in the proper pulp system of chalcopyrite and sphalerite, the difference of flotation speed is obvious. The difference of flotation speed and process structure can be used to optimize the efficient separation of copper and zinc.
Agar et al application S.kelebek a classical kinetic model R = R∞ (1-exp - Kt) studied the characteristics of the deposited oxide pentlandite and pyrrhotite and two parameters Kelsa11 floating speed of the mechanical model, It found that due to the activation of metal ions and hydrophobic interaction polysulfide promote the flotation. At the same time, excessive oxidation causes the fast-floating particles to become slow-floating particles, and the slow-floating particles become non-floating mineral particles, thereby causing loss of flotation concentrate.
In the flotation process, the flotation dynamics of the flotation machine is an extremely important parameter in the development process of the flotation machine. It has a direct influence on the flotation effect. Therefore, many scholars from different angles to the flotation machine. The flotation dynamics were analyzed and researched, and the insights of the flotation machine and the flotation column were presented. Wang Yanling took Xiqu and Ximing native slime as experimental research objects. Through the narrow-grain coal slurry flotation kinetics test, the variation law of flotation kinetics and the dynamics under different impeller rotation speed and aeration volume of flotation machine were studied. The influence of the parameters. The results show that for 0.5~1mm narrow-grained slime, under the condition of changing the rotation speed and aeration of the flotation machine while maintaining other conditions, the impeller speed and the aeration volume can be effectively optimized. Improve the flotation kinetic parameters of the slime.
Huang Guangyao's flotation kinetics of horizontal filling medium flotation column is difficult to recover from the fine-grained scheelite (-19μm) flotation. The research shows that the flotation rate constant and apparent gas velocity, bubbles The size of the group, the bubble and the collision, adhesion and shedding probability of the mineral particles are related. It is revealed that the decrease of the bubble diameter is beneficial to the increase of the flotation rate constant of the fine-grained mineral particles, and the optimization of the flotation column is designed to produce more suitable. The microbubbles increase the flotation rate constant of the fine-grained mineral particles.
Han Wei took the flotation of nickel ore as the test object, and studied the flotation kinetics of JFC-150 flotation machine. The fluid dynamics parameters were studied by investigating the multiphase flow characteristics inside the flotation machine. The effects of flotation kinetic parameters were analyzed and the relationship between the parameters and the flotation machine flotation kinetics were analyzed under eight different impeller speeds and nine different flotation aeration pressures. According to the results of kinetics research, it provides a reference for optimizing the design of flotation machine internal and external environment and flotation machine.
On the basis of the probability model, Shen Zhengchang et al. established a flotation dynamics model of the inflation rate and turbulence intensity of the inflatable flotation machine. The KYF inflatable flotation machine was used to conduct flotation experiments on the Dongguashan ore sample. The influence of the aeration amount and the rotational speed on the flotation effect, the error analysis results of the test data indicate the rationality of the model.
Chen Dong et al. through the multi-flotation process dynamics research and mineral separation to discuss the requirements of various areas in the large flotation machine tank, the flotation machine should be large, efficient and energy-saving, and must ensure that the flotation tank can be filled with enough When the air is measured, the impeller should be able to generate a large slurry flow rate under the condition of lower pressure head. The stator should be beneficial to turn the rotating ore flow generated by the impeller into a radial ore flow, and maximize the height of the transportation area to establish a relatively stable flow. The separation zone and smooth foam layer shorten the foam residence time.
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