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In order to optimize the capacity and separation performance of column flotation equipment, pressure difference method was used to monitor gas holdup in flotation column. By adjusting the feed rate and feed concentration, the variation of carrying capacity and gas holdup profile in the axial was analyzed, with their internal relations and effect on separation performance also investigated. It is shown that the axial gas holdup increases from the bottom to the top when the feed rate is less than critical velocity. But it is opposite when more than or equal to critical velocity, which decreases with the increase of feed concentration. Increasing feed rate, the carrying capacity fist increases and then decreases, whose inflection point just is the critical velocity. The feed concentration increase can help improve the carrying capacity and the combustible recovery within a certain range. The carrying capacity prediction model is proposed with the squared correlation coefficient R² = 0. 873, which achieves a relatively high fitting precision. [ABSTRACT FROM AUTHOR]

BP neural network model was used to predict the cleaned coal ash and combustible recovery in different operational conditions. Taking the circulation pressure, air flow, dosage of collector and frother as input set, the BP neural networkas prediction model was proposed to estimate the cleaned coal ash and combustible recovery as outputs. It is shown that BP neural network model can estimate the separation index quite satisfactorily in which the relative errors between the predicted values and experimental values are both less than 5% for the cleaned coal ash and combustible recovery. [ABSTRACT FROM AUTHOR]

Two-phase, three-dimensional (3D) numerical simulation was performed to predict the mineralization efficiency of the pipe flow unit of a micro-bubble floatation column. Based on the numerical model, the length parameter of pipe flow unit was optimized, and get a coherent result with industrial test. The results show that eulerian multiphase model can be used to calculate the gas-fluid flow in pipe unit accurately. For pipe unit, the mineralization effect of different pipe lengths can be qualitatively evaluated by the value of k (turbulent kinetic energy). The volume integral value of k grows logarithmically with the increase of L(pipe length). Namely, the increment speed of k is fast at the beginning, and then not obvious when L is increasing. Pipe length has no effect on the maximal value of k. 2. 5 m is a proper length for the research object. Bauxite recovery increases 2.79% when L is extended from 0. 3 m to 2.5 m in industrial test. [ABSTRACT FROM AUTHOR]

Processing objects is a kind of hard-to-float and high-ash fine coal which collected in Kailuan mining. Flotation rate experiment was designed for investigating the process characteristics of fine coal. Size analysis and density analysis of five cleans and fine-grained of the flotation rate experiment were studied. The mineral morphology of flotation rate experiment cleans was observed by scanning electron microscopy(SEM). The results show that fine mud contamination exists throughout the flotation process. The fine mud content in J1, J2, J3, J4 and J5 is similar, but gradually increases in its product. With the conduct of flotation, the flotation rate of high-ash fine mud (ash content> 50% ) reduces, and the operation recovery of fine mud per unit time also reduce. Flotation rate and cumulative yield of heterogeneity fine mud increase with its size and density reducing. The way of high-ash fine mud into clean coal products is mechanical entrainment and covering the surface of coarse-grained coal by SEM and Stokes number(St) analysis. [ABSTRACT FROM AUTHOR]