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Effects of different factors during the de-silication of diaspore by direct flotation

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International Journal of Mining Science and Technology 2012年第3期22卷 341-344页

作者： Huang Gen Zhou Changchun liu jiongtian School of Chemical Engineering and Technology China University of Mining & Technology Xuzhou 221116 China

Most of the bauxite resources in China are kaolinite-diaspore bauxite of middle to low grade, with a fine dissemination, and are difficultly separated. Direct flotation de-silication has been shown to be an effec- tive method for de-silication of diaspore. In this study the effect of different factors, including pulp tem- perature, density, pH value, depressant, and collector dosage, on direct flotation of diaspore were investigated by laboratory experiments. The optimum conditions were identified and the flotation perfor- mance was improved. The results show that under optimum conditions （a pulp temperature around 40℃, a pulp density from 30% to 33g, a pH value from 9.0 to 10.0, an air flow rate of 0.5 m3/（m2 rain）, a dispersant level from 35 to 70 g/t, and a collector level around 1000 g/t） an AI/Si ratio of 6.97 is obtained starting from an initial Al/Si ratio of about 4.71. The recovery of A1203 under these conditions was 86.94%.

关键词： DiasporeDirect notationDe-silicationFlotation conditions

Simulating a fuzzy level controller for flotation columns

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Mining Science and Technology 2011年第6期21卷 815-818页

作者： Liao Yinfei liu jiongtian Wang Yongtian Cao Yijun School of Chemical Engineering and Technology China University of Mining ＆ Technology Xuzhou 221116 China

Level control in flotation columns is an important factor that influences the recovery and the grade of concentrate from the column. A flotation column is a nonlinear, multi-variable problem with changeable parameters that traditional methods have difficulty controlling. We have applied fuzzy control methods to the flotation column and tested the performance of the design by Matlab/Simulink simulation. The simulations show that level control in the flotation column becomes smoother and more rapid with the fuzzy controller. Compared to PID control methods the overshoot in valve position, the adjustment time, and the robustness of the controller are all improved. This indicates that it is suitable to model fuzzy controllers in applications for the study of automatic control of flotation column.

关键词： Flotation column Fuzzy control Level Simulation

Coal petrology characteristics of middlings from Qianjiaying fat coal mine

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International Journal of Mining Science and Technology 2013年第5期23卷 777-782页

作者： Zou Wenjie Cao Yijun Zhang Zhijun liu jiongtian School of Chemical Engineering and Technology China University of Mining & Technology National Engineering Research Center of Coal Preparation and Purifcation China University of Mining & Technology School of Chemical and Environmental Engineering China University of Mining & Technology

The objective of this paper is to evaluate the coal petrology characteristics of slack middlings(13–0.5 mm)of dense media separation and flotation middlings from Qianjiaying fat coal preparation *** composition,macerals distribution,microlithotype and mineral occurrence of the two middlings were studied by XRD analysis and polarized light microscopy *** distribution and wettability of the float-and-sink products separated from the middlings after grinding was investigated to determine the liberation *** show that there are more vitrinite and mineral,but less inertinite in slack middlings than in flotation *** associated with mineral in slack middlings is 69.85%,by volume,which is 17.86%higher than that in flotation *** in slack middlings are dominated by pyrite and clay,which are disseminated with the diameter less than2 *** main mineral in flotation middlings is clay with size range of 2–20 *** macerals in the slack middlings are diffcult to liberate due to the fne-grained *** grinding,macerals associated with minerals in the slack middlings decrease to 46.73%,by volume,which is higher than in flotation middlings by 25.89%,by *** slack middlings with poor liberation degree,density fractions below1.8 g/cm3is hydrophobic with contact angle above 71.5°.For the well liberated flotation middlings,there is signifcant wettability difference among the float-and-sink *** research is the theoretical basis to realize re-separation of middlings.

关键词： Middlings Macerals Mineral liberation Wettability

A single-phase turbulent flow numerical simulation of a cyclonic-static micro bubble flotation column

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International Journal of Mining Science and Technology 2012年第1期22卷 95-100页

作者： Yan Xiaokang liu jiongtian Cao Yijun Wang Lijun School of Chemical Engineering and Technology China University of Mining&TechnologyXuzhou 221116China School of Power Engineering China University of Mining&TechnologyXuzhou 221116China

Improved fluid dynamics can enhance the separation efficiency of flotation methods. A Computational Fluid Dynamics simulation using FLUENT was performed to model the fluid environment of a cyclonic-sta- tic micro bubble flotation column. The simulation results visually show the interior flow and illustrate mix- ing of the different flows within the apparatus. An analysis of the distribution in velocity and vorticity was used to analyze the separation mechanism and the synergism of the component parts and to strengthen the design of each unit. The conclusions are that axial back mixing and vortexes still exist in the separation unit even in the presence of packing media. The inverted cone structure near the tangential inlet （cone 1 ） within the cyclonic unit is the main reason for this. The cone 1 structure enhances swirling and focuses energy within the inner area of the cone where there are abundant bubbles. As a result slowly floating minerals are forcibly recovered and railings are effectively separated within this unit. However, cone 1 also reduces the vorticity downstream from it, which reduces the efficiency of railings separation within this part. Therefore, the design of cone 1 should be based on the principles of lessening disturbances to the column unit while strengthening the separation effect of the cyclonic unit. Also, the axial distance between the paired cyclonic structures at the bottom of the column （cone 2） and cone 1 poses tough requirements because of an interaction between separation of the middlings and railings.

关键词： Cyclonic-static micro bubble flotationcolumn CFD Flow field Vorticity magnitude Optimization design

Flotation and adsorption of novel Gemini decyl-bishydroxamic acid on bastnaesite:Experiments and density functional theory calculations

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International Journal of Mining Science and Technology 2023年第10期33卷 1193-1202页

作者： Longhua Xu Chang liu Jiushuai Deng Donghui Wang Kai Xue Yan Wang Jinping Meng jiongtian liu School of Chemical Engineering Zhengzhou UniversityZhengzhou 450001China Key Laboratory of Solid Waste Treatment and Resource Recycle Ministry of EducationSouthwest University of Science and TechnologyMianyang 621010China School of Chemical&Environmental Engineering China University of Mining&Technology-BeijingBeijing 100083China State Key Laboratory of Mineral Processing Beijing 100160China

Rare earth element is an important strategic metal,but the supply of high purity rare earth ores is growing slowly,which is in sharp contradiction with the rapidly growing *** flotation has been confirmed to be an effective method to separate bastnaesite from its gangue ***,the traditional collectors are facing serious problems in flotation separation of minerals,requiring the addition of excess depressant and regulator in the flotation ***,we proposed and synthesized novel Gemini hydroxamic acids Octyl-bishydroxamic acid(OTBHA),Decyl-bishydroxamic acid(DCBHA)and Dodecyl-bishydroxamic acid(DDBHA)as the collectors in bastnaesite-barite flotation *** effect of different carbon chain lengths on the molecular properties were explored by density functional theory(DFT)*** possessed a stronger reactivity compared with OCBHA and *** flotation results verified the consistency of the computational calculation about the performance prediction of Gemini hydroxamic *** with OCBHA and DDBHA,DCBHA displayed superior collecting affinity toward bastnaesite,and did not float *** potential results showed that the presence of DCBHA increased the potential of bastnaesite,while it had almost no effect on barite,indicating DCBHA had a stronger affinity for ***,Fourier transform infrared(FTIR)and X-ray photoelectron spectroscopy(XPS)analyses indicated that the adsorption mechanism was due to two hydroxamate groups of DCBHA co-anchored on bastnaesite surface by forming five-membered hydroxamic―(O―O)―Ce *** addition,atomic force microscopy(AFM)clearly observed that DCBHA uniformly aggregated on bastnaesite surface,which increased surface contact angle and improved the hydrophobicity of bastnaesite.

关键词： Gemini-hydroxamic acid Bastnaesite DFT Flotation Adsorption mechanism

Effect of a cyclonic flotation column on the separation of magnesium from phosphate ore

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Mining Science and Technology 2011年第5期21卷 647-650页

作者： Li Guosheng liu jiongtian Cao Yijun Wang Dapeng School of Chemical Engineering and Technology China University of Mining ＆ Technology Xuzhou 221008 China

This study was performed to investigate the effects of the cyclonic separation mechanism on the removal of magnesium from phosphate ore. An analysis of the particle-bubble collision mechanism in a cyclonic force field was used to design two different pulp circulation systems for a cyclonic-static micro-bubble flotation column （FCSMC）. Experiments comparing the two conditions were then conducted. Size analysis of the feed and separated products was conducted with a BXF cyclone size analyzer. The results show that about 34.60% of the total MgO content in the feed exists in the -10 μm fraction. This demonstrates that magnesium removal from phosphate ore has the characteristics of a micro-fine particle flotation problem. Under conditions of cyclonic circulation the MgO level of the concentrate is 1.74g, which is lower than that obtained from the column operated in direct-flow circulation by 0.34%, These results indicate that the cyclonic circulation mechanism of the FCSMC can promote removal of micro-fine particles containing magnesium. This is attributed to the function of surface flotation and to the reduction of the lower separation limit under conditions of cyclonic circulation.

关键词： Flotation columnCyclonic separationPhosphate oreRemoval of magnesium

Effects of clay and calcium ions on coal flotation

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International Journal of Mining Science and Technology 2013年第5期23卷 689-692页

作者： Zhang Zhijun liu jiongtian Xu Zhiqiang Ma Liqiang School of Chemical & Environmental Engineering China University of Mining & Technology School of Chemical Engineering and Technology China University of Mining & Technology

The microflotation of three single minerals,mixed coal–kaolinite and mixed coal–montmorillonite were examined to study the effects of clay and calcium ions on coal *** results show that the ash content of flotation concentrate increases by 3%in the presence of clay minerals,and the ash content would further increase by 3%in co-presence of clay minerals and high concentration of Ca2+.Scanning electron microscope(SEM)images and elemental spectrum analysis indicate that fne clay particles that coat on the coal surface,which is called slime coating,can affect the coal *** slime coating would be induced much more easily in the presence of Ca2+.

关键词： Microflotation Clay Calcium ions Slime coating

Numerical simulation of a self-absorbing microbubble generator for a cyclonic-static microbubble flotation column

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Mining Science and Technology 2010年第1期20卷 88-92页

作者： LI Lin liu jiongtian WANG Lijun YU Hesheng School of Chemical Engineering and Technology China University of Mining & Technology Xuzhou 221116 China School of Mechanical and Electrical Engineering China University of Mining & Technology Xuzhou 221116 China Schulich School of Engineering University of Calgary Calgary T2N1N4 Canada

The Cyclonic-Static Microbubble Flotation Column (FCSMC) is currently a widely used, novel type of flotation device. The self-absorbing microbubble generator is the core component of this device. The structure of the microbubble generator directly influences flotation column performance by affecting bubble size and distribution as well as gas holdup in the column. However, the complicated flow inside the generator results in high R&D costs and difficulty in testing. Thus, the CFD software, FLUENT, was used to simulate the gas-liquid two-phase flow inside a self-absorbing microbubble generator. The effect of area ratio, a key structural parameter, was studied in detail. Critical flow-field parameters including velocity, turbulent kinetic energy, minimum static pressure and gas holdup were obtained. The simulation results demonstrate that the optimum area ratio is 3.

关键词： self-absorbing microbubble generator flotation column two-phase flow numerical simulation

Distribution, occurrence and enrichment causes of gallium in coals from the Jungar Coalfield, Inner Mongolia

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Science China Earth Sciences 2011年第7期54卷 1053-1068页

作者： WANG WenFeng QIN Yong liu XinHua ZHAO JianLin WANG JunYi WU GuoDai liu jiongtian Key Laboratory of CBM Resources and Reservoir Formation Process Ministry of Education China University of Mining and Technology Xuzhou 221116 China School of Resources and Earth Science China University of Mining and Technology Xuzhou 221116 China Key Laboratory of Coal Processing and Efficient Utilization Ministry of Education China University of Mining and Technology Xuzhou 221116 China

We collected eleven bench samples of No. 6 coal from the Heidaigou Surface Mine, Jungar Coalfield, Inner Mongolia, China, and four samples from the affiliated coal preparation plant. Based on these samples, we used inductively coupled-plasma mass spectroscopy, X-ray diffraction, scanning electron microscope with an energy-dispersive X-ray spectrometer techniques, and borehole exploration data, to investigate the distribution, occurrence and enrichment causes of gallium （Ga） in the coals. Our results show：（1） Gallium is significantly enriched in the coal seams from the study area, with an average content of 18.8-26.0 ppm. Gallium is distributed heterogeneously in the coals, and reaches ore-forming scales only in No. 6 coal of Heidaigou Surface Mine, not in the other mining districts of Jungar Coalfield. （2） On the horizontal plane, Ga is enriched in the main minable coals from the northern and middle part of the coalfield. In the vertical profile, Ga content in the coal seams is higher at the base of Taiyuan Formation （Nos. 8 and 9） and Shanxi Formation （Nos. 3 and 4） than at the top of the Taiyuan Formation. Within the identical coal seam, Ga content is higher in the benches near the roof and floor than in the middle section. （3） Gallium in the coals is associated mainly with kaolinite and boehmite. Additionally, Ga may be adsorbed to some extent by humic acid, resulting in a high level in weathering coal. （4） Geological factors affect Ga enrichment in coal, such as the prop- erty of parent rocks in the source area, the sedimentary environment, organic matter, structure, and past magmatic hydrothermal activity. Especially, Ga content in parent rocks plays a leading role. （5） The mobility and precipitation of trace elements like Ga are controlled principally by the geochemical behavior of the major element A1. Terrestrial and transgressive environments can cause the precipitation of bauxite, whereas marine-continental depositional environments may cause the separati

关键词： coal gallium distribution occurrence enrichment causes Jungar