Research on Effect of Magnetized Pulp on Coal Slime Flotation

Jun.2004Journal of China University of Mining & TechnologyVol. 14 No. 1Research on Effect of Magnetized Pulon Coal slime flotationBIAN Bing-xin(边炳鑫)23,XlAO,Jin-li(肖健丽)3,CHEN Qing(陈清如), WEI LU-bin(韦鲁滨)(1. State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China2. Key Laboratory of Environmental Science and Engineering of High School ofJiangsu Province, Suzhou 215011, China3. Heilongjiang Institute of Science and Technology, Harbin 150027, Chi4. School of Chemical & Environmental Engineering, CUMT, Beijing 100083, ChinaAbstract: Effect of magnetization on oxygen concentration, pH, surface zeta potential, and wet heat of flotationpulp were researched. The result shows that magnetization treatment can improve the floatability of coal andincrease the difference in wet heat among coal, refuse, and pyrite, which is favorable for slime flotation and forFur and ash from coalKey words magnetization process; flotation; floatability pulpCLC number: TD923+7 Document code: A Article ID: 1006-1266(2004)01-0037-05The main foundation of mineral particle surface components by mineral analysis and selects relativesurface propertpure sample to study individual componentbetween particles. The effective separation cant bemple is the main coking coal collected fromrealized if only the difference in surface naturalfine coal from Lingshan Coal Preparation Plantproperty between particles is used. In order to of Anshan with an ash confent of w(Aad)=6.41%enlarge such difference,wee chemical orPyrite andcollected from thephysical means to change the surface property of gangue hill of Lingshan Coal Preparation Plantmineral particle[1-3. The authors intend to study the Pyrite sample has been separated and processedeffect of magnetization process on pulp properties according to a certain flow process 5. Gangue issuch as oxygen concentration.value. suhand-selected coarse shale, no obvious pyriteZeta potential, and wet heat so as to improve the insertion is found (we(A d)=80. 62%)flotation effectCoal of 0. 125--0 075, mmgangue of 0.0750. 045 mm, and pyrite of 0. 075-0. 045 mm haveexpeRimenbeen used to prepare individual component pulp and1 Samplesto measure the oxygen concentration and ph valueBased on pure mineral sample preparation of flotation pulp0.045 mm sample has beenmethod in mineral flotationability study 4 and in used to analyze surface Zeta potential and wet heatcombination of features that coal, pyrite and gangue 1.2 Reagentsare a complex composed of organic matter andinorganic matter, this test determines main mineralYH中国煤化工 sed in this test are listedCNMHGReceived date: 2003-07-0Foundation item Naturalscience Research Programmer of Jiangsu Province High School P. R C(o3KJB440133): China Postdoctoral ScienceFoundation (2003033337): China Coal Science Foundation (97 Process 11907 ) Creative Programmer of Key UniversityTeachers of Heilongjiang Province P. R CBiograph HadHEg-xin (1962-). male, from Taian Shandong Province, professor, Ph. D, engaged in the research on treatment of solid38Journal of China University of mining & TechnologyVol 14 No. 1Table 1 Flotation agents in the experimentagent name code molecular formulapurityolecular weightroduction areaChOhuse oil >87%Shanghai Chemical Reagent CompanyThin diesel oil 0C5-17)HIndustrial productsDa Qing Oil Refinery1.3 Magnetization equipmentused in the experiment are listed in Table 2.The magnetizatioRectifierthe authors and is used to regulate magneticRectifierinteraction intensity with agitation intensity beingadjustable. The structure of the magnetized deviceFig. 1Direct-current4 Analysis equipmentThe main analysis and measurement equipmentFig 1 Construction of the magnetization equipmentTable 2 Measurement equipment in the experimentMeaH measurementPHS-2C acidometer PHS-29A±0.001Shanghai Science Instrument PlantE-potential meterZetamaster%UK Malvern Companyoxygen conntration ox0.1mg·1-1Germanys ScientificmeasurementMagnetic interactionIntensity measuringDigit MagnetometerCTS24Shanghai Zhenhong Industrialany lte.5 Magnetization flotation testintensity B=2T, agitateth n=200r/Individual component"magnetization flotation room temperature t=20 C, thXFG flotation machine. The concentration of individual component flotation pulpvolume of the flotation machine is 60 mL and the is determined as 50 g/L. The oxygen content inwater for flotation is the un-magnetized distilled 500 mL of pulp is shown in Fig. 2Accord9.5adjustable range of magnetization equipment, the9.0agent system is determined to have a collecting8agent usage of 1.5 kg/tls, a frothing agent usageof 100 g/t, an agent ratio of 15 1, a pulp0246810121416adjusting time of 2 min, a collecting agent adjustingtime of 1 min, a frothing agent adjusting time of 1Fig 2 Effect of magnetization time uponmin, a magnetic interaction intensity B of 0oxygen concentration of pulp0. 35T, a magnetization time of 0-15 min, and anIt can be seen from Fig. 2 that the pH values ofgitation rotational speed of 200 r/mithree pulpsincrease with the increaseAfter flotation, the floating matter is filtered, of magnetization time. But the gangue pulp showsdried, and weighed so that the mineral up floatingratio can be calculatedH中国煤化study that in order toCNMHUI UAy gell aCtivation, adding a certain2 Result and Discussionamount of oxygen to control the concentration is2. 1 Effect of magnetization process on oxygenbeneficial to mineral flotation 6. Fig. 2 indicatesco丹黢捃nthat the pulp oxygen concentration increases afterOn the conditions of magnetic interaction being magnetized and shows that magnetizationbian Bing-xin et alResearch on Effect of Magnetized Pulp on Coal Slime39process is favorable for slime flotationbetween mineral and collecting agent is good. The2. 2 The effect of magnetization process on data in Table 3 indicate that the decreasingflotation pulp PH valuemagnitude of electric potential of coal in magnetizedOn the conditions of B=0.2 T, n=200 r/ light diesel oil is great. So the reaction betweenand a room temperature of t= 20 C, the magnetized light diesel oil and coal strengthens. Fornship between different magnetization time gangue and pyrite, the change of electric potentialand individual component pulp pH value is before and after magnetization is just the oppositedetermined. The result can be seen in Fig. 3.indicating that the collecting action of light diesel oilon gangue and pyrite decreases after magnetization2. 4 Effect of magnetization on surfaceOn the conditions of B=0.2T, n=200 r/10121415min. tmin, and room temperature t=25 Cthe wet heat of coal, gangue, and pyriteFig 3 Relation of magnetization time with PHrespectively reacting with distilled water and lightAs we can see in Fig. 3, three pulp ph values diesel oil before and after being magnetized are listedmonotonously increase with the increase of in Table 4magnetization timeTable 4 Wet heat of w2. 3 The effect of magnetization process onacting to mineral before and after magnetizationmineral surface Zeta potentialet heat/(J·g1)On the conditions of B=0.2T, nin, magnetization time (=5 min, and room1,0284,58211.113temperature t=20 C, the s potentials of coalMagnetized distilled water 0.215 1 4.116Thin diesel oil4,04591,83023.2185gangue, and pyrite respectively in distilled waterMagnetized thin diesel oil 6. 7 0.276 2.7077magnetized distilled water, the pulp consisting oflight diesel oil and coal particles, and the pulpItan be sseen from Table 4 that the wet heatconsisting of magnetized light diesel oil and cocoal, gangmagnetizedparticles are listed in Tabledistilled water is lower than that to non-magnetizeddistilled water. However, the wet heat of coalTable 3 Contrast of mineral surface potentialreacting to magnetized light diesel oil is higher thanbefore and after magnetization v/mVthat to non-magnetized light diesel oil. The wetganguepyriteDistilled water8.00heat of gangue, pyrite reaction to magnetized lightMagnetized distilleddiesel oil is lower than that to non-magnetized dieselThin diesel oil0,5magnetized thin diesel oil37.23+0Because the absorption is a decreasing course ofIt can be seen from Table 3 that in magnetizedsurlacefree energy, the decreasing energy isdistilled water, the surface potential of coreleased in the form of heat energy. The greater thedecreases but that of gangue and pyrite increase. In中国煤化工 he affinity between solidmagnetized light diesel oil, the surface potential ofCAMH Ger the reaction will becoal decreases from -35 00 mV to -37 23 mV TEl able 4 Indicate that the absorptionand that of pyrite increases from -6. 50 mv toability of water after being magnetized to mineral5.70mVdecreases and the decreasing magnitude of wet heate方芳数据of coal is quite great. So maggnetizing water Is notpotential of mineral surface decreases, the reaction only favorablefor enhancing coal floatability, butJournal of China University of Mining & TechnologVol 14 No. 1also for enlarging the difference in floatability of pyrite is basically stable when B is 0-0.1 Tbetween coal, gangue, and pyrite. Therefore, It is The up-floating ratio of pyrite decreases withfavorable for improving the effect of slime flotation magnetic interaction intensity increasing when Band removing sulfur and ash from coal.greater than 0. 1 T. The up-floating ratio of gangueThe absorption heat of magnetized light diesel is basically stable when B is 0-0.2 T. The upoil acting on coal increases while that on gangue and floating ratio slightly increases when B is 0.2pyrite decreases, indicating that the magnetization 0. 25 T(because there is a certain carbon matter inprocess can enhance the adhesive strength of light gangue); then the up-floatdiesel oil on coal surface, and reduce the action of markedly. But the change in gangue up-floatinglight diesel oil on gangue and pyrite.ratio is smaller than that of coal2.5 Effect of magnetization time on flotationThe flotation test results of three individualcomponents are listed in Fig 4. It can be seenFig. 4 that the up-floating ratio of55monotonously increases with magnetization time,but if t is greater than 7 min the up-floating ratio45gradually becomes stable. The up-floating ratio of00.51.01.52.02.53.03.5pyrite decreases with magnetization time when tB/kGs3-7 min but when t is greater than 7 min, the upFig 5 Result of pulp magnetization flotationfloating ratio is basically stable. The effect of pulpunder different magnetization intensitymagnetization time on gangue up-floating ratio ismore obvious than on pyritetrenttemperature 20 C)3 Concl usions1) Magnetization treatment can bring abouthe change in oxygen concentration, PH, surfacial, and wet heatulp. And themagnetizationFig 4 Result of pulp magnetization flotation with timeaffect magnetization effect of flotation pull(B-2 kGs, agitation strengthen=200 r/min2)Magnetization treatment of flotation pulproom temperature 20 C)can improve the floatability of coal and increase the2. 6 Effect of magnetic interaction intensity on difference in wet heat between coal, gangue, andpulp flotationpyriteThe effect of magnetic interaction intensity on3)Magnetization process can enhance thepulp magnetization flotation is listed in Figadhesive strength of light diesel oil on coal surfaceWhen magnetic interaction intensity B is greater and decrease the collecting action of light dieselthan 0. 1 T, the up-floating ratio of coal on gangue and pyrite, and improve the selectivity oflotonously increases with magnetic interaction light diesel oil, which is favorable for enhancing theintensity increasing and it gradually becomes stableTH中国煤化工 or removing sulfur andwhen B is greater than 0. 2T. 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