Research on Factors Affecting Flotation and Desulfurization of Coal by Electrochemical Method

Influence of factors such as potential of electrolyte, electrolyzing time, concentration of electrolyte, and pH value on flotation and desulfurization of coal was researched. The result shows that the electrochemical reduction can enhance the desulfurization effect and increase the yield of clean coal under certain conditions. So it is an effective method.     

Electrolytic reduction of Nantong coal and model compounds with oxygenic functional groups in an aqueous NaCl solution

Electrolytic reductions of oxygenic functional groups (OFGs) on coal surface and coal model compounds with OFGs in an aqueous NaCl solution are studied by electrochemical methods combined with GC/MS, GC and FTIR analyses. Different elec-trode reactions, their corresponding potentials and dynamic equations during the processes are investigated. The results show that benzoic acid, benzaldehyde, benzalcohol and hypnone are reduced to benzaldehyde and benzalcohol, methoxybenzene and benzal-cohol, toluene and styrene, respectively, at the cathode. The corresponding electrode potentials and dynamic equations are deter-mined. The electrolytic reduction also leads to an increase in the contents of hydroxyl groups and aliphatic moieties and a corre-sponding decrease in those of carboxyl and carbonyl groups in Nantong coal, a high-sulfur coal, an enhancement in the flotation desulfurization of the coal. ER also reduces organic sulfur and FeS2 in the coal.     

Thermodynamic Analysis of Desulfurization of Fine Coal by Electrochemical Reduction Flotation

Problems in desulfurization of coal by electrochemical reduction is analyzed and calculated. The resultshows that 1) the △_rG_m function of the reaction of pyrite into FeS and the modifying reaction decreasing theoxygenous functions on coal surface is smaller than zero in a spontaneous reaction, and greater than zero in a non-spontaneous reaction; 2) the △_rG_m value can be adjusted by pH and the dosage of electrolyte to make it be greaterthan zero, which is favorable for the modifying reaction and useful for desulfurization of coal. The research hasprovided a theoretical foundation for determining reasonable technical parameters of desulfurization     

煤炭洗选脱硫研究

简述了我国煤炭洗选脱硫现状及各种洗选脱硫方法,介绍了研制成功的煤炭洗选脱硫两大关键设备——无压给料重介旋流器和旋流微泡浮选柱的工作原理、脱硫性能及脱硫工艺与应用实践,无压给料旋流器给料方式独特,介质入口曲线选择合理,抗耐磨性能好;旋流微泡浮选柱柱体高度低,两段式结构设计新颖,微泡发生器的节能性及体外配置工作可靠性大大提高,两者配合使用对煤炭的全粒级洗选脱硫可达到满意的脱硫效果．     

电解还原法强化高硫煤浮选脱硫机理研究

采用电解还原法对高硫煤预处理后，使煤表面的含氧官能团减少，疏水性增强；同时，黄铁矿表面初始氧化产物如单质硫和多硫化物被还原，亲水性增强．煤粒和黄铁矿颗粒两者的表面性质向相反的方向改性，从而实现强化浮选分离的目的，理论上分析了煤和黄铁矿表面的改性机理，并通过试验验证了电解还原法强化浮选能够明显地降低浮选精煤中的硫分．对不同煤样的浮选结果表明：北宿煤样的黄铁矿脱除率可达89％以上。     

超声波辐射下煤的电化学脱硫研究

以NaCl溶液为电解质溶液,在超声波辐射下对高硫煤样进行超声电化学脱硫。采用正交试验法确定适宜的脱硫条件,通过单因素试验研究煤浆浓度、NaCl浓度、电解电压和电解时间对煤样脱硫率的影响,比较不同催化剂和电化学辅助手段对脱硫效果的影响。结果表明,电解电压为10V、电解时间为90min、煤浆浓度为20g／L、NaCl浓度为1．0mol／L、以FeCl2为催化剂时超声辅助电化学脱硫的效果最好,脱硫率达80．8％。煤质分析和红外光谱分析表明超声电化学不仅能脱除煤中的硫分,而且能有效地脱除其中的灰分并提高煤的发热量。     

药剂与超声波处理的选煤方法研究

采用浮选药剂和超声波技术相结合的方法进行了煤的浮选试验 ,结果表明 :BET作为煤的浮选药剂 ,比 GF,FS2 0 2两种常用药剂用量少 ,分别是它们的 1 /1 0和 1 /1 0 0 ;此外 ,BET选择性强 ,对煤系黄铁矿捕收性差 ,浮选黄铁矿时用 BET的上浮物是用 GF,FS2 0 2时的 1 /1 0～1 /2 0 .超声波的强化作用进一步提高了抑制剂的作用效果 ,使脱硫降灰的指标有了明显的提高(达 1 5 %以上 ) ,如介休煤样的黄铁矿脱硫率在 85 %左右 ,脱硫完善度达到 6 8.97% .抑制剂 Ca O和水玻璃同时使用可以提高脱硫降灰效果 ,比二者单独使用效果好     

Effect and influence factors of sulfur removal in coal with fungus

The influence of coal desulfurization by fungus was experimentally studied. The results suggest that fungus can effectively remove inorganic and organic sulfur in coal, and main influences of desulfurization by fungus of pH value, temperature, coal slurry concentration and coal granularity were studied by orthodox experiment and the optimal experimental conditions are′as follows: pH value 6, temperature 45 ℃, coal slurry concentration 10% and coal granularity 100 μm. Under above conditions, fungus car remove up to 44.96% total sulfur and 54. 87% inorganic sulfur within two days, and their desulfurization rates will increase along with time. Compared with sulfolobas, desulphurization by fungus is steady and more effective, and has advantage of high speed.     

高硫煤电化学调浆浮选脱硫XRD谱研究

对山东兖州,内蒙乌达高硫煤进行了电化学调浆处理,运用X－射线衍射（XRD）测试技术从定性,定量两个方面对高硫煤电化学调浆浮选脱硫进行了研究,实证了煤中黄铁矿被氧化作为多硫化铁的事实。结果表明,电化学调浆不破坏煤的结构,经过电化学调浆浮选,能有效的脱除煤中硫,尤其是黄铁矿硫,它是一种温和,无污染,高效的脱硫新方法。     

Nanobubble generation and its applications in froth flotation(part Ⅳ): mechanical cells and specially designed column flotation of coal

Coal is the world's most abundant fossil fuel.Coal froth flotation is a widely used cleaning process to separate coal from mineral impurities.Flotation of coarse coal particles,ultrafine coal particles and oxidized coal particles is well known to be difficult and complex.In this paper,the nanobubbles' effects on the flotation of the varying particle size,particle density and floatability coal samples were evaluated using a bank of pilot scale flotation cells,a laboratory scale and a pilot scale specially designed flotation column.The parameters evaluated during this study include the flow rate ratio between the nanobubble generator and the conventional size bubble generator,the superficial air velocity,collector dosage,frother concentration,flotation feed rate,feed solids concentration,feed particle size,and the superficial wash water flow rate,etc.The results show that the use of nanobubbles in a bank of mechanical cells flotation and column flotation increased the flotation recovery by 8%～27% at a given product grade.Nanobubbles increased the flotation rate constants of 600～355,355～180,180～75,and 75～0 microns size coal particles by 98.0%,98.4%,50.0% and 41.6%,respectively.The separation selectivity index was increased by up to 34%,depending on the flotation feed characteristics and the flotation conditions.     

Main influence factors on desulfurization of coal by sulfolobas

1　INTRODUCTIONHighsulfurcoalwhichletsoutpoisonousandharm fulgassuchassulfurdioxideintheprocessofcoalcom bustion ,isamainfactortoform greatareaacidrainandoccupiesonethirdreservesoftotalcoalinChina .Manhaspaidmuchattentiontoseriousenvironmentpollutionmadebysulfurincoalandsearchedforaspeed ,low costandeffectivetechnologyofdesulfurizationwhichhasbecomeasignificantenvironmentprotectiontasknowadays[1] .Coaldesulfurizationcanbesortedintofore burning ,aflame burningandafter burningbyburningproce…     

Effect and influence factors of sulfur removal in coal with fungus

The influence of coal desulfurization by fungus was experimentally studied. The results suggest that fungus can effectively remove inorganic and organic sulfur in coal, and main influences of desulfurization by fungus of pH value, temperature, coal slurry concentration and coal granularity were studied by orthodox experiment and the optimal experimental conditions are as follows: pH value 6, temperature 45 °C, coal slurry concentration 10% and coal granularity 100 μm. Under above conditions, fungus can remove up to 44.96% total sulfur and 54.87% inorganic sulfur within two days, and their desulfurization rates will increase along with time. Compared with sulfolobas, desulphurization by fungus is steady and more effective, and has advantage of high speed. Foundation item: Project(2002AA649220) supported by Hi-tech Research and Development Programe; project(1667) supported by the Postdoctoral Science Foundation of Central South University     

SFC型充填式浮选柱的研究及应用

国内外大量研究结果表明充填式浮选柱是一种可供选矿、化工、造纸和废水处理等行业用于精选细粒矿物、粉煤除灰脱硫及其它物料分离的设备,与目前所用的浮选设备相比,具有结构简单,能耗低、分选效率高、操作容易等优点。     

煤的微生物脱硫的实验研究

煤中硫的脱出可以减轻对环境的污染,而煤的生物充是很有前景的一种脱硫方法,利用空气搅拌法,研究了内蒙古自治区酸性矿井水、土壤液、城市污未和工厂废液对乌达雀儿沟煤中硫的脱出能力,经过２ｄ细菌２和１５ｄ脱硫,发现除城市污水外,其余的均能脱掉煤中部分硫,硫脱除率２６．９５－３８．７７％;而且,中性环境与酸性环境有着几乎一致的硫脱除率。     

Coal flotation using wash oil as a new type of collector

The use of wash oil as a coal collector is proposed to overcome the disadvantages of regular collectors in coal slime flotation. These disadvantages include high price, limited sources and high consumption. The effect of additives on flotation was studied and an innovative "one rough separation-one cleaning separation" flotation technology was developed. The experimental results show that the clean coal ash content decreases by about 1.36% and the clean coal yield declines by around 10% with the application of the depressant. There is an increase of 3.76% in the yield of clean coal and a decrease of 0.40% in the ash content caused by utilizing a dispersant. An ultimate product having an ash content of 10.78% and yield of 70.12% can be attained using a combination of dispersant and depressant. The use of this new technology decreases the ash content by 1.21%, decreases the yield by 2.80% and an increases the coal flotation perfect index by 2.03%. Compared to common flotation, the utilization of the new technology reduces ash by 0.17%, increases yield by 5.3% and increases perfect index by 4.18%.     

Main influence factors on desulfurization of coal by sulfolobas

By orthodox experiment, the main influence factors of desulfurization by sul folobas of pH value, temperature, coal slurry concentration and coal granularity are studied in detail and the optimal experimental conditions were also obtained. The experimental results demonstrate that sul folobas being kind of linking-heat, acidophilic and self-supported bacterium with double characters can effectively remove inorganic and organic sulfur in coal. The superlatively desulfurization rate is up to 48.57% total sulfur and 41.71% inorganic sulfur within 10 d and its desulfurization rate can be greatly affected by the four factors above mentioned. Therefore, the optimum conditions of desulfurization are obtained by comprehensive experiment and they are as following: pH value 3, temperature 70°C, coal slurry concentration 10% and coal granularity 150 μm, respectively. Moreover, the repetition experimental results confirm that the desulfurization by sul folobas is steady. Foundation item: The National Advanced Technology Research and Development Project (863 Project 2002AA649220) Biography of the first author: HE De-wen, postdoctor, born in April 1968, majoring in solid waste pollution control and resource, environmental assessment and plan.     

Original potential flotation of galena and its industrial application

1　ＩＮＴＲＯＤＵＣＴＩＯＮＥｌｅｃｔｒｏｃｈｅｍｉｃａｌｔｅｃｈｎｉｑｕｅｓｈａｖｅｂｅｅｎａｐ ｐｌｉｅｄｉｎｍａｎｙｉｎｖｅｓｔｉｇａｔｉｏｎｓｏｆｓｕｌｆｉｄｅｆｌｏｔａｔｉｏｎｓｙｓｔｅｍｓ,ａｎｄｅｆｆｅｃｔｓａｎｄｃｏｎｔｒｏｌｏｆｐｏｔｅｎｔ     

不同煤阶煤表面改性的FTIR谱研究

用傅立叶变换红外光谱（FTIR）方法对煤样进行了测试,研究了煤表面改性前后官能团含量的变化。结果表明,随着煤的变质程度增高,含氧官能团减少。当采用不同的电化学法还原处理后,不同变质程度煤的含氧官能团也都有不同程度的减少。含氧官能团的减少能使煤的疏水性增强,同时黄铁矿表面的亲水性增强,有利于浮选脱硫的进行。     

含硫低品位锡尾矿的综合利用

某低品位锡尾矿中锡和硫的品位分别为０．２７％和５．０７％,具有综合回收价值,锡和硫在－０．０２５ ｍｍ粒级的分布率分别为６１．６４％和７６．７４％,综合回收难度较大. 试验结果表明,摇床和磁选均没有显著地选别效果,浮选则可以较好地达到选别的目的;选别工艺上,可先使用浮选预先脱硫,脱硫后进一步选别锡;相对于摇床,浮选能更有效地回收锡;硫化矿的存在会显著影响锡的选别,较为彻底的脱硫可改善锡的浮选指标;使用三段浮选脱硫工艺,硫的脱除率可达９０％以上;脱硫的过程中会损失部分的锡,可通过对硫粗精矿再磨后,完成锡和硫的进一步分离;通过浮选闭路流程,最终可获得硫品位和回收率分别为４２．７１％和８９．８４％的硫精矿,以及锡品位和回收率分别为３．１６％和６０．３７％的锡精矿.     

喷射旋液脱硫塔脱硫性能研究

煤炭燃烧后产生的大量二氧化硫造成了严重的污染问题。湿法脱硫是当今用于烟气脱硫的主要方法。介绍了一种新型的脱硫设备---喷射旋液脱硫塔,实验研究了操作条件对其脱硫性能的影响,并综合考虑对压降的影响,得到了较优的操作条件。研究表明该设备具有良好的脱硫除尘效果,双层塔盘的脱硫效率可达到９０％以上。