Published in Journal of Central South University
Presently, ilmenite concentrates from Odisha Sands Complex at Chhatrapur, India are utilized to produce TiO2 slag by direct smelting in an electric arc furnace. However, the process involves the consumption of excess electrical energy and difficulty in handling the arc furnace due to frothing effects. A more efficient process of pre-reducing the il...
Upgrading ilmenite to obtain synthetic rutile is a key step of chlorination process to produce titanium dioxide. Hydrochloric acid leaching is a preponderant process to produce high quality synthetic rutile. Ascertaining appropriate roasting pretreatments to alter the phase compositions and microstructure of ilmenite and solve the problems that occ...
选用3种不同煤焦,采用程序升温和恒温实验方法,在固定床上考察了不同实验条件下的NO转化率和C对NO选择性,分析了煤焦脱硝的机理和影响因素。实验结果表明:NO和O2在煤焦表面发生化学吸附所形成的络合物在脱硝过程中起着关键作用,影响C-NO反应和C-O2反应的竞争与协作关系。在所考察的煤焦中锡林浩特褐煤焦脱硝效果最好,当温度为723 K时烟道气中NO还原率可达99%;在温度623~923 K、O2浓度0~5%范围内,提高温度和O2浓度均有利于提高NO转化率,而降低O2浓度有利于提高C对NO选择性;烟道气中NO浓度越高,其转化率越低,但C对NO选择性越高。
利用盐湖氯化镁和硫酸制备七水硫酸镁,将七水硫酸镁脱水得到无水硫酸镁.采用天然气还原热解无水硫酸镁得到高纯氧化镁.通过单因素实验考察了还原热解温度、热解时间、硫酸镁的粒径和天然气气体流量对硫酸镁转化率的影响,通过正交试验优化了还原热解的条件.采用X射线衍射和扫描电镜对还原热解产物进行分析和表征.氧化镁的最佳制备条件:热解温度为1000℃,热解时间为30 min,硫酸镁粒径为75μm,天然气气体流量为25 mL·min~(-1).温度是影响硫酸镁转化率的主要因素.在最佳制备条件下,硫酸镁的转化率达到99.27%,氧化镁的纯度达到99.5%,制取的氧化镁单分子均匀,表面为多孔蓬松,具有高比表面积.
针对低品位富镁软锰矿,研究了预脱镁—黄铁矿还原酸浸—制备硫酸锰。结果表明,在液固体积质量比3.5∶1、温度35℃、反应时间4h条件下,矿石脱镁率为86%;以脱镁渣为原料,在反应温度95℃、反应时间3h、物料配比n(MnO2)∶n(FeS2)∶n(H2SO4)=1∶0.18∶2.0条件下,锰浸出率为97%;所得硫酸锰的纯度较高,达到工业硫酸锰行业标准。
Crack-free GaN epitaxial layer was obtained through inserting 80 nm graded AlGaN buffer layer between GaN epilayer and high temperature AlN buffer on 2-in Si(111) substrates by metal organic chemical vapor deposition. This paper investigated the influence of AlGaN buffer thickness on the structural properties of the GaN epilayer. It was confirmed f...
A sandwich structured substrate was designed for quantitative molecular detection using surface enhanced Raman scattering (SERS), in which the probe molecule was sandwiched between silver nanoparticles (SNPs) and silver nanoarrays. The SNPs was prepared using Lee-Meisel method, and the silver nanoarrays was fabricated on porous anodic aluminum oxid...
We combine interferometric lithography and inductively coupled plasma etching to fabricate GaAs subwavelength grating (SWG) which mimics the moth eye structures. Through the modification of morphology parameters, including profile, height and packing fraction, tapered, high-aspect-ratio and closely-packed GaAs SWGs are obtained. The measurement of ...
在内径50mm的搅拌流化床内进行了平均粒径239nm的氧化铁粉的流态化及氢气还原实验.结果表明,床中氧化铁颗粒以聚团鼓泡形式实现完全流化,最小流化速度为0.025m/s,最大床层膨胀比为2.0.在500℃下用氢气还原该氧化铁粉的反应过程为:Fe2O3→Fe3O4→Fe,Fe颗粒的粒径比Fe2O3小,有颗粒烧结现象,由Fe引起的颗粒烧结和粘结作用可能导致失流.与普通流化床相比,搅拌能使流化时间由3min延长至15min,使失流时样品的金属化率由15%提高至76%.
利用可视流化床分别研究了Fe2O3和Fe粉在流化过程中黏结失流发生的过程.结果表明,Fe2O3在惰性气氛中流化不发生黏结失流,而在还原气氛中发生黏结失流,且黏结发生时间恰好是铁晶核析出的初始阶段.Fe颗粒在还原和惰性气氛中流化均出现黏结失流现象.铁的生成是产生黏结的前提条件.当Fe颗粒流化温度从700℃升高到750℃时,黏结临界时间提前了11min,表明金属铁的表面特性是导致黏结的主要内因.扫描电镜分析表明,Fe和Fe2O3表面形成的纳微结构是导致Fe2O3流化还原黏结失流的重要因素.
