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Effect of CaO/SiO_(2) Slag Mass Ratio on Dissolution Rate of Alumina-based Refractory Ceramics

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China's Refractories 2023年第1期32卷 30-34页

作者： ZENG Fanbo HUANG Ao WANG Xinlian LI Shenghao ZHANG Shuzhe QU Pengcheng GU Huazhi The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081China

The dissolution of alumina-based refractory ceramics in CaO-Al2O3-SiO_(2)slag melts was performed based on the in-situ observation system of an ultra-high-temperature laser confocal microscope,and the effect of the CaO/SiO_(2)slag mass ratio(C/S ratio)on the dissolution rate of alumina-based refractory ceramics was *** results indicate that the dissolution rate increases with an increase of the C/S ratio and is mainly controlled by *** the early stage of dissolution,for all C/S ratios,the dissolution process conforms to the classical invariant interface approximation *** the later stage of dissolution,when the C/S ratio is≥6,the dissolution process is significantly different from the model above because of the formation of a thick interfacial layer,which can be explained by dissolution kinetics.

关键词： alumina-based refractory ceramics CaO/SiO2 mass ratio dissolution rate diffusion control in-situ observation

Kinetics of oxidation-precipitation of cobalt(Ⅱ) from solution by ozone

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Transactions of Nonferrous Metals Society of China 2010年第S1期20卷 42-45页

作者：田庆华郭学益易宇李治海 School of Metallurgical Science and Engineering Central South University

In order to precipitate cobalt(Ⅱ) in cobalt chloride solution, a novel method using ozone as the precipitant for its strong oxidability was proposed. The results show that the precipitation reaction is diffusion-controlled. The main factors affecting the oxidation rate such as the stirring speed, solution temperature, ozone partial pressure, initial concentration and flow rate were investigated. The kinetics equation of each condition was established. The results indicate that the oxidation rate is independent of the initial concentration or solution temperature. The oxidation rate increases obviously with increasing the stirring speed. The linear relationship between ozone partial pressure or flow rate and oxidation rate is found.

关键词： ozone diffusion control cobalt chloride oxidation kinetics

Kinetic Investigations on the Leaching of Niobium from a Low-Grade Niobium-Tantalum Ore by Concentrated KOH Solution

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Chinese Journal of Chemical Engineering 2004年第2期12卷 202-207页

作者：周宏明郑诗礼张懿 Institute of Process Engineering Chinese Academy of Sciences Beijing 100080 China

The leaching kinetics of niobium from a low-grade niobium-tantalum ore by concentrated KOH solu-tion under atmospheric pressure has been studied. Significant effects of reaction temperature, KOH concentration, stirring speed, particle size and inass ratio of alkali-to-ore on the dissolution rate of niobium were examined. The experimental data of the leaching rates and the observed effects of the relevant operating variables were well in-terpreted with a shrinking core model under diffusion control. By using the Arrhenius expression, the apparent activation energy for the dissolution of niobium was evaluated. Finally, on the base of the shrinking core model, the rate equation was established.

关键词： clean process leaching kinetics KOH niobium-tantalum ore diffusion control

Formation Mechanism of PPS as Antireflection Coating

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Semiconductor Photonics and Technology 2005年第1期11卷 32-36,39页

作者： WANGHai-yan SUNXiao-feng ZHANGYu-xiang LIWei-qiang LUJing-xiao KeyLab.ofMater.Phys. InstituteofPhys.Eng.ZhengzhouUniversityZhengzhou450052CHN

The whole chemical etching process on a P-type polycrystalline silicon substrate with resistivity 1-2Ω·cm is described. The formation mechanism of porous polycrystalline silicon（PPS） microstructure was investigated. Those how the initial pits were formed and an uniform morphology of PPS was obtained are explained. Two types of etching mechanism were characterized as defect control reaction and diffusion control reaction. The morphology formed after the isotropic acidic solution etching with different etching time and HF/HNO3 concentration was compared with the effect of the same etching process after anisotropic alkaline etching. The study showed that the thickness of porous polycrystalline silicon layer with chemical acidic etching entirely depended on the existence of various types of defects.

关键词： diffusion control Defect control Point defect Line defect