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Removal of magnesium and calcium from electric furnace titanium slag by H_3PO_4 oxidation roasting-leaching process

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Transactions of Nonferrous Metals Society of China 2018年第2期28卷 356-366页

作者：郑富强郭宇峰刘水石邱冠周陈凤姜涛王帅中南大学资源加工与生物工程学院长沙410083 中冶长天国际工程有限责任公司长沙410083

H3PO4 oxidation roasting followed by HCl acid leaching was proposed to remove magnesium and calcium from electric furnace titanium slag containing 3.12% MgO and 0.86% CaO. XRF, XRD and SEM techniques were used to characterize the composition, mineral phase component and microstructure of the titanium slag. The H3PO4 oxidation thermodynamic, mineral phase transformation, microstructure, element distribution in titanium slag during H3PO4 oxidation process and leaching process were investigated. The thermodynamic analysis indicated that H3PO4 could promote the decomposition of MgTi2O5 and CaSiO3. The results indicated that H3PO4 could effectively promote the transformation of titanium-bearing mineral to rutile and enrich the impurities in MxTi（3-x）O5 into phosphate which could be removed by acid leaching process. Under the studied conditions, the leaching rates of magnesium and calcium reached 94.68% and 87.19%, respectively. The acid leached slag containing 0.19% MgO and 0.13% CaO（mass fraction） was obtained.

关键词： titanium slag oxidation roasting leaching H3PO4 magnesium calcium rutile

oxidation roasting of molybdenite concentrate

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Transactions of Nonferrous Metals Society of China 2015年第12期25卷 4167-4174页

作者：王璐张国华党杰周国治北京科技大学钢铁冶金新技术国家重点实验室北京100083

In order to investigate the oxidation roasting of molybdenite concentrate in pure oxygen atmosphere, experiments at 673, 723, 773, 873 and 973 K were carried out. The phase transitions and morphology evolutions of the samples obtained at different temperatures after reacting for different time were analyzed by X-ray diffraction（XRD） and scanning electron microscopy（SEM）. The results showed that molybdenite concentrate was oxidized directly to Mo O3 in pure oxygen atmosphere. There were remarkable changes of the morphologies of products with the increase of the roasting temperature. It was also found that sintering phenomenon occurred during the roasting process in pure oxygen when the temperature was above 873 K. The composition of sintered sample was mainly comprised of Mo O3 and some unreacted Mo S2.

关键词： oxidation roasting molybdenite concentrate morphology sintering

roasting oxidation behaviors of ReS_2 and MoS_2 in powdery rhenium-bearing, low-grade molybdenum concentrate

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Transactions of Nonferrous Metals Society of China 2019年第4期29卷 840-848页

作者： Xiao-hui FAN Qiong DENG Min GAN Xu-ling CHEN School of Minerals Processing and Bioengineering Central South UniversityChangsha 410083China

The oxidation roasting process of molybdenum concentrate has significant advantages in industrial ***,utilization of low-grade mineral has many problems because it is more complex than the standard *** this study,the oxidation behaviors of powdery rhenium-bearing low-grade molybdenum concentrate were investigated through thermodynamic calculation,roasting experiments,thermogravimetric analysis,and phase *** results obtained show that oxidation of MoS2 begins at 450℃,and MoO3 reacts with metal-oxide forming molybdate at 600℃.Finally,MoO3 can be dissolved in ammonia with a maximum content of approximately 80%.The volatile speed of Re was considerably slower than the oxidation speed of MoS2 because the nonvolatile products ReO2 and ReO3 were generated in reactions among MoS2,SO2,and *** final volatilization rate of Re was almost 70%.This study determined the problems related to the roasting of low-grade molybdenum concentrate,which lays the scientific foundations for subsequent enhancement of molybdenum and rhenium extraction.

关键词： low-grade molybdenum rhenium oxidation roasting thermodynamics phase evolution

Separation chemistry and clean technique of cerium(IV): A review

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Journal of Rare Earths 2014年第8期32卷 681-685页

作者：邹丹陈继李德谦 State Key Laboratory of Rare Earth Resources Utilization Changchun Institute of Applied Chemistry Chinese Academy of Sciences Graduate School of the Chinese Academy of Sciences

The separation method of changeable valence RE element of cerium （Ce） was reviewed in this paper. Solvent extraction is the most effective and efficient method to separate Ce（IV） from RE（III）, usually accompanied with fluorine （F） and phosphor （P） from bastnaesite and monazite etc. By roast or wet-air oxidation, Ce（III） of bastnaesite and monazite was oxidized into Ce（IV）, and Cyanex923 and [A336][P507] have been investigated to co-extract and recover Ce（IV）, F and P from H2SO4 leaching liquor, leading to favorable conditions for the subsequent separation of Th（IV） and RE（III）. The interaction of Ce（IV） and F and/or P enhances the roasting, leaching and extraction of Ce（IV） due to increasing of the stability of Ce（IV）, and the formation of CeF3 and CePO4 after reductive stripping will benefit the utilization of F and P. For dealing with RE ores of high-content Ce, the clean process of oxidation roasting and Ce（IV）-F separation for Sichuan bastnaesite highlights the advantages of Ce（IV） based clean technique, which firstly demonstrates the comprehensive utilization of Ce（IV）, Th（IV）, F and RE（III） and prevention of environmental pollution from fountainhead. A preliminary flowsheet of two-step oxidation and extraction of Ce（IV） for Bayan Obo mixed ores was further proposed to process the oxidation and extraction of Ce（IV） in presence of both F and P, indicating the possibility of similar effects with clean process of Sichuan bastnaesite. Ce（IV） separation chemistry and clean technique will open up new realms for light RE resources utilization, meeting“Emission Standards of Pollutants from Rare Earths Industry”promulgated by China’s Ministry of Environment Protection （MOP） in 2011.

关键词： Ce(IV) oxidation roasting wet-air oxidation extraction rare earths