Transactions of Nonferrous Metals Society of China The Chinese Journal of Nonferrous Metals

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中国有色金属学报

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第31卷    第7期    总第268期    2021年7月

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文章编号:1004-0609(2021)-07-1952-13
辉钼精矿的氧化焙烧
王 璐1, 4,李梦超1,阙标华1,薛正良2,张国华3,蓝文韬4

(1. 武汉科技大学 钢铁冶金新工艺湖北省重点实验室,武汉 430081;
2. 武汉科技大学 省部共建耐火材料与冶金国家重点实验室,武汉 430081;
3. 北京科技大学 钢铁冶金新技术国家重点实验室,北京100083;
4. 佛山(华南)新材料研究院,佛山 528200
)

摘 要: 纯氧条件下对辉钼精矿的氧化焙烧行为展开基础研究,并结合最佳模型拟合法、TG-DTA、SEM-EDS和热力学软件FactSage 7.3等方法和手段对实验结果进行分析。结果表明:精矿在723 K和773 K下不能完全氧化,然而当温度升至873 K时,精矿能完全氧化生成三氧化钼(MoO3)。在较高温度下,如873 K和773 K时,精矿的氧化焙烧过程由界面化学反应控速;然而在较低温度下,如723 K时界面化学反应和形核长大模型共同发挥作用。反应过程中,产物由初始颗粒形态逐渐转变成具有层状结构的片状形貌,并且在晶面指数(020)、(040)、(060)和(0100)等晶面上衍射峰强度显著增加,表明生成的MoO3具有一定的各向异性和择优长大倾向。辉钼精矿的氧化焙烧过程符合挥发-冷凝机理,期间伴随着少量中间产物二氧化钼(MoO2)的生成。焙烧过程中产生的烧结现象是局部温度的升高和低熔点共晶体的形成共同作用所致。结合热力学数据本文还理论分析了主要杂质元素在焙烧过程中的演变规律及其对烧结行为的影响机制,并提出有效降低烧结现象发生的可行方案。

 

关键字: 辉钼精矿;氧化焙烧;三氧化钼;烧结现象

Oxidation roasting of molybdenite concentrate
WANG Lu1, 4, LI Meng-chao1, QUE Biao-hua1, XUE Zheng-liang2, ZHANG Guo-hua3, LAN Wen-tao4

1. Hubei Provincial Key Laboratory for New Processes of Ironmaking and Steelmaking, Wuhan University of Science and Technology, Wuhan 430081, China;
2. The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, China;
3. State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China;
4. Foshan (Southern China) Institute for New Materials, Foshan 528200, China

Abstract:The current work focus on the oxidation roasting behavior of molybdenite concentrate in high-purity oxygen atmosphere on the basis of the authors’ previous paper. The best modeling fit, TG-DTA, SEM-EDS and thermodynamic calculation method were adopted to analyze the experimental data. The results show that molybdenite concentrate cannot be reacted completely at 773 K and 723 K; when the temperature is increased to 873 K, however, the raw material can be oxidized to molybdenum trioxide (MoO3) completely. Combining the normalization and model fit methods, the work concludes that the rate-controlling step for the oxidization of molybdenite concentrate in the range of 773 K to 873 K is the interfacial chemical reaction. When the temperature is below 773 K, however, interfacial chemical reaction and nucleation and growth models both worked. It is also found that the morphology of obtained product transforms from previous particle shape to the final needle-like structure during the whole reaction process. XRD patterns show that the obtained needle-like product has an intense diffraction peak for the crystal indices of (020), (040), (060), and (0100), indicating its anisotropy and prior growth up tendency. Oxidation roasting processes of molybdenite concentration obey the vaporization- condensation mechanism with the formation of molybdenum dioxide (MoO2) as the intermediate product is also obtained. The study results also conclude that the occurrence of sintering phenomenon are due to the combined actions of the increase of local temperature and the formation of low-melting-point eutectics during the roasting process. With the help of FactSage 7.3 thermodynamic software, the transformation laws of the main impurities components and its effect on the sintering phenomenon during the roasting processes were also theoretically analyzed. The current work may play positive roles on understanding the roasting behavior of molybdenite concentrate and improve the service life of multiple heart furnaces.

 

Key words: molybdenite concentrate; oxidation roasting; molybdenum trioxide; sintering phenomenon

ISSN 1004-0609
CN 43-1238/TG
CODEN: ZYJXFK

ISSN 1003-6326
CN 43-1239/TG
CODEN: TNMCEW

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