Oxidation/Volatilization Characteristics and Kinetics of Roasting Process of Molybdenum Concentrate AITranslate

［1］（路晓龙， 李天恩. 新疆某低铜辉钼矿浮选试验研究 ［J］.黄金， 2023， 44（3）： 53.）

X L Lu， T E Li. Experimental study on the flotation of a low-copper molybdenite in Xinjiang ［J］.Gold， 2023， 44（3）： 53.

［2］Lasheen T A， El-Ahmady M E， Hassib H B， Helal A S. Molybdenum metallurgy review： hydrometallurgical routes to recovery of molybdenum from ores and mineral raw materials ［J］.Mineral Processing and Extractive Metallurgy Review， 2015， 36（3）： 145.

［3］（代淑娟， 刘子源， 胡志刚. 辽宁某含金银铜硫矿选矿试验研究 ［J］.铜业工程， 2024， （3）： 61.）

S J Dai， Z Y Liu， Z G Hu. Experimental study on beneficiation of gold and silver-bearing copper ore in Liaoning province ［J］.Copper Engineering， 2024， （3）： 61.

［4］（甘敏， 范晓慧， 张麟， 姜涛， 邱冠周， 王勇， 邓琼， 陈许玲. 低品位钼精矿氧化焙烧过程的反应行为 ［J］.中国有色金属学报， 2014， 24（12）： 3115.）

M Gan， X H Fan， L Zhang， T Jiang， Y Wang， Q Deng， X L Chen. Reaction behavior of low grade molybdenum concentrates in oxidation roasting process ［J］.The Chinese Journal of Nonferrous Metals， 2014， 24（12）： 3115.

［5］Li X B， Wu T， Zhou Q S， Qi T G， Peng Z H， Liu G H. Kinetics of oxidation roasting of molybdenite with different particle sizes ［J］.Transactions of Nonferrous Metals Society of China， 2021， 31（3）： 842.

［6］（王倩， 刘晨辉， 张利波， 高冀芸， 王访， 代莹. 微波氧化焙烧辉钼矿制备三氧化钼及机理 ［J］.中国有色金属学报， 2023， 33（6）： 2015.）

Q Wang， C H Liu， L B Zhang， J Y Gao， F Wang， Y Dai. Preparation and mechanism of molybdenum trioxide by microwave oxidation roasting of molybdenite ［J］.The Chinese Journal of Nonferrous Metals， 2023， 33（6）： 2015.

［7］（王连勇， 张井凡， 蔡九菊， 刘智凯.钼精矿无碳焙烧工艺分析 ［J］.稀有金属与硬质合金， 2013， 41（1）： 8.）

L Y Wang， J F Zhang， J J Cai， Z K Liu. Analysis for molybdenum concentrate carbon-free roasting process ［J］.Rare Metals and Cemented Carbides， 2013， 41（1）： 8.

［8］（王磊， 郭培民， 庞建明， 赵沛. 钼精矿真空分解过程中的物相及形貌变化 ［J］.稀有金属， 2016， 40（1）： 64.

L Wang， P M Guo， J M Pang， P Zhao. Phase and morphology evolution in vacuum decompsition process of molybdenum concentrate ［J］.Chinese Journal of Rare Metals， 2016， 40（1）： 64.

［9］Marin T， Utigard T， Hernandez C. Roasting kinetics of molybdenite concentrate ［J］.Canadian Metallurgical Quarterly， 2009， 48（1）： 73.

［10］Wang L， Zhang G H， Dang J， Chou K C. Oxidation roasting of molybdenite concentrate ［J］.Transactions of Nonferrous Metals Society of China， 2015， 25（12）： 4167.

［11］Wang M， Yang S P， Guo S Q， Cao S W， He K. Microwave-activated roasted molybdenum dioxide to produce low sulfur molybdenum oxide ［J］.Rare Metal Materials and Engineering， 2020， 49（1）： 48.

［12］Djellabi R， Fatafta A K. Ultrasound assisted （photo） piezocatalysis for boosted oxidation of organic pollutants： fundamentals and mechanisms ［J］.MetaResource， 2025， 2（1）： 1.

［13］（宇文超， 刘秉国， 张利波， 曲雯雯， 蒋永林. 基于多重扫描速率法的辉钼矿氧化焙烧动力学参数分析 ［J］.化学反应工程与工艺， 2018， 34（4）： 359.）

W C Yu， B G Liu， L B Zhang， W W Qu， Y L Jiang. Analysis of kinetic parameters of molybdenite oxidation roasting based on the multiple scanning rate method ［J］. Chemical Reaction Engineering and Technology， 2018， 34（4）： 359.

［14］（刘起航， 赵晓微， 田顺治， 冯卫国， 刘东新. 钼焙砂氨浸过程中钾的释放动力学研究 ［J］.稀有金属， 2024， 48（11）： 1591.）

Q H Liu， X W Zhao， S Z Tian， W G Feng， D X Liu. Release kinetics of potassium during ammonia leaching of molybdenum calcine ［J］.Chinese Journal of Rare Metals， 2024， 48（11）： 1591.

［15］（杨双平， 郭拴全， 张攀辉， 王磊， 张晓， 何凯， 厉学武， 党文静. 辉钼矿氧化焙烧动力学研究 ［J］.过程工程学报， 2016， 16（6）： 1016.）

S P Yang， S Q Guo， P H Zhang， L Wang， X Zhang， K He， W J Dang. Kinetics of moiybdenum in oxidation roasting process ［J］.The Chinese Journal of Process Engineering， 2016， 16（6）： 1016.

［16］Wilkmirsky I， Otero A， Balladares E. Kinetics and reaction mechanisms of high-temperature flash oxidationof molybdenite ［J］.Metallurgical and Materials Transactions B， 2010， 41（1）： 3.

［17］（蒋正帅， 夏飞龙， 张姗姗， 张强， 张敏. 低品位铝土矿的高效脱硫脱硅工艺研究 ［J］.有色金属科学与工程， 2022， 13（3）： 26.）

Z S Jiang， F L Xia， S S Zhang， Q Zhang， M Zhang. Study on efficient desulfurization and desilication process of low-grade bauxite ［J］.Nonferrous Metals Science and Engineering， 2022， 13（3）： 26.

［18］（符新科， 孙博， 杨猛， 韩晓波， 翟钰华， 王伟安， 李小明.钼精矿多膛炉氧化焙烧炉床底料增厚机理分析 ［J］.中国有色冶金， 2023， 52（4）： 73.）

X K Fu， B Sun， M Yang， X B Han， Y H Zhai， W A Wang， X M Li. Thickening mechanism of furance bed bottom material of multi-hearth furnace oxidation roasting for molybdenum concentrate metallurgy ［J］.China Nonferrous Metallurgy， 2023， 52（4）： 73.

［19］（杨永明， 王枝梅， 袁翠宏， 王梅， 王虹， 陈艳宏. 电感耦合等离子体发射光谱法测定铀钼合金中钼 ［J］. 分析试验室， 2023， 42（1）： 108.）

Y M Yang， Z M Wang， C H Yuan， M Wang， H Wang， Y H Chen. Determination of molybdenum content in uranium-molybdenum alloy by inductively coupled plasma emission spectrometry ［J］.Chinese Journal of Analysis Laboratory， 2023， 42（1）： 108.

［20］Kim B S， Lee H I， Choi Y Y， Kim S. Kinetics of the oxidative roasting of low grade mongolian molybdenite concentrate ［J］.Materials Transactions， 2009， 50（11）： 2669.

［21］（赵加爱， 王宏明， 陈卫文， 李桂荣， 曹磊， 刘琴杨. 低品位镍钼矿加钙焙烧及直接热还原热力学研究 ［J］. 稀有金属， 2014， 38（6）： 1114.）

J A Zhao， H M Wang， W W Chen， G R Li， L Cao， Q Y Liu. Thermodynamic analysis on direct thermal reduction process of low-grade Ni-Mo ores ［J］.Chinese Journal of Rare Metals， 2014， 38（6）： 1114.

［22］（肖超， 肖连生， 夏允， 曾理， 高从堦. MoS2-CaO-O2系热力学分析及应用 ［J］.稀有金属， 2016， 40（4）： 356.）

C Xiao， L S Xiao， Y Xia， L Zeng， C K Gao. Thermodynamic analysis of MoS2-CaO-O2 system and its application ［J］.Chinese Journal of Rare Metals， 2016， 40（4）： 356.

［23］Gan M， Fan X H， Chen X L， Wu C Q， Ji Z Y， Wang J J， Qiu G J， Jiang T. Reaction mechanisms of low-grade molybdenum concentrate during calcification roasting process ［J］.Transactions of Nonferrous Metals Society of China， 2016， 26（11）： 3015.

［24］（李小明， 翟钰华， 邹冲， 王伟安， 李彬. 钼精矿焙烧过程中杂质化合物对烧结行为的影响 ［J］.中国有色金属学报， 2024， 34（2）： 549.）

X M Li， Y H Zhai， C Zou， W A Wang， B Li. Effect of impurity compounds on sintering behavior of molybdenum concentrate during roasting process ［J］.The Chinese Journal of Nonferrous Metals， 2024， 34（2）： 549.

［25］（卜春阳， 曹维成， 王璐， 张国华， 孙国栋， 王大航， 常贺强， 宋成民， 周国治， 何凯. 辉钼矿烧结现象研究 ［J］.中国钼业， 2018， 42（1）： 8.）

C Y Bu， W C Cao， L Wang， G H Zhang， G D Sun， D H Wang， H Q Chang， C M Song， G Z Zhou， K He. Study on sintering phenomenon during the roasting processes of molybdenite by air ［J］.China Molybdenum Industry， 2018， 42（1）： 8.

［26］（王磊， 郭培民， 孔令兵， 赵沛， 田志凌. 加碳条件下钼精矿真空冶炼过程中主要杂质元素的行为分析 ［J］.中国有色金属学报， 2020， 30（2）： 438.）

L Wang， P M Guo， L B Kong， P Zhao， Z L Tian. Behavior analysis of main impurity elements in vacuum smelting of molybdenum concentrate with carbon ［J］.The Chinese Journal of Nonferrous Metals， 2020， 30（2）： 438.

Basic Information:

DOI：10.13373/j.cnki.cjrm.XY24020016

Chinese Library Classification Number:TF841.2

Citation Information:

China has abundant molybdenum resources, the majority of which are in the form of molybdenite, which has the highest industrial value. However, the grade and roasting behavior of molybdenum concentrate are different due to different subsequent flotation and pretreatment processes of molybdenum ore mined. To maintain the smooth progress of the reaction, external heat sources are still required for the industrial roasting of molybdenum concentrate. With the wide application of low-grade molybdenum concentrate, it has also brought many problems. It is simple to produce molybdate during the roasting of low-grade molybdenum concentrate, which is challenging to remove, if the temperature is too high or the roasting time is too long. The formed molybdate leads to the decrease of MoO₃ content. Low grade molybdenum concentrate has a high impurity component content, which hinders the concentrate's ability to oxidize. The phenomenon of sintering takes place during the roasting process, leading to a high rate of residual sulfur and MoO₂ in the molybdenum calcine. Therefore, in order to meet the quality of molybdenum calcine, it is necessary to analyze the roasting characteristics and calorific value of various concentrate grades. In this study, five types of molybdenum concentrates processed from different production areas were selected, and the elemental composition and microstructure of the molybdenum concentrates were characterized by inductively coupled plasma (ICP) and scanning eectron microscope (SEM）. The characteristics of oxidation and volatilization in five different grades of molybdenum concentrate during roasting process were studied by simultaneous thermogravimetry-differential scanning calorimetry-mass spectrometry (TG-DTG-DSC-MS）, and the heat release characteristics and linear equations during the roasting process of molybdenum concentrate. Coats-Redfern method was used to calculate the activation energy of different grades of molybdenum concentrate and to determine the limiting step of the reaction in the oxidation/volatilization stage. The results showed that roasting process of molybdenum concentrate was divided into three stages. In the first stage (45~400 ℃）, the moisture and flotation agents in molybdenum concentrate began to volatilize. In the second stage (400~630 ℃）, MoS₂ oxidation to produce MoO₃ and SO₂.In the third stage (630~1000 ℃）, the formed MoO₃ began to undergo significant sublimation and volatilization. While molybdenum was in a different grade during the oxidation stage, this had no bearing on the temperature at which oxidation begins and finishes. The molybdenum grade had a significant effect on the oxidation rate. When the molybdenum grade increased from 48% to 56%, the corresponding maximum oxidation rate increased from 0.065 to 0.095 mg·min⁻¹. When the roasting temperature increased from 600 to 630 ℃, the quality of concentrate with molybdenum grade of 48% increased by 6%. Due to the presence of a large amount of impurity oxides in this grade of molybdenum concentrate, which combined with SO₂ to form sulfates. The calorific value measured by low grade molybdenum concentrate calorimeter was obviously less than the theoretical calorific value. The low-grade molybdenum concentrate contained a significant amount of impurity oxides in addition to the primary MoS₂ phase. The heat released by the impurity oxides during the reaction was 500 J·g⁻¹, which was much smaller than the heat value of MoS₂ oxidation. The calorific value obtained by calorimeter, DSC integration and thermodynamic method was correlated with molybdenum grade. The calorific value equation of molybdenum concentrate calculated by thermodynamics was y=17.74x-0.029, and the fitting degree was R²=0.99. The calorific value equation measured by calorimeter was y=239.36x-7273.91, and the fitting degree was R²=0.91. The calorific value equation y=35.29x-915.05 was obtained by DCS integration, and the fitting degree was R²=0.93. In industrial production, the heat generation during roasting could be effectively predicted based on the grade of molybdenum concentrate.The sublimation/volatilization stage was mainly divided into three parts due to different mechanisms of action：first step (630~720 ℃）was MoO₃sublimate. Second step (721~870 ℃) was MoO₃ melting and volatilizing, and as a result of the eutectic reaction between the formed low melting point molybdate and MoO₃, the melting point of MoO₃ had decreased from the original 795 ℃ to about 750 ℃. At this temperature, MoO₃ melted significantly, which aggravated the volatilization of MoO₃. Third step (871~1000 ℃) was MoO₃ volatilizing and decomposition of unstable molybdate. The activation energy during the oxidation stage of different grade molybdenum concentrates was 120~135 kJ·mol⁻¹, and the control step of the reaction was interfacial chemical reaction. During the sublimation/volatilization stage, the activation energy of molybdenum grade with 51%~56% was 340~360 kJ·mol⁻¹, and the control step of the reaction was nucleation and nucleation growth, while the activation energy of molybdenum grade with 48%~49% was 238~240 kJ·mol⁻¹, and the control step of the reaction was internal diffusion. Different grades of molybdenum concentrate were used together, and the high calorific value of high grade concentrate in the early stage was used reasonably to realize the thorough oxidation reaction of low grade concentrate, so as to inhibit the volatilization and sintering of MoO₃.