CaCO3抑制三氧化钼挥发热力学及动力学分析.pdf

第3卷第1期
特殊钢
Vol 33. No. 1
12·2012年2月
SPECIAL STEET
February 2012
CaCO3抑制三氧化钼挥发热力学及动力学分析
朱航宇李正邦杨海森刘吉刚
(钢铁研究总院冶金工艺研究所,北京100081)
摘要三氧化钼(MoO3)的挥发特性是导致Mo收得率较低的主要原因,采用CaCO3对MoO3进行稳定化处
理是抑制MoO3挥发的行之有效的方法。从热力学及动力学角度研究了CaCO3和M0O3低温固相反应。结果表
明,二者在450℃就可反应生成稳定CaMo04,600~700℃反应速率较快且MoO3未开始挥发,在此温度区间对
MoO2预处理效果较好。采用 Coats- Redfern法计算了不同升温速率下CaCO。和Mo03固相反应动力学参数,活化
能(E)和指前因子(A)分别为167.45kJ/mol、1.,22×107s',速率常数ん=1.22×10xexp(-20140/T)。
关键词碳酸钙三氧化钼抑制挥发热力学动力学
An Analysis on Thermodynamics and Kinetics of Volatilization of
Molybdenum Trioxide Inhibited by Caco
Department of Metallurgical Technology, Central lion ng Haisen and Liu Jigang
gyu
and Steel Research Institute, Beijing 100081)
Abstract The volatilization characteristic of molybdenum trioxide(Mo is the main reason led to low yield of Mo
Ao0 stabilizing-treated by Cao is an effective way to inhibit the volatilization of Moo,. The low-temperalure
solid phase reaction between Mo, and Ca(O has been studied according to thermodynamics and kinetics law. Results
show that Moo, and Caco may react at 450 to form stable Camo, the reaction is faster at 600-700C and there is
no volatilization of Moo, therefore it is available to pre-treated Moo, at the temperature range. The Caco, and Moo, solid
phase reaction kinetics parameters at different heating speed are calculated by Coats-redfern function, the activation energy
(E)and pre-exponential factor(A )are respectively 167. KJ/mol and 1. 22 s, and the reaction rate constant k
22x107xexp(-20140
Material Index Calcium Carbonate, Molybdenum Trioxide, Inhibiting latinization, Thermodynamics, Kinetics
由于三氧化钼和钼酸钙较钼铁在价格上的优磨并采用飞利浦APD-10型X射线衍射仪进行物相
势,用之代替钼铁作为添加剂冶炼含钼合金钢在20及成分的半定量分析。
世纪80年代国内已有相关研究-?,但钥的收得率
热重实验部分采用HTC-1/2热重分析仪记录不
较低末得到广泛应用。国外治炼含钼合金钢的添加同升温速率下CaCO和MoO3的固相反应情况。各
剂主要有3种:钼铁、钼酸钙以及三氧化钼和沥青粘实验样品成分组成及反应后失重见表1。
结剂压制成的煤基三氧化钼块
表1试验样品组成及反应后失重
还原,因此炼钢过程中直接加入碳酸钙和三氧化,xup
1 Ingredient of test samples and mass loss after re-
或对碳酸钙和三氧化钼进行预处理使之生成钼酸
组成/%
编号
质量/温度
失重/
钙,利用钢液还原钼酸钙生产含钼合金钢也是行之有
Caco]
g
效的方法。碳酸钙抑制氧化钼挥发本质上是利用
者低温固相反应生成不易挥发且易被还原的钼酸钙
T-359.0240.983.
T459.0240.983.0
从而达到冶炼含钼合金钢的目的。
59.02
T-6
1实验材料及方法
980.0925~]20018.1
1000.00825~120042.5
M0O3和CaCO3均为AR级试剂,200℃烘烤12
TG-3100-0.00725~120087.7
h后按摩尔比1:1配料并在研钵中研磨混合均匀
混匀后样品分别置于瓷坩埚内,待马弗炉升至2热力学数据计算
试验温度放人样品,恒温30min,反应后的混合物研
碳酸钙和三氧化钼固相反应方程式为: