废Mo-Ni催化剂焙烧的热力学分析  

Thermodynamic Analysis on Roasting of Spent Mo-Ni Catalyst

作　　者：黄少波[1] 陈星宇[1] 张文娟[1] 赵中伟[1] 

机构地区：[1]中南大学冶金与环境学院,湖南长沙410083

出　　处：《稀有金属》2015年第12期1115-1122,共8页Chinese Journal of Rare Metals

基　　金：国家自然科学基金项目(U1402274)资助

摘　　要：废加氢脱硫类催化剂中常包含一定量的硫和积碳,这些硫化物以及积碳会给废催化剂中有价金属回收造成极大困难,因此工业上和研究中往往在提取金属之前,采用空气氧化焙烧法对废催化剂进行预处理。针对废Mo-Ni催化剂在焙烧中可能生成NiMoO_4,NiAl_2O_4等复合氧化物的问题,本文对Mo-Ni-S-O系、Al-Ni-S-O系、Al-Mo-Ni-S-O系的热力学平衡图进行了绘制。Mo-Ni-S-O系热力学平衡图表明,高SO_2分压条件下（lg（pSO_2/pθ）=-2）,生成NiMoO_4的起始温度为700~790℃,而低SO_2分压下（lg（pSO_2/pθ）=-4）,生成NiMoO_4的起始温度则为530~580℃。Al-Ni-S-O系热力学平衡图表明,高SO_2分压下（lg（pSO_2/pθ）=-2）,生成NiO·Al_2O_3的起始温度为620~660℃,而低SO_2分压下（lg（pSO_2/pθ）=-4）,生成NiO·Al_2O_3的起始温度则为530~560℃。Al-Mo-Ni-S-O系热力学平衡图表明,焙烧温度低于530℃时,NiMoO_4较NiO·Al_2O_3更稳定,焙烧生成的复合氧化物主要为NiMoO_4,而温度高于530℃时,生成的复合氧化物为主要NiO·Al_2O_3。在采用空气氧化焙烧时,焙烧温度应低于530℃,也可采用高SO_2浓度的硫酸化焙烧工艺。Spent hydrodesulfurization （HDS） catalyst always contains deposited coke and sulfur, which is harmful to metal recovery process. So, roasting in air is commonly employed to remove coke and sulfides prior to leaching process. To avoid the generation of mixed oxides like NiMoQ and NiAI：O4 in the roasting of spent Mo-Ni catalyst, predominance diagrams of Mo-Ni-S-O, A1-Ni-S-O and A1-Mo-Ni-S-O systems at 500 and 600 ℃ were prepared in this work. It was indicated from the thermodynamic equilibrium diagram of Mo-Ni-S-O system that the initial NiMoQ generation temperature was 700 - 790℃ at high partial pressure of SO2 （ lg（Pso2/p0 ） =- 2 ） and 530 - 580 ℃ at low partial pressure of SOz （lg（Pso2/p0） =-4）. For AI-Ni-S-O system, initial NiO Al2O3 forming temperature was 620 -660 ℃ at lg（Pso2/p0） =-2 and 530 - 560 ℃ at lg（Pso2/p0） =- 4. The predominance diagram of A1-Mo-Ni-S-O system showed that NiMoO4 was more stable than NiO Al2O3 , NiMoO4 was the main mixed oxide when the roasting temperature was less than 530 ℃. In short, thermodynamic analysis suggested that calcination temperature should be lower than 530℃ in practical roasting in air. Additionally, higher SO2 concentration would be in favor of oxidizing roasting.

关 键 词：废催化剂 多金属 优势区域图 硫化物焙烧 复合氧化物 

分 类 号：TF111.31[冶金工程—冶金物理化学]