Investigations on the microwave absorption properties and thermal behavior of vanadium slag: Improvement in microwave oxidation roasting for recycling vanadium and chromium

JOURNAL OF HAZARDOUS MATERIALS

卷:395

Article

Li, Kangqiang¹  Jiang, Qi¹  Gao, Lei²  Chen, Jin¹  Peng, Jinhui^1,2  Koppala, Sivasankar³  Omran, Mamdouh⁴  Chen, Guo^1,2,3 

[1] Kunming Univ Sci & Technol, Key Lab Unconvent Met, Minist Educ, Kunming 650093, Yunnan, Peoples R China

[2] Yunnan Minzu Univ, Key Lab Green Chem Mat Univ Yunnan Prov, Kunming Key Lab Energy Mat Chem, Kunming 650500, Yunnan, Peoples R China

[3] Dalian Univ Technol, Panjin Inst Ind Technol, Panjin 124221, Liaoning, Peoples R China

[4] Univ Oulu, Fac Technol, Proc Met Res Grp, Oulu, Finland

关键词: Vanadium slag;    Chromium;    Microwave absorption properties;    Thermal behavior;    Microwave oxidation roasting;   

DOI  :  10.1016/j.jhazmat.2020.122698

来源: Elsevier

【 摘 要 】

Vanadium slag contains high contents of vanadium and chromium with complex and dense structures, hence microwave heating instead of conventional methods is expected to destroy the dense structure and further to improve the extraction rate of vanadium and chromium, and exploring its dielectric properties is the prerequisite work. Microwave absorption properties and thermal behavior of vanadium slag were investigated. Results indicated that vanadium slag endowed excellent microwave absorption properties, with minimum epsilon(r)' value of 34.447 (F/M). Dielectric properties of vanadium slag varied with temperature, which changing trend was matched to the three stages of microwave heating characteristics identified by heating rates. Meanwhile, the changing process of dielectric properties also corresponded to the three processes of thermogravimetric characteristics: dehydration stage (30 degrees C-280 degrees C), oxidation decomposition of olivine phase and normal spinel phase (280 degrees C-650 degrees C), and oxidation decomposition of vanadium chromium spinel (650 degrees C-950 degrees C). Moreover, the maximum dielectric constant and highest microwave heating rate of vanadium slag both appeared at the temperature regime of 500 degrees C-550 degrees C, which was also the main temperature regime for oxidation decomposition of olivine phase and normal spinel phase in vanadium slag, demonstrating the appropriate process temperature for microwave heating technology to recycle vanadium slag.

【 授权许可】

Free