Effect of quaternary basicity on reduction behavior of iron-bearing dust pellets  

作　　者：Tao Yang Jing-shu An Xing-wang Li Shuang Liu Xu Gao Lei Ma Jie Lei Hong-ming Long 

机构地区：[1]School of Metallurgical Engineering,Anhui University of Technology,Ma’anshan 243032,Anhui,China [2]Key Laboratory of Metallurgical Emission Reduction&Resources Recycling(Anhui University of Technology),Ministry of Education,Ma’anshan 243002,Anhui,China

出　　处：《Journal of Iron and Steel Research International》2023年第7期1356-1366,共11页

基　　金：support from the Outstanding Youth Fund of Anhui Province(Grant No.2208085J19);the National Key Research and Development Program of China(Grant No.2022YFC3901405).

摘　　要：The treatment of iron-bearing dusts and sludges by the rotary hearth furnace process has the advantage of sufficient utilization of valuable metals and a high impurity removal rate,but the lower strength of the metallized product needs to be addressed.The effects of quaternary basicity R4(w(CaO+MgO)/w(SiO_(2)+Al_(2)O_(3)))on the reduction behavior and physical and chemical properties of metallized pellets,including phase composition,compressive strength,microstructure and soft melting area,were investigated with FactSage thermodynamic software and experiments.The strength of metallized pellets depended on the gangue composition,such as CaO,MgO,Al_(2)O_(3) and SiO_(2),due to the altered chemical composition,physical phase composition,microscopic morphology and stability of the slag phase.The reduction of carbon-bearing pellets was significantly promoted by suitable basicity.The lower basicity(R_(4)<1.4)facilitated the formation of low melting point iron-containing compounds from SiO_(2) and Al_(2)O_(3) with FeO,resulting in increased liquid phase generation,but lower metallization rate,due to the hindered precipitation and growth of iron grains.Interestingly,the higher basicity(R_(4)>1.8)also increased the amount of liquid phase and improved the strength of the pellets,due to the granular iron crystals bonded into sheets.Notably,the main component of the liquid phase in high-basicity conditions was calcium ferrite.Although the additional amount of liquid phase was beneficial to the strength of the metallized pellets,calcium disilicate was formed at R_(4)=1.6,resulting in a reduction in the compressive strength of the pellets to 1521.9 N/pellet.

关 键 词：Metallurgical solid waste Iron-bearing dust Iron-bearing sludge Rotary hearth furnace Quaternary basicity Metallized pellet High-temperature performance Metallized pellet High-temperature performance 

分 类 号：X705[环境科学与工程—环境工程]