(上海大學(xué) 上海市現(xiàn)代冶金與材料制備重點(diǎn)實(shí)驗(yàn)室，上海 200072)
摘 要: 采用熱重分析、X射線衍射、掃描電鏡和光學(xué)顯微鏡等技術(shù)對(duì)攀枝花預(yù)氧化鈦精礦的H2還原行為進(jìn)行研究，包括H2還原反應(yīng)的動(dòng)力學(xué)、還原產(chǎn)物的物相轉(zhuǎn)變及顯微結(jié)構(gòu)的變化規(guī)律。結(jié)果表明：預(yù)氧化鈦精礦在1 100 ℃還原80 min后還原度達(dá)到96.04%；在溫度為1 000 ~1 150 ℃范圍內(nèi)，還原過程受界面化學(xué)反應(yīng)控制，表觀活化能為95.25 kJ/mol。在還原過程中將會(huì)形成M3O5型(M=Ti, Fe, Mg等)固溶體，導(dǎo)致還原難度加大。顯微結(jié)構(gòu)表明，還原反應(yīng)由顆粒邊緣向內(nèi)部進(jìn)行，而Mg元素在未反應(yīng)內(nèi)核的富集阻礙了預(yù)氧化鈦精礦的進(jìn)一步還原。
關(guān)鍵字: 預(yù)氧化鈦精礦；H2；還原；動(dòng)力學(xué)；物相；顯微結(jié)構(gòu)
（Shanghai Key Laboratory of Modern Metallurgy and Materials Processing, Shanghai University, Shanghai 200072, China）
Abstract:Reduction behavior of Panzhihua pre-oxidized ilmenite in hydrogen atmospheres, such as reduction kinetic, phase transformation and microstructures of reduced products was investigated by thermo-gravimetric，X-ray diffractometry (XRD), scanning electron microscopy (SEM), and optical microscopy. The results show that the reduction degree reaches 96.04% when the pre-oxidized ilmenite concentrates are reduced at 1 100 ℃ for 80 min and the reduction reaction is controlled by interfacial chemical reaction with the activation energy of 95.25 kJ/mol at 1 000-1 150 ℃. The M3O5 (M is Fe, Ti, Mg, etc) solid solution forms in the reduction process, in which the reduction difficulty increases. Microstructure analysis shows that the reaction takes place from the exterior of the grain to its interior and the enrichment of Mg in the unreacted area restricts the further reduction of pre-oxidized ilmenite.
Key words: pre-oxidized ilmenite; hydrogen; reduction; kinetics; phase; microstructure
