(西安建筑科技大學(xué) 冶金工程學(xué)院，西安 710055)
摘 要: 針對鐵以鐵橄欖石形式存在而難以直接還原磁選回收的問題，采用在鎳渣中配加CaO提升鎳渣碳熱還原速率及鐵金屬化率的技術(shù)思路。將添加劑與鎳渣按比例混合并配加適量還原劑后，在高溫爐中進(jìn)行還原，結(jié)合熱力學(xué)計算及產(chǎn)物特征分析結(jié)果，研究添加劑強(qiáng)化還原的機(jī)理及還原效果。結(jié)果表明：CaO的加入有效促進(jìn)了硅酸鐵的解離，強(qiáng)化了還原過程，還原速率加快，金屬相在渣相中的形態(tài)結(jié)構(gòu)發(fā)生改變，金屬鐵的聚集長大明顯，有利于后續(xù)分離回收。隨著CaO添加量由0增加到10 %(質(zhì)量分?jǐn)?shù))，還原產(chǎn)物的金屬化率和Fe顆粒平均粒徑呈先增大后減小的趨勢，F(xiàn)eO含量和殘?zhí)剂孔兓?guī)律相反。在CaO添加量為8 %時，還原產(chǎn)物中鐵的金屬化率和粒徑達(dá)到峰值，分別為87.25%和41.3 μm。
關(guān)鍵字: 鎳渣；氧化鈣；碳熱還原；添加劑
（School of Metallurgical Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, China）
Abstract:Aiming at the problem that iron exists in the form of fayalite and the difficulty in direct reduction of the magnetic separation and recovery, the technical idea for adding CaO in nickel slag to improve the carbothermal reduction rate and iron metallization rate of nickel slag was used. The additive and the nickel slag were mixed in proportion and added with an appropriate amount of reducing agent, and they were reduced in a high temperature furnace. Combined with the thermodynamic calculation and product characteristic analysis results, the mechanism and the reduction effect of the additive strengthening reduction were studied. The results show that the addition of CaO can effectively promote the dissociation of iron silicate, strengthen the reduction process, accelerate the reduction rate, change the morphology of the metal phase in the slag phase, and increase the aggregation of metallic iron, which is beneficial for subsequent separation and recovery. As the amount of CaO increases from 0% to 10%, the metallization rate of the reduction product and the average particle size of Fe particles increases first and then decreases, with the changes of FeO content and residual carbon amount being opposite. The added amount of CaO being 8%, the metallization ratio and particle diameter of iron in the reduced product peak at 87.25% and 41.3 μm, respectively. With the added amount of CaO being 8%, the metallization rate and particle diameter of iron in the reduction products peak at 87.25% and 41.3 μm, respectively.
Key words: nickel slag; calcium oxide; carbothermal reduction; additive
