((華中科技大學(xué) 環(huán)境科學(xué)與工程學(xué)院，武漢 430074))
摘 要: 以拜耳法赤泥為原料，經(jīng)直接還原焙燒−磁選回收鐵，磁選殘?jiān)糜谏a(chǎn)建筑材料。該赤泥中的氧化鐵含量27.93%，并以赤(褐)鐵礦為主要存在狀態(tài)。在探討了焙燒溫度、焙燒時(shí)間、炭粉及添加劑用量等因素對(duì)實(shí)驗(yàn)結(jié)果影響的基礎(chǔ)上，得出較理想的焙燒條件。在該條件下，經(jīng)磨細(xì)磁選后所得精礦中，總鐵含量89.05%，金屬化率96.98%，回收率81.40%，可用作海綿鐵。磁選殘?jiān)鼡饺胂医?jīng)壓力成形、蒸汽養(yǎng)護(hù)，試件抗壓強(qiáng)度可以達(dá)到24.10 MPa，可用于生產(chǎn)蒸養(yǎng)磚等建材。殘?jiān)谡麴B(yǎng)前后主要礦物組成由霞石轉(zhuǎn)化為鈣鋁黃長(zhǎng)石，熱力學(xué)分析證明了在實(shí)驗(yàn)條件下該反應(yīng)發(fā)生的可能性。
關(guān)鍵字: 拜耳法赤泥；鐵回收；建材；綜合利用
（(School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China)）
Abstract:Recovery of iron was investigated from red mud (RM) with direct reduction roasting process followed by magnetic separation, and building materials were prepared from residues from magnetic separation process. The effects of different parameters on recovery efficiency of ferrous were studied. The optimum reaction parameters were obtained. The results show that the content of Fe2O3 in RM is 27.93%, and hematite and limonite are the major crystalline phase. With the optimum parameters the content of iron in the magnetic separated part is 89.05%, the metallization ratio is 97.69% and the recovery ratio is 81.40%. Construction bricks can be prepared from the residues with the addition hydrated lime followed by mould in a hydraulic machine, and cured with an autoclaved steam. The mean compressive strength of the brick specimens is 24.10 MPa. Main mineral phases are transformed from nepheline in residues to gehlenite in the autoclaved brick specimens. The feasibility of the mineral phase transformation under the experimental conditions is proved by thermodynamics calculation analysis.
Key words: red mud; Bayer process; iron recovery; building materials; comprehensive utilization
