Optimization of feed blends to enhance the roasting performance of pellets made from Western Australian ultrafine magnetite concentrate
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摘要: 進行了西澳超細粒磁鐵精礦分別配加國產磁鐵精礦和巴西赤鐵精礦制備氧化球團礦的實驗研究.結果表明，以100%西澳超細磁鐵精礦為原料制備氧化球團礦時，球團預熱及焙燒性能較差，在預熱溫度為1050℃、預熱時間20 min及焙燒溫度1300℃、焙燒時間40 min的條件下，預熱球團和焙燒球團礦抗壓強度分別為每個502和2313 N.西澳超細粒磁鐵精礦配加40%國產磁鐵精礦或20%巴西赤鐵精礦時，球團適宜預熱溫度由1050℃分別降低到950和975℃，適宜的焙燒溫度由1300℃分別降低到1250和1280℃；而且焙燒球團礦的抗壓強度分別提高到每個2746 N和每個2630 N.焙燒球團礦的微觀結構研究表明：配加國產磁鐵精礦后，焙燒球團礦中Fe2O3晶粒發育優良，晶粒間互聯程度提高，晶粒粗大，孔隙率低，固結更加緊密.配加20%巴西赤鐵精礦時，焙燒球團礦中Fe2O3晶粒基本連接成片，Fe2O3晶體發育良好.優化配礦是改善西澳超細粒磁鐵精礦球團礦預熱及焙燒性能的有效途徑.Abstract: The conducted roasting tests were studied which pellets were made from blends of Western Australia ultrafine (WAU) magnetite concentrate and domestic magnetite concentrate or Brazilian hematite concentrate. The results show that the pellets made from 100% WAU magnetite concentrate exhibit inferior preheating and roasting performance under the following conditions:preheating at 1050℃ for 20 min and roasting at 1300℃ for 40 min, with compressive strengths of the preheated and fired pellets of each pellet 502 N and 2313 N, respectively. When blended 40% domestic magnetite concentrate or 20% Brazilian hematite concentrate with 60% or 80% WAU magnetite concentrate, the appropriate preheating and firing temperatures of the pellets are reduced from 1050℃ to 950℃ and 975℃, and from 1300℃ to 1250℃ and 1280℃, respectively. Moreover, the compressive strength of the fired pellets obviously improves to more than each pellet 2500 N. The microstructure of fired pellets made from WAU and domestic magnetite concentrate is characterized by fully grown Fe2O3 grains and close interlinkages among the hematite grains, which leads to low porosity and strong consolidation. In contrast, 20% Brazilian hematite concentrate blended with WAU magnetite concentrate yields nearly grown Fe2O3 grains in the fired pellets and only relatively close interlinkages between the hematite grains. The preheating and roasting performance of WAU magnetite concentrate pellets can be improved by optimizing the ore matching.
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參考文獻
[13] Yang C C, Zhu D Q, Pan J, et al. Oxidation and induration characteristics of pellets made from Western Australian ultrafine magnetite concentrates and its utilization strategy. J Iron Steel Res Int, 2016, 23(9):924 [20] Wynnyckyj J R, Fahidy T Z. Solid state sintering in the induration of iron ore pellets. Metall Trans, 1974, 5(5):991 [21] Kumar T K S, Viswanathan N N, Ahmed H M, et al. Estimation of sintering kinetics of oxidized magnetite pellet using optical dilatometer. Metall Mater Trans B, 2015, 46(2):635 [22] Zhu D Q, Yang C C, Pan J, et al. Insight into the consolidation mechanism of oxidized pellets made from the mixture of magnetite and chromite concentrates. Metall Mater Trans B, 2016, 47(2):1010 [23] German R M, Suri P, Park S J. Review:liquid phase sintering. J Mater Sci, 2009, 44(1):1 -
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