Study on Evolution of Phase Precipitation in High Aluminum Slags

doi:10.12068/j.issn.1005-3026.2018.07.017

Abstract

Abstract: To improve the leaching performance of high alumina slags， DSC and SEM-EDS analyses were employed to study the phase precipitation behaviors of high alumina slags during solidification with controlled cooling rates. The effects of cooling rate，n(CaO)/n(Al₂O₃) and MgO content on the evolution of phase precipitation were discussed. The results show that when the cooling rate increases， the solidification process tends to have severer segregation， the C₂S phase transformation becomes more insufficient and the particle turns obviously coarse， so that the self-pulverization and leaching performance deteriorate. With the increase of n(CaO)/n(Al₂O₃) in the slags， the precipitation temperature of C₁₂A₇ rises and the activities of precipitation phases increase gradually as CA→C₁₂A₇→C₃A. When the slags contains MgO， the phase of C₂MS₂ appears， which is detrimental to the phase transition of C₂S. More importantly， MgO enriching in aluminum-bearing phase leads to the formation of Q phase， which deteriorates greatly the leaching and recovery rate of alumina.

Key words: high aluminum slag, phase precipitation, cooling rate, n(CaO)/n(Al₂O₃), MgO content

CLC Number:

TF821

LI Qiang， PAN Tao， ZHANG Han-yang， DING Hao. Study on Evolution of Phase Precipitation in High Aluminum Slags[J]. Journal of Northeastern University Natural Science, 2018, 39(7): 995-999.

References

[1]袁致涛，高太，印万忠，等.我国难选铁矿石资源利用的现状及发展方向［J］.金属矿山，2007，10(1):1-6.(Yuan Zhi-tao，Gao Tai，Yin Wan-zhong，et al.Status quo and development orientation of China’s refractory ore resource utilization ［J］.Metal Mine，2007，10(1):1-6.)
[2]Privastava S M，Pan S K，Prasad N，et al.Characterization and processing of iron ore fines of Kiriburu deposit of lndia ［J］.International Journal of Mineral Processing，2001，61(2):93-107.
[3]Rao K H，Narasimhana K S.Selective flocculation applied to Barsuan iron ore tailings ［J］.International Journal of Mineral Processing，1985，14(1):67-75.
[4]Ravishankar S A，Pradip M G，Deo R，et al.Selective flocculation of iron oxide-kaolin mixtures using a modified polyacrylamide flocculent ［J］.Bulletin of Materials Science，1988，10(5):423-433.
[5]Sarkar B，Das A，Roy S，et al.In depth analysis of alumina removal from iron ore fines using teetered bed gravity separator ［J］.Mineral Processing & Extractive Metallurgy，2008，117(1):48-55.
[6]Ercaj E，Apak R.Furnace smelting and extractive metallurgy of red mud:recovery of TiO₂，A1₂O₃ and pig iron ［J］.Journal of Chemical Technology and Biotechnology，1997，70(3):241-246.
[7]李强，张作良，邹宗树.一种复杂难选铝铁共生矿熔融分离方法:0076400.7［P］.2013-05-08.(Li Qiang，Zhang Zuo-liang，Zou Zong-shu.A method for combining ironmaking with alumina recovery based on a novel iron bath smelting reduction process with thick slag for alumina-rich iron ore:0076400.7［P］.2013-05-08.)
[8]Zhang Z L，Li Q，Zou Z S.Reduction properties of high alumina iron ore cold bonded pellet with CO-H₂ mixtures ［J］.Ironmaking and Steelmaking，2014，41(8):561-567.
[9]张作良，李强，李明明，等.气基预还原处理高铝铁矿石［J］.东北大学学报(自然科学版)，2013，34(4):556-559.(Zhang Zuo-liang，Li Qiang，Li Ming-ming，et al.Treatment of high aluminium content iron ore by gas based prereduction［J］.Journal of Northeastern University(Natural Science)，2013，34(4):556-559.)
[10]李承志，何奕波，李强，等.厚渣层熔融还原铁浴混合特性的物理模拟［J］.东北大学学报(自然科学版)，2014，35(9):1266-1270.(Li Cheng-zhi，He Yi-bo，Li Qiang，et al.Physical simulation of fluid mixing in a smelting reduction iron bath with thick slag layer［J］.Journal of Northeastern University(Natural Science)，2014，35(9):1266-1270.)
[11]He Y B，Tang B，Li Q，et al.Comprehensive static model of an iron bath smelting reduction process with thick slag for alumina-rich iron ore［J］.ISIJ International，2015，55(10):2135-2144.
[12]Bredig M A.Polymorphism of calcium orthosilicate ［J］.Journal of the American Ceramic Society，1950，33(2):188-192.
[13]孙会兰.12CaO·7Al₂O₃和γ-2CaO·SiO₂渣系氧化铝溶出性能及机理的研究［D］.沈阳:东北大学，2008.(Sun Hui-lan.Study on leaching performance and mechanism of slag system of 12CaO·7Al₂O₃andγ-2CaO·SiO₂［D］.Shenyang:Northeastern University，2008.)