The compressive strength of pellets is of great significance for the evaluation of pellets quality indexes. In this paper, the chemical composition, mineral phase composition and microstructure of pellets were analyzed by ICPAES, XRD, OM and SEM-EDS through oxidation roasting and gas-based reduction experiments. The effect mechanism of thermal regulation on the compressive strength and reduction performance of pellets was explained by the micro-indicators such as porosity, Vickers hardness and morphological structure of pellets. The results showed that with the increase of the roasting temperature and the extension of the roasting time, the internal porosity of the oxidized pellets was reduced, while the compressive strength of the pellets was continuously improved, and the roasting temperature had a greater influence on the compressive strength. However, the increase in porosity of the reduced pellets weakened the intergranular bonding between the particles, which led to a reduction in compressive strength.
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References
1.
PrabowoSWLongbottomRJMonaghanBJet al.Phase transformations during fluidized bed reduction of New Zealand titanomagnetite ironsand in hydrogen gas. Powder Technol. 2022;398:117032–117047. DOI:10.1016/j.powtec.2021.117032.
2.
ChengGJXingZXYangHet al.Effects of high proportion unground sea sand ore on the preparation process and reduction performance of oxidized pellets. Minerals. 2021;11(1):87–103. DOI:10.3390/min11010087.
3.
WrightJBLoveringJF.Electron-probe micro-analysis of the iron–titanium oxides in some New Zealand ironsands. Min Mag. 1965;35(272):604–621. DOI:10.1180/minmag.1965.035.272.04.
4.
ParkEOstrovskiO.Reduction of titania–ferrous ore by carbon monoxide. ISIJ Int. 2003;43(9):1316–1325. DOI:10.2355/isijinternational.43.1316.
5.
XingZXChengGJGaoZXet al.Optimization of experimental conditions on preparation of oxidized pellets with New Zealand sea sand ore. Metall Res Technol. 2020;117:411–421. DOI:10.1051/metal/2020043.
6.
WangZPinsonDChewSet al.Behavior of New Zealand irons and during iron ore sintering. Metall Mater Trans B. 2016;47:330–343. DOI:10.1007/s11663-015-0519-3.
7.
XingZXChengGJYangHet al.Experimental research on preparation of oxidized pellets with high proportion sea sand mine. Vol. 10. Beijing: The 12th CSM Steel Congress; 2019. p. 1–4. DOI:10.26914/c.cnkihy.2019.058725
8.
LongbottomRJOstrovskiOParkE.Formation of cementite from titanomagnetite ore. ISIJ Int. 2006;46(5):641–646. DOI:10.2355/isijinternational.46.641.
9.
XingZXChengGJGaoZXet al.Effect of incremental utilization of unground sea sand ore on the consolidation and reduction behavior of vanadia–titania magnetite pellets. Metals (Basel). 2021;11(2):269–286. DOI:10.3390/met11020269.
10.
QinYLLingQFZhangKet al.Influence of sea sand on sintering of V–Ti–Fe concentrate – a case study from Indonesia. Minerals. 2021;11(8):793–803. DOI:10.3390/min11080793.
11.
LongbottomRJInghamBReidMHet al.In situ neutron diffraction study of the reduction of New Zealand ironsands in dilute hydrogen mixtures. Miner Process Ext Metall. 2019;128(3):183–192. DOI:10.1080/03719553.2017.1412877.
12.
ZhangAMonaghanBJLongbottomRJet al.Reduction kinetics of oxidized New Zealand ironsand pellets in H2 at temperatures up to 1443 K. Metall Mater Trans B. 2020;51:492–504. DOI:10.1007/s11663-020-01790-3.
13.
WrightJB.Iron-titanium oxides in some New Zealand ironsands. N.Z J Geol Geophys. 1964;7(3):424–444. DOI:10.1080/00288306.1964.10422094.
14.
WrightJB.Heating experiments on New Zealand ironsands and the presence of pseudobrookite. N.Z J Geol Geophys. 1967;10(3):659–665. DOI:10.1080/00288306.1967.10431084.
15.
ParkEOstrovskiO.Reduction of titania–ferrous ore by hydrogen. ISIJ Int. 2004;44(6):999–1005. DOI:10.2355/isijinternational.44.999.
16.
ParkEOstrovskiO.Effects of preoxidation of titania–ferrous ore on the ore structure and reduction behavior. ISIJ Int. 2004;44:74–81. DOI:10.2355/isijinternational.44.74.
17.
LongbottomRJMonaghanBJNightingaleSAet al.Strength and bonding in reduced ironsand-coal compacts. Ironmak Steelmak. 2013;40:381–389. DOI:10.1179/1743281212Y.0000000050.
18.
LongbottomRJMonaghanBJMathiesonJG.Development of a bonding phase within titanomagnetite-coal compacts. ISIJ Int. 2013;53:1152–1160. DOI:10.2355/isijinternational.53.1152.
19.
ZhaoYQSunTCZhaoHYet al.Effect of reductant type on the embedding direct reduction of beach titanomagnetite concentrate. Int J Miner Metall Mater. 2019;26:152–159. DOI:10.1007/s12613-019-1719-7.
20.
LiXHKouJSunTCet al.Effects of calcium compounds on the carbothermic reduction of vanadium titanomagnetite concentrate. Int J Miner Metall Mater. 2020;27:301–309. DOI:10.1007/s12613-019-1864-z.
21.
LvQWangWSJinYCet al.Influence of New Zealand sea sand proportioning ratio on metallurgical properties of vanadium-titanium-bearing sinter of Cheng steel. Iron Steel Vanadium Titanium. 2010;31(3):80–83.
22.
ZhangYPZhangJLWangZYet al.Sintering characteristics of titanium sands after grinding and its influence mechanism on the quality of sinter. Chin J Eng. 2016;38(4):468–475. DOI:10.13374/j.issn2095-9389.2016.04.004.
23.
XingZXMaJChengGJet al.Study on the high-temperature sintering characteristics and sintering mechanism of sea sand vanadium titanomagnetite based on microsintering. J Sustain Metall. 2022;8:1358–1369. DOI:10.1007/s40831-022-00570-4.
24.
LingXElliottRBaratiM.Effect of sintering and porosity development on direct reduction of manganese ore pellets. JOM. 2021;73:334–344. DOI:10.1007/s11837-020-04479-9.
25.
WuHChunTJWangPet al.Consolidation mechanism of fluxed hematite pellets. J Iron Steel Res Int. 2022;29:1526–1534. DOI:10.1007/s42243-022-00744-0.
26.
FangXHShenSBLiNet al.An innovative method to increase vanadium extraction from vanadium slag by increasing the porosity of roasted pellet. Steel Research Int. 2020;91(3):1900533–1900543. DOI:10.1002/srin.201900533.
27.
RogersBMCostaILMZhuWDet al.Sintering, hardness and cation inversion of nanocrystalline beryllium–magnesium aluminate ceramics. Ceram Int. 2022;48(11):15116–15123. DOI:10.1016/j.ceramint.2022.02.041.
28.
LiuSFLiYZWangYet al.Selective laser melting of WC-Co reinforced AISI 1045 steel composites: microstructure characterization and mechanical properties. J Mater Res Technol. 2022;19:1821–1835. DOI:10.1016/j.jmrt.2022.05.158.
29.
PanYChenSJiaYL.Enhancing the Vickers hardness, melting point and thermodynamic properties of hafnium dodecaboride. RSC Adv. 2019;9:33625–33632. DOI:10.1039/C9RA07702B.
