Influence of the Moisture Content on the Flowability of Fine-Grained Iron Ore Concentrate

Authors: C. Lanzerstorfer, M. Hinterberger

Abstract:

The iron content of the ore used is crucial for the productivity and coke consumption rate in blast furnace pig iron production. Therefore, most iron ore deposits are processed in beneficiation plants to increase the iron content and remove impurities. In several comminution stages, the particle size of the ore is reduced to ensure that the iron oxides are physically liberated from the gangue. Subsequently, physical separation processes are applied to concentrate the iron ore. The fine-grained ore concentrates produced need to be transported, stored, and processed. For smooth operation of these processes, the flow properties of the material are crucial. The flowability of powders depends on several properties of the material: grain size, grain size distribution, grain shape, and moisture content of the material. The flowability of powders can be measured using ring shear testers. In this study, the influence of the moisture content on the flowability for the Krivoy Rog magnetite iron ore concentrate was investigated. Dry iron ore concentrate was mixed with varying amounts of water to produce samples with a moisture content in the range of 0.2 to 12.2%. The flowability of the samples was investigated using a Schulze ring shear tester. At all measured values of the normal stress (1.0 kPa – 20 kPa), the flowability decreased significantly from dry ore to a moisture content of approximately 3-5%. At higher moisture contents, the flowability was nearly constant, while at the maximum moisture content the flowability improved for high values of the normal stress only. The results also showed an improving flowability with increasing consolidation stress for all moisture content levels investigated. The wall friction angle of the dust with carbon steel (S235JR), and an ultra-high molecule low-pressure polyethylene (Robalon) was also investigated. The wall friction angle increased significantly from dry ore to a moisture content of approximately 3%. For higher moisture content levels, the wall friction angles were nearly constant. Generally, the wall friction angle was approximately 4° lower at the higher wall normal stress.

Keywords: Iron ore concentrate, flowability, moisture content, wall friction angle.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1129638

References:

[1] A.K. Singh, and M. Sumesh, (Eds.), Iron & Steel – Vision 2020, Nagpur: Indian Bureau of Mines, 2011.
[2] J.A. Herbst, Y.C. Lo, and B. “Flintoff, Size Reduction and Liberation,” in: Principles of Mineral Processing,, M.C. Fuerstenau, K.N. Han Eds., Englewood: Society for Mining, Metallurgy, and Exploration Inc., 2003, pp. 61-118.
[3] G. Lumay, F. Boschini, K. Traina, S. Bontempi, J.-C. Remy, R. Cloots, and N. Vandewalle, “Measuring the flowing properties of powders and grains,” Powder Technol., vol. 224, pp. 19-27, 2012.
[4] D. Schulze, Pulver und Schüttgüter. Fließeigenschaften und Handhabung, Berlin: Springer-Verlag, 2006.
[5] D. Schulze, and J. Schwedes, „Das Fließverhalten und die Silolagerung von REA-Gips,“Chem. Ing. Tech. vol. 63, no. 3, pp. 256-275, 1991.
[6] E. Teunou and J.J. Fitzpatrick, “Effect of relative humidity and temperature on food powder flowability,” J. Food Eng., vol. 42, no. 2, pp. 109-116, 1999.
[7] M.A.E. Plinke, D. Leith, R. Hathaway, and F. Löffler, “Cohesion on Granular Materials,” Bulk solids handling, vol. 14, no. 1, pp. 101-106, 1994.
[8] E. Emery, J. Oliver, T. Pugsley, J. Sharma, and J. Zhou, “Flowability of moist pharmaceutical powders,” Powder Technol., vol. 189, no. 3, pp. 409-415, 2009.
[9] J.J. Fitzpatrick, T. Iqbal, C. Delaney, T. Twomey, and M.K. Keogh, “Effect of powder properties and storage conditions on the flowability of milk powders with different fat contents,” J. Food Eng., vol. 64, no. 4, pp. 435-444, 2004.
[10] I.A.S.Z. Peschl, “Quality Control of Powders for Industrial Application,” powder handling & processing, vol. 1, no. 4, pp. 357-363, 1989.
[11] H. Rumpf, Particle Technology, New York: Chapman and Hall, 1990.
[12] J.J. Fitzpatrick, K. Barry, P.S.M. Cerqueira, T. Iqbal, J.O. Neill, and Y.H. Roos, “Effect of composition and storage conditions on the flowability of dairy powders,” Int. Dairy J., vol. 17, no. 4, pp. 383-392, 2007.
[13] A.W. Jenike, Storage and flow of solids, Bulletin 123, Engineering Experiment Station, Salt Lake City: University of Utah, 1964.
[14] D. Schulze, “Round robin test on ring shear testers,” Adv. Powder Technol., vol. 22, no. 2, pp. 197-202, 2011.
[15] ÖNORM EN ISO 8130-3, Pulverlacke; Bestimmung der Dichte mit einem Pyknometer durch Flüssigkeitsverdrängung. Wien: Austrian Standards plus, Jänner 2011.
[16] C. Lanzerstorfer, “Mechanical and flow properties of residue from dry desulphurization of iron ore sinter plant off-gas,“Environ. Eng. Sci., vol. 32, no. 11, pp. 970-976, 2015.
[17] J. Seville, U. Tüzün, and R. Clift, Processing of Particulate Solids. London: Blackie Academic & Professional, 1997.
[18] A. Rushton, A.S. Ward, and R.G. Holdich, Solid-Liquid Filtration and Separation Technology, Weiheim: VCH Verlagsgesellschaft, 1996.
[19] C. Lanzerstorfer, “Influence of the Moisture Content on the Flowability of Blast Furnace Dust,” Proc. 2nd World Congress on Mechanical, Chemical and Material Engineering (MCM'16), August 22-23, Budapest; 2016, Paper No. MMME 129.