Document Type : Original Research Paper


1 Mining Engineering Department, Engineering Faculty, Sahand University of Technology, Tabriz, Iran

2 Mining Engineering Department, Engineering Faculty, Urmia University, Urmia, Iran


Structural changes of mechanically-activated ilmenite during milling by a planetary mill are monitored and determined as a function of the milling time. The maximum specific BET surface area of 10.76 m2/g is obtained after 150 min of milling. The results obtained indicate that agglomeration of the particles occurs after 45 min of milling. The maximum X-ray amorphization degree of ca. 95% has been calculated after 150 min of milling. Estimation of the stored energy reveals that the X-ray amorphization degree has a dominant contribution to the excess enthalpy of the activated materials. The surface-weighted crystallite size in the ground ilmenite reaches 4.45 nm, which corresponds to the volume-weighted crystallite size of 8 nm and 11.18 nm obtained by the Williamson-Hall and Rietveld methods, respectively. After 150 min of mechanical activation, the root mean square strain, , increases to 0.78%, which corresponds to the strains of 1.43% and 1.04% obtained from the Williamson-Hall and Rietveld methods, respectively. Reduction in the crystallite size leads to the contraction of the ilmenite unit cell after 150 min. The reaction rate constant of the ilmenite dissolution increases by over 58 times after 150 min of milling. Activation energy of the dissolution reaction decreases from 57.45 kJ/mol to 41.09 kJ/mol after 150 min of milling.


[1]. Lin I. (1998). Implications of fine grinding in mineral processing mechanochemical approach. Journal of thermal analysis and Calorimetry. 52 (2):453-61.
[2]. Baláž P. (2000). Extractive metallurgy of activated minerals: Elsevier.
[3]. Boldyrev V., Tkáčová K (2000). Mechanochemistry of solids: past, present, and prospects. Journal of materials synthesis and processing. 8 (3-4):121-32.
[4]. Tkáčová K. (1989). Mechanical activation of minerals: Veda.
[5]. Welham N. and Llewellyn D. (1998). Mechanical enhancement of the dissolution of ilmenite. Minerals Engineering. 11 (9):827-41.
[6]. Chen Y., Williams J., Campbell S., and Wang G. (1999). Increased dissolution of ilmenite induced by high-energy ball milling. Materials Science and Engineering: A. 271 (1-2):485-90.
[7]. Li C., Liang B., Guo L-h, and Wu Z-b. (2006). Effect of mechanical activation on the dissolution of Panzhihua ilmenite. Minerals Engineering. 19 (14):1430-8.
[8]. Li C., Liang B., Wang H. (2008). Preparation of synthetic rutile by hydrochloric acid leaching of mechanically activated Panzhihua ilmenite. Hydrometallurgy. 91 (1-4):121-9.
[9]. Sasikumar C., Rao D., Srikanth S., Mukhopadhyay N., and Mehrotra S. (2007). Dissolution studies of mechanically activated Manavalakurichi ilmenite with HCl and H2SO4. Hydrometallurgy. 88 (1-4):154-69.
[10]. Sasikumar C., Rao D., Srikanth S., Ravikumar B., Mukhopadhyay N., and Mehrotra S. (2004). Effect of mechanical activation on the kinetics of sulfuric acid leaching of beach sand ilmenite from Orissa, India. Hydrometallurgy. 75 (1-4):189-204.
[11]. Zhang L., Hu H., Wei L., Chen Q., and Tan J. (2010). Hydrochloric acid leaching behaviour of mechanically activated Panxi ilmenite (FeTiO3). Separation and Purification Technology. 73 (2):173-8.
[12]. Zhang L., Hu H., Wei L., Chen Q., and Tan J. (2010). Effects of mechanical activation on the HCl leaching behavior of titanaugite, ilmenite, and their mixtures. Metallurgical and Materials Transactions B. 41 (6):1158-65.
[13]. Pourghahramani P. and Forssberg E. (2006). Comparative study of micro-structural characteristics and stored energy of mechanically activated hematite in different grinding environments. International Journal of Mineral Processing. 79 (2):120-39.
[14]. Pourghahramani P. and Azami M.A. (2015). Mechanical activation of natural acidic igneous rocks for use in cement. International Journal of Mineral Processing. 134:82-8.
[15]. Senna M. (1989). Determination of effective surface area for the chemical reaction of fine particulate materials. Particle and Particle Systems Characterization. 6 (1-4):163-7.
[16]. Krumm S., editor WINFIT 1.2: version of November 1996 (The Erlangen geological and mineralogical software collection) of “WINFIT 1.0: a public domain program for interactive profile-analysis under WINDOWS”. XIII Conference on clay mineralogy and petrology, praha; 1994.
[17]. Langford J.I. and Wilson A. (1978). Scherrer after sixty years: a survey and some new results in the determination of crystallite size. Journal of Applied Crystallography. 11 (2):102-13.
[18]. Pourghahramani P. and Forssberg E. (2006). Micro-structure characterization of mechanically activated hematite using XRD line broadening. International Journal of Mineral Processing. 79(2):106-19.
[19]. Warren B.E. (1969). X-ray Diffraction: Courier Corporation.
[20]. Bourniquel B., Sprauel J., Feron J., and Lebrun J., editors. (1989). Warren-Averbach Analysis of X-ray Line Profile (even truncated) Assuming a Voigt-like Profile. International Conference on Residual Stresses. Springer.
[21]. Rietveld H. (1969). A profile refinement method for nuclear and magnetic structures. Journal of applied Crystallography. 2 (2):65-71.
[22]. Young R. Editor. (1993). The Rietveld Method. Oxford University Press.
[23]. T. Degen MS, E. Bron, U. König, G. Nénert. (2014). The High-score suite. Powder Diffraction Volume 29 (Supplement S2):S13-S8.
[24]. Pourghahramani P. and Akhgar B. (2015). Characterization of structural changes of mechanically activated natural pyrite using XRD line profile analysis. International Journal of Mineral Processing. 134:23-8.
[25]. Li J. and Hitch M. (2016). Characterization of the micro-structure of mechanically-activated olivine using X-ray diffraction pattern analysis. Minerals Engineering. 86:24-33.
[26]. Balzar D. (1999). Voigt-function model in diffraction line-broadening analysis. International union of crystallography monographs on crystallography. 10:94-126.
[27]. Suryanarayana C, Norton MG. (1998). X-ray diffraction: a practical approach.. New York, Plenum Publishing Corporation.
[28]. Holland T. and Redfern S. (1997). Unit cell refinement from powder diffraction data: the use of regression diagnostics. Mineralogical Magazine. 61 (1):65-77.
[29]. Schubert E.F. (2015). Doping in III-V semi-conductors: E. Fred Schubert.
[30]. Kumar R., Bakshi S., Joardar J., Parida S., Raja V., and Singh Raman R. (2017). Structural Evolution during Milling, Annealing, and Rapid Consolidation of Nano-crystalline Fe–10Cr–3Al Powder. Materials. 10 (3):272.
[31]. Qin W., Nagase T., Umakoshi Y., and Szpunar J. (2007). Lattice distortion and its effects on physical properties of nanostructured materials. Journal of Physics: Condensed Matter. 19 (23):236217.
[32]. Cammarata R.C. and Sieradzki K. (1994). Surface and interface stresses. Annual Review of Materials Science. 24 (1):215-34.
[33]. Nazarov A., Romanov A., and Valiev R. (1996). Random disclination ensembles in ultrafine-grained materials produced by severe plastic deformation. Scripta materialia. 34 (5):729-34.
[34]. Tromans D. and Meech J. (2001). Enhanced dissolution of minerals: stored energy, amorphism and mechanical activation. Minerals Engineering. 14 (11):1359-77.
[35]. Wagner M. (1992). Structure and thermodynamic properties of nano-crystalline metals. Physical Review B. 45 (2):635.
[36]. Chattopadhyay P., Nambissan P., Pabi S., and Manna I. (2001). Polymorphic bcc to fcc transformation of nano-crystalline niobium studied by positron annihilation. Physical Review B. 63 (5):054107.
[37]. Ohlberg S. and Strickler D. (1962). Determination of percent crystallinity of partly devitrified glass by X-ray diffraction. Journal of the American Ceramic Society. 45(4):170-1.
[38]. Sasikumar C., Srikanth S., Mukhopadhyay N., and Mehrotra S. (2009). Energetics of mechanical activation–Application to ilmenite. Minerals Engineering. 22 (6):572-4.
[39]. Avrami M. (1939). Kinetics of phase change 1. J Chem Phy. 7:1103.