The Mineralogical and Chemical Composition of the Strongly Magnetic Egyptian Black Sand Altered Ilmenite
Received: 9 May 2023 | Revised: 30 May 2023 | Accepted: 6 June 2023
Corresponding author: Mohamed Ismail Moustafa
The Egyptian black sand contains several types of altered ilmenite grains which have various magnetic susceptibility values, ranging from the strongly paramagnetic, such as ilmenite, to the non-magnetic, such as rutile grains. The altered ilmenite grains of relatively higher mass magnetic susceptibility, separated at 0.1, 0.2, 0.25, and 0.35 A using the Frantz isodynamic magnetic separator, were investigated. Both brown and black altered grains were investigated using the binocular microscope and the Cameca SX-100 microprobe. Most analyzed spots of grains are composed mainly of pseudorutile (psr) and leached pseudorutile (lpsr), with the contents of TiO2 and Fe2O3 ranging between 56.76 and 78.09% and 37.98 and 12.16%, respectively. The Ti/(Ti+Fe) ratio ranges between 0.59 and 0.85. The chemical formula range of the investigated psr-lpsr is Fe2.07-0.54Ti3O9-4.68(OH)0-4.32. The lowest cationic iron content of the lpsr phase is 0.5 with a corresponding molecular formula of Fe0.5Ti3O4.5(OH)4.5. In the detected leached ilmenite spots, the cationic Fe2+ ranges between 0 and 2.46, while the cationic Fe3+ ranges between 0.17 and 1.94. The Ti/(Ti+Fe) ratio ranges between 0.51 and 0.6, and the Fe/Ti ratio ranges between 0.91 and 0.67. Considering the chemical formula of ilmenite is Fe3Ti3O9, the leached ilmenite formulas have the composition Fe2.72-2.02Ti3O9 with the minimum value of total iron being equal to 2.02. Some of the contained inclusions may be responsible for the acquired magnetic characteristics of some of the detected altered grains. The powdered X-ray diffraction patterns of the investigated different magnetic grains were detected before and after heating at 1100 oC for one hour. The hexagonal psr/lpsr structure is more unstable at 1100 oC than the tetragonal rutile structure. According to the calculations of the molecular formulas for the detected alteration phases, the lowest iron content of the altered lpsr is much lower than that previously reported. Also, during the alteration process, the alteration mechanism is changed in the region of 68-70 wt % of contained TiO2. Then, in the late alteration stages, the lpsr structure does not suddenly collapse but gradually produces other associated mineral phases.
Keywords:black sand, magnetic, nonmagnetic, leucoxene, leached ilmenite, leached pseudorutile
C. Palmer, "Arizonite, ferric metatitanate," American Journal of Science, vol. 28, pp. 353–356, Oct. 1909.
J. L. Overholt, G. Vaux, and J. L. Rodda, "The nature of ‘arizonite,’" American Mineralogist, vol. 35, no. 1–2, pp. 117–119, Feb. 1950.
L. E. Lynd, H. Sigurdson, C. H. North, and W. W. Anderson, "Characteristics of titaniferous concentrates," Mining Engineering, vol. 6, pp. 817–824, 1954.
V. T. Allen, "Is leucoxene always finely crystalline rutile?; discussion," Economic Geology, vol. 51, no. 8, pp. 830–833, Dec. 1956.
S. A. Tyler and R. W. Marsden, "The nature of leucoxene," Journal of Sedimentary Research, vol. 8, no. 2, pp. 55–58, Aug. 1938.
S. W. Bailey, R. J. Weege, E. N. Cameron, and H. R. Spedden, "The alteration of ilmenite in beach sands," Economic Geology, vol. 51, no. 3, pp. 263–279, May 1956.
S. W. Bailey and E. N. Cameron, "Is leucoxene always finely crystalline rutile?; reply," Economic Geology, vol. 52, no. 6, pp. 716–720, Sep. 1957.
M. D. Karkhanavala, A. C. Momin, and S. G. Rege, "An x-ray study of leucoxene from Quilon, India," Economic Geology, vol. 54, no. 5, pp. 913–918, Aug. 1959.
B. H. Flinter, "Malayan ilmenite vs. arizonite," Economic Geology, vol. 55, no. 5, pp. 1068–1070, Aug. 1960.
B. H. Flinter, "The alteration of Malayan ilmenite grains and the question of ‘arizonite,’" Economic Geology, vol. 54, no. 4, pp. 720–729, Jun. 1959.
L. E. Lynd, "Alteration of ilmenite," Economic Geology, vol. 55, no. 5, pp. 1064–1068, Aug. 1960.
A. K. Temple, "Alteration of ilmenite," Economic Geology, vol. 61, no. 4, pp. 695–714, Jun. 1966.
N. P. Subrahmanyam, N. K. Rao, D. Narasimhan, G. V. U. Rao, N. K. Jaggi, and K. R. P. M. Rao, "Alteration of beach sand ilmenite from Manavalakurichi: Tamil Nadu, India," Journal of Geological Society of India, vol. 23, no. 4, pp. 168-174, 1982.
A. D. Bykov, "Proarizonite as a secondary mineral due to supergene alteration of ilmenite," Doklady Akademii nauk SSSR, vol. 156, pp. 567–570, 1964.
S. R. Austin, "Ilmenite, magnetite, and feldspar alteration under reducing conditions," Economic Geology, vol. 55, no. 8, pp. 1758–1759, Dec. 1960.
J. W. Gruner, "The decomposition of ilmenite; discussion," Economic Geology, vol. 54, no. 7, pp. 1315–1316, Nov. 1959.
D. Carroll, "Ilmenite alteration under reducing conditions in unconsolidated sediments," Economic Geology, vol. 55, no. 3, pp. 618–619, May 1960.
J. A. Hartman, "The titanium mineralogy of certain bauxites and their parent materials," Economic Geology, vol. 54, no. 8, pp. 1380–1405, Dec. 1959.
F. Dimanche and P. Bartholome, "The alteration of ilmenite in sediments," Minerals Science Engineering, vol. 8, no. 3, pp. 187- 200, 1976.
M. T. Frost, I. E. Grey, I. R. Harrowfield, and C. Li, "Alteration profiles and impurity element distributions in magnetic fractions of weathered ilmenite," American Mineralogist, vol. 71, no. 1–2, pp. 167–175, Feb. 1986.
I. E. Grey and A. F. Reid, "The structure of pseudorutile and its role in the natural alteration of ilmenite," American Mineralogist, vol. 60, no. 9–10, pp. 898–906, Oct. 1975.
R. R. Anand and R. J. Gilkes, "Some alumina and silica in weathered ilmenite grains is present in clay minerals a response to Frost et al. (1983)," Mineralogical Magazine, vol. 49, no. 350, pp. 141–145, Mar. 1985.
E. F. Lener, "Mineral Chemistry of Heavy Minerals in the Old Hickory Deposit, Sussex and Dinwiddie Counties, Virginia," M.S. thesis, Virginia Tech, Blacksburg, VA, USA, 1997.
C. C. Gonçalves and P. F. A. Braga, "Heavy Mineral Sands in Brazil: Deposits, Characteristics, and Extraction Potential of Selected Areas," Minerals, vol. 9, no. 3, Mar. 2019, Art. no. 176.
A.-A. M. Abdel-Karim, S. M. Zaid, M. I. Moustafa, and M. G. Barakat, "Mineralogy, chemistry and radioactivity of the heavy minerals in the black sands, along the northern coast of Egypt," Journal of African Earth Sciences, vol. 123, pp. 10–20, Nov. 2016.
M. I. Moustafa, "Some Mineralogical Characteristics of the Egyptian Black Sand Beach Ilmenite Part I: Homogeneous Ilmenite and Titanhematite-Ferriilmenite Grains," Engineering, Technology & Applied Science Research, vol. 12, no. 6, pp. 9614–9631, Dec. 2022.
M. I. Moustafa, "Some Mineralogical Characteristics of the Egyptian Black Sand Beach Ilmenite Part IΙ: Rutile-Ilmenite and the Various Titanhematite Grains," Engineering, Technology & Applied Science Research, vol. 12, no. 6, pp. 9640–9653, Dec. 2022.
T. Chernet and L. Pakkanen, "Estimation of ferric iron, crystal water and calculation of chemical formulae for altered ilmenite from electron microprobe analyses, based on stoichiometric criteria," Geological Survey of Finland, vol. 36, pp. 23–28, 2003.
M. I. Moustafa, "Mineralogical Characteristics of the Separated Magnetic Rutile of the Egyptian Black Sands," Resource Geology, vol. 60, no. 3, pp. 300–312, 2010.
M. I. Moustafa, "Mineralogy and beneficiation of some economic minerals in the Egyptian black sands," Ph.D. dissertation, Mansoura University, Mansoura, Egypt, 1999.
A. Mucke and J. N. Bhadra Chaudhuri, "The continuous alteration of ilmenite through pseudorutile to leucoxene," Ore Geology Reviews, vol. 6, no. 1, pp. 25–44, Feb. 1991.
G. Pe-Piper, D. J. W. Piper, and L. Dolansky, "Alteration of ilmenite in the Cretaceous sandstones of Nova Scotia, southeastern Canada," Clays and Clay Minerals, vol. 53, no. 5, pp. 490–510, Oct. 2005.
M. T. Frost, I. E. Grey, I. R. Harrowfield, and K. Mason, "The dependence of alumina and silica contents on the extent of alteration of weathered ilmenites from Western Australia," Mineralogical Magazine, vol. 47, no. 343, pp. 201–208, Jun. 1983.
S. Tetsopgang, J. Koyanagi, M. Enami, and K. Kihara, "Hydroxylian pseudorutile in an adamellite from the Nkambe area, Cameroon," Mineralogical Magazine, vol. 67, no. 3, pp. 509–516, Jun. 2003.
I. E. Grey and C. Li, "Hydroxylian pseudorutile derived from picroilmenite in the Murray Basin, southeastern Australia," Mineralogical Magazine, vol. 67, no. 4, pp. 733–747, Aug. 2003.
S. S. Ahmed, M. Y. Miah, C. Qumruzzaman, M. N. Zaman, A. B. Alam, and P. K. Biswas, "Alteration and Exsolution Characteristics of Ilmenites of Moheskhali Island, Chittagong, Bangladesh," Bangladesh Journal of Scientific and Industrial Research, vol. 45, no. 1, pp. 17–26, 2010.
C. Klein and S. Hurlbut, Manual of Mineralogy, 21st Edition. New York, NY, USA: John Wiley & Sons, 1993.
R. A. Fellows, A. R. Lennie, A. W. Munz, D. J. Vaughan, and G. Thornton, "Structures of FeTiO3 (0001) surfaces observed by scanning tunneling microscopy," American Mineralogist, vol. 84, no. 9, pp. 1384–1391, Sep. 1999.
M. I. Moustafa, M. A. Tashkandi, and A. M. El-Sherif, "Detecting Mineral Resources and Suggesting a Physical Concentration Flowsheet for Economic Minerals at the Northern Border Region of Saudi Arabia," Engineering, Technology & Applied Science Research, vol. 12, no. 3, pp. 8617–8627, Jun. 2022.
How to Cite
MetricsAbstract Views: 213
PDF Downloads: 153
Copyright (c) 2023 Mohamed Ismail Moustafa
This work is licensed under a Creative Commons Attribution 4.0 International License.
Authors who publish with this journal agree to the following terms:
- Authors retain the copyright and grant the journal the right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
- Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) after its publication in ETASR with an acknowledgement of its initial publication in this journal.