Extraction 2018 pp 2869-2879 | Cite as

Molybdenite Polytypism and Its Implications for Processing and Recovery: A Geometallurgical-Based Case Study from the Bingham Canyon Mine, Utah

Conference paper
Part of the The Minerals, Metals & Materials Series book series (MMMS)


Contrary to other sulfide minerals, where recovery is principally liberation controlled, the recovery of molybdenite is more complex. It is this complexity that initiated a geometallurgical investigation of molybdenites from Bingham Canyon. The aim of this investigation was to determine the effect mineralogy and/or mineralogical attributes have on recovery. All samples were analyzed using normal mineralogical techniques. The results reveal the presence of two distinctly different types of molybdenite. These have been identified as the two polytypes of molybdenite: i.e. hexagonal (2H); and rhombohedral (3R). The 2H-polytype occurs as textbook-shaped particles in quartz-molybdenite veins that are located in the current pit bottom. The 3R-polytype occurs as disseminated, “ball”-shaped particles with a dull or frosted appearance and are concentrated along the margins of the current pit. Concerning their metallurgical behavior, each type exhibits unique metallurgical properties that are consistent with those reported in the published literature. The 2H-polytype is easily ground and kinetically “faster” floating with surface attributes that are amenable to higher rates of recovery. This results in the production of a high quality concentrate under normal operating conditions. The 3R-polytype, by comparison, is difficult to grind and kinetically “slower” floating with surface attributes that are less amenable to recovery. Therefore, in deposits with higher concentrations of the 3R-polytype, modifications to the normal operating parameters may be necessary to improve recovery. This investigation highlights the necessity for understanding the mineralogical characteristics of any economic mineral(s), as these will have a direct impact on recovery.


Molybdenite Porphyry ores Geometallurgy Ore handling Mineral processing Ore mineralogy 



The author would like to acknowledge the Management of Rio Tinto Kennecott for granting time and resource to compile and write the work in this report. Many thanks also to the many individuals throughout RTKC for the useful discussions and assistance with various matters. In particular I would like to thank Amy Lamb, Michael MacDonald, Sarah Schwarz, Tracy Smith, Ron Sorensen and Steve Whites for their valuable feedback. I would also like to thank Cameron MacArthur for preparing all of the polished blocks and Nicolas Brady for his assistance with the running and processing some of the samples on the XRD.


  1. 1.
    Newberry RJJ (1979) Polytypism in molybdenite (I): a non-equilibrium impurity-induced phenomenon. Am Miner 64:758–767Google Scholar
  2. 2.
    Dickinson RG, Pauling L (1923) The crystal structure of molybdenite. J Am Chem Soc 45:1466–1471CrossRefGoogle Scholar
  3. 3.
    Bell RE, Herfert RE (1957) Preparation and characterization of a new crystalline form of molybdenum disulfide. J Am Chem Soc 79:3351–3354CrossRefGoogle Scholar
  4. 4.
    Traill RJ (1963) A rhombohed polytype of molybdenite. Can Mineral 7:524–526Google Scholar
  5. 5.
    Frondel JW, Wickman FE (1970) Molybdenite polytypes in theory and occurrence, II. Some naturally-occurring polytypes of molybdenite. Am Miner 55:1857–1875Google Scholar
  6. 6.
    Wickman FE, Smith DK (1970) Molybdenite polytypes in theory and occurrence. I. theoretical considerations of polytypism in molybdenite. Am Mineral 55:1843–1856Google Scholar
  7. 7.
    Ayres D (1974) Distribution and occurrence of some naturally-occurring polytypes of molybdenite in Australia and Papua New Guinea. J Geol Soc Aust 21:273–278CrossRefGoogle Scholar
  8. 8.
    da Silva TP, Figueiredo M-O, de Oliveira D, Veiga JP, Batista MJ (2013) Molybdenite as a rhenium carrier: First results of a spectroscopic approach using synchrotron radiation. Journal of Minerals and Materials Characterization and Engineering 1:207–211CrossRefGoogle Scholar
  9. 9.
    Babcock RC, Ballantyne G, Phillips C (1997) Summary of the Geology of the Bingham District, Utah. In: John DA, Ballantyne G (eds) Geology and ore deposits of the Oquirrh and Wasatch Mountains, Utah. Society of Economic Geologists, Littleton, Colorado, pp 113–132Google Scholar
  10. 10.
    Seedorf E, Dilles JH, Proffett JM Jr, Einaudi MT, Zurcher L, Stavast WJA, Johnson DA, Barton MD (2005) Porphyry deposits: Characteristics and origin of Hypogene features. In: Hedenquist JW, Thompson JFH, Goldfarb RJ, Richards JP (eds) Economic Geology 100th Anniversary Volume. Society of Economic Geologists, Littleton, Colorado, pp 251–298Google Scholar
  11. 11.
    Triffett B, Veloo C, Adair BJI, Bradshaw D (2008) An investigation of the factors affecting the recovery of molybdenite in the Kennecott Utah Copper bulk flotation circuit. Miner Eng 21:832–840CrossRefGoogle Scholar
  12. 12.
    Forbes G, Bradshaw D (2007) Aspect ratio analysis of liberated molybdenite. Internal Kennecott Utah Copper Corporation Company reportGoogle Scholar
  13. 13.
    Triffett B, Bradshaw D (2008) The role of morphology and host rock lithology on the flotation behavior of molybdenite at Kennecott Utah Copper. In: Paper presented at the 9th international congress for applied mineralogy: ICAM 2008, Brisbane, Australia, 8–10 September 2008Google Scholar
  14. 14.
    Hernlund RW (1961) Extraction of molybdenite from copper flotation product. q Colo Sch Min 56:177–195Google Scholar
  15. 15.
    Sutulov A (1977) Flotation recovery of molybdenum. Can Metall Q 16:37–47CrossRefGoogle Scholar
  16. 16.
    Shirley JF (1980) Byproduct molybdenite plant design. Can Min J 27–28Google Scholar
  17. 17.
    Newberry RJJ (1979) Polytypism in molybdenite (II): relationships between polytypism, ore deposition/alteration stages and rhenium contents. Am Miner 64:768–775Google Scholar
  18. 18.
    Wanhainen C, Nigatu W, Selby D, McLeod CL, Nordin R, Bolin N-J (2014) The distribution, character, and rhenium content of molybdenite in the Aitik Cu-Au-Ag-(Mo) deposit and its southern extension in the northern Norrbotten ore district, northern Sweden. Minerals 4:788–814CrossRefGoogle Scholar
  19. 19.
    Nakhaei F, Irannajad M (2014) Investigation of effective parameters for molybdenite recovery from porphyry copper ores in industrial flotation circuit. Physicochem Probl Miner Process 50:477–491Google Scholar
  20. 20.
    Takéuchi Y, Nowacki W (1964) Detailed crystal structure of rhombohedral MoS2 and systematic deduction of possible polytypes of molybdenite. Schweiz Mineral Petrogr Mitt 44:105–120Google Scholar
  21. 21.
    Crozier RD, Ottley D (1978) Processing of copper sulphide ores: froth flotation reagents—a review. Mining Magazine 332Google Scholar
  22. 22.
    Ornelas Tabares J, Madrid Ortega I, Reyes Bahena JL, Sánchez López AA, Valdez Pérez D, López Valdivieso A (2006) Surface properties and floatability of molybdenite. Paper presented at 2006 China-Mexico Workshop on Minerals Particle Technology, San Luis Potosí, Mexico, August 2006 p 115–124Google Scholar
  23. 23.
    Zanin M, Ametov I, Grano S, Zhou L, Skinner W (2009) A study of mechanisms affecting molybdenite recovery in a bulk copper/molybdenum flotation circuit. Int J Miner Process 93:256CrossRefGoogle Scholar
  24. 24.
    Gerson AR, Smart RStC, Li J, Kawashima N, Weedon D, Triffett B, Bradshaw D (2012) Diagnosis of the surface chemical influences on flotation performance: copper sulfides and molybdenite. Int J Miner Process 16:106–109Google Scholar
  25. 25.
    Chander S, Fuerstenau DW (1974) The effect of potassium diethyldithiophosphate on the interfacial properties of molybdenite Transactions of the Institute of Mining and Metallurgy 83:180–185Google Scholar
  26. 26.
    Giles DL, Schilling JM (1972) Variation in rhenium content of molybdenite. In: Paper presented at twenty-fourth international geological congress section 10 pp 145–152Google Scholar

Copyright information

© The Minerals, Metals & Materials Society 2018

Authors and Affiliations

  1. 1.Rio Tinto Kennecott Utah CopperSouth JordanUSA

Personalised recommendations