Facile purification of locally mined gypsum and its use for preparing nano-hemihydrates


  • Luqman Ayodeji ADAMS Department of Chemistry, University of Lagos, Nigeria
  • Enobong Essien Department of Chemical and Food Sciences, Bells University of Technology, Ota, Nigeria
  • Taiwo Aiyeloro Department of Chemical and Food Sciences, Bells University of Technology, Ota, Nigeria
  • Stella Oseyomon Department of Chemistry, University of Lagos, Nigeria
  • John Makanjuola Department of Dentistry, College of Medicine, University of Lagos, Nigeria


Gypsum, Hemihydrate, Retrograde solubility, Microwave energy, Purification


Gypsum has a wide range of applications, in interior decorations, building construction, supplements or implants in orthopaedics to mention a few. However, in many developing countries including Nigeria, there is still a large-scale importation despite huge available natural deposits. In this study, a facile method to purify locally-mined gypsum has been explored based on the mineral retrograde solubility in water. The purified gypsum was investigated for its elemental composition in comparison to the crude sample and a commercially obtained medical-grade gypsum using X-ray fluorescence (XRF). The results showed that the purified gypsum contained 94.05% CaSO4 compared with the crude which had a CaSO4 content of 58.10%. Hemihydrates obtained by the treatments of the purified gypsum in an oven, autoclave and microwave gave different morphologies when observed under a scanning electron microscope (SEM). Transmission electron microscopy (TEM) showed that particle sizes of all the hemihydrates were within the range 9 nm to 32 nm, but the microwave-derived sample exhibited the most desirable morphological characteristics which could impart high mechanical performance. We have reported here a new facile method for purifying gypsum ore that can have huge commercial benefits.


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How to Cite

L. A. ADAMS, E. Essien, T. Aiyeloro, S. Oseyomon, and J. Makanjuola, “Facile purification of locally mined gypsum and its use for preparing nano-hemihydrates”, J. Met. Mater. Miner., vol. 31, no. 3, pp. 106-110, Sep. 2021.



Original Research Articles