Geochemical and mineralogical assessment of secondary gypsum in Al-Najaf, Iraq and employment as raw material for cement industry


Author : Mohanad R.A. Al-Owaidi, Mohammed L. Hussein, Ruaa Issa MuslimPublication : Bulletin of the Geological Society of MalaysiaNumber : 72Page : 215 - 222Year : 2021DOI : doi.org/10.7186/bgsm72202117


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Bulletin of the Geological Society of Malaysia, Volume 72, November 2021, pp. 215 - 222

Geochemical and mineralogical assessment of secondary gypsum in Al-Najaf, Iraq and employment as raw material for cement industry

Mohanad R.A. Al-Owaidi1,*, Mohammed L. Hussein2, Ruaa Issa Muslim3

1 Department of Applied Geology, College of Science, University of Babylon, 51002 Hilla, Babylon, Iraq
2 Department of Building & Construction Engineering Technologies, College of Al-Mustaqbal University, 51001 Hilla, Babylon, Iraq
3 Department of Geology, College of Science, University of Wasit, 52001 Kut, Wasit, Iraq
* Corresponding author email address: sci.mohanad.rasim@uobabylon.edu.iq

Abstract: The Portland cement industry is one of the strategic industries in any country. The basis of an industry success is the availability of raw materials and, the low extraction in addition to transportation costs. The Bahr Al-Najaf region is abundant with limestone rocks but lacks primary gypsum. An investigation had been carried out to identify the source of secondary gypsum as an alternative to primary gypsum. Twelve boreholes were drilled for a depth of 2 m, as the thickness of suitable secondary gypsum layer ranges from 1 to 1.5 m. The mineralogical study revealed the predominance of gypsum followed by quartz and calcite, with an average of 62.9%, 19.6% and 14.35%, respectively. The geochemical analysis revealed that the content of SO3 is appropriate and ranging from 41.92% to 32.89% with an average of 37.73%. The SO3 content is within an acceptable range. The mean abundance of the major oxides of the study area may be arranged as SO3 > CaO> SiO2> MgO> Al2O> Fe2O3. The insoluble residue was at an acceptable rate. The laboratory experiments for milling secondary gypsum with clinker has successfully proven the production of Portland cement that matches the limits of the Iraqi Quality Standard (IQS) No. 5 of 1984. Great care must be taken when using secondary gypsum; secondary gypsum must be mixed well to maintain the chemical properties before blending with clinker and utilizing in the cement mill in the cement plant.

Keywords: Secondary gypsum, clinker, Portland cement, Najaf

DOI: https://doi.org/10.7186/bgsm72202117