Enhancing Gold Assaying Crucibles in Ghana: Optimizing Fosu Clay Grog with Sintered Mullite for Improved Performance

Abstract:

Due to material and structural issues, fire-assaying crucibles used for analyzing precious metals in ores have encountered challenges related to poor thermal cycling in Ghana’s sub-Saharan region. This study aimed to enhance the crucibles by analyzing aluminosilicate minerals' multiphase development using X-ray diffraction and understanding the effects of composition determined by X-ray fluorescence on thermal behavior and water absorption observed through optical microscopy. The improved crucible design exhibited enhanced thermal cycling stability and lower permeability to the assay charge. Analysis showed that Fosu Clay (FC) demonstrated promise with a favorable Al₂O₃:SiO₂ ratio and low impurities; mullite was identified as the primary phase formed at high temperatures, with quartz and cristobalite also present. Introducing 6% CSM dopant to FC increased the mullite content while supporting the transformation from quartz to cristobalite. The optimal crucible sample included coarse and fine-doped grog with an FC-clay binder, demonstrating excellent thermal stability, adequate porosity, and water absorption. Adjusting the percentage of doped grog further increased mullite content while reducing silica content; this suggests that locally produced improved crucibles are feasible through sintering commercial clay with mullite doping and precise composition adjustments.

• Periodical: International Journal of Engineering Research in Africa (Volume 70)
• Pages: 53-68
• DOI: https://doi.org/10.4028/p-Ez8uQF
• Online since: July 2024
• Authors: Yong Dan Hou*, Lemuel Gbologah, Derrick Boateng Asante, Parpah Senanu Kwawukume
• Keywords: Coarse Grog Size, Crucible, Grog, Mullite, Phase Development, Thermal Cycling

References

[1] E. E. Bugbee, A Textbook of Fire Assaying, in: John Wiley and Sons, Inc. London, 1922.

[2] Y. Hou, L. Gbologah, D. B. Asante, and P. S. Kwawukume, Compositional and Structural Deficiencies Causing Failure of Local Fire Assaying Crucibles in Ghana, International Journal of Engineering Research in Africa, 51 (2020) 57–70.

DOI: 10.4028/www.scientific.net/jera.51.57

[3] J. Shi, H. Xu, F. Shu, M. Ren, and Z. Lu, A PCA-Based Method for Remanufacturing Process Optimization from Sustainability Aspect, International Journal of Industrial Engineering: Theory, Applications and Practice, 30 (2023) 986-998.

[4] H. J. Kleebe, F. Siegelin, T. Straubinger, and G. Ziegler, Conversion of Al2O3-SiO2 Powder Mixtures to 3:2 Mullite Following the Stable or Metastable Phase Diagram, Journal of the European Ceramic Society, 21 (2001) 2521–2533

DOI: 10.1016/s0955-2219(01)00275-8

[5] P. Beeley, Foundry Technology, Second edi. Oxford: Butterworth-Heinemann, 2001.

[6] C. Sadik, I.-E. El Amrani, and A. Albizane, Recent Advances in Silica-Alumina Refractory: A Review, Journal of Asian Ceramic Societies, 2 (2014) 83–96.

DOI: 10.1016/j.jascer.2014.03.001

[7] F. Gonzales, C. L. Eggerding, and J. B. Niklewski, Process for Forming Mullite, U.S. Patent 4,272,500. (1981)

[8] D. Frulli, Production and Properties of Refractory Raw Materials Based on Andalusite and Mullite – Influence of Impurities in the Refractory Behavior, Materials Science 8 (2016) 1–4.

[9] K. G. Skinner, W. H. Cook, R. A. Potter, and H. Palmour, Effect of TiO2, Fe2O3, and Alkali on Mineralogical and Physical Properties of Mullite-Type and Mullite- Forming A12O3-SiO, Mixtures: I, Journal of the American Ceramic Society. 36 (1953) 349–356.

DOI: 10.1111/j.1151-2916.1953.tb12816.x

[10] J. Y. Appiah, Clay Samples from the Western Region of Ghana, X-Ray Analysis, Chemical Analysis, Bleaching Properties, and Suitability for Cement Clinker Production, Semantic Scholar, (2015)

[11] A. Yaya, E. K. Tiburu, M. E. Vickers, J. K. Efavi, B. Onwona-Agyeman, and K. M. Knowles, Characterisation and Identification of Local Kaolin Clay From Ghana: A Potential Material for Electroporcelain Insulator Fabrication, Applied Clay Science. 150 (2017) 125–130.

DOI: 10.1016/j.clay.2017.09.015

[12] E.K. Arthur and E. Gikunoo, Property Analysis of Thermal Insulating Materials Made From Ghanaian Anthill Clay Deposits, Cogent Engineering.7 (2020) no. 1.

DOI: 10.1080/23311916.2020.1827493

[13] R. B. Asamoah, E. Nyankson, E. Annan, B. Agyei-Tuffour, J. K. Efavi, K. Kan-Dapaah, V. A. Apalangya, L. N. W. Damoah, D. Dodoo-Arhin, E. K. Tiburu, S. K. Kwofie, B. Onwona-Agyeman and A. Yaya, Industrial Applications of Clay Materials From Ghana (A Review), Oriental Journal of Chemistry. 34 (2018) 1719–1734.

DOI: 10.13005/ojc/340403

[14] J.A.B.K. Ata, Preliminary Investigation of Ghanaian Clays for Decolorisation in the Vegetable Oil Industry, Ghana Journal of Agricultural Science, 11 (1978) 75–80.

[15] D. Dodoo-Arhin, D. S. Konadu, E. Annan, F. P. Buabeng, A. Yaya and B. Agyei-Tuffour, Fabrication and Characterisation of Ghanaian Bauxite Red Mud-Clay Composite Bricks for Construction Applications, American Journal of Materials Science, 3 (2013) 110–119.

DOI: 10.1016/j.cscm.2017.05.003

[16] E. Endene, S. S. R. Gidigasu, and S. K. Y. Gawu, Engineering Geological Evaluation of Mfensi and Afari Clay Deposits for Liner Application in Municipal Solid Waste Landfills, SN Applied Sciences, 2 (2020) 1–10.

DOI: 10.1007/s42452-020-03887-5

[17] P. S. Kwawukume, Material Specifications for the Production of High Density Refractory Brick with Locally Available High Alumino-Silicates, Journal of the University of Science and Technology, 19 (1999) 47–55.

[18] S. Obiri, D. Essumang, F.A. Armah, B. Ason, Geochemical Properties of Kaolin Deposits in the Central Region, Ghana : A Multivariate Statistical Approach, Research Square (2022)1-15.

DOI: 10.21203/rs.3.rs-1850542/v1

[19] T.A. Tagbor, K.A. Boakye, J. Sarfo-Ansah, and E. Atiemo, "A Study of the Pozzolanic Properties of Anfoega Kaolin," International Journal of Engineering Research and Applications. 5 (2015) 28–33.

[20] D. K. Smith, Nomenclature of the Silica Minerals and Bibliography, Power Diffraction. 13 (1998) 2–19.

[21] A.O. Surendranathan, An Introduction to Ceramics and Refractories. CRC Press. 2014.

DOI: 10.1201/b17811

[22] S.L. Msibi, Effect of Recycled Bauxite Grog Addition on Andalusite-Containing Refractory Castables for Tundish Applications, Master Thesis, (2018)

[23] A.R. Chesti, Refractories: Manufacture, Properties and Applications. Prentice-Hall of India, 1986.

[24] M.A.G. Elngar, F.M. Mohamed, S. A. H. El-Bohy, C. M. Sharaby, and M. E.-M. H. Shalabi, Factors Affected the Performance of the Fire Clay Refractory Bricks, Górnictwo i Geoinżynieria, 4 (2014).

[25] C. M. F. Vieira, J. Alexandre, and S. N. Monteiro, Effect of the Particle Size of the Grog on the Properties and Microstructure of Bricks, Materials science forum, 530 (2006) 438–443.

DOI: 10.4028/www.scientific.net/msf.530-531.438

[26] C. Tang, K. Li, W. Ni, and D. Fan, Recovering Iron from Iron Ore Tailings and Preparing Concrete Composite Admixtures, Minerals, 9 (2019) 1–14, 2019.

DOI: 10.3390/min9040232

[27] C. Sylwan, S. Reichardt, and T. Eriksson, Thermal Shock Resistance and Effects of Quenching on Two Max Phase Bulk Materials, Materials Science, Semantic Scholar, (1996).

[28] K. Li, D. Wang, H. Chen, and L. Guo, Normalized Evaluation of Thermal Shock Resistance for Ceramic Materials, Journal of Advanced Ceramics, 3 (2014) 250–258.

DOI: 10.1007/s40145-014-0118-9

[29] G. Xu, Q. Dong, X. Zhang, and M. Li, A Novel Methodology for Process Parameter Optimization Based on Support Vector Data Description, International Journal of Industrial Engineering: Theory, Applications and Practice., 27 (2020) no. 5.

[30] B. Kanka and H. Schneider, Sintering Mechanisms and Microstructural Development of Coprecipitated Mullite, Journal of Materials Science, 29(1994) 1239–1249.

DOI: 10.1007/bf00975071

[31] S. Ashlock and A. Scheer, The Effect of Iron Oxide Impurities on the Hot Properties of Mullite, Proceedings UNITECR 2022 Congress. 17th Biennial Worldwide Congres on Refractories, 2022.

[32] S. Lee, Y. J. Kim, and H. S. Moon, Phase Transformation Sequence from Kaolinite to Mullite Investigated by an Energy-Filtering Transmission Electron Microscope, Journal of the American Ceramic Society. 82, 10 (1999) 2841–2848.

DOI: 10.1111/j.1151-2916.1999.tb02165.x

[33] I. M. Bakr, Densification Behavior, Phase Transformations, Microstructure and Mechanical Properties of Fired Egyptian Kaolins, Applied. Clay Science. 52, (2011) 333–337.

DOI: 10.1016/j.clay.2011.03.002

[34] A. Ghorbel, M. Fourati, and J. Bouaziz, Microstructural Evolution and Phase Transformation of Different Sintered Kaolins Powder Compacts, Materials Chemistry and Physics. 112 (2008) 876–885.

DOI: 10.1016/j.matchemphys.2008.06.047

[35] R.M. German, P. Suri, and S.J. Park, Review: Liquid Phase Sintering, Journal of Materials Science, 44(2009) 1–39.

[36] Information on https://www.britannica.com/science/quartz (accessed on May 15, 2023).

[37] E. Ringdalen, Changes in Quartz During Heating and the Possible Effects on Si Production, 67(2015) 484–492.

DOI: 10.1007/s11837-014-1149-y

[38] A. Gualtieri and M. Bertolani, Mullite and Cristobalite Formation in Fired Products Starting From Halloysitic Clay, Applied Clay Science, 7 (1992) 251–262.

DOI: 10.1016/0169-1317(92)90013-d

[39] N. Fosu, B. Owusu, and J. R. Dankwah, Carbothermal Upgrading of the Awaso Bauxite Ore using Sawdust and Coconut Shells as Reductant , Ghana Mining Journal. 15(2016) 58–64.

DOI: 10.4314/gm.v16i2.8

[40] W. Wang, D. Weng, and X. Wu, Thermal Behavior of Zirconia-doped Mullite Gel Fibers, Progress in Natural Science: Materials International. 22 (2012) 213–218.

DOI: 10.1016/j.pnsc.2012.04.002

[41] X. Li, S. Niu, D. Wang, J. Li, Q. Jiao, X. Guo, X. Xu, Microstructure and Crystallization Kinetics of Silica-Based Ceramic Cores with Enhanced High-Temperature Property, Materials (Basel) 16 (2023) 1–12.

DOI: 10.3390/ma16020606

[42] A. K. Chakraborty, Mullite Phase, in: Phase Transformation of Kaolinite Clay, Springer, 2014, pp.235-272.

DOI: 10.1007/978-81-322-1154-9_21

[43] R.C. Breneman and J.W. Halloran, Effect of Cristobalite on the Strength of Sintered Fused Silica Above and Below the Cristobalite Transformation, Journal of American Ceramic Society, 98 (2015) 1611–1617.

DOI: 10.1111/jace.13505

[44] N. Traon, T. Tonnesen, and R. Telle, Estimation of Damage in Refractory Materials after Progressive Thermal Shocks with Resonant Frequency Damping Analysis, Journal of Ceramic Science and Technology, 172 (2016) 165–172.

[45] C. Gupta, Fuels, in: Furnaces and Refractories. PHI Learning, 1977.

[46] Y. Luo, H. Gu, M. Zhang, A. Huang, H. Li, C. Yu, T. Li, P. Yan., Research on Thermal Shock Resistance of Porous Refractory Material by Strain-Life Fatigue Approach, Ceramics International. 46 (2020) 14884–14893.

DOI: 10.1016/j.ceramint.2020.03.015