Siltation of Ore Particles in Leaching Tanks: Causative Factors and Mitigation Measures
Keywords:
Siltation, deflloculation, settling velocity, grindingAbstract
Siltation involves the accumulation of sediment over a considerable period of time and this may occur in closed systems like leaching tanks. Most mining companies in Ghana experience siltation problems during leaching of gold ore. This paper examines the potential causes and possible mitigation measures of siltation. Particle size analysis, slurry settling rate tests and agitation efficiency analysis were used in identifying causative factors of siltation whiles deflocculation test and grind analysis were conducted to ascertain mitigation measures. Results from the study indicated that, high settling velocity of particles, inefficient milling and classification, poor slurry agitation and particle flocculation were the major causative factors leading to siltation. Size analysis results revealed P67 of 106 µm instead of P80 of 106 µm, a situation which affects particle suspension by agitators leading to siltation. This study therefore suggests that increase in milling residence time and particle deflocculation are potential remediation measures for curbing siltation. Extended grinding of ball mill feed resulted in 94% passing 106 µm while settling velocity was reduced by 71% after deflocculant addition at 1000 ppm.
References
Amankwah, R. K. and Ofori-Sarpong, G. (2011),
“Microwave heating of gold ores for enhanced grindability and cyanide amenabilityâ€, Journal of Minerals Engineering 24, pp 541 – 544.
Anon.(2015), Mixing and Agitation, http://www.pacontrol.com/process-information-book/Mixing%20and%20Agitation%2093851_10.pdf.
Concha, F. (2009), “Settling Velocities of Particulate
Systemsâ€, Department of Metallurgical Engineering, University of Concepción, 20pp.
Ersoy, B. (2004) “Effect of pH and Polymer Charge
Density on Settling Rate and Turbidity of Natural Stone Suspensionsâ€, International Journal of Mineral Processing, Elsevier Science & Technology Books, pp. 207-216.
Konadu, K. T., Abaka-Wood, G. B. and Ofori-Sarpong, G. (2014), “Gold Loses due to Silt Formation in Leaching Tanksâ€, In: Proceeding of the 3rd UMaT Biennial International Mining and Mineral Conference, pp. 289-293.
Larsson, M., Hill, A. and Duffy. J., (2012), “Suspension Stability; Why Particle Size, Zeta Potential and Rheology are Importantâ€, Annual Transactions of the Nordic Rheology Society, Vol. 20, 6 pp.
Song, J., Wang, F., Li, X., Zhao, L., Li, W., Huang, H. and Su. M. (2012), “Influence of Ball Milling Parameter on the Refined Effect of Quartz Sandâ€, Second International Conference on Materials, Mechatronics and Automation Lecture Notes in Information Technology, Vol. 15, 5 pp.
Walsh, D. E, (1988), “A Study of Factors Suspected of Influencing the Settling Velocity of Fine Gold Particlesâ€, Mineral Industry Research Laboratory 210 O’Neill Research Laboratory, University of Alaska Fairbanks, Fairbanks, Alaska 99775-1180, 43 pp.
Wills, B. A. (2006), Mineral Processing Technology, seventh edition, Elsevier Science & Technology Books, Maryland Heights, Missouri, USA, 450pp.
Zchimmer and Schwarz, (2009). Mechanisms of action of deflocculants and dispersants inceramic bodies, Ceramics. GmbH & Co. KG. Chemische Fabriken, Lahnstein, Germany, pp.15.
Downloads
Published
Issue
Section
License
Copyright © 2021 University of Mines and Technology (UMaT), Tarkwa. Ghana