X-Ray computed tomography for 3D analysis of gangue mineral rejection by gravity preconcentration of sulfidic gold ores

Abstract

Specific gravity washability curves used in the coal industry to define the theoretical gravity separation efficiency can be used in the same way for evaluation of preconcentration operations in the metal mining industry. These theoretical metal recovery/gangue rejection curves, which establish the maximum in gravity separation efficiency, can be determined from three-demensional (3D) image analysis by high resolution X-ray microtomography (HRXMT) rather than by sink-float analysis using heavy liquid fractionation. In this way, the tedious, time-consuming, and toxic use of heavy liquids for laboratory sink-float analysis is avoided. In addition to the theoretical gravity separation efficiency curves by HRXMT, further 3D particle information on mineral composition and texture is obtained, including grain size distribution. Experimental HRXMT results for two sulfidic gold ores are presented and compared to the results from dense media cyclone experiments in order to evaluate the efficiency of gangue mineral rejection.

Keywords

Gold gangue rejection preconcentration density separation ore characterisation 3D microtomography gold ore processing process mineralogy

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References

Buades

, Coll

, Morel

J-M.

2005. A non-local algorithm for image denoising. Comput Vis Pattern Recognition, 2005. CVPR 2005. IEEE Comput Soc Conf. 2:60–65.

Lin

, Miller

JD.

2005. 3D characterization and analysis of particle shape using X-ray microtomography (XMT). Powder Technol. 154(1):61–69. doi: 10.1016/j.powtec.2005.04.031

Lin

, Neethling

, Courtois

, Dobson

, Lee

PD.

2016. Multi-scale quantification of leaching performance using X-ray tomography. Hydrometallurgy. 164:265–277. doi: 10.1016/j.hydromet.2016.06.020

McGrath

2014. A study of the behaviour of free gold in flash flotation and gravity recovery [PhD thesis]. Perth, Western Australia: Curtin University.

McGrath

, O'Connor

, Eksteen

JJ.

2015. A comparison of 2D and 3D shape characterisations of free gold particles in gravity and flash flotation concentrates. Miner Eng. 82:45–53. doi: 10.1016/j.mineng.2015.04.022

Miller

, Lin

, Garcia

, Arias

2003. Ultimate recovery in heap leaching operations as established from mineral exposure analysis by X-ray microtomography. Int J Miner Process. 72(1-4):331–340. doi: 10.1016/S0301-7516(03)00091-7

Murphy

, Van Zyl

, Domingo

2012. Underground preconcentration by ore sorting and coarse gravity separation. Proceedings of Narrow vein mining conference; Mar 26–27; Perth, Australia, p. 26–27.

Nguyen

, Nguyen

, Lin

, Miller

JD.

2018. Application of high-resolution X-ray microcomputed tomography for coal washability analysis. Miner Eng. 124:137–148. doi: 10.1016/j.mineng.2018.05.027

Valery

, Duffy

K-A.

2017. Why preconcentrate, and how? Mining Magazine, Jul, p. 46–47.

10.

Wang

, Lin

, Miller

JD.

2016. 3D image segmentation for analysis of multisize particles in a packed particle bed. Powder Technol. 301:160–168. doi: 10.1016/j.powtec.2016.05.012

11.

Wang

, Lin

, Miller

JD.

2017. Quantitative analysis of exposed grain surface area for multiphase particles using X-ray microtomography. Powder Technol. 308:368–377. doi: 10.1016/j.powtec.2016.11.047

12.

Wills

, Finch

2015. Wills’ mineral processing technology: an introduction to the practical aspects of ore treatment and mineral recovery. Oxford, UK: Butterworth-Heinemann, Elsevier.