Insights into Ferric Leaching of Low Grade Metal Sulfide-Containing ores in an Unsaturated Ore Bed Using X-ray Computed Tomography

Abstract

Abstract:The distribution of the metal-bearing mineral grains within a particulate ore prepared for leaching, and the impact of this spatial heterogeneity on overall extraction efficiency is of key importance to a mining industry that must continuously target ever-reducing grades and more complex ore bodies. If accessibility and recovery of the target minerals is to be improved, a more detailed understanding of the behaviour of the system must be developed. We present an in situ analysis using X-ray computed tomography to quantify the rates of volume reduction of sulfide mineral grains in low grade agglomerated copper bearing ores during a miniature laboratory scale column leaching experiment. The data shows the scale of the heterogeneity in the leaching behaviour, with an overall reduction of sulphide mineral grains of 50%, but that this value masks significant mm 3 to cm 3 scale variability in reduction. On the scale of individual ore fragments, leaching efficiency ranged from 22% to 99%. We use novel quantitative methods to determine the volume fraction of the sulfide that is accessible to the leachate solution.

X-ray Microcomputed Tomography (µCT) for Mineral Characterization: A Review of Data Analysis Methods

“…Such reviews mostly analyze the applicability and performance of µCT systems for different cases of mineral analysis. Potential new applications were identified through addressing the advancement made in the µCT instruments, such as dual-energy µCT [1,17], in situ experiments during acquisition [27,28], the use of diffraction and phase contrast modes [29,30], as well as sub-micron resolution [1,31,32].…”

Multimodal assessment of the curing of agglomerated ores in the presence of chloride ions

“…The XMT based assessments have been widely used to quantify liberation (Miller et al, 2009;Reyes et al, 2018), structural changes (Kareh et al, 2014;Ram et al, 2020), preferential breakage (Garcia, Lin and Miller, 2009), and leaching extent (Lin, 2015;Dobson et al, 2017;Yang et al, 2019) in mineral samples. A disadvantage of using XMT, though, is that different sulphides will present similar attenuation values when exposed to an X-ray beam.…”

Effect of X-Ray µCT Scanning on the Growth and Activity of Microorganisms in a Heap Bioleaching System

“…Non-surface grain leaching within large particles cannot be investigated selectively via traditional experimental methods reliant on bulk measurements, 2D or destructive methodologies. However, it can be studied using high resolution, non-destructive 3D X-ray Micro Computed Tomography (μCT), an imaging technique for investigation of the internal structure of opaque objects [6,7,8]. In bioleaching the main leaching reagent is ferric ion (Fe 3+ ), which is regenerated from ferrous ion (Fe 2+ ) by iron oxidising bacteria and archaea.…”

“…In bioleaching the main leaching reagent is ferric ion (Fe 3+ ), which is regenerated from ferrous ion (Fe 2+ ) by iron oxidising bacteria and archaea. In previous leaching studies using X-ray μCT, ferric ion was supplied in excess rather than using micro-organisms due to concerns that X-ray irradiation may affect metabolic activity [6,7,8], including ferrous iron oxidation. Useful data were obtained on the impact of grain position in the ore particle and voidage on leachability.…”