Characterization of solute transport parameters in leach ore: inverse modeling based on column experiments

Abstract

Heap leaching is essentially a process in which metals are extracted from mine ores with lixiant. For a better understanding and modeling of this process, solute transport parameters are required to characterize the solute transport system of the leach heap. For porous media like leach ores, which contain substantial gravelly particles and have a broad range of particle size distributions, traditional small-scale laboratory experimental apparatus is not appropriate. In this paper, a 2.44 m long, 0.3 m inner diameter column was used for tracer test with boron as the tracer. Tracer tests were conducted for 2 bulk densities (1.92 and 1.62 g/cm³) and 2 irrigation rates (2 and 5 L/ (m²·h^-1)). Inverse modeling with two-region transport model using computer code CXTFIT was conducted based on the measured breakthrough curves to estimate the transport parameters. Fitting was focused on three parameters: dispersion coefficient D, partition coefficient β, and mass transfer coefficient ω. The results turned out to fall within reasonable ranges. Sensitivity analysis was conducted for the three parameters and showed that the order of sensitivity is β>ω>D. In addition, scaling of these parameters was discussed and applied to a real scale heap leach to predict the tracer breakthrough.

Keywords

leach ore / tracer test / inverse modeling / parameter up-scaling

References

[1] Al-Yahyai R, Scheffer B, Davies F S, Munoz-Carpena R (2006). Characterization of soil-water retention of a very gravelly loam soil varied with determination method, Soil Sci, 171(2): 85–93

[2] Bouffard S C, Dixon D (2001). Investigative study into the hydrodynamics of heap leaching processes. Metallurgical and Materials Transactions B, 32: 763–776

[3] Clark M E, van Buuren C B, Dew D W, Eamon M A (2006). Biotechnology in minerals processing: Technological breakthroughs creating value. Hydrometallurgy, 83: 3–9

[4] Coram-Uliana N J, van Hille R P, Kohr W J, Harrison S T L (2006). Development of a method to assay the microbial population in heap bioleaching operations. Hydrometallurgy, 83: 237–244

[5] Dixon D (2000). Analysis of heat conservation during copper sulphide heap leaching. Hydrometallurgy, 58: 27–41

[6] Gelhar L W, Rehfeldt K R (1992). A critical review of data on field-scale dispersion in aquifers. Water Resou Res, 28(7): 1955–1974

[7] Haggerty R, Harvey C F, von Schwerin C F, Meigs L (2004). What controls the apparent timescale of solute mass transfer aquifers and soils? A comparison of experimental results. Water Resou Res, 40(1): W01510

[8] Maraqa M (2001). Prediction of mass-transfer coefficient for solute transport in porous media. J ContamHydrol, 53: 153–171

[9] McLaughlin J, Agar G E (1991). Development and application of a first order rate equation for modeling the dissolution of gold in cyanide solution. Minerals Engineering, 4: 1305–1314

[10] Milczarek M A, Zyl D, Peng S, Rice R C (2006). Saturated and unsaturated hydraulic properties characterization at mine facilities: are we doing it right? 7th ICARD, March 26–30, St. Louis MO, USA. Lexington: American Society of Mining and Reclamation (AMSR), 1273–1286

[11] Miller J D, Lin C L, Garcia C, Arias H (2003). Ultimate recovery in heap leaching operations as established from mineral exporsure analysis by X-ray microtomography. Int J MinerProcess, 72: 331–340

[12] Petersen J, Dixon D (2002). Systematic modeling of heap leach processes for optimization and design. EPD Congress 2002, TMS, Warrendale, PA, 757–771

[13] Petersen J, Dixon D (2006). Competitive bioleaching of pyrite and chalcopyrite. Hydrometallurgy, 83: 40–49

[14] Poulsen T G, Moldrup P, Iverson B V, Jacobsen O H (2002). Three-region Campbell model for unsaturated hydraulic conductivity in undisturbed soils, Soil Sci Soc Am J, 66: 744–752

[15] Rawlings D E (2002). Heavy metal mining using microbes. Annu Rev Microbiol, 56: 65–91

[16] Sanchez-Chacon A E, Lapidus G T (1997). Model for heap leaching of gold ores by cyanidation. Hydrometallurgy, 44: 1–20

[17] Sato T, Tanahashi H, Loaiciga H A (2003). Solute dispersion in a variably saturated sand.ƒWater Resources Research,ƒ39(6): 1155–1161

[18] Toride N, Leij F J, van Genuchten M T (1995). The CXTFIT code for estimating transport parameters from laboratory or field tracer experiments, US Salinity Lab, Riverside, Calif

[19] Wan R Y, LeVier K M (2003). Solution chemistry factors for gold thiosulfate heap leaching. Int J MinerProcess, 72: 311–322

[20] Watling H R (2006). The bioleaching of sulphide minerals with emphasis on copper sulphides–A review. Hydrometallurgy, 84: 81–108

RIGHTS & PERMISSIONS

Higher Education Press and Springer-Verlag Berlin Heidelberg