The influence of rock characteristics on acid leach extraction and re-extraction of Cu-oxide and sulfide minerals

Helle, Sonia; Jerez, Óscar; Kelm, Ursula; Pincheira, M.; Varela, Bob

doi:10.1016/j.mineng.2009.09.016

Cited by 10 publications

(6 citation statements)

References 4 publications

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“…Thus, careful characterisation of the ore pre-and post-curing should establish which minerals react over the duration of the curing, and to what extent. In particular, X-ray diffraction can verify structural breakdown of minerals, particularly in the finer particle size fractions [34]. Further such work would need to be conducted on ores of different gangue mineralogy to establish differences in gangue reactivity under curing and heap conditions.…”

Section: Other Factors Affecting Mineral-acid Interactionsmentioning

confidence: 99%

Acid-Gangue Interactions in Heap Leach Operations: A Review of the Role of Mineralogy for Predicting Ore Behaviour

Chetty

2018

Minerals

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Abstract:Heap leaching accounts for a fifth of global copper production, sourced primarily from porphyry ores, yet metal recoveries are often not optimal. Gangue, and its interaction with acid, plays an important role in such processes. Thus, a proper understanding of gangue minerals present in the ore, their textural relationships relative to particle size distribution, reactivity with acid under different conditions, and relationship to lithotypes and geological alteration in the orebody, is necessary to predict ore behaviour in the comminution, agglomeration, curing and heap leach unit operations. Mineralogical tools available for characterisation are routine X-ray diffraction, optical microscopy, automated scanning electron microscopy, and electron probe microanalysis, accompanied by more recent advancements in hyperspectral infrared imaging and X-ray computed tomography. Integrated use of these techniques allows mineral abundance, textural relationships and mineral chemistry to be addressed over the range of particle and agglomerate sizes. Additionally, diagnostic leach results can be better interpreted when calibrated against robust mineralogical data. The linkage of ore attributes, metallurgical behaviour and their distribution in the orebody forms an integral part of a geometallurgical approach to predicting, and addressing, changes during the heap leaching process. Further investigation should address the fundamentals of gangue reaction with strong acid, and concomitant structural breakdown during curing and agglomeration processes, and how this differs from gangue-acid reactivity under weaker acid conditions, combined with temperature and fluid flow effects of heap leaching. Pre-and post-characterisation is necessary to understand and quantify the effects of variables for gangue-acid reactivity in these various operations. The characterisation outcomes should lead to a refinement of the hierarchy of gangue mineral reactivity under different conditions of comminution and leaching, and how these in turn relate to identified ore types that are mined.

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Section: Other Factors Affecting Mineral-acid Interactionsmentioning

confidence: 99%

Acid-Gangue Interactions in Heap Leach Operations: A Review of the Role of Mineralogy for Predicting Ore Behaviour

Chetty

2018

Minerals

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“…In the experiment, the three main condition variables (factors) that affect the leaching process (amount of concentrated sulfuric acid, leaching temperature, and leaching time) were selected based on the CCD module design. The experiments were later analyzed using the response surface methodology [15,16].…”

Section: Methodsmentioning

confidence: 99%

Response Surface Methodology for Optimization of Copper Leaching from Refractory Flotation Tailings

et al. 2018

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Response surface methodology is used to optimize the leaching process for refractory flotation copper tailings. The proportion of the refractory combination oxide copper (chrysocolla) is 64.84%. At present, few studies have examined the leaching of chrysocolla. In this study, we examine the effects of several variables, including the amount of concentrated sulfuric acid, leaching temperature, and leaching time, on leaching efficiency. Using a response surface methodology, we develop a quadratic model relanbting all the above experimental variables with leaching efficiency. The resulting model is highly consistent with experimental data. According to the model, the factor with the greatest influence on leaching efficiency is the amount of concentrated sulfuric acid. According to the model, the optimal leaching conditions are 85 kg/t concentrated sulfuric acid, a leaching temperature of 68.51 • C, and a leaching time of 4.36 h. The actual measured leaching efficiency under these conditions is 85.86%, which is close to the value of 86.79% predicted by the model. We study the leaching processes using scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) surface scan analyses. Both methods allow us to explore the content of the main element and visually observe its distribution, allowing us to develop effective methods for treating low-grade oxide ores.

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“…• Scenario 1 (standard operation): Leaching of copper oxides and secondary copper sulfides adding sulfuric acid only. The leaching of secondary sulfides with sulfuric acid slows down the process of extracting ore from the rock, increasing the time required until the marginal extraction of ore is negligible [12,34]. From the graphical analysis of copper recovery for each production campaign (see Figure 5), a decrease in the expected recovery of copper ore can be observed in sulfide mineral leaching campaigns using sulfuric acid as reagent (without incorporating additives), due to the slower dissolution kinetics of the secondary copper sulfides.…”

Section: Simulated Scenariosmentioning

confidence: 99%

“…standard operation): Leaching of copper oxides and secondary copper sulfides adding sulfuric acid only. The leaching of secondary sulfides with sulfuric acid slows down the process of extracting ore from the rock, increasing the time required until the marginal extraction of ore is negligible[12,34].  Scenario 2 (proposed operation): Leaching of oxides with sulfuric acid and leaching of secondary sulfides with chloride.…”

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Optimization of the Heap Leaching Process through Changes in Modes of Operation and Discrete Event Simulation

et al. 2019

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The importance of mine planning is often underestimated. Nonetheless, it is essential in achieving high performance by identifying the potential value of mineral resources and providing an optimal, practical, and realistic strategy for extraction, which considers the greatest quantity of options, materials, and scenarios. Conventional mine planning is based on a mostly deterministic approach, ignoring part of the uncertainty presented in the input data, such as the mineralogical composition of the feed. This work develops a methodology to optimize the mineral recovery of the heap leaching phase by addressing the mineralogical variation of the feed, by alternating the mode of operation depending on the type of ore in the feed. The operational changes considered in the analysis include the leaching of oxide ores by adding only sulfuric acid (H2SO4) as reagent and adding chloride in the case of sulfide ores (secondary sulfides). The incorporation of uncertainty allows the creation of models that maximize the productivity, while confronting the geological uncertainty, as the extraction program progresses. The model seeks to increase the expected recovery from leaching, considering a set of equiprobable geological scenarios. The modeling and simulation of this productive phase is developed through a discrete event simulation (DES) framework. The results of the simulation indicate the potential to address the dynamics of feed variation through the implementation of alternating modes of operation.

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The influence of rock characteristics on acid leach extraction and re-extraction of Cu-oxide and sulfide minerals

Cited by 10 publications

References 4 publications

Acid-Gangue Interactions in Heap Leach Operations: A Review of the Role of Mineralogy for Predicting Ore Behaviour

Acid-Gangue Interactions in Heap Leach Operations: A Review of the Role of Mineralogy for Predicting Ore Behaviour

Response Surface Methodology for Optimization of Copper Leaching from Refractory Flotation Tailings

Optimization of the Heap Leaching Process through Changes in Modes of Operation and Discrete Event Simulation

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