Towards fundamentally based heap leaching scale-up

Staden, P.J. van; Petersen, Jochen

doi:10.1016/j.mineng.2021.106915

Cited by 7 publications

(3 citation statements)

References 20 publications

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“…These secondary recyclable resources require low-cost, environmentally-friendly, and efficient mining methods. Since 1980s, heap leaching, which crushes ores and then packs them in heaps [3,4], has been successfully industrialized in the United States, Canada, Chile, South Africa, China, and other countries. The agglomeration, as an effective pretreatment method of crushed ores, is widely utilized in the heap leaching of copper oxides, copper sulfides, laterite nickels, and uranium minerals.…”

Section: Introductionmentioning

confidence: 99%

Hydrodynamic Hysteresis and Solute Transport in Agglomerated Heaps under Irrigation, Stacking, and Bioleaching Controlling

et al. 2022

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Hydrodynamic hysteresis exists widely in agglomerated heaps with well-developed intra-pores, and it directly affects solute transports and bioleaching reaction. In this paper, the dynamic liquid retention behavior under different heap porosity and irrigation condition is quantified via a novel real-time, in-situ liquid retention characterizing system (RILRCS), and the potential effects of initial liquid retention on solute transport and leaching reaction are carefully discussed. The results show that the immobile liquid is dominant in agglomerated heaps. The ratio of immobile and mobile liquid (η) dynamically changes due to mineral dissolution and new flow path appearances. The η normally increases and mobile liquid occupies a higher proportion due to acidic leaching reactions, especially at a smaller Rg (10.32 mm) and a larger u (0.10 mm/s). The dynamic liquid retention is more sensitive to the diameter of packed feeds (Rg) and superficial flow rate (u) instead of leaching reactions. This might be because the damage of leaching reaction on minerals pores/voids is limited and cannot extensively change the potential pore channels or fluid flow paths. Based on pulse tracing and conductivity tests, we reveal that the solute resides longer under a slower u and smaller packed Rg condition, which corresponds well with desirable copper leaching efficiency. Specifically, the liquid hysteresis behavior is more obvious at a lower u (0.01 mm/s) and smaller Rg (10.32 mm). This paper gives a good reference to ascertain the liquid retention and hydrodynamic hysteresis and promote mineral leaching performance.

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Section: Introductionmentioning

confidence: 99%

Hydrodynamic Hysteresis and Solute Transport in Agglomerated Heaps under Irrigation, Stacking, and Bioleaching Controlling

et al. 2022

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“…It is commonly recognized that valuable metal ions continuously transfer between the reaction interface and the leaching solution, eventually obtaining pregnant leaching solution (PLS) and metal products [4]. In this leaching procedure, the leachate is regarded as the key medium of bacteria, soluble oxygen, and metallic ions [5][6][7]. The leachate could mainly include mobile and immobile liquids, and both simultaneously exist in this unsaturated ore heap.…”

Section: Introductionmentioning

confidence: 99%

Understanding the Effect of Stepwise Irrigation on Liquid Holdup and Hysteresis Behavior of Unsaturated Ore Heap

2021

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Liquid is a crucial medium to contain soluble oxygen, valuable metal ions, and bacteria in unsaturated heap leaching. Liquid retention behavior is the first critical issue to be considered to efficiently extract low-grade minerals or wastes. In this study, the residual liquid holdup of an unsaturated packed bed was quantitatively discussed by liquid holdup (θ), residual liquid holdup (θresidual), relative liquid holdup (θ’), and relative porosity (n*) using the designed measuring device. The detailed liquid holdup and the hysteresis behavior under stepwise irrigation are indicated and discussed herein. The results show that relative porosity of the packed bed was negatively related to particle size, and intra-particle porosity was more developed in the −4.0 + 2.0 mm packed bed. The higher liquid retention of the unsaturated packed bed could be obtained by using stepwise irrigation (incrementally improved from 0.001 to 0.1 mm/s) instead of uniform irrigation (0.1 mm/s). It could be explained in that some of the immobile liquid could not flow out of the unsaturated packed bed, and this historical irrigation could have accelerated formation of flow paths. The θ was sensitive to superficial flow rate (or irrigation rate) in that it obviously increased if a higher superficial flow rate (u) was introduced, however, the θresidual was commonly affected by n* and θ’. Moreover, the liquid hysteresis easily performed under stepwise irrigation condition, where θ and θresidual were larger at u of the decreasing flow rate stage (DFRS) instead of u of the increasing flow rate stage (IFRS). These findings effectively quantify the liquid retention and the hysteresis behavior of ore heap, and the stepwise irrigation provides potential possibility to adjust liquid retention conditions.

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“…The heap leaching technique is the most widely used technique at the industrial level within the hydrometallurgical processes for oxidized copper ores. The widespread use of heap leaching is due to its simplicity, and the fact that it entails short residence times, where it is generally necessary to reduce the size of the ore in crushers without the need to go through milling [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Pretreatment of Copper Sulphide Ores Prior to Heap Leaching: A Review

Neira

Pizarro

Quezada

et al. 2021

Metals

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Although the main cause of hydrometallurgical plant closures is the depletion of oxidized copper minerals reserves, the lack of new hydrometallurgy projects also contributes to these closures. One solution is to be able to process copper sulphide ores hydrometallurgically. However, it is widely known that sulphide copper ores—and chalcopyrite in particular—have very slow dissolution kinetics in traditional leaching systems. An alternative to improve the extraction of copper from sulphide ores is the use of a pretreatment process. Several investigations were developed evaluating the effects of pretreatment, mainly in the extraction of copper from chalcopyrite in chloride media. This study presents a review of various pretreatment methods prior to heap leaching to aid in the dissolution of copper from sulphide ores. Different variables of pretreatment that affect the extraction of copper were identified, including the type of salts used in agglomeration, curing time, and curing temperatures. Successful cases such as the implementation of the CuproChlor® process (use of calcium chloride), and various pilot studies using sodium chloride and temperature, show that pretreatment is an alternative that aids in the dissolution of copper from sulphide ores.

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Towards fundamentally based heap leaching scale-up

Cited by 7 publications

References 20 publications

Hydrodynamic Hysteresis and Solute Transport in Agglomerated Heaps under Irrigation, Stacking, and Bioleaching Controlling

Hydrodynamic Hysteresis and Solute Transport in Agglomerated Heaps under Irrigation, Stacking, and Bioleaching Controlling

Understanding the Effect of Stepwise Irrigation on Liquid Holdup and Hysteresis Behavior of Unsaturated Ore Heap

Pretreatment of Copper Sulphide Ores Prior to Heap Leaching: A Review

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