However, the microbial community structure and functional differentiation in different parts of a biological heap leaching system are still unknown. In this study, metagenomic sequencing was used to fully illuminate the microbial community differentiation in the pregnant leach solution (PLS) and leaching heap (LH) of a BHL system.
The acid concentration of the lixiviant, the flowrate of lixiviant, and the rate of aeration of the heap all need to be balanced to ensure that the heap does not get too hot (which will cause the bacteria to die) or too cold (which slows down the rate of leaching) (Dixon, 2000; …
Heap leaching can take anything from a couple of months to several years. In the case of gold recovery, heap leaching generally requires 60 to 90 days to leach the ore, compared to the 24 hours required by a conventional agitated leach process. Gold recovery is also usually only 70% compared with 90% recovery in an agitated leach plant.
Bioleaching of sulfide minerals by bacteria, mainly Thiobacillus ferrooxidans (T. f.) and Thiobacillus thiooxidans, plays an important role in hydrometallurgy because of its economic and environmental attractions. The surveys of production process and the bacterial oxidation activity in the heap bioleaching were investigated. The results show that pH value is high, bacteria biomass and …
An adequate supply of oxygen is a prerequisite for good growth and high activity of the leaching bacteria. In the laboratory this can be achieved by aeration, stirring, or shaking. On a technical scale, particularly in the case of dump or heap leaching, …
T h e similar problems exist (cell • g - 1 ) 1.lU Jian-she, et al: Bacterial oxidation activity in heap leaching • 377 • As shown in Tables 2 and 3, primary copper up r e m a r k a b l y after 60 h inoculation, showing that sulfide are mainly of copper and clayish matrix the oxidation rate of …
bacterial heap leaching of low-grade chalcopyrite ores and the acid heap leaching of nickel laterites. A complete programme of heap leach testwork typically involves a sequence of bottle roll tests and column tests, followed by piloting on test heaps. The initial testwork is aimed at determining the amenability of the ore to heap leaching,
Heap leaching - newly mined run-of-the-mine (ROM) material (intermediate grade, oxides and secondary sulfides) is deposited in a heap on an impervious natural surface or a pad and leached. ROM may be leached as mined or may be partially crushed and mixed with acid prior to depositing on heap. ... Commercial application of bacterial leaching ...
Bacterial oxidation activity in heap leaching. December 2004; ... Bacterial leaching in a culture medium at initial pH 2 resulted in increased solubilisation of the metals for both concentrates ...
Examples are copper heap leaching on the edge of the Great Sandy Desert, northwestern Australia, nickel/copper heap leaching in sub-arctic conditions or copper leaching in the tropics . Typical irrigation rates per square meter of surface are in the range 5–10 L·h −1.
Bacterial heap leaching has advantages due to the claim of being able to selectively attack chalcopyrite which avoids the build-up elemental sulfur that is …
Heap leaching is an industrial mining process used to extract precious metals, copper, uranium, and other compounds from ore using a series of chemical reactions that absorb specific minerals and re-separate them after their division from other earth materials. Similar to in situ mining, heap leach mining differs in that it places ore on a liner, then adds the chemicals via drip systems to the ...
Heap leaching of copper has been practiced for several decades, mostly with oxide ores. Probably bacteria aided some of these oxide operations, but this was without serious study. This is the subject of the current paper for determining the role of chemolitotrophic bacteria in the chemical (acid) heap leach operation at Sarcheshmeh Copper Mine.
The objectives of any copper heap bacterial leaching should encompass the following main points: 1) Characterise ore for particle size, elemental composition, mineralogy, acid consumption and bioleaching potential. 2) Evaluate copper bioleaching in columns with crushed ore. 3) Characterise heat generation during sulfide oxidation
A bacterial-assisted heap leach process is employed for the solubilization of a metal from a refractory ore containing fines and/or clay wherein at least a portion of the metal is solubilized by the bacterial oxidation of sulfides and the concomitant or sequential dissolution of the metal into a leaching …
Heap leaching is usually carried out in the open and on slightly sloping ground covered with a watertight plastic sheet or clay layer onto which a heap of crushed ore is placed. The heap is sprayed with the leaching solution which percolates or flows down through it and dissolving and carrying away the metals as it goes. ... the bacteria that ...
Bacterial leaching is the extraction of metals from their ores using microorganisms. Microbial technology offers an eco ... Heap leaching requires the preparation of the ore, primarily size reduction, so as to maximise mineral-lixiviant interaction and the laying of an impermeable base to prevent
The evolution of microbial populations involved in simulated-heap leaching of a polymetallic black schist sulfide ore (from the recently-commissioned Talvivaara mine, Finland) was monitored in aerated packed bed column reactors over a period of 40 weeks. The influence of ore particle size (2-6.5 mm …
Heap bio leaching is the process to extract precious metals like gold, silver, copper and uranium from their ore by placing them on a pad (a base) in a heap and sprinkling a bacterial leaching ...
After leaching for 270 days, copper dissolution reached 80% for Heap 1 with particle size of − 30 mm, and 65% for Heap 2 with particle size of − 50 mm. The monthly solution chemistry of pregnant leach solution (PLS) and raffinate is shown in Table 5. Metal extractions calculated using solids analysis are presented in Table 6 and Fig. 5.
Heap leaching is an industrial mining process used to extract precious metals, copper, uranium, and other compounds from ore using a series of chemical reactions that absorb specific minerals and re-separate them after their division from other earth materials. Similar to in situ mining, heap leach mining differs in that it places ore on a liner, then adds the chemicals via drip systems to the ...
The application of heap leaching to more refractory chalcopyrite material is still under development. Figure 1 – Relationship between ore grade and method of recovery During sulphide heap leaching, bacterial activity can be utilised to catalyse the oxidation of iron, which acts as an electron carrier between the mineral and oxygen for
7.4.5: Heap Leaching Method. ... bacterial action, as from metal oxidizing bacteria for example, is critical to the success of the process. A variation of heap leaching involves constructing the "heap" in a dump, and calling it dump leaching. Large containment vessels are being used on …
• Heap leaching of gold ore started to gain promenence in the late 1960's when it was applied on a large scale to low grade ores that were uneconomic to procees by conventional tank leach methods. • The first use of cyanide for leaching of gold and silver ores was in England in 1887 by J.S. MacArthur.
Heap leach operations typically employ some form of modelling and forecasting tools to predict cash flow margins and project viability. However, these vary from simple spreadsheets to phenomenological models, with more complex models not commonly employed as they require the greatest amount of time and effort. Yet, accurate production modelling and forecasting are essential for managing ...
Bacterial Leaching Experiments . In order to determine the influence of ferrous and ferric iron addition on the bioleaching of the copper concen-trate, shake flasks experiments were carried out in the presence and absence of 0.1 M of the mentioned cations.
The evolution of microbial populations involved in simulated-heap leaching of a polymetallic black schist sulfide ore (from the recently-commissioned Talvivaara mine, Finland) was monitored in aerated packed bed column reactors over a period of 40 weeks. The influence of ore particle size (2-6.5 mm and 6.5-12 mm) on changes in composition of ...
12 Copper Heap Leach • Limited application to oxide ores or secondary sulphide ores using bacterial leach. • About 20% of world copper production. • For oxide ores, recovery only slightly reduced - with 2 to 4 month leach times. • Produces high purity 99.999% Cu. • Cost effective for copper production in range of US$0.35 to 0.50 per lb Cu.
Heap leaching is a tried and tested mining technique enabling the processing of different kinds ... of iron and sulphur oxidation by certain natural bacteria may also catalyze the leaching process. Lateritic ore deposits, the major resources of aluminum, nickel, platinum, cobalt and some gold, ...
The water is recycled again after metal extraction and regeneration of the bacteria in an oxidation pool (Fig. 12.1a). (b) Heap Leaching: The ore is arranged in a big heap, which is treated with water as in slope leaching. The recovery of metals and other processes are conducted just like in slope leaching (Fig. 12.1b). (c) In-Situ Leaching: