قائمة الطعام
See more on academic.oup
WEBlarge-scale operations involved in bacterial leaching, percola tion leaching is preferred commercially. The principal commercial methods are in situ, dump, heap and vat …
Petersen, J. Heap leaching as a key technology for recovery of values from low-grade ores – a brief overview. Hydrometallurgy 165, 206–212 (2016). Article CAS Google Scholar
Leaching of Cu is normally carried out by dump or heap leaching processes which is cost efficient in terms of installation and operation and requires use of acidophilic iron oxidising bacteria A. ferrooxidans to retain Fe in its oxidized form to cause solubilization of Cu from copper sulfide ore (Panda et al. 2015; Wang et al. 2020; Yin et …
Bacterial heap-leaching: Practice in Zijinshan copper mine. Hydrometallurgy 83: 77-82. Article CAS Google Scholar Sand W, Gehrke T, Josza P-G, Schippers A. 2001. (Bio)chemistry of bacterial leaching – direct vs indirect bioleaching. Hydrometallurgy 51: 115-129. Google Scholar ...
A heap leaching (HL) to SXEW is one of the most well-known processes for low-grade copper oxide ore processing and production [3] [4] [5]. In recent times, as high-grade copper deposits have ...
The microbial community in a biological heap leaching (BHL) system is crucial for the decomposition of ores. 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 …
Bacterial heap leaching of refractory gold/sulfide ores. Min Eng 1994; 7: 619–631. Google Scholar Bennett JW, Harries JR, Pantelis G et al. Limitations on pyrite oxidation rates in dumps set by air transport mechanisms. In: Salley J, McCready RGL, Wichlacz PL, eds. Biohydrometallurgy. Canada Centre for Mineral and Energy Technology, 1989: 551 ...
The most successful copper heap leaching operations have been those processing copper oxides and secondary copper sulphides (Table 1).Chalcocite (Cu 2 S) is the main copper sulphide mineral mined at bioleaching operations. Some of the chalcocite heap operations began as oxide (chemical) leach operations and were converted to …
The bacterial succession in bioheap leaching solutions allowed the leaching cycle stages to be described as: i) Acid conditioning and soluble copper releasing, ii) …
ties. Precious-metal heap leaching, developed in the late 1960s, was another giant leap forward in the long history of recovering precious metals, es-pecially gold. Precursors to Heap Leaching In Nevada, evolving milling technology began with the Washoe process of pan amalgamation developed on ia City's Comstock Lode in the early 1860s.
Bacterial heap leaching 627 For the simulations in Figures 1 and 2 the ferric and ferrous content in the influent to the heap was considered to be constant, which is a fair representation of the conditions in the experimental column leaches. The ferric-to-ferrous ratios of the solution fed were fairly constant due to bacterial action in the ...
The Leaching Process. Bacteria perform the key reaction of regenerating the major ore oxidizer which in most cases is ferric iron as well as further ore oxidation. The reaction is performed at the bacterial cell membrane. In the process, free electrons are generated and used for the reduction of oxygen to water which produces energy in the ...
Heap leaching generates a pregnant leach solution (PLS) containing 1–6 g/L Cu²⁺, which is sent to solvent extraction and electrowinning for copper production.
Heap leaching is leaching performed on low to medium grade ores. The ores must have enough valuable material to justify additional size reduction. ... One important factor that complicates the evaluation of bacterial leaching kinetics is the dynamic nature of bacterial populations and the diversity of types of bacteria within the …
The Effect of Aeration on Copper Leaching Kinetics. Figure 2 shows the copper concentration in the PLS and the cumulative extraction with and without aeration. Despite the lower cyanide soluble copper grade and larger particle size in the heap with aeration, which are unfavorable conditions for leaching, the aerated heap yielded PLS …
Bacteria • Count on solids ... Heap leaching as a hydrometallurgical process is one of the cheapest methods and particularly useful in the case of ores with a low metal content. These ...
Adding bacteria to the heap leaching to increase the leaching rate of chalcopyrite is the current mainstream heap leaching process of chalcopyrite. However, there are many factors that affect the leaching efficiency in the process of biological heap leaching, of which temperature and climate are the main influencing factors.
The majority of heap leaching operations use sulphuric acid as the lixiviant and rely upon microbial Fe(II) oxidation to generate the ferric ions necessary for sulphide oxidation. Process water management is directed towards minimal water use and …
A Bacterial Heap Leaching Approach for the Treatment of Low Grade Primary Copper Sulphide Ore, 3rd S. African Conf. on Base Metals, SAIMM Symp. Series S39, ISBN 1-91. P. 471-484.[11]
1.. IntroductionBacterial leaching of agglomerated ore in heaps was responsible for 200,000 t/year of cathode copper in 1998 Bustos and Espejo, 1998, Walsh et al., 1998.Despite the successful operation of three stand-alone bacterial heap leaching facilities in two continents, the technology has been characterized by lower-than …
The heap leaching technology was pioneered in the U.S.A., but significant advancements were made to it in Chile, ... In direct bacterial leaching, the bacterial cell comes into direct contact with the surface of the sulfide mineral, and the oxidation process occurs through several enzymatic steps. On the other hand, in indirect bioleaching ...
Slope leaching: Finely ground ores (up to 100,00 tons) are dumped in large piles down a mountainside and continuously sprinkled with water containing Thiobacillus. The water is collected at the bottom and …
The copper ore before heap bioleaching consists of about 9% pyrite, about 0.8% copper sulfides (mainly chalcocite), 50% silica, and other gangue minerals, with very few alkaline gangues. Heap leaching is stacked with run-of-mine, and pyrite oxidation results in excessive acid and iron accumulation in the cycling solution during the leaching.
The GENMIN Group has being carrying out research on the bacterial heap leaching process for a number of years, and has successfully demonstrated the process on a laboratory and large column scale for ores containing acid-consuming gaugue and for ores where the gangue is not acid-consuming. In addition, mathematical models have …
The results showed that the concentration of leaching bacteria was related to the leaching temperature, and heap leaching worked in a topâˆ'down manner. Firstly, the top part of the heap was cooled with the addition of new leachate, which encouraged the growth of leaching bacteria and accelerated bioleaching of the chalcocite.
Of these techniques, bacterial heap leaching has been widely used to recover metals because it is economical, environmentally friendly, easy to operate, and has large-scale practical applications [14,15,16]. However, to the best of the author's knowledge, bacterial heap leaching for granite-type uranium deposits has not previously been …
Industrial biomining of chalcopyrite is typically carried out in large scale heaps that suffer from the downsides of slow and poor metal recoveries. In an effort to mitigate these drawbacks, this...
Bosecker K (1977) Studies in the bacterial leaching of nickel ores. In: Schwartz W (ed) Conference Bacterial Leaching 1977. GBF Braunschweig, Verlag Chemie, Weinheim, pp 139–144. ... Franzidis JP, Petersen J (2015) Heap leaching technology – current state, innovations and future directions: a review. Min Proc Extr …
• Bacterial lixiviant flow rates to heap (Panda et al., 2012a; Pradhan et al., 2008) • Mass transfer • Microbial adaptation ability ... modeling aspects in heap leaching systems should focus much on the dynamic aspects such as to predict the actual leaching behavior in a freshly stacked heap as well as at different periods of leaching ...
Heap leaching. Stage 1: acidophilic chemolithotrophic bioleaching for copper for eight months. Stage 2: bacterial leaching using microbial protein hydrolysate in the presence of thiosulphate and copper ions to solubilize gold and silver; crushed size less than 10 mm, pH: 9.5–10.0, for 30 days, irrigation rate: 200 L/ton of ore per 24 h ...
حقوق النشر ©2000- 2024 شركة شنغهاي زينيث
