Feasibility of Bioaugmentation with Iron/Sulfur Oxidizing Acidophiles to Enhance Copper Bioleaching from a Flotation Copper Ore

2015 ◽  
Vol 768 ◽  
pp. 447-457
Author(s):  
Li Juan Zhang ◽  
Feng Mao ◽  
Kai Li ◽  
Xin Hua Chen ◽  
Hong Bo Zhou
Keyword(s):  
Microbial Growth ◽  
Early Stage ◽  
Sulfur Oxidation ◽  
Copper Extraction ◽  
Copper Ore ◽  
Inoculum Concentration ◽  
Cell Numbers ◽  
Iron Sulfur ◽  
Copper Leaching ◽  
Sulfur Oxidizing

The feasibility of one strategy of bioaugmentation was assessed to enhance copper extraction from chalcopyrite. Bioaugmentation consisted of the re-addition of one iron/sulfur oxidizing acidophile (Acidithiobacillus caldus, Ferroplasma thermophilumorLeptospirillum ferriphilum) into the early stage (on the 5thday) of the bioleaching system. The strain selection and inoculum concentration of bioaugmentation were separately investigated by comparing changes in the bioleaching performance and leached solid residues. Results indicated that bioaugmentation with three augmented strains synergistically promoted the total microbial growth and increased the cell numbers, and then accelerated the iron/sulfur oxidation, thereby catalytically regenerated the copper leaching agents of Fe3+and H+compared to the unamended control. Finally, an enhancement in copper extraction was detected and moreover positively correlated with the introducing cell numbers. Particularly, re-addition ofL.ferriphilumon the 5thday showed the best improvement in copper leaching, which remarkably shortened the incubation time (12 days) of almost full copper extraction while only 85.8% of copper was leached after 24 days in the control. Therefore, bioaugmentation could be a useful bio-remedy to improve the bioleaching kinetics and level of copper ore.

Effects of Copper Extraction-Stripping Loops on Entrainment in Aqueous Raffinate

2014 ◽  
Vol 908 ◽  
pp. 18-21
Author(s):  
Yan Jun Liu ◽  
Xiao Rong Liu ◽  
Hui Li ◽  
Yong Sheng Li ◽  
Qing Li ◽  
...  
Keyword(s):  
Surface Tension ◽  
Solvent Extraction ◽  
Early Stage ◽  
Organic Chemical ◽  
Copper Extraction ◽  
Organic Chemicals ◽  
Stabilization Mechanism ◽  
Absolute Value ◽  
Copper Solvent Extraction ◽  
Average Size

Effects of extraction-stripping loops of organic phase on organic chemical entrainment in the aqueous raffinate in copper solvent extraction were studied in this paper. Results demonstrated that the total amount of organic chemicals lost in the aqueous raffinate decreased with the increase of times of extraction-stripping loops but reached largest at third loop. Entrainment was the dominate way of organic chemicals losing in the aqueous raffinate at early stage of the loops. The formation of entrainment and its stabilization mechanism was also studied. The average size of entrained droplet trended to increase with extraction-stripping loops increasing. Meanwhile, the absolute value of zeta potential trended to decrease. The surface tension of the aqueous raffinate increased after reaching the minimum value 41.3 mN/m at the 3rd loop. It showed that the formation of entrained droplets and its stability were mainly affected by the surface tension of aqueous raffinate.

scholarly journals Sulfur bacteria promote dissolution of authigenic carbonates at marine methane seeps

2021 ◽  
Author(s):  
Dalton J. Leprich ◽  
Beverly E. Flood ◽  
Peter R. Schroedl ◽  
Elizabeth Ricci ◽  
Jeffery J. Marlow ◽  
...  
Keyword(s):  
Carbonate Rocks ◽  
Sulfur Oxidation ◽  
Methane Seeps ◽  
Etch Pits ◽  
Active Dissolution ◽  
Authigenic Carbonates ◽  
Sulfur Bacteria ◽  
Sulfur Oxidizing ◽  
Sulfur Oxidizing Bacteria

AbstractCarbonate rocks at marine methane seeps are commonly colonized by sulfur-oxidizing bacteria that co-occur with etch pits that suggest active dissolution. We show that sulfur-oxidizing bacteria are abundant on the surface of an exemplar seep carbonate collected from Del Mar East Methane Seep Field, USA. We then used bioreactors containing aragonite mineral coupons that simulate certain seep conditions to investigate plausible in situ rates of carbonate dissolution associated with sulfur-oxidizing bacteria. Bioreactors inoculated with a sulfur-oxidizing bacterial strain, Celeribacter baekdonensis LH4, growing on aragonite coupons induced dissolution rates in sulfidic, heterotrophic, and abiotic conditions of 1773.97 (±324.35), 152.81 (±123.27), and 272.99 (±249.96) μmol CaCO3 • cm−2 • yr−1, respectively. Steep gradients in pH were also measured within carbonate-attached biofilms using pH-sensitive fluorophores. Together, these results show that the production of acidic microenvironments in biofilms of sulfur-oxidizing bacteria are capable of dissolving carbonate rocks, even under well-buffered marine conditions. Our results support the hypothesis that authigenic carbonate rock dissolution driven by lithotrophic sulfur-oxidation constitutes a previously unknown carbon flux from the rock reservoir to the ocean and atmosphere.

Insights into Heap Bioleaching at the Agglomerate-Scale

2017 ◽  
Vol 262 ◽  
pp. 185-188 ◽  
Author(s):  
Alison Cox ◽  
Christopher G. Bryan
Keyword(s):  
Interstitial Cell ◽  
Cell Concentration ◽  
Low Grade ◽  
Dissolved Metals ◽  
Copper Ore ◽  
Cell Numbers ◽  
Liquid Phases ◽  
Heap Bioleaching ◽  
Cell Concentrations ◽  
The Difference

Previous agglomerate-scale heap bioleaching studies have outlined the variations in cell numbers of the liquid and attached phases during colonisation of sterilised ore by a pure culture. In this study, a mixed mesophilic culture was used in agglomerate-scale columns containing non-sterilised low-grade copper ore. Over a six - month period, columns were harvested at various intervals to provide snapshots of the metal distribution and the quantity, location, and ecological variations of mineral-oxidizing microbes within the ore bed. The initial colonisation period in this experiment was dissimilar to previous work, as the indigenous community was retained within the ore-bed throughout acid agglomeration. The overall colonisation phase lasted for approximately 1,000 hours until cell concentrations stabilised. In each column, less than 0.05% of the total cells were found in the leachate, 15-20% in the interstitial phase and the remaining ~80% were attached to the mineral surface. Once cell numbers had stabilised, interstitial cell concentrations were approximately 2,000× greater than those in the leachate. This difference persisted for the duration of the experiment. Copper concentrations in the two liquid phases generally decreased over time, but were on average 50× higher in the interstitial phase. Iron concentrations were more stable, but again were 30× higher in the interstitial phase. This demonstrates that that the difference in cell concentration between the leachate and interstitial phases cannot be explained through diffusion gradients within the system as it is much greater than those observed for the dissolved metals. It also shows that the specific environmental conditions of the interstitial and attached cells are very different to those inferred through analysis of leachates alone.

IN VITRO DEGRADATION OF MIMOSINE BY MICROORGANISMS FROM THE ESOPHAGEAL SAC OF VOLES (Microtus arvalis)

1986 ◽  
Vol 66 (2) ◽  
pp. 547-551 ◽  
Author(s):  
H. KUDO ◽  
K.-J. CHENG ◽  
W. MAJAK ◽  
J. W. HALL ◽  
T. ARAI ◽  
...  
Keyword(s):  
Pyridine Ring ◽  
Microbial Growth ◽  
Early Stage ◽  
Microtus Arvalis ◽  
In Vitro Degradation ◽  
Ruminal Microorganisms ◽  
Highly Active ◽  
Alfalfa Hay ◽  
Degradation Rates

The microbiota in the esophageal sac of voles fed either cubed alfalfa hay or concentrate pellets were assayed to determine their capacity to anaerobically degrade mimosine in vitro. Differences (P < 0.01) were found between the two diets during the growth phase. The sac contents of voles fed concentrate pellets degraded mimosine and 3-hydroxy-4-(1H)-pyridone (DHP) rapidly, but inocula from voles fed cubed alfalfa hay only hydrolyzed mimosine to DHP. Degradation of the pyridine ring occurred at the early stage of incubation, concurrently with microbial growth. Thereafter, degradation rates appear to have been almost negligible and very similar for both diets. These results agree with previous data obtained with ruminal microorganisms, where highly active inocula were also associated with animals on concentrate diets. Key words: Detoxification, hydrolysis, esophageal sac, mimosine, 3-hydroxy-4- (1H)-pyridone, voles

scholarly journals Effects of Fe+2 and Fe+3 in Pretreatment and Leaching on a Mixed Copper Ore in Chloride Media

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 866
Author(s):  
María E. Taboada ◽  
Pía C. Hernández ◽  
Aldo P. Padilla ◽  
Nathalie E. Jamett ◽  
Teófilo A. Graber
Keyword(s):  
Chloride Concentration ◽  
Solution Concentration ◽  
Copper Extraction ◽  
Curing Time ◽  
Ferrous Ions ◽  
Copper Ore ◽  
Second Stage ◽  
Acid Consumption ◽  
Nacl Concentration ◽  
Leaching Solution

A study of the pretreatment stage and subsequent leaching of a mixed copper ore with different chloride solutions containing iron was carried out. The first stage considered pretreatment tests to decide the best conditions. Two levels of each factor were analyzed, 20 and 50 kg/t of NaCl, 17 and 25 kg/t of H2SO4, 0 and 25 kg/t of Fe2(SO4)3·9.2H2O, 0 and 25 kg/t of Fe2SO4·7H2O, and a curing time of 15 and 30 days. The results showed a significant effect of NaCl and curing time on the extraction, and less effect was found with the variation of acid and iron salts. The second stage included column leaching using a solution with 0.5 g/L of Cu+2, 80 g/L of Cl−, 10 g/L of H2SO4, and variable concentrations of ferric and ferrous ions (0 and 2 g/L). The best copper extraction of 80.2% was found considering a pretreatment of 30 days, 25 kg/t of H2SO4, 50 kg/t of NaCl, and a leaching solution concentration described previously with 2 g/L of Fe+2. The results showed the leaching of all copper oxide species and 20% of the copper sulfide species. In addition, there was a reduction in the acid consumption as the resting time increases. Furthermore, to evaluate a possible decrease in time and acid in pretreatment and chloride in leaching, tests including 10 and 25 kg/t of H2SO4 and 1, 15, and 30 days of curing and a diminution of the NaCl concentration to 20 g/L (content from seawater) were executed. The results showed a significant effect on curing time below 15 days. Furthermore, the slight influence of the decrease of acid on copper extraction gives cost reduction opportunities. The diminution of chloride concentration (80 to 20 g/L) in leaching solution decreases the extraction from 79% to 66.5%. Finally, the Mellado leaching kinetic model was successfully implemented.

Bioleaching of Low-Grade Copper Sulfide Ore Using a Colum Reactor

2009 ◽  
Vol 71-73 ◽  
pp. 409-412
Author(s):  
Wen Qing Qin ◽  
Yan Sheng Zhang ◽  
Shi Jie Zhen ◽  
Jun Wang ◽  
Jian Wen Zhang ◽  
...  
Keyword(s):  
Iron Concentration ◽  
Mixed Cultures ◽  
Copper Recovery ◽  
Low Grade ◽  
Leaching Rate ◽  
Ministry Of Education ◽  
Copper Ore ◽  
Copper Leaching ◽  
Pure Cultures ◽  
Mixed Bacteria

The effects of several variables on the column bioleaching of copper sulphide ore have been investigated. The copper ore contained chalcopyrite as the main sulfide minerals and bornite and chalcocite as the minor minerals. The experiment was carried out using bench-scale column leach reactors designed in Key Lab of Biometallurgy of Ministry of Education, which were inoculated with the pure mesophile bacteria (Acidithiobacillus ferrooxidans) and thermophile bacteria (Sulfobacillus), respectively, and the mixed bacteria which contain both iron- and sulfur-oxidizing bacteria. The results show that the mixed cultures were more efficient than the pure cultures alone and the maximum copper recovery 53.64% was achieved using the mixed cultures after 85 days. The leaching rate of chalcopyrite tended to increase with the increased dissolved ferric iron concentration. The effect of particle size on the rate of the copper leaching was also investigated, and it was shown that the copper bioleaching rate decreases as the amount of fines increase, which limits the permeability, thus decreases leaching rate. Jarosite and elemental sulphur formed in the column were characterized by the X-ray and EDS.

Patterned Copper Sulfide Thin Films: a Method for Studying Leaching Behaviour

2017 ◽  
Vol 70 (1) ◽  
pp. 26
Author(s):  
Rachel S. Brokenshire ◽  
Anthony Somers ◽  
Miao Chen ◽  
Angel A. J. Torriero
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Copper Extraction ◽  
Redox Potentials ◽  
X Ray ◽  
Copper Dissolution ◽  
Copper Leaching ◽  
Dissolution Behaviour ◽  
Leaching Behaviour ◽  
Resultant Film

An experimental study on copper leaching from Cu1.85S thin films is presented, wherein copper extraction is quantitatively evaluated by changes in film thickness measured by white light interferometric profilometry. Changes in the film morphology and elemental composition, as assessed by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy, are used to confirm that the loss in film thickness is due to changes in the copper content and that the resultant film species is consistent with the mechanism of copper dissolution. The Cu1.85S thin films were synthesized by chemical bath deposition. The leaching behaviour of copper from the films was investigated in acidic ferric sulfate media at pHs 1, 2, and 3, and pH 1 at redox potentials of ~350–650 mV versus Ag/AgCl in 3 M KCl. The changes in the film thickness and copper sulfur ratio were shown to reflect copper dissolution behaviour from chalcocite. Leaching of the Cu1.85S films demonstrated a greater decrease in film thickness as pH decreased. In addition comparison of the order of reaction as a function of proton concentration in non-oxidative dissolution of Cu1.85S (0.06) and as a function of iron(iii) concentration in ferric oxidation of Cu1.85S (0.40) shows that the proton dissolution reaction is negligible. Leaching of the Cu1.85S films at redox potentials of up to ~476.4 mV versus Ag/AgCl in 3 M KCl produced covellite and demonstrated greater decreases in film thickness with increases in the redox potential. Leaching of the films above ~476.4 mV resulted in the formation of spionkopite and demonstrated a much lesser decrease in film thickness. These results are consistent with Eh-pH diagrams for the Cu–S–H2O system.

Biooxidation of Carbonaceous Refractory Gold Ores by an Iron-Sulfur-Oxidizing Mixotrophic Bacterium at Neutral pH

2015 ◽  
Vol 1130 ◽  
pp. 440-444 ◽  
Author(s):  
R. Winarko ◽  
M. Zaki Mubarok ◽  
I.N. Rizki ◽  
Siti Khodijah Chaerun
Keyword(s):  
Extracellular Polymeric Substances ◽  
Extraction Yield ◽  
Ionic Form ◽  
Ferric Ions ◽  
Gold Extraction ◽  
Cyanide Ion ◽  
Solution Ph ◽  
Iron Sulfur ◽  
Refractory Gold ◽  
Sulfur Oxidizing

The ability of an iron-sulfur-oxidizing mixotrophic bacterium to treat two types of sulfide-rich carbonaceous refractory gold concentrates from Sulawesi and Sumatra in Indonesia was studied in comparison with an acidophilic chemolithotrophic bacterium Acidithiobacillus ferrooxidans. Over the course of the biooxidation experiments, the pH of the solution tended to rise (pH>5) due to the high content of acid-consuming minerals such as carbonates in both concentrates. Ferric ions were frequently observed to precipitate due to high solution pH. The BIOXskc employed in this study was able to increase the gold extraction from low sulfidic carbonaceous refractory gold concentrates by ~15% higher than that by using At. ferrooxidans. It was also capable of treating carbonaceous matters which causes preg-robbing effect and retaining iron in ionic form due presumably to the production of extracellular polymeric substances (EPS) under high solution pH. Nevertheless, BIOXskc also reduced the gold extraction yield of high sulfidic gold concentrates because of passivation effect. It is suggested that the precipitation of iron and sulfur on the surface of sulfide minerals during biooxidation may prevent cyanide ion contact with gold.

scholarly journals Investigation of the use of ammonium acetate as an alternative lixiviant in the leaching of malachite ore

2013 ◽  
Vol 19 (1) ◽  
pp. 25-34 ◽  
Author(s):  
Asım Künkül ◽  
Abdulvahap Gülezgin ◽  
Nizamettin Demirkiran
Keyword(s):  
Ammonium Acetate ◽  
Solution Concentration ◽  
Copper Extraction ◽  
Leaching Rate ◽  
Selective Leaching ◽  
Liquid Ratio ◽  
Copper Ore ◽  
Experimental Parameters ◽  
Leaching Reaction ◽  
Kinetics Of

The solutions containing ammonia allow for selective leaching of the copper from a copper ore. In this study, the leaching and kinetics of malachite ore were examined using ammonium acetate solutions as an alternative lixiviant. The effects of some experimental parameters on the leaching of malachite ore were investigated. A kinetic model to represent the effects of these parameters on the leaching rate was developed. It was determined that the leaching rate increased with increasing solution concentration, temperature and stirring speed, and decreasing particle size and solid-to-liquid ratio. It was found that the leaching reaction followed the mixed kinetic control model. The activation energy of this leaching process was determined to be 59.6 kJmol-1. Consequently, it was determined that ammonium acetate solutions could be used as an effective leaching agent for the copper extraction form malachite ore.

Coupling Flow-Reaction-Transmission during Square Column Leaching Processes

2013 ◽  
Vol 734-737 ◽  
pp. 698-702
Author(s):  
Jin Zhi Liu ◽  
Yu Hang Li ◽  
Bao Hua Yang
Keyword(s):  
Numerical Simulation ◽  
Hydraulic Conductivity ◽  
Leaching Rate ◽  
Analysis Software ◽  
Copper Ore ◽  
Column Leaching ◽  
Changing Trends ◽  
Copper Leaching ◽  
Leaching Experiment ◽  
Flow Reaction

This paper designs a square column leaching experiment to probe the coupling flow-reaction-transmission. 2.372 kg of Yanglas copper ore with a grade of 1.25% was loaded in a 6×6 cm2 column whose height is 60 cm. A 28-day leaching gave an approximate copper yield of 14.5 gram, which is an equivalence of copper leaching rate being 50%. Hydraulic conductivity was measured. The changing trends are analyzed by mathematical analysis software Eviews and Matlab, and the numerical simulation was conducted.

Sign in / Sign up

Export Citation Format

Share Document