Iron oxidation and precipitation in a simulated heap leaching solution in a Leptospirillum ferriphilum dominated biofilm reactor

2007 ◽  
Vol 88 (1-4) ◽  
pp. 67-74 ◽  
Author(s):  
Bestamin Ozkaya ◽  
Erkan Sahinkaya ◽  
Pauliina Nurmi ◽  
Anna H. Kaksonen ◽  
Jaakko A. Puhakka
Keyword(s):  
Iron Oxidation ◽  
Heap Leaching ◽  
Biofilm Reactor ◽  
Leptospirillum Ferriphilum ◽  
Leaching Solution

Bio-Heap Leaching of Primary Copper Sulfide Ore by JOGMEC

2017 ◽  
Vol 262 ◽  
pp. 99-102
Author(s):  
Tatsuya Shinkawa ◽  
Tadashi Chida ◽  
So Furukawa ◽  
Taro Kamiya
Keyword(s):  
Copper Sulfide ◽  
Heap Leaching ◽  
Sulfide Ores ◽  
High Iron Content ◽  
Iron Oxidizing Bacteria ◽  
Acid Consumption ◽  
Sulfide Ore ◽  
Leaching Solution ◽  
Sulfur Oxidizing ◽  
Copper Sulfide Ore

JOGMEC has been carrying out the study on primary copper sulfide ores leaching for recovering copper economically and efficiently by heap leaching. In our study, we have been using the primary copper sulfide ore produced in an IOCG deposit. The ore is characterized by high iron content and high acid consumption in leaching. For the optimization of the leaching, the conditions such as ore size, agglomeration, pH and irrigation rate of leaching solution were examined with column leach tests. The best result was over 80 % extraction of copper in 150 days with leaching solution of 1 M sulfuric acid and temperature of 45 °C. In this experiment, the fines of the ore sample were removed before putting it into the column to keep the permeability of the ore bed. In these column leach tests, the Fe2+/total-Fe ratio of PLS decreased gradually by the activity of naturally grown iron-oxidizing bacteria. The bacteria in PLS, which have the ability of iron-oxidizing and sulfur-oxidizing, were identified by next-generation sequencing as Acidithiobacillus caldus and Sulfobacillus thermosulfidooxidans. We also carried out bench-scale tests with about 200 tons of the primary copper sulfide ores. Iron-oxidizing and sulfur-oxidizing bacteria were identified in the leaching solution as same with column leach tests. It is considered that the bacteria worked in the leaching solution and on the surface of the ores.

A Novel Apparatus to Determine the Bio-Oxidation Kinetics of Sessile Leptospirillum ferriphilum

2013 ◽  
Vol 825 ◽  
pp. 238-241 ◽  
Author(s):  
Porogo Duku ◽  
Sanet H. Minnaar ◽  
Susan T.L. Harrison ◽  
Jochen Petersen
Keyword(s):  
Oxidation Kinetics ◽  
Iron Oxidation ◽  
Packed Bed ◽  
Leptospirillum Ferriphilum ◽  
Oxidation Rates ◽  
Cell Counts ◽  
Ferrous Iron Oxidation ◽  
Uptake Rates ◽  
Carbon Utilisation ◽  
Kinetics Of

A novel apparatus was developed to test the ferrous iron oxidation kinetics of Leptospirillum ferriphilum in predominantly sessile culture, by combining a CSTR under wash-out conditions with a packed bed of inert ceramic saddles. Results indicate that a dense culture of sessile bacteria is established rapidly, which achieves high oxidation rates in all experiments with a yield in terms of CO2 uptake rates comparable or higher to what has been measured in planktonic culture. However, the yield in terms of cell counts changes dramatically, indicating a substantial shift in carbon utilisation in the sessile culture. The apparatus is feasible as a method to study iron oxidation kinetics of sessile cultures, providing it is operated at sufficiently high recycle ratios.

Kinetics of Microbial Ferrous-Iron Oxidation by Leptospirillum Ferriphilum: Effect of Ferric-Iron on Biomass Growth

2009 ◽  
Vol 71-73 ◽  
pp. 259-262 ◽  
Author(s):  
Tunde Victor Ojumu ◽  
Jochen Petersen
Keyword(s):  
Ferrous Iron ◽  
Microbial Growth ◽  
Ferric Iron ◽  
Iron Oxidation ◽  
Iron Concentration ◽  
Biomass Concentration ◽  
Reaction Conditions ◽  
Leptospirillum Ferriphilum ◽  
Ferrous Iron Oxidation ◽  
Kinetics Of

The kinetics of microbial ferrous-iron oxidation have been well studied as it is a critical sub-process in bioleaching of sulphide minerals. Exhaustive studies in continuous culture have been carried out recently, investigating the effects of conditions relevant to heap bioleaching on the microbial ferrous-iron oxidation by Leptospirillum ferriphilum [1-3]. It was postulated that ferric-iron, which is known to be inhibitory, also acts as a stress stimulus, promoting microbial growth at higher total iron concentration. This paper investigates this phenomenon further, by comparing tests run with pure ferrous-iron feeds against those where the feed is partially oxidised to ferric at comparable concentrations. The findings clearly suggest that, contrary to reactor theory, it is indeed ferrous iron concentration in the reactor feed that determines biomass concentration and that ferric iron concentration has little effect on microbial growth. Further mathematical analysis shows that the phenomenon can be explained on the basis of the Pirt equation and the particular reaction conditions employed in the test work.

Kinetics of Ferrous Iron Oxidation by Leptospirillum Ferriphilum at Moderate to High Total Iron Concentrations

2009 ◽  
Vol 71-73 ◽  
pp. 255-258 ◽  
Author(s):  
K. Penev ◽  
D. Karamanev
Keyword(s):  
Ferrous Iron ◽  
Iron Oxidation ◽  
Iron Concentration ◽  
Total Iron ◽  
Effect Of Temperature ◽  
Leptospirillum Ferriphilum ◽  
Ferrous Iron Oxidation ◽  
High Concentrations ◽  
Kinetics Of ◽  
Total Iron Concentration

The effects of temperature, pH and iron concentration on the kinetics of ferrous iron biooxidation by a free suspended culture of Leptospirillum ferriphilum were studied in shake flasks and a circulating bed bioreactor at moderate to high total iron concentration. The kinetic study showed that there are two distinct modes of iron biooxidation: growth associated and non-growth associated, depending on the pH of the medium. There were also distinctive maxima of the effect of temperature and pH on the rate of biooxidation. A kinetic model of the process was proposed, based on an electrochemical-enzymatic model. The proposed model indicates that at moderate to high concentrations (above ~12 g/L), the total iron concentration becomes the single most prominent inhibiting factor.

The Effect of Aluminium and Magnesium Sulphate on the Rate of Ferrous Iron Oxidation by Leptospirillum ferriphilum in Continuous Culture

2007 ◽  
Vol 20-21 ◽  
pp. 156-159 ◽  
Author(s):  
Tunde Victor Ojumu ◽  
Jochen Petersen ◽  
Geoffrey S. Hansford
Keyword(s):  
Continuous Culture ◽  
Ferrous Iron ◽  
Oxidation Process ◽  
Iron Oxidation ◽  
Leach Solution ◽  
Potential Region ◽  
Leptospirillum Ferriphilum ◽  
Ferrous Iron Oxidation ◽  
Low Concentrations ◽  
Kinetics Of

In heap bioleaching the dissolution of gangue minerals from igneous ore materials can lead to the build-up of considerable concentrations of Mg and Al sulphates in the recycled leach solution. This may interfere with microbial ferrous iron oxidation, which drives the oxidation of the target minerals. The kinetics of the oxidation process have been well studied for Leptospirillum and Acidithiobacillus species in tank systems. Although not directly comparable, kinetic parameters derived for tank systems do apply also for heap bioleach conditions. In the present study the effect of solution concentrations of Mg and Al as sulphate at individual concentrations of 0 to 10 g/L and combined concentrations 0 to 16 g/L each has been investigated in continuous culture using Leptospirillum ferriphilum. Increasing the concentrations of the salts increasingly depresses the rate of ferrous iron oxidation and also shifts the viable range more and more into the low potential region. Al significantly reduces the amount of carbon maintained in the reactor (assumed to be commensurate with biomass), whereas Mg actually enhances it at low concentrations. In both cases, however, the rate is always depressed. The results indicate that heap cultures are likely to perform sub-optimally in those operations where build-up of dissolved gangue minerals is not controlled.

Inhibition Kinetics of Iron Oxidation by Leptospirillum ferriphilum to Residual Thiocyanate Present in Bioremediated Cyanidation Tailings Wastewater

2017 ◽  
Vol 262 ◽  
pp. 350-353
Author(s):  
Catherine J. Edward ◽  
Athanasios Kotsiopoulos ◽  
Susan T.L. Harrison
Keyword(s):  
Ferrous Iron ◽  
Iron Oxidation ◽  
Small Scale ◽  
Inhibition Kinetics ◽  
Batch Experiments ◽  
Oxidation Activity ◽  
Leptospirillum Ferriphilum ◽  
Low Level ◽  
Process Operation ◽  
Kinetics Of

Inhibition of iron oxidation by Leptospirillum ferriphilum in the presence of thiocyanate (SCN-) was studied in small-scale batch experiments. The L. ferriphilum culture was challenged with SCN- over a range of 0 mg/l to 10 mg/l. The data showed that L. ferriphilum was able to utilise ferrous iron at low-level concentrations of SCN- (0.25 mg/l to 1.75 mg/l), however exhibited a reduction in oxidation rate relative to the control (0 mg/l). Moreover, introduction of SCN- at low-level concentrations resulted in a lag in iron oxidation activity, specifically at concentrations of 1 mg/l, 1.25 mg/l and 1.75 mg/l. No iron oxidation was observed at SCN- concentrations above 1.75 mg/l, indicating complete inhibition. As L. ferriphilum is the dominant iron oxidising bacteria within biooxidation tanks, evidence of sustained iron oxidation activity at low-level SCN- concentrations affirms the potential of recycling bioremediated cyanidation wastewater within biooxidation circuits in bioprocesses for gold recovery from sulfidic minerals as residual SCN- concentrations in remediated effluent are reportedly lower than 0.25 mg/l. The inhibition kinetics of this system need to be explored further in order to develop a deeper understanding of the system such that it may be applied to inform process operation.

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