The Method of Extracting Copper and Gold by Bacterial Leaching
The methods of extracting gold and copper have significant differences
and therefore require separate attention. Prior to leaching occurring,
either a tailings pile must be built up upon a base of impermeable
rock or a series of holes drilled into the ore, to provide access for
the bacteriaα.
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At process one the bacteria thiobacillus ferro-oxidans and
thiobacillus thio-oxidans, naturally occurring bacteria that obtain
the energy that they need to survive by oxidising Fe2+ and S2- ionsα,
are added to the copper ore. The bacteria in the acidic leaching
solution then convert the insoluble sulphide minerals into a solution
containing Cu2+, Fe2+, Fe3+ and SO42- ions. The acidic solution
provides the optimum pH for the bacteria to work at. Following the
bacterial action, the solution is drained off of the impermeable rock
or pumped out of the ground through the remaining holes and the
remaining solution prepared for concentration and extraction of the Cu2+
ions.
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Extraction and stripping then occur, here the copper ions are
selectively removed from the leaching solution by the "ligand exchange
solvent extractionγ " method. During this a good ligand (a molecule
containing one or more unshared pairs of electronsδ ) is dissolved in
an organic solvent, such as kerosene, which is immiscible with water.
This solution is mixed with ater containing Cu2+ ions and a
displacement reaction occurs.
Cu2+ (aq) + 2LH(organic) → CuL2(organic) + 2H+(aq) Equation 1γ
The copper ions are transferred from the water where they are of a
high concentr...
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... is likely to be placed and a thorough environmental
impact assessment carried out to ensure that the processes do not
cause undue environmental damageι. Finally governmental permission
must be obtained before commercial activity can take placeι.
References
α - Article 1 from examination pack: Mining with microbes, John
Merson.
β - How hydrometallurgy and the SX/EW process made copper the "green"
metal, William
Dresher.
γ - Article 2 from examination pack: Extracting copper from leaching
solutions.
δ - Columbia electronic encyclopaedia.
ε - www.allrefer.com/reference/encyclopaedia
η - Article 3 from examination pack: A golden opportunity, Jack
Barrett and Martin Hughes.
θ - www.gaiaguys.net
ζ - Wikipedia, the free online encyclopaedia.
ι - www.deh.gov.au/industry
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The objective of this experiment was to perform extraction. This is a separation and purification technique, based on different solubility of compounds in immiscible solvent mixtures. Extraction is conducted by shaking the solution with the solvent, until two layers are formed. One layer can then be separated from the other. If the separation does not happen in one try, multiple attempts may be needed.
What if there was a way to clean up radioactive waste spills? To clean it out of waters for safe consumption? For years and years people have seen the ways that bacteria can clean up oil spills and nuclear waste, and where baffled on how they did so. How did something so small, clean up a mess so big? Gemma Reguera and her team at Michigan State have solved the age long question. They have decided that bacteria do so by a hair like pili. The pili acts much like a conductive wire, by transferring electrons. Geobacter Sulfurreduncen is one of the many bacteria that do so. The energy conducted by the pili, in turn powers the bacteria. Geobacter, for short, is able to both isolate and, in a sense, kill off uranium in contaminated ground water. So my question is, how effective would it be to clean out mass amount of uranium? First I had to learn about Geobacter and the types of waste created.
The experiment we did was Copper Cycle. We reverted the copper to its elemental form after a chain of reactions. We performed a series of reactions, starting with copper metal and nitric acid to form copper (ii) nitrate. Then we reacted copper with sodium hydroxide, sulfuric acid, nitric acid and zinc to form precipitates. In conclusion our percent recovery was 40.38%.
the iron ore to iron. In the other cases of metals the most common way
Once the mixture had been completely dissolved, the solution was transferred to a separatory funnel. The solution was then extracted twice using 5.0 mL of 1 M
Due to the natural processes of magma flow, hydrothermal gradients, sedimentation, and evaporation, minerals are concentrated in various areas of the Earth’s crust. Obtaining these minerals for human use involves four general steps. • Locating the minerals • Then, extracting the minerals from the Earth in the form of ore or rock Then, processing (smelting) the ore to separate the impurities from the desired mineral. Finally, creating a useful product from the minerals. Procedure 1.
The Electrolysis of Copper Sulphate Aim Analyse and evaluate the quantity of Copper (Cu) metal deposited during the electrolysis of Copper Sulphate solution (CuSo4) using Copper electrodes, when certain variables were changed. Results Voltage across Concentration of solution electrode 0.5M 1.0M 2.0M 2 5.0 10.6 19.5 4 10.5 19.8 40.3 6 14.3 26.0 60.2 8 15.2 40.4 80.3 10 15.0 40.2 99.6 12 15.1 40.0 117.0 Analysing/Conclusion The input variables in this experiment are; concentration of the solution and the voltage across the electrodes. The outcome is the amount of copper gained (measured in grams) at the electrodes. By analyzing the graph, we can see the rapid increase of weight gained for the 2.0 molar concentration as the gradient is steeper.
The bacteria and wastewater is mixed in an aeration tank and therefore the contaminants are removed by action of sorption and series of breakdown by the bacteria.
However, when the pH levels reach a certain stage, the iron can then precipitate out, coating sediments with the characteristic yellow, red or orange colourings (D.E.P. 2, 2002; U.S.G.S. ; U.S.E.P.A., 2002). The rate that A.M.D. advances is also influenced by the presence of certain bacteria (Doyle; U.S.G.S). A.M.D. that has dissolved heavy metals such as copper, lead and mercury can contaminate ground and surface water.
Metal industry is the base of any modern and civilized countries. The demand of metals
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of Copper Sulphate. To do this I plan to work out the amount of water
In our days, mining for resources is inevitable. The resources we need are valuable in everyday life. Such resources mined up are coal, copper, gold, silver, and sand. However, mining poses environmental risks that can degrade the quality of soil and water, which can end up effecting us humans if not taken care of and many of the damages are irreversible once they have occurred.