Some areas were reported to contain 23grams of gold per tonne, but assays generally showed less than 5grams of gold per tonne. Trial crushings in yielded grams of gold from The irregular and patchy nature of the mineralisation reduces the economic potential of this deposit. Traces of molybdenite and a copper silicate were reported to occur in thin quartz veins in the area.
To understand the basic principles of copper extraction from ores To understand the basis of it s purification by electrolysis To identify some common uses of copper Extracting copper from its ores The method used to extract copper from its ores depends on the nature of the ore.
Chalcopyrite also known as copper pyrites and similar sulfide ores are the commonest ores of copper.
The ores typically contain low percentages of copper and have to be concentrated before refining e. Chalcopyrite extracted from Zacatecas, Mexico. Image used with permission from Rob Lavinsky iRocks.
The Process The concentrated ore is heated strongly with silicon dioxide silica and air or oxygen in a furnace or series of furnaces.
The copper II ions in the chalcopyrite are reduced to copper I sulfide which is reduced further to copper metal in the final stage. The iron in the chalcopyrite ends up converted into an iron II silicate slag which is removed.
Most of the sulfur in the chalcopyrite turns into sulfur dioxide gas. This is used to make sulfuric acid via the Contact Process. An overall equation for this series of steps is: Exploring the redox processes in this reaction It is worthwhile spending some time sorting out what the reducing agent is in these reactions, because at first sight there does not appear to be one!
Or, if you look superficially, it seems as if it might be oxygen! The oxidation states of the elements oxygen in the gas and copper in the metal are 0. That means that both the copper and the oxygen have been reduced decrease in oxidation state. The sulfur has been oxidized increase in oxidation state.
The reducing agent is therefore the sulfide ion in the copper I sulfide. You have to use some chemical knowledge as well. So use that information to work out what has been oxidized and what reduced in this case! Once again, the sulfide ions are acting as the reducing agent. Extracting of Copper from Other Ores Copper can be extracted from non-sulfide ores by a different process involving three separate stages: Reaction of the ore over quite a long time and on a huge scale with a dilute acid such as dilute sulfuric acid to produce a very dilute copper II sulfate solution.
Concentration of the copper II sulfate solution by solvent extraction. The very dilute solution is brought into contact with a relatively small amount of an organic solvent containing something which will bind with copper II ions so that they are removed from the dilute solution.
The solvent must not mix with the water. The copper II ions are removed again from the organic solvent by reaction with fresh sulfuric acid, producing a much more concentrated copper II sulfate solution than before. Electrolysis of the new solution. Copper II ions are deposited as copper on the cathode for the electrode equation, see under the purification of copper below.
The anodes for this process were traditionally lead-based alloys, but newer methods use titanium or stainless steel. The cathode is either a strip of very pure copper which the new copper plates on to, or stainless steel which it has to be removed from later.
Purification of copper When copper is made from sulfide ores by the first method above, it is impure. The blister copper is first treated to remove any remaining sulfur trapped as bubbles of sulfur dioxide in the copper - hence "blister copper" and then cast into anodes for refining using electrolysis.
Electrolytic Refining The purification uses an electrolyte of copper II sulfate solution, impure copper anodes, and strips of high purity copper for the cathodes. The diagram shows a very simplified view of a cell.
At the cathode, copper II ions are deposited as copper. The concentration of the solution should stay the same. All that happens is that there is a transfer of copper from the anode to the cathode.
The cathode gets bigger as more and more pure copper is deposited; the anode gradually disappears.An investigation was carried out to study the dissolution of cobalt and copper from a Cu– Co oxidized ore using organic acids.
The ore used in this study originated from the Central African Copper Belt region and contained very high levels of well-oxidized copper (2–8%) and cobalt (1–4%) minerals. in which K 3, K 2 and K 1 are the reaction rate constants for linolenic, linoleic and oleic acid, respectively.
The K3 is much larger than K2 and K,. In nearly all hydrogenations, linolenic acid is transformed into compounds which are less saturated.
Copper extraction refers to the methods used to obtaining copper from its ores. The conversion of copper consists of a series of chemical, physical, and electrochemical processes. Methods have evolved and vary with country depending on the ore source, local environmental regulations, and other factors.
Oxidised copper ore bodies . Bioleaching is the extraction of metals from their ores through the use of living ashio-midori.com is much cleaner than the traditional heap leaching using cyanide.
Bioleaching is one of several applications within biohydrometallurgy and several methods are used to recover copper, zinc, lead, arsenic, antimony, nickel, molybdenum, gold, silver, and cobalt.
Demonstration. An alkaline solution of glucose acts as a reducing agent and reduces added methylene blue from a blue to a colourless form. Shaking the solution raises the concentration of oxygen in the mixture and this oxidises the methylene blue back to its blue form.
IntroductionWorld copper production has increased steadily in the period –, from 9 Mt to 16 Mt per annum, and is predicted by the Australian Bureau of Agricultural and Resource Economics (ABARE) to reach close to 18 Mt in