Chemical supply pure copper cathode plate12/11/2023 ![]() ![]() It shouldn't be asked at this level anyway.Ĭopper can be extracted from non-sulphide ores by a different process involving three separate stages: However, if the copper was in the +1 state originally, then the sulphide ions are reducing Fe(III) to Fe(II).īecause of the uncertainty, I have just deleted the paragraphs about this. If it was true, then you can show that the sulphide ions are reducing Cu(II) to Cu(I). Note: Until I added the questions in July 2015, I had always assumed (on no good evidence - never a good idea!) that chalcopyrite contained copper and iron both in the +2 oxidation state - but that may well be wrong. I don't feel qualified to go any further with this. There is also apparent disagreement in the literature about whether chalcopyrite contains Cu(II) and Fe(II) or Cu(I) and Fe(III). The other reaction is more difficult to deal with, because you can't work out all of the oxidation states by following the simple rules - there are too many variables in some of the substances. The reducing agent is therefore the sulphide ion in the copper(I) sulphide. The sulphur has been oxidised (increase in oxidation state). That means that both the copper and the oxygen have been reduced (decrease in oxidation state). In sulphur dioxide, the oxygen has an oxidation state of -2 and the sulphur +4. The oxidation states of the elements oxygen (in the gas) and copper (in the metal) are 0. In the copper(I) sulphide, the copper is +1 and the sulphur -2. Let's look at the oxidation states of everything. I can only look at the second reaction because it is the only one I can be confident about. If you choose to follow this link, use the BACK button on your browser to return to this page later. If you aren't sure, then either follow this link (which could take you some time) or skip this bit completely if you don't need to be able to do it. Note: You aren't going to make much sense of this next bit if you don't have a good working knowledge of oxidation states (oxidation numbers). It is worthwhile spending some time sorting out what the reducing agent is in these reactions, because at first sight there doesn't appear to be one! Or, if you look superficially, it seems as if it might be oxygen! But that's silly! The end product of this is called blister copper - a porous brittle form of copper, about 98 - 99.5% pure.Įxploring the redox processes in this reaction Try this page from The Essential Chemical Industry as a starter. If you are working at a higher level, or want proper technical details of particular methods, you will need to look elsewhere. This quick summary is probably unsuitable for anything other than UK A level purposes. One of these does the whole thing in a single furnace, and the equations above probably best represent that particular process. ![]() The problem is that there are all sorts of variations on this extraction. Warning! This is a simplified version of the process - an attempt to condense the whole thing down to two fairly straightforward equations. The copper(I) sulphide produced is converted to copper with a final blast of air. Much like in the Blast Furnace, the calcium carbonate is involved in the production of the slag.Īn overall equation for this series of steps is: This is used to make sulphuric acid via the Contact Process. Most of the sulphur in the chalcopyrite turns into sulphur dioxide gas. ![]() The iron in the chalcopyrite ends up converted into an iron(II) silicate slag which is removed. The copper(II) ions in the chalcopyrite are reduced to copper(I) sulphide (which is reduced further to copper metal in the final stage). The concentrated ore is heated strongly with silicon dioxide (silica), calcium carbonate and air or oxygen in a furnace or series of furnaces. Note: You will find a brief description of froth flotation on the introduction to metal extraction page. The ores typically contain low percentages of copper and have to be concentrated by, for example, froth flotation before refining. Getting copper from chalcopyrite, CuFeS 2Ĭhalcopyrite (also known as copper pyrites) and similar sulphide ores are the commonest ores of copper. Sulphide ores such as chalcopyrite are converted to copper by a different method from silicate, carbonate or sulphate ores. The method used to extract copper from its ores depends on the nature of the ore. Before you get too bogged down in the extraction of copper, make sure that you need it for whatever syllabus you are using. This page looks at the extraction of copper from its ores, its purification by electrolysis, and some of its uses. ![]()
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