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Copper Extraction Experiment

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Oh. Dash it, hold on, I’ll fix it…. (Metallurgy?) Yes, metallurgy is a science about getting metals out of rocks, and metallurgists or mineral processing engineers are the people who do exactly that. (Ah!) One of the jobs a metallurgist is interested in, is extracting as much mineral as possible from an ore and that rocks contains the minerals, they then want to convert much of minerals into metal. It is can be using in the variety ways such as… … (Let´s go on man, how do we get the metal out of rocks?) Well, one way of doing this is by something called SOLVENT EXTRACTION The way it works is after mineral ore containing copper has been mined and crushed, the ore is piled into a heap. Now the stacked ore heap is washed with a dilute sulfuric acid. The copper dissolves to form a blue solution called “copper sulfate” but it is not all over yet, because we want copper metal, not copper sulfate. Well this is the real fun begins. A process called... SOLVENT EXTRACTION has to happen before electrowinning can take place. (Easy tiger, we getting a bit head of ourselves here aren´t we) Yes! We are only looking at the SOLVENT EXTRACTION part today. Heap leaching produces only low concentrations of copper in the aqueous copper solution, see left! and this is too weak to allow a successful electrowinning of the copper metal. Also the leach solution contains dissolved iron, as well as copper and iron, shouldn’t reach the electrowinning stage. (mh! in English…) What this means in the solvent extraction process, we´re purifying the solution, so it contains only copper and also concentrating it ready for electrowinning, see right! (So, what do we need to get started?) … Well, safety comes first, so we need cover shoes, long trousers, a long sleeve shirt, these are all necessary, and don’t forget gloves to protect your fingers and safety glasses to protect your eyeballs. (Right of course) And this is the equipment and the chemicals that we will be using at the completion of this experiment. By completing this experiment, you will determine the number extraction stages, that are required to fully load the organic phase with copper. Now chemists and metallurgical engineers do it this to collect the extraction data for varying conditions that may be encountered in the industrial process, and to construct extraction isotherms. They use these isotherms, to determine optimums numbers stage needed for the extraction and stripping processes, and to determine how large the reactors needs to be. (Dude…in English) You want to know how many times you have to go through the process, before the extractant won’t take any more copper. In this way, it´s possible to minimize time and cost in the obtaining the copper. (Yes good! good! let’s get started, what do we do first) All right! Well you need to begin with a prepared solvent extractant; 200 ml of this is placed in the separating funnel. Next, 200 ml of the copper sulfate leach solution. (And that’s the blue stuff, right?) Yes! That’s right, the blue stuff. 200 ml of the blue colored copper sulfate leach solution is added. Next, we insert the rubber stopper into the top of the separating funnel and shake the mixture vigorously for 2 whole minutes. (Gee! That’s a lot of shaking) Well, the leach solution and organic phase are mixed like this to extract copper ion, but not iron ions from the aqueous layer, and dissolve them in the organic layer, the vigorous mixing increases the surface area of contact between the aqueous and organic phases, so increasing the overall rate of reaction, and hence reducing the time required to reach the chemical equilibrium. (Excuse me) I’m sorry, we’re shaking it up to increase the chance of contact between the copper and the extractant. It just happens faster in that way. (Ah! Sweet) Now we allow the phases of separate and this will take approximately 1 minute (Hey you! What’s the go! It changed colors and formed layers?) When the extractant molecules come in contact with the copper cathodes, they form a complex called CHELATE. The chelated species is soluble in the kerosene and not in the aqueous layer. So when the two Invisible liquid are allowed to settle, they actually separate out! The refinate can then beside off, leaving behind of organic phase, that is somewhat enriched in copper, just as we are doing now. (What’s he up to now?) Now we are measuring and recording the ph of extracted aqueous phase, we´re also using eye colorimetry, to determine the copper ion concentration remaining in the aqueous layer… (Right… And then?). It will make more sense later, if the organic phases mixed again with Fresh PLS (Pregnant leach solution) even more copper cathodes ions will be chelated, further enriching the organic phase with copper. Sufficient contacting steps are undertaken, to ensure that the organic phase is loaded to optimum capacity with copper (Ah! So what you say is do we do it over and over to get as is much copper as we can) That’s right! (I get this!) Let’s observe carefully as we conduct the same procedure a further five times, then we’ll take a closer look at the copper ion concentration, at the end of each phase. (Whatever you say, you are the doc… doc, so what is go with comparing the samples). Well we are checking to determine the concentration of copper in each aqueous layer samples. (Yeah! But surely there is a machine that can do that) Yes! There is, it’s called the colourimeter, it works by using a wave length of about 625 nanometers, to measure the absorbents of the solutions by drawing a Bier-Lambert curve, it is possible to get the concentration of each of the samples. (So if my school didn’t have one of those fancy gadgets, we could do what he is doing). Correct again my young apprentice. (Right) What does that even mean? (I don’t know) Well, by using a technique called eye colourimetry. And this is where you can compare color of copper sulfate solutions with a known concentration, with the resultant solution that you have, by holding each samples up to the light along side the standards, it’s possible to make a good approximation of copper ion concentration. (mh! interesting) That´s sound like the end! But I’m not going to give you the result here, oh no! Then you wouldn’t have to make the experiment or think for yourself and where is the fun in that. Subtitled by: Francisco Cortés and Julio Quiroga

Video Details

Duration: 6 minutes and 20 seconds
Country: United States
Language: English
Views: 381
Posted by: darko on Jun 2, 2010

copper extraction experiment in lab

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