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Please help a struggling student with a school project

2007

Can you please direct my email to anyone that can help me.

Our professor gave us 1 KG of this already processed concentrated material.
It contains the following:
Cu-Copper with 8.19 %
Pb-Lead with 6.31%
Fe-Iron with 6.73%
Ag-Silver with 0.041%
Au-Gold with 0.10%

We are to extract each material to it pure form. I need some serious help. Can anyone please tell me the step by step how to do this? In very simple, basic descriptions.

Thank you so much ahead of time.

Sincerely yours,

Dale Wilson
Student - Miami, Florida, USA

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Must you process the entire 1000 g? That is a lot.

One way to proceed would be to dissolve the alloy in nitric acid, then use selective precipitation to drop each metal. The various precipitates could then be smelted back down to the metals.

The precipitation scheme is basic inorganic chemistry, which I would leave you to research.

Dave Wichern
Consultant - The Bronx, New York
2007

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First of three simultaneous responses --

Is this in metallic (alloy) form or in a powder form? Also, what is the balance of the material? What you gave does not add up to 100%, and it makes a MEGA difference.

James Watts
- Navarre, Florida
2007

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Second of three simultaneous responses -- 2007

Hi struggling student,

May I suggest that you contact an Assay Company or anyone doing Assay work ... they use all the acids and should be able to tell you exactly which will dissolve what ... and not, perhaps, attack the others

Freeman Newton [deceased]
(It is our sad duty to advise that Freeman passed away
April 21, 2012. R.I.P. old friend).

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Third of three simultaneous responses --

Your metals add up to 21.371%
What is the remainder? It may have a bearing on the separation and it certainly affects how you get the lot into solution.
Standard inorganic analysis techniques will separate the elements in the form of hydroxides, sulfides, etc. with more work to get the elements.
If you have the technology, you can go for a controlled voltage electrolytic separation. You will probably need a potentiostat and the knowledge to use it. By changing the cathode at each voltage step you can get the elements directly. Because the silver is only 41mg in total, you may want to precipitate that out at the appropriate step or dissolve it off the cathode with nitric and reduce with ...well I will leave you some of the work.

Geoff Smith
Hampshire, England
2007