Metal finishing Q&As since 1989

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Stripping away gold tubing from quartz

I am a grad student in geology doing high temperature/pressure experiments on quartz prisms. The quartz prisms are welded into small pieces of gold tubing and then placed in an apparatus to take them to high P & T conditions.

My problem is that I need to get the prisms out of the gold capsules without breaking them. The usual method of snipping the capsule open causes the quartz to fracture.

I am looking into electroplating the gold off of the quartz, however I only seem to find information on electroplating gold on to items (i.e.: a metal ion solution --gold potassium cyanide?, (+) anodes, and a (-) cathode of the thing to be plated)

I was wondering if anyone might have any information or resources on how to go about removing the gold? Would it be possible to dissolve the capsules into a solution, and then electroplate the dissolved gold out of the solution? My capsules are 4.75 mm external diameter, 4.5 mm internal diameter, and approximately 3 cm long, about 3 grams of gold or so.

Any help would be very appreciated!

Thanks,

Jessica Fallon
grad student - College Station, Texas
2004

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Gold is inert, so you will find it very difficult to strip. The only solution that will attack gold is aqua regia and I suspect it will also attack your prism! Anodic dissolution of gold in a cyanide solution will also work, but before you start handling cyanide, you must be aware it is extremely toxic and if not used correctly could kill you and others. One other thought - if the gold is only very thin, you may be able to remove it by electron bombardment.

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2004