>Date: Mon, 03 Nov 1997 09:51:32 +0000
>To: Sil Horwitz <silh@iag.net>
>From: Keith Dowsett <kdowsett@rpms.ac.uk>
>Subject: Re: Silver and nitric acid
>
>At 19:57 02/11/97 -0500, you wrote:
>
><Snip>
>
>>
>>> Eventually i'd like to dig out some silver ore (I know a locale), dissolve
>>>the rock, extract the silver, form the silver nitrate,
>>
>>Depends on the compound of silver in the ore. If it's silver sulfide, you
>>will get poisonous hydrogen sulfide gas as it dissolves. If it's silver
>>oxide, you will almost have to boil the nitric acid to get the silver
>>compound to dissolve. Silver sulfate won't dissolve at all, and must be
>>calcined with charcoal (or equivalent) to extract the silver, which can
>>then be dissolved.
>
>IIRC the ore is usually crushed and separated in floatation tanks first,
>then calcined (gives off noxious sulphur dioxide) before smelting with
>charcoal. This gives an alloy which may contain some or all of the
>following, lead, zinc, silver, gold, and cadmium. The latter are only ever
>present in tiny levels usually.
>
>Most silver ores contain substantial amounts of lead, especially sulphide
>ores. You may be able to separate silver from lead based on the fact that
>silver sulphate is less soluble than lead sulphate, but I don't think it's
>famously easy. Anyone know how the romans did it? Cupellation?
(end of forwarded msg)
Now do you see why I didn't recommend making your own silver nitrate? <g>
<<sil>>
Sil Horwitz, FPSA
Technical Editor, PSA Journal
silh@iag.net