Brian Ellis wrote :

>
> I agree that recycling would be the ideal, but I wonder to what extent
> the electronics industry would accept non-virgin grade solder,
> especially as requirements for fine-line SMD work can be very critical?
> I don't believe this problem would arise with most other applications
> for solder, representing about 50% of the consumption, but I do believe
> that we shall always require Grade A solder, hence mostly from freshly
> smelted tin. (Solders and Soldering, Manko, p. 46)

Since I applaud Brians efforts to discuss lead free issues rationally,  I
would like to clear up a commonly held metallurgical misconception that the
above text implies ( whilst declaring in advance my interest as being a
supplier of solder ).

Following smelting ( the process by which metal oxides are reduced to
metal ) there is invariably need for the smelter to refine its metal output
to produce the Grade A or fresh (sic) tin.

Such refining process ( usually electro refining or pyro metallurgical
techniques ) can also be undertaken by recyclers  so that the resulting
solder has contaminant levels which meet or indeed exceed those which can be
achieved using Grade A tin.

So, subject to the laws of economics, the entire tin lead requirement of the
electronics industry could be met from recycled sources.

Perhaps this would be a more worthwhile development if we are truly
interested in "joined up" environmental protection.


Malcolm Noble
Alco-Met (Solders) Ltd

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