Hi Mike!
There are a number of key points here.
Reclaimed solders indistinguishable in quality from "virgin" tin based have
been used successfully for many years in many markets worldwide.
Many of the industrial solder markets e.g. auto heat exchangers or even
"came lead" for windows are now lead-free. All consumer solder is
lead-free. This mean's there is a very rapidly declining "sink" for high
lead solder materials.
For the next 15 years most of the recycle stock will be lead-containing as
lead-free hasn't started working itself through the life cycle in bulk, so
tin will need to be separated from lead. The best economic technology
struggles to reduce the lead level in tin cost-effectively below 0.2%.
Smelting doesn't work and really sophisticated multi-step processes are
needed.
Even "virgin tin" has a finite lead content by the way. You can imagine
what will happen to tin prices if the recycle circuit material is removed
from the equation!
European manufacturers will be obliged to have a significant recycled
content in their products. As solder is about 7% by weight of the circuit
board and as about 70% is not practical to recycle using existing
technology (brominated epoxy and glass fiber), it will be important to them
to use recycled solder.
So what do we do? Let's really work on recycling more solder and be
prudent when we set limits and specifications - let's include the recyclers
in the loop or we might get into a cost-prohibitive situation. In
particular, taking the lead limit below 0.2% will really pinch the tin
supply for the foreseeable (15 year+) future. In addition if manufacturers
are unable to dispose of dross, containers etc. to solder reclaimers as
they do now, there will be another significant cost increase.
Alan Rae
VP Technology
Cookson Electronics
225 Foxborough Blvd. Suite 150
Foxborough MA 02035
508 541 5843 fax 508 541 5871
617 803 7712 cell
Mike Fenner
<[log in to unmask] To: [log in to unmask]
o.uk> cc:
Sent by: Subject: Re: [LF] Recycling Solder
Leadfree
<Leadfree@IPC
.ORG>
04/02/01
01:24 PM
Please
respond to
Mike Fenner
You are right, but you need to pay close attention to the semantics
here: "virgin grade" and "virgin metal" are not quite the same thing.
There is also a distinction between recycled and refined.
I have always understood "virgin grade" to mean metal that is as pure
as freshly mined i.e. never been used "virgin metal". Virgin grade
can be achieved by refining recycled metal.
So far as I know all suppliers use virgin grade, with most electronic
grade suppliers also claiming further unique refining/processing
in-house.
After use electronic grade material is still pure enough for non
electronic use and so can be recycled as a lesser grade, and this
itself can then be recycled, [with some alloying additions and
corrections] for another less demanding application and so on till
there is nowhere to go except back to a big smelting company who will
clean the material right up by a true refining process to restart the
cycle.
Mike
----- Original Message -----
From: "Brian Ellis" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Monday, April 02, 2001 5:20 PM
Subject: Re: [LF] Recycling Solder
> Malcolm
>
> Yes, I agree with you that it is theoretically possible to purify
> recycled solder back to Grade A levels, and that to extract tin from
> cassiterite requires purification to remove some other metals.
However,
> it would seem economically more difficult to do so, in view of the
great
> mix of different impurities (metals and non-metals) in recovered
solder,
> compared with the few in ore. Also, the major solder producers have
> extolled the virtues of virgin-grade solder for so many years that
users
> will take a long time before they accept recycled solder which has
> traditionally been considered as OK for plumbers but not for us.
>
> Brian
>
> Alco-Met wrote:
> >
> > 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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