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j_sum1
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I think I will use NaOH to remove the Fe. I like the idea of ammonia but my source of ammonia for my home lab is floor cleaner and so it doesn't make
practical sense.
As an aside, I think this might make a good project for my students next year. They are required to do an EEI (extended experimental investigation).
They get to choose but I get to make suggestions. Start with a lantern battery and isolate as many elements as possible. Lots of opportunities to
learn some good techniques including filtration, washing, drying, selective precipitation, crystallisation, even pyrolysis of the case. I'm looking
at one in front of me. It has:
pvc case
zinc cups
copper wires and terminals
graphite electrodes with copper wire in the centre
lead/zinc solder
mixture of MnO2/graphite powder wet with a solution of ZnCl2 (and perhaps some NH4Cl2)
cardboard/paper
There is a lot that students could investigate here and plenty to learn. Maybe even calcining the cardboard and casting the zinc.
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blogfast25
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j_sum1:
Surely if you're a teacher you have access to clean NH3? Having said that, of course it works with NaOH too.
The only problem with your project is that battery crud is real messy: the graphite conductor that's part of the dry electrolyte stains everything!
Some parents might not be so pleased if their beautiful broods come back with black fingernails and stained clothes. Make sure you do a dry run, just
you, to evaluate that.
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j_sum1
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I don't mix work and play. School chemicals and equipment stay at school.
[edited to add]
It seems to me to be not sensible to blur the lines between professional and private too much. I don't order chemicals or equipment through the
school accounts. I don't do personal projects at school. I don't want my workplace in any way held accountable for what I do at home -- not good
from a legal and risk assessment perspective.
Knowledge however is transferable. So if I am learning practical details about separation of Fe from Mn then my students may as well benefit from
that. As for the mess from battery gunk: that's what lab-coats are for.
(I have been fortunate to have gotten hold of some chemicals that would otherwise have been dumped. And I have been able to acquire some broken
glassware and re-purpose it. It is stupid to waste stuff that I can use and would probably buy anyway. It is also stupid to pay for disposal if I
can do it.)
[Edited on 17-11-2014 by j_sum1]
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DraconicAcid
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Ammonium manganese phosphate is fairly insoluble; I don't know if iron phosphate is as insoluble...
(ETA: No- all metals other than alkali metals will interfere with this precipitation.)
[Edited on 18-11-2014 by DraconicAcid]
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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