Australia's Science Forum

I have heaps on CuSO4 and AlKSO4 waste crystals and I was wondering if anyone has a prac or activity that would use it all. I wonder if we could make a big crystal with it all, as I've seen huge CuSO4 crystals. if I dissolve it all and evaporate some of the liquid to concentrate it a bit would the seed crystal theory work? Otherwise where do you get rid of it, seems overkill to send it off for chemical collection.

I'm stuck with heaps of copper sulfate waste, too. I've evaporated it down and could use it to make a saturated solution, but we never seem to need it here. I also have a couple of winchesters of mixed copper waste, but I know it is mostly c/sulfate. I have left it in a beaker to evaporate, to reduce the volume, which helps. I can't put any down the sink because of the septic system - so the usual methods are no good as there is still a chance of residual copper going down the sink.
At this stage, I am just sending it off for disposal.

There are ways to treat copper sulfate to make it safe for disposal. One I've heard mentioned is putting steel wool in it, although I haven't yet tried it myself. There's a recommendation for this on Science Assist:
https://assist.asta.edu.au/question/431 ... id=3be8dee

Once you have grown your copper sulphate crystals and finished looking at them you can grind them back to a powder and store them away for next time. Saves on a lot of waste. We have done this for a couple of years and haven't had any issues with them reforming, I also keep some whole as seeds if needed.

mtg wrote: ↑23 Oct 2019, 11:37 I wonder if we could make a big crystal with it all, as I've seen huge CuSO4 crystals.

I'm actually taking any CuSO4 and Alum crystals from the pracs and resaturating solutions to grow a set of crystals in the prep room. In just a few weeks I've grown a nice looking octahedral Alum crystal that's about 4cm from tip to tip. The CuSO4 didn't come out quite as good (looks like rock candy) but I didn't use the best seed crystal for it. It grows quite quickly tho, so I could probably try to make a better seed crystal from the prac leftovers.
I've given them to the teachers to show the students since it has been a couple of weeks since that prac and they really enjoy seeing the big crystals! I intend to keep growing them all year just to see how big I can get them. Then I'll start over next school year with a new seed

No reason we can't have a little fun ourselves, right?

J.Speaks wrote: ↑05 Mar 2021, 14:48 No reason we can't have a little fun ourselves, right?

Absolutely!

We evaporate off us much as we can then out for DG waste... it's a pain and costs but we are short on space so need to keep our DG store clear. Rather pay a few dollars and have our Chem store safe and clutter free.

Anna Z wrote: ↑07 Mar 2021, 09:44 We evaporate off us much as we can then out for DG waste... it's a pain and costs but we are short on space so need to keep our DG store clear. Rather pay a few dollars and have our Chem store safe and clutter free.

I evaporate it all off and reuse again next year for the same crystallisation prac.