aluminium potassium sulphate and copper sulphate crystals

[mtg]

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.

[Merilyn1]

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.

[Milo]

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

[Smithy73]

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.

[J.Speaks]

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.

CuSO4 Crystal.jpg

Alum Crystal.jpg

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?

[RosalieL]

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

Absolutely!

[Anna Z]

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.

[Wayne]

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.

[Pm706Narrogin]

Definitely keep your "waste" as it's completely reusable.

When the students are done, we get the test tubes back, heat them to make the crystals fall back into solution and pour it back into containers until next year. Then you just decant the liquid, scoop the crystals that have accumulated into your beaker to help it along and with a bit of luck it'll be right first try. Although usually it needs a bit of tweaking (either more copper sulphate or a bit more water).

Saves on having to make new supersaturated solution every year

[bucketchem]

yes i would reuse copper sulfate for crystallisation, but if you have too much you can react it with a carbonate and the copper carbonate can go in the bin.
not 100% sure on the disposal of the potash, would definitely keep this also and i dont think a carbonate reaction would be any help here

[Pm706Narrogin]

The potash is non-hazardous and can go down the sink according to NSW guidance.

Depending on the amount I had, I would wash to waste with a lot of water and consider pouring out smaller amounts over a longer period of time to break up the load so to speak.

[Labbie]

The potash is non-hazardous and can go down the sink according to NSW guidance.

Depending on the amount I had, I would wash to waste with a lot of water and consider pouring out smaller amounts over a longer period of time to break up the load so to speak. DO NOT FFORGET most of the older schools have a sup or pit, check with your GA or Head for the plans of your school,