Barium carbonate
Conundrum, Fri Oct 04 2013, 05:38AMHi all.
I recently acquired some barium carbonate and now have to test it for purity.
Also have some:- copper oxide, yttrium oxide and other assorted metal oxides.
Can any of you nice chemistry boffins suggest a way I might be able to test these
for iron and nickel content?
Apparently for HTSC less than 1 part in 10 exp 7 is the lower limit of working, ideally
99.99% purity of the starting materials is required for Y123 to work.
Re. synthesis, this isn't as bad as I thought as a workaround for the oxygen annealing
is to use a domestic microwave with an oxygen hookup to the quartz boat so it only
needs 1 hour calcination and 1 hour of O2 rather than the usual 36.
This can be done using any oxygen source from simple electrolysis in a U-tube to the
good old fashioned H2O2/MnO2 method.
I am able to send small amounts by post as long as they are less than 0.5 grams as
"research grade materials for analysis" , stored in a screw top container and securely wrapped.
Turns out that ceramics are permitted after all but you have to know who to ask
Re: Barium carbonate
Bored Chemist, Sat Oct 05 2013, 03:35PM
Sub ppm analysis isn't something you are likely to get working in a home lab unless you are prepared to put a lot of effort into it. Among other things, many reagents won't be that pure- for example if you dissolve the BaCO3 in acid as part of the analysis, you need acid with much less than 1 part Ni or Fe in 10^7.
It's almost certainly going to be better to send some to a lab for analysis.
What analytical equipment have you got?
Bored Chemist, Sat Oct 05 2013, 03:35PM
Sub ppm analysis isn't something you are likely to get working in a home lab unless you are prepared to put a lot of effort into it. Among other things, many reagents won't be that pure- for example if you dissolve the BaCO3 in acid as part of the analysis, you need acid with much less than 1 part Ni or Fe in 10^7.
It's almost certainly going to be better to send some to a lab for analysis.
What analytical equipment have you got?
Re: Barium carbonate
Conundrum, Wed Oct 09 2013, 08:54PM
Basic stuff such as microscope, oscilloscope, frequency counter. Might be able to kludge together a spectrometer using old webcam, tube and DVD segment as the prism to separate out the lines.
-A
Conundrum, Wed Oct 09 2013, 08:54PM
Basic stuff such as microscope, oscilloscope, frequency counter. Might be able to kludge together a spectrometer using old webcam, tube and DVD segment as the prism to separate out the lines.
-A
Re: Barium carbonate
Bored Chemist, Sat Oct 12 2013, 03:18PM
Have you got plenty of time?
The big problem you have is that, unless you pay a lot for high purity reagents you could easily add traces of Ni and Fe to the material you are working with.
There is a potential way round that: add reagents as gases, Ni and Fe compounds are not usually volatile.
So, if you put some BaCO3 in a clean glass dish and put it in a closed container with another dish containing hydrochloric acid the acid will evaporate, condense on the BaCO3 and dissolve it to form a solution of BaCl2. You can't seal the container- the CO2 has to be able to escape. The sort of plastic container used to store food is probably a good choice. Use a clear one if you can.
OK, given time, that will give you a slightly acidic solution of BaCl2.
Take the dish of HCl out of the container and replace it with a dish containing ammonia solution.
That should get rid of any excess acid in the solution.
Then you need to produce H2S in the container by the reaction of dilute acid with a sulphide such as ferrous sulphide which can be obtained by the reaction of iron filings with powdered sulphur.. You need to make sure that no spray of droplets from the reaction can get to the BaCl2 solution- a plug of cotton wool in the neck of a bottle would probably do the trick.
If there's iron, lead, nickel or any of a lot of other "heavy metals" present in the BaCO3 then they will form a brown/ black precipitate when exposed to H2S.
It's a lot of trouble, it will be slow and it's not hugely sensitive but it would show up serious contamination by Fe or Ni.
I still think you should pay for an assay of it instead.
Bored Chemist, Sat Oct 12 2013, 03:18PM
Have you got plenty of time?
The big problem you have is that, unless you pay a lot for high purity reagents you could easily add traces of Ni and Fe to the material you are working with.
There is a potential way round that: add reagents as gases, Ni and Fe compounds are not usually volatile.
So, if you put some BaCO3 in a clean glass dish and put it in a closed container with another dish containing hydrochloric acid the acid will evaporate, condense on the BaCO3 and dissolve it to form a solution of BaCl2. You can't seal the container- the CO2 has to be able to escape. The sort of plastic container used to store food is probably a good choice. Use a clear one if you can.
OK, given time, that will give you a slightly acidic solution of BaCl2.
Take the dish of HCl out of the container and replace it with a dish containing ammonia solution.
That should get rid of any excess acid in the solution.
Then you need to produce H2S in the container by the reaction of dilute acid with a sulphide such as ferrous sulphide which can be obtained by the reaction of iron filings with powdered sulphur.. You need to make sure that no spray of droplets from the reaction can get to the BaCl2 solution- a plug of cotton wool in the neck of a bottle would probably do the trick.
If there's iron, lead, nickel or any of a lot of other "heavy metals" present in the BaCO3 then they will form a brown/ black precipitate when exposed to H2S.
It's a lot of trouble, it will be slow and it's not hugely sensitive but it would show up serious contamination by Fe or Ni.
I still think you should pay for an assay of it instead.
Re: Barium carbonate
Steve Conner, Sat Oct 12 2013, 04:46PM
You could get it assayed, but wouldn't it be cheaper to just buy some barium carbonate etc of known purity from a supplier like Sigma Aldrich? It's not used for making drugs or bombs so there should be no issues.
Steve Conner, Sat Oct 12 2013, 04:46PM
You could get it assayed, but wouldn't it be cheaper to just buy some barium carbonate etc of known purity from a supplier like Sigma Aldrich? It's not used for making drugs or bombs so there should be no issues.
Re: Barium carbonate
Dr. Slack, Mon Oct 14 2013, 07:19AM
The first thing to do will be to do a dummy run, using none of the suspect material (so Fe content exactly zero), but all the other reagents and glassware you will need for the analysis. This does two things
a) a dry run for the analysis, might throw up somethings you hadn't thought of
b) analyses the residuals in your reagents and on your equipment, can you use shop HCl, or do you need the analar stuff that costs twice as much as the actual product? Are your cleaning procedures adequate?
Dr. Slack, Mon Oct 14 2013, 07:19AM
The first thing to do will be to do a dummy run, using none of the suspect material (so Fe content exactly zero), but all the other reagents and glassware you will need for the analysis. This does two things
a) a dry run for the analysis, might throw up somethings you hadn't thought of
b) analyses the residuals in your reagents and on your equipment, can you use shop HCl, or do you need the analar stuff that costs twice as much as the actual product? Are your cleaning procedures adequate?
Re: Barium carbonate
Conundrum, Wed Nov 06 2013, 10:32AM
OK, thanks.
Do you have any suggestions on grinding?
I have a mortar and pestle, and have sulphuric acid for cleaning.
Maybe I should make an electronic mortar and pestle grinding device :)
Conundrum, Wed Nov 06 2013, 10:32AM
OK, thanks.
Do you have any suggestions on grinding?
I have a mortar and pestle, and have sulphuric acid for cleaning.
Maybe I should make an electronic mortar and pestle grinding device :)
Re: Barium carbonate
Shrad, Wed Nov 06 2013, 10:05PM
a ball mill with mice balls inside a metal can that you can shut close with a plastic cover, and that you rotate using a laser printer paper roller on a motor
typical homemade ball mill
Shrad, Wed Nov 06 2013, 10:05PM
a ball mill with mice balls inside a metal can that you can shut close with a plastic cover, and that you rotate using a laser printer paper roller on a motor
typical homemade ball mill
Re: Barium carbonate
Conundrum, Thu Nov 07 2013, 06:06AM
Thanks, will give this a try
EDIT: If anyone wants them I have 10g of Y2O3, BaCO3 and CuO ready to go.
I can adjust amounts of the last two if someone wants to make some 1-2-3 and
have some strontium carbonate on order as well.
Conundrum, Thu Nov 07 2013, 06:06AM
Thanks, will give this a try
EDIT: If anyone wants them I have 10g of Y2O3, BaCO3 and CuO ready to go.
I can adjust amounts of the last two if someone wants to make some 1-2-3 and
have some strontium carbonate on order as well.
Re: Barium carbonate
Bored Chemist, Sat Nov 09 2013, 06:48PM
If you ball mill the stuff in a metal can, you don't need an analysis.
The iron content will be more than a few ppm.
Bored Chemist, Sat Nov 09 2013, 06:48PM
If you ball mill the stuff in a metal can, you don't need an analysis.
The iron content will be more than a few ppm.
Re: Barium carbonate
Conundrum, Sun Nov 10 2013, 09:18AM
Yes, i intend to use copper.
A possibility is to use a low temp fusing alloy such as BiSnPb or BiSn as this should be iron free.
Conundrum, Sun Nov 10 2013, 09:18AM
Yes, i intend to use copper.
A possibility is to use a low temp fusing alloy such as BiSnPb or BiSn as this should be iron free.
Re: Barium carbonate
Bored Chemist, Sun Nov 10 2013, 08:20PM
Are you sure that copper etc are less of a problem than Fe?
Bored Chemist, Sun Nov 10 2013, 08:20PM
Are you sure that copper etc are less of a problem than Fe?
Re: Barium carbonate
Conundrum, Thu Nov 14 2013, 07:31AM
I see what you are saying, Fe and Cu are chemically similar so Fe contamination of the balls is possible.
Would I be better off using ceramic balls for this?
EDIT: Got strontium
Anyone need any, let me know.
I tried the BaCO3+TiO2 experiment, 3 minutes in the nukerwave but no effect on weight.
I assume that it needs over 400C to do anything, can someone else try this and let me know please?
-A
Conundrum, Thu Nov 14 2013, 07:31AM
I see what you are saying, Fe and Cu are chemically similar so Fe contamination of the balls is possible.
Would I be better off using ceramic balls for this?
EDIT: Got strontium
Anyone need any, let me know.
I tried the BaCO3+TiO2 experiment, 3 minutes in the nukerwave but no effect on weight.
I assume that it needs over 400C to do anything, can someone else try this and let me know please?
-A
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