33 replies to this topic

[Bonny]

For my GF to sell at craft sales and for friends etc... I am going to make pine cones that burn with different colours. For red the directions I have are to soak in a solution of SrCl2 in water.
http://chemistry.abo...a/aa052703a.htm

Not having any SrCl2 on hand, I will need to make some from SrCO3 and HCl. I am assuming after reaction, in a perfect world,I should be left with SrCl2 dissolved in water. Using pottery SrCO3 there will likely be some contamination to be filtered before I can evaporate water to collect the salt...
Any help would be appreciated.

[MMMMMM Pyro]

Yeah, thats pretty much right, with 1 difference, it should follow the following scheme:

Metal Carbonate + Acid = Salt + Water + Carbon Dioxide

And hence the following reaction:

SrCO3 + 2HCl = SrCl2 + CO2 + H2O

Hope this helps!

Regards,

Mike

[Anders Greenman]

Do this outside as the sulfur dioxide smell will be quite strong. I have calculated the weight ratio for you:

Assuming this reaction SrCO3 + 2 HCl => SrCl2 + CO2 + H2 + O

148g/mol SrCO3
241g/mol 30% HCl

Yield: 158g SrCl2

This is not very accurate and you'l probably need to add some more HCl. Continue until no CO3 remains.
I've done this before, and it works great. Gives a nice, pure Strontium Chloride

[MMMMMM Pyro]

the sulfur dioxide smell will be quite strong.

There is no Sulphur in the reaction!

Also.... there would be no Hydrogen or {Monatomic {or even Diatomic...}} Oxygen produced...

Regards,

Mike

Edited by MMMMMM Pyro, 24 July 2007 - 11:59 PM.

[Anders Greenman]

In theory, no, but pottery grade Strontium Carbonate contains some sulphide impurities and you'l smell them
About the oxygen and hydrogen, you're right, but at some stage they are formed separately, but in this type of equillibrium writing them will be wrong indeed.
But this doesn't affect the weight relationship between HCl and CO3. And as I said, it's very inaccurate, but does the job.

Edit: Correction, Sulphide.

Edited by Anders Greenman, 26 July 2007 - 05:59 PM.

[YT2095]

the smell comes from the Sulphide contamination, making H2S gas (it`s quite toxic and stinks of rotten eggs), I have found that this contam isn`t as great in Sr carb as it is with Ba, Ba carb can be quite unbearable.

the addition of a little H2O2 will get rid of most of the smell but you will lose a little of the product in way of insoluble Sulphate.

you can use an excess of either also, if you`re going to filter it then excess carb is best, if you plan on heat drying it then a little excess HCl is ok too, heating will get rid of any trace H2S and also evap the HCl.

I prefer the excess Carb and a good filtering personally.

edit: something else I thought I`de add, is that unlike Calcium chloride (a close relative of Strontium) is doesn`t suffer the same problems trying to crystalise it, in fact it`s about as soluble as house salt.
now with that in mind, depending on the concentration of your HCl, you may find if it quite strong that you`ll get SrCl2 crystals forming at the bottom of your reaction vessel, you`ll need to add more plain water to dissolve these if you plan to filter after, you`ll be throwing away good product if you don`t

also if you have Nitric acid, make some strontium nitrate also, even if it`s just a test tube, and then let that crystalise, it`ll form 2 different shaped crystals, I`ll not ruin the surprise but get yourself a magnifying glass and take a look at them, they`re truly beautiful!

Edited by YT2095, 26 July 2007 - 11:31 AM.

[Bonny]

Thanks everyone for the tips. I will hopefully try the reaction tonight.
I've successfully made Ba(NO3)2 with nitric acid and BaCO3 and experienced the H2S stink. Took awhile to get that one to work...
Hopefully less H2S produced from the SrCO3 and HCl. I don't have any HNO3 to make Sr(NO3)2 right now, but might try that later.I have made red stars that I'm happy with using SrCO3, because of difficulties acquiring Sr(NO3)2. I'm now curious about seeing the crystals making me more likely to try to make it.

[Bonny]

Just did the reaction. My HCl said 31.45% conc. I used about 500g HCl and 300g SrCO3. I added extra SrCO3 after the reaction had stopped. Didn't notice H2S stink as I was wearing respirator.I left the stuff for about 20 min. When I came back it resembled cream of wheat cereal (you guys got that over there?) Anyway it was very thick and milky looking. When I stirred it was gritty,almost like stirring wet sand. When I get some distilled water (thought I had some) I plan to dilute,filter and evaporate. Any other suggestions?

[YT2095]

you can use plain tap water for thit part, as there will be far more soluble contaminants in the pottery grade carbonate than you`ll ever get in 100`s of litres of tap water, besides it`s only calcium a little Mg and perhaps some Iron in water anyway, and possibly Chlorine (hardly a prob since it`s a chloride your Making).

save your money and use boiled and cooled tap water

Edited by YT2095, 27 July 2007 - 07:30 AM.

[Bonny]

you can use plain tap water for thit part, as there will be far more soluble contaminants in the pottery grade carbonate than you`ll ever get in 100`s of litres of tap water, besides it`s only calcium a little Mg and perhaps some Iron in water anyway, and possibly Chlorine (hardly a prob since it`s a chloride your Making).

save your money and use boiled and cooled tap water

The end product at this point definately looks like a thick,damp layer of salt. I'll use boiled tap water this weekend, then just need to wait for evaporation...
Thanks

[Bonny]

I now have a 4l pot evaporating after filtering out the undissolved carbonate and whatever else was in there...
I realized however that the use for which I am making the SrCl2 calls for a saturated solution to soak pine cones in. I think I will use about 1/2 and allow the rest to evaporate to collect the salt for later use.
My question is can I boil off some (or most) of the liquid without effecting my "crop"? Although the temp here has been 30C and hotter, the humidity is high also, so it takes forever to evaporate a large amount of liquid.

[YT2095]

you can boil all you like, you`re Well bellow the decomp temp of SrCl2.

it melts at 1148 and boils at 1523 kelvin, I suspect the water will be long gone before it gets that hot

as the soln evaps (at room temp), as soon as a crystal or 2 forms, you have your saturated soln

[Bonny]

I'm just assuming, but the same procedure should work to make Copper chloride using HCL and copper carbonate? I also have copper oxide but would sooner use up the carbonate as I rarely use it in coloured star comps.
Thanks.

[YT2095]

it will work yes, I have some here that I made doing exactly that.

you may need to add water to the HCl though as it will form a brown/Yellow version with the blue and make the reaction stick, to keep things simple the plain Blue version (hydrated) is fine.
you can always convert to the brown later with gentle heat.

again, do the carbonate in Excess and test the ph to make sure it`s not low (acid) and then Filter and crystalise


edited to add: if you have Carbonate and run out of the oxide, strong heating of the carbonate will leave you the Oxide CuO

Edited by YT2095, 07 August 2007 - 02:59 PM.

[Bonny]

it will work yes, I have some here that I made doing exactly that.

you may need to add water to the HCl though as it will form a brown/Yellow version with the blue and make the reaction stick, to keep things simple the plain Blue version (hydrated) is fine.
you can always convert to the brown later with gentle heat.

again, do the carbonate in Excess and test the ph to make sure it`s not low (acid) and then Filter and crystalise
edited to add: if you have Carbonate and run out of the oxide, strong heating of the carbonate will leave you the Oxide CuO

I have some that I bought for use in stars etc... and I think it is a green/blue colour. For these pinecones, I don't want to use up my "good stuff". In this application, would any (brown/yellow or blue) be suitable? I think it needs to be soluble in water to be absorbed...