The Strontium I needed to dissolve in dil HCl till neutral and filter. Then re precipitate the carbonate by adding Pot carbonate solution. Filtering and washing several times in distilled H2O. The purity of colour is far better than the straight impure carbonate as supplied,
The Barium presents more of a problem as quite often barium and sodium sulphide is present as an impurity. After dissolving the crude carbonate a strong smell of Hydrogen sulphide is often evident. Upon standing a cloud of Barium sulphate from oxidised sulphide forms for many days afterwards. Air aggitation of the solution hastens the oxidation of sulphide to sulphate.. After standing the filtered solution is then either re precipitated as carbonate by the addition of pot carbonate. Then after filtering washing and drying be dissolved in nitric acid and crystalised forming Barium Nitrate which is almost AR quality in purity. Or it has the correct amount of Sodium chlorate added to form barium chlorate which is fractionally crystalised out, separated and recrystalised several times to eliminate any sodium.
You have to be aware that any sulphide present in the Barium carbonate is very dangerous if it should be mixed into a comp containing chlorate.
The Alchemist
Edited by The Alchemist, 27 April 2004 - 02:17 AM.
