Theory/Rationale:
To make dragon egg stars one needs lead oxide or bismuth oxide. Lead compounds are toxic and bismuth oxide is almost impossible to find. I only needed a few grams of bismuth oxide so decided to see if I could make it from bismol tablets. I did not try liquid PeptoBismol as it contains aluminum, magnesium and silicon compounds. These elements would remain in various compounds contaminating the desired bismuth oxide product
A look at the label of a generic brand of tablets I found showed the only ingredient that would not be volatile or burnable was the Bismuth portion of the bismuth subsalicylate. Intense heat should convert that to bismuth oxide and or bismuth carbonate. Both of these are useable in dragon egg formulas. The remaining ingredients were sugars and flavorings that should all burn off under high heat.
Unfortunately I did not record the brand at the time. Some tablet brands contain Calcium Carbonate so these brands will probably not work without some additional purification steps to get rid of the resulting Calcium compounds
NOTE: With only ~0.1 grams Bi2O3 yield per tablet it is NOT a way to make a lot.
I bought 30 tablets for 2 dollars so about 66 cents per gram Bi2O3. This is fine for my microscale needs but for someone needing more that would be about 300 dollars per pound !
For larger amounts I found bismuth subnitrate at a ceramic supply for
$18/pound, and that can be converted to Bi2O3 at about 80% yield. So
for those who need a lot: try to locate the unobtainable oxide or buy the subnitrate from the ceramic supply and convert it.
Now on to the process:
The tablets as purchased:
I crushed the tablets though this is probably not needed as they will be burnt to a crisp anyway
The powder is placed on a metal plate for heating. The plate is held with pliers or similar tool for safety.
Wearing safety gloves and glasses, the pills are heated with a bunsen burner or propane torch.
This brand contained a lot of sugar which melted and blackened:
Finally the sugars and other organic ingredients burned. This is what we want: to drive them off as carbon dioxide and water etc.
The bismuth will remain behind as bismuth oxide and/or bismuth carbonate.
Continue heating after the flames subside. The glowing areas are compounds continuing to be oxidized.
This looks almost ready but continue heating till what remains is the light yellow bismuth oxide
This is the final product and should be scraped off and weighed to see what the yield was:
To see if the product was useable bismuth compounds I made a micro-batch of dragon egg formula and tested the several 1mm stars by igniting with a torch.
A later test will be to prime the egg stars and see if they can perform in standard settings.
