Arsenic Extraction From Realgar

David Aldridge



Arsenic can be won from Realgar by reacting the powdered mineral with Fe filings. The result will be solid As, and solid FeS. This needs to be done under a hood, as some of the As is inevitably vaporised into Arsine.


Fe: 1 Mol is equal to 55.847 g

As: 1 Mol is equal to 74.92159g

S : 1 Mol is equal to 32.066 g



If we break up everything into 1/10th of a mole for each of the elements (The As and the S are still chemically bonded, we are just figuring out how much of each element is present), we would find that 1/10th of a mol of each would equal...

55.847g Fe = 5.6g Fe
74.921g As = 7.5g As
32.066g S = 3.1g S


Thus, the approximate amount of each chemical that would be needed it as follows...

10.8g AsS
05.6g Fe

By combining these two compounds into a finely-ground mixture, and heating until the Fe is red hot, we can extract the As from the Realgar quite quickly. In The End, we would obtain the following (if the reaction went 100% as expected)...

8.9g FeS
5.6g As


The equation for this reaction would be as follows...

AsS(s) + Fe(s) --> FeS(s) + As(s)


Always remember to follow proper lab safety when working with any chemical. Especially when working with an element as toxic as As!

-David Aldridge

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