Tellurium: Bismuth Telluride Calcined with Soda and Oil, Air Blown through the Leach (Thorpe 1913)

Roasting bismuth telluride with soda and oil in a closed pot turns the tellurium into sodium telluride, which dissolves in water. Air drawn through the solution throws the tellurium out again as a grey powder. Result: grey tellurium powder. Source: Thorpe, Dictionary of Applied Chemistry vol. 5 (1913), p. 433. Not given: amounts, temperature and which oil. Picture drawn by Youblob.