Pyrites Flue Dust: Caught in the Dust Chambers of Maletra Shelf Burners (Benker, Lunge 1913)

Sulphuric acid works burnt pyrites smalls on the shelves of Maletra burners to make sulphur dioxide. The gas carries fine dust out of the burner; dust chambers on top of and behind the burners let it settle. When the pyrites contains thallium, this dust is where it collects. Result: pyrites flue dust from the flues and dust chambers; each burner compartment burns 20 to 24 cwt of pyrites a day. Source: G. Lunge, The Manufacture of Sulphuric Acid and Alkali vol. I (1913), pp. 469-470, Mr Benker's practice. Not given: how often the chambers are emptied, how much dust. Sulphur dioxide is a poisonous gas; thallium dust is poisonous. Picture drawn by Youblob.