(This discussion was inadvertently lost in filing. It is published with apologies to the author and discussors for the delay and in the belief the information included is significant.)
Conduits for the disposal of corrosive fumes are very often constructed of sheet lead curved and “burned” to form ducts. There are many instances, especially in the chemical and metallurgical industry where fumes containing fluorine and/or hydrogen fluoride along with moisture and other gases are being successfully handled in sheet lead ducts and in some cases, lead pipe. For example, many ore roasting operations evolve fluorine along with sulfur dioxide and other gases. In the recovery of these gases, particularly when converted to sulphuric acid, lead-lined ducts and chambers are employed. Those illustrated are part of the St. Joseph Lead Company’s gas purification system at Josephtown, Pa., at which fluorine is encountered in the unpurified gas. At several large chemical plants...
