Today's #WorkerWednesday photo dates to around 1945, and shows an operator cleaning scale from a zinc roaster during an early stage in the sulfuric acid manufacturing process at the East Chicago works of DuPont's Grasselli Chemicals Department plant.
Sulfuric acid is and was used by manufacturers of fertilizer, petroleum, textile, iron and steel, paint and pigment, chemical, explosives, and other industries. In the process seen here, finely ground zinc sulfide ore is blown into the roaster, where it is burned with air to produce sulfur dioxide and zinc oxide. The zinc oxide was be reduced to zinc metal and the sulfur dioxide was converted into sulfuric acid by either contact or chamber process.
This photograph is part of Hagley Library's collection of DuPont Company Product Information photographs (Accession 1972.341). To see more material from this collection online now, click here to visit its page in our Digital Archive.