DE2907139

An apparatus for the sulfatizing roasting of a selenium-containing raw material, especially the anode slime from copper electrolysis, with sulfuric acid at a raised temperature, the apparatus comprising a furnace chamber having a feed pipe for feeding a slurry of a finely-divided, selenium-containing raw material and sulfuric acid into the furnace chamber, an outlet for withdrawing the roasted solid from the furnace chamber, an outlet for discharging the selenium bearing gases produced during the sulfating roasting, members for heating the slurry in the furnace chamber, and devices for transferring, as a layer, the slurry fed into the furnace chamber from the slurry feed point towards the outlet for solid, the members for transferring the slurry being one or more combinations of a tray which supports slurry and a scraper which scrapes the tray, at least some of the slurry-heating members being mounted in the tray in order to heat it.