Abstract: A method and apparatus for producing expanded clay or expanded shale finished product in a straight-line continuous rotary tube kiln provided with charging and discharge ends at respectively opposite ends of the kiln, the kiln being divided into a preheating zone and an expansion zone following one another in the direction from the charging end to the discharge end, the preheating zone being more proximate to the charging end and the expansion zone being more proximate to the discharge end, a stationary burner disposed in the vicinity of the discharge end and a mantle burner which rotates together with the kiln and which is located to heat the preheating zone.

Abstract: In a process and apparatus for producing an expanded particulate product in a rotary tubular kiln presenting an essentially linear product conveying and treating region free of lateral offset, in which a burner at the discharge end of the kiln operates to introduce heat into the conveying and treating region, raw material is introduced into the conveying and treating region via the charging end and is conveyed through a preheating zone following the charging end in order to dry and heat that material, the material is then conveyed into an expansion zone following and preheating zone to produce the expanded product, and the expanded product is discharged via the discharge end, additional heat is supplied to the raw material by means of at least one additional burner, preferably a mantle burner, located in the conveying and treating region between the first-mentioned burner and the charging end.