A horizontal pyrolysis furnace has a kiln and two barrels. The two barrels are respectively a processing barrel rotatably disposed in the kiln and a takeover barrel detachably connected with the processing barrel. Each one of the two barrels has a gate assembly and at least one spiral guiding plate. The gate assembly of the processing barrel is mounted on an end of the processing barrel, and extends out from the kiln. The two gate assemblies of the two barrels are detachably connected such that the two barrels are able to rotate synchronously. The at least one spiral guiding plate is fixed on an inner surface of one of the two barrels, and the spiral guiding plates of both barrels have an identical helical direction.

A horizontal pyrolysis furnace has a kiln and two barrels. The two barrels are respectively a processing barrel rotatably disposed in the kiln and a takeover barrel detachably connected with the processing barrel. Each one of the two barrels has a gate assembly and at least one spiral guiding plate. The gate assembly of the processing barrel is mounted on an end of the processing barrel, and extends out from the kiln. The two gate assemblies of the two barrels are detachably connected such that the two barrels are able to rotate synchronously. The at least one spiral guiding plate is fixed on an inner surface of one of the two barrels, and the spiral guiding plates of both barrels have an identical helical direction.

Dust Da containing zinc and iron is charged in a rotative cylindrical kiln base body 11 of an indirect-heating rotary kiln 10 and is subjected to heat treatment in the kiln base body so that zinc contained in the dust is volatilized. The volatilized zinc is guided to a treatment device 30 through an exhaust pipe 31 disposed at a discharge part 16 of the rotary kiln and is recovered. A residue Db resulting from the treatment in the kiln base body is transferred from a residue outlet 16b disposed at the discharge part 16 of the rotary kiln to a burner device 40, in which the residue is combusted and heated.

Apparatus. methods. and systems for heat treatment of solid materials utilizing an indirect rotary calciner comprising one or more thermal expansion tolerant inner tubes fixed to an outer rotating shell. for example. by one or more resilient support members. The described methods of thermal treatment may be particularly utilized with cement and lime production processes and/or other heat treatment applications. such as pyrolysis.