...as a variant...

The invention relates to an incinerator (1) having a combustion chamber (2) that is at least partially enclosed by a housing (3), wherein the combustion chamber (2) has at least one ash outlet (4), to which at least one afterburner gate (5) for unburned components of ash (6) is allocated.
http://www.google.com.na/patents/CN103492807A?cl=en
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Bottom ash is discharged from the rotary combustor to an afterburner grate and then into a wet quench pit. From there, the moist ash is conveyed to an ash load-out or storage area prior to disposal.
https://www3.epa.gov/ttnchie1/ap42/ch02/final/c02s01.pdf
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A tenth of the original feed volume exits the combustor as ash, while the remaining material is further combusted in an afterburner grate.
https://researchspace.ukzn.ac.za/bitstream/handle/10413/5875...

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Waste is fed directly from the receiving area into the
upper end of the tilted combustor. As the waste tumbles
down the length of the rotating barrel, it dries and then
progressively lmrns. Ash dropping out ofthe lower end is
al)out one-tenth of the original waste volume; remaining
unliurned material is more completely combusted in an
afterburner grate

...the rotary combustor onto a fixed afterburner grate located
beneath the combustor outlet.

Conventional technologies for the thermal destruction
of wastes are often faced with operation at high temperatures
with relatively low throughputs and must use
afterburners and scrubbers.

https://dokumen.tips/documents/innovative-thermal-destructio...