Lime Production: A traditional kiln at Bounoura, Algeria
Practical Action
A stone retaining wall supports the backfilling around the kiln. The backfilling provides
additional insulation and acts as a ramp to allow a truck to be driven to the top of the kiln for
loading the stone. This wall is constructed in ashlar stone with a clay mortar, its thickness
varies between 80 cm at the base to 40 cm at the top, and the height is approximately 4
metres. In the lowest part of the kiln a door of 1.2m width and 1.8m height allows access for
the oil burner and afterwards discharge of the burned lime. When loading the kiln an arch of
larger stones is made around the opening where the burner will be placed (see diagrams) so
that a large empty space exists for the burner flame to pass through.
Once the stones are arranged, the burner
is placed at the middle of the door in
order to fill the gap, then the firing
process begins. This requires 8000 litres
of light fuel oil per batch.
Oil is delivered to the burner through a
pipe leading from the oil storage
container. The pipe leads to a chamber
through which compressed air from a
compressor is passed.
Figure 1: Building the limestone vault – the first stage of charging the kiln.
This forces the oil out through a narrower pipe or nozzle where it is ignited. The oil comes out
of the nozzle at a high velocity so that a flame of good length can be produced. The flash
point of light fuel oil is around 65°C compared to 160°C for heavy fuel- oil so no preheating
of the burner is necessary. Any lighted material will ignite the burner.
Figure 2: Kiln
filled, ready for
firing
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