A SMALL LIME KILN
FOR BATCH AND CONTINUOUS
FIRING
CONSTRUCTION DETAILS AND EVALUATION OF AN
EXPERIMENTAL KILN
Introduction
In 1996 ITDG (now Practical Action)
commissioned Paragon Ceramics Ltd to
build an experimental lime kiln at Dedza in
Malawi. Paragon designed the kiln in
partnership with local lime burners. It
works with a variety of fuels and can be
operated as a batch or continuous
production kiln. Where wood is the only
fuel option, the kiln works well burning
softwood which could be grown on a
managed plantation. Good quality hydrated
lime and lime putty have been produced for
building. These notes are a practical guide
on how to build the kiln, and explain its
operation. Because it is experimental the
Dedza kiln is small. Anyone who wishes to
build a bigger kiln should seek further
advice.
Background
In Malawi lime burning is often a seasonal,
dry weather, activity for small farmers who
use traditional ‘box’ kilns. These are
rectangular structures with walls of
limestone boulders bonded with mud
mortar. A typical box kiln would be about
4m long, 2.5m wide and 1.5m high. These
kilns are charged with alternate layers of
firewood (usually indigenous hardwood) and
limestone to a level above the height of the
walls. Traditional kilns use a lot of fuel,
mainly because of their shape and a great
deal of heat is lost through the top. Firewood
is very scarce in lime burning areas in
Malawi and deforestation is a major problem.
Box kilns generally do not produce good
quality lime because to do so would use a lot
of firewood and cost too much.
Figure 1: The construction of the
experimental klin, Dedza, Malawi.
Photo credit: Practical Action/Kelvin Mason
Figure 2: Malawian box kiln
Photo credit: Practical Action/Kelvin Mason
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