BENEFICIATION
best products to build with due to their
lower life cycle carbon footprint,” says Von
Wielligh.
The tunnel kiln, which Corobrik
currently uses to manufacture bricks, is
generally considered the most efficient type
of mass-production kiln in the world.
A large portion of competitor companies
are using older, less-efficient firing
technologies, such as clamp kilns, and are
under increasing pressure because of the
technologies’ environmental impact.
Von Wielligh says the biggest challenge
with his tunnel kiln – and others of its
30-year-old generation – is that energy
is the biggest input cost in brickmaking,
and at best only incremental changes can
be made to the energy consumption of
existing plant. “Major improvements have
been made in technology over the years in
terms of energy efficiency – as installed at
Corobrik’s new factory under construction.
The reject rate at the highly automated
Midrand plant is 1-2%, while the equivalent
rate at a labour-intensive clamp kiln is 10-
20%. The difference is the level of handling.
Because energy is the biggest expense,
Von Wielligh explains that every innovation
has as its starting point reducing gas
consumption (as well as improving brick
quality). This is primarily achieved by
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Wet cut bricks being machine loaded onto kiln cars.
reducing the mass of the brick, and using
as much as possible of the carbonaceous
material from the quarry as heating fuel.
Further refinements to the processing
procedure have resulted in a reduction in
the water usage – such as reducing the bulk
of the bricks with air holes. Von Wielligh
explains that reducing water consumption
in the process also reduces the energy
consumption. “In addition, by replacing
light bulbs we’ve taken 50kW/hour out
of the system. We’ve also replaced the
compressor with a newer model that uses
considerably less energy. In total, we’ve
taken out over 100 000kW hours a month,
and are looking to pilot solar panels for the
administration block, potentially expanding
on that if it proves viable,” he says.
QUARRY SA | JULY/AUGUST 2019_35