In response
to the global shortage of raw materials, the German government has issued a
national resource efficiency programme. The extraction of raw materials is to
be severely restricted. Conversely, resource efficiency is to be increased by
means of recycling. Against this background, the talk begins by taking the
famous broader view beyond the horizon. What is the situation with resource
efficiency in other parts of the world?
Irrespective
of any ranking, one thing is certain: bricks have been made from clay for over
6 000 years and clay is a fossil resource. Clay is formed by weathering,
erosion, transport and sedimentation over millions of years in geological
periods. With a global clay consumption of around 430 mill. t per year, it is
also clear that the reserves of clay are dwindling – it is only a question of
time. At first glance it may seem that we do not need to worry about this too
much, after all there is enough clay in Germany. But the impression is
misleading. Really good clay is already scarce today. In respect of regional
raw material reserves, a crucial factor is that the best, that is the
surface-near clays have already been exhausted by the brickworks. The extent to
which the clay brick and tile industry has been affected is consequently
documented by the rising volume of externally supplied clays and the strong
dependence on nationally operating clay suppliers.
What could
recycling solutions look like? What other possibilities are there to reduce the
consumption of natural resources while maintaining the same economic
performance? According to current research projects, the use of finely ground
broken bricks presents one technically feasible option.
In the
paper, supplementing the above option, another approach is presented. This
concerns the exploitation of alternative clay potential produced in mineral
washing of non-metallic minerals. The potential volume of material is so huge
that the entire amount could not even be absorbed by the clay brick and tile
industry. A study of the Deutsche Rohstoffagentur (DERA – German Mineral
Resources Agency) in 2010 showed that a large part of this washing sludge is
potentially suitable for use in the clay brick and tile industry. The grain
size ranges of these substances fit almost perfectly into the grain size range
of common brick bodies. And the mineral composition does not look too bad
either, so that use of these materials appears possible in the production of
both clay masonry bricks and roofing tiles.
But here
too there is a limiting factor: more than 90% of the washing sludge is
currently landfilled and can therefore not be used in the clay brick and tile
industry. Less than 10% of the washing slurries are dewatered on filter presses
so that they could be used in the form of filter cake. What we urgently need
therefore are filter presses instead of sludge landfills. It is important: the
filter presses must be in the vicinity of the brickworks. After all resource
efficiency should not be bought with bulk transport.
Suddenly a
potential of regionally available raw materials is opened up, of which we had
no longer dared to dream. That really would be a brilliant contribution to the
assured supply of raw materials.
EurGeol Dr. Lutz Krakow, ClayServer GmbH, Ostercappeln-Venne, Germany
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