Civil Engineering Reference
In-Depth Information
Table 12.1:
Industrial by-products and their uses in building
Material
Industry
Areas of use
Gypsum
Zinc works, oil- and coal-fired power
station, brick factory, production of
artificial fertilizer
Oil- and gas-fired power station,
refineries
Production of ferro-silica and silica
Plasterboard, Portland cement
Sulphur
Sulphur-based render, sulphur-based
concrete, paper production
Reinforcement in concrete products,
pozzolana
Pozzolana, thermal insulation (slag
wool)
Pozzolana
Pozzolana, thermal insulating
aggregate in render and concrete
Silicate dust
Blast furnace slag
Iron foundries
Fly ash
Fossil meal
Coal-, oil- and gas- fired power stations
Oil refineries
Power station gypsum has similar technical properties to natural gypsum.
Even the content of heavy metals and radioactivity is about the same as in the
natural substance. Power station gypsum is therefore appropriate for both plas-
terboard and plaster and as a raw material for Portland cement.
Phosphorous gypsum has a higher likelihood of unwanted constituents
because of the raw material used. Gypsum is also a by-product of other indus-
tries, e.g. in the production of phosphoric acid and titanium oxide, but contains
large quantities of unwanted materials such as heavy metals.
Sulphur
Sulphur has been used for a long time in the building industry to set iron in con-
crete, e.g. for setting banisters in a staircase. At the end of the nineteenth centu-
ry the first sulphur concrete blocks came onto the market.
Sulphur has a melting point of a little less than 120°C, and when melted binds
well with many different materials. It can replace other materials used in casting,
e.g. Portland cement. Sulphur concrete is waterproof and resistant to salts and
acids. It should not be used with alkaline substances such as cement and lime.
Sulphur can also be used in mortar and render, but because of its short setting
time this can cause practical problems.
Sulphur dioxide is emitted in large quantities from industries where gas and
oil are burned, but it is possible to clean up 80-90 per cent of these emissions.
The temperature for working molten sulphur is around 135-150°C. There is
probably little chance of the emission of hazardous doses of either hydrogen
sulphide or sulphur dioxide at these temperatures, though even the slightest
emission of the former gives a strong, unpleasant smell. The workplace should
