Cement from Dyckerhoff

The lime stone, the basic for the cement production, is excavated with hydraulic bucket excavators or by drilling and detonating in quarries. With heavy load vehicles or heavy duty vehicles it is transported to the buckets where the rocks are crushed. After the excavation of the raw material, quarries experience semi-natural land reclamation or re-cultivation following landscaping guidelines.

From the crusher the material is transported via conveyer belt to a blending bed. In the blending bed the raw material (lime stone, sand, clay) is pre-mixed to the needed compound and homogenized. This is a condition for a consistent clinker and cement quality. From here the raw material is transported via conveyer belt to the plant. The complete production from the blending bed to the finished cement into the cement silo is controlled by the control center, the “brain” of the plant, which is supported by most modern computer technology. The production of the cement clinker takes place in a kiln, which has four different installations. In the raw material treatment the raw material is dried and grinded to fine raw powder. For energy saving reasons hot emissions from the preheater and from the cooling of the clinker are used for the drying process.

The raw powder homogenization takes place in the blending silo; the composition of the raw powder is corrected here and a constant product quality as well as a functional kiln is guaranteed. The prepared powder is transported into the kiln – the core of the cement production process. In front is a preheater in which the kiln emissions heat the raw powder up to 800°C. At the outlet of the slightly bent kiln the raw powder is burnt to Portland cement clinker with a temperature of 1,450°C. As grained, light glowing mass the clinker falls onto the cooling grid. Here it is cooled down to 150°C by air and is transported via conveyer belts to the clinker halls or silos. The emitting very hot air from this cooling process is recycled in the kiln heating as combustion air. Through the procedural connection of all installations of the four different kinds, clinker is produced with as low as possible fuel usage. The kilns today are not anymore fired exclusively with primary fuels as coal and gas, but as well can use the energetic potential of various residues – the so-called secondary fuels. Environmental friendly used are old tires, fibers and plastic waste, solvent etc. The complete burning is carefully observed and controlled due to following the federal guidelines for emissions.

In the next grinding process the cement clinker is grinded in cement mills (e.g. ball mills) with adding of gypsum and/or anhydrite to different Portland cements. By additional grinding of lime stone and/or granulated cinder Portland composite or furnace cements develop. The different kinds of cement are stored in cement silos until being sold. From there they are transported with silo trucks or via train with tank wagons to the customer. A smaller part is filled in modern packing stations into bags. Palletizing machines take over the hard work of piling onto standard palettes.