Cement industry is considered to have a leading and important role in the development of the urban renaissance and in the construction of economic facilities and projects, as it is directly connected to the process of construction and rehabilitation.
Cement is defined mineral as a mixture of clay, CaCo3, CaSo3 in different mixing ratios after these are incinerated inside special furnaces used for this purpose.
Cement is generally functioning as a binding material and normally the cement factories are built nearby the clay processing plants in order to reduce the cost of transportation of raw materials. The polluted materials produced from these cement factories vary in quantity and quality according to the operation processes followed and the to the methods adopted for removing all sludge and waste materials that are produced due to these operations.
There are two major processes for cement production- these are called wet or dry processes. In the 1st all al of the raw materials are crushed and mixed with water and the product (slurry) will be transported to the furnaces, while in the dry process, all the produced mixture will be dried out prior to moving into the furnaces.
The raw materials used for cement production are:
- Silicate sands.
- Clay and bauxite sand (medium sized particles composed from the residual layers, e, g. clay with low content of water).
- Carbonate rocks.
- Iron oxide-this is used as fluxing agent or as dissolving agent to reduce the high temp. Generated from the chemical processes.
- Gypsum-this is added in the final stages.
- Chemical materials used mainly for analysis and assessing the quality of the product.
- Oils and other lubricants used for the maintenance of equipment.
- Natural gas and fuel gas for the furnaces which are designed and manufactured to be able to utilize more than one type of fuel.