USES AND LIMITATIONS WHEN USING SECONDARY MATERIALS

Residues from industrial processes and from quality-controlled refuse collection can be used as secondary raw materials or secondary fuels i n the production of Portland cement. This usage is linked to condition s and is restricted by them-in each individual case. - Legal licensing and emission-relevant conditions must be met dependably. - The qualit y of the cement must not be impaired with respect to its structural ca pabilities or its environmental compatibility. - The production proces s must not be impaired and the safety of the workplace must be ensured . - There must be no additional pollution of the environment. These re quirements give rise to criteria which limit the quantity of secondary materials used or even exclude them entirely. If taking these criteri a into account and bearing in mind the necessary capital expenditure a nd allowing for the increased expenditure on control and quality assur ance, it is cost-effective to use these materials then a valuable cont ribution is made to relieving the load on the environment. When using secondary materials it is possible to take advantage of an environment ally friendly, residue-free disposal technology which preserves natura l resources by using existing locations and the process engineering ca pabilities of cement production system; at the same time it is possibl e to reduce the raw material and fuel costs for cement production.