EFFECT OF CEMENT KILN DUST SUBSTITUTION ON CHEMICAL AND PHYSICAL PROPERTIES AND COMPRESSIVE STRENGTH OF PORTLAND AND SLAG CEMENTS

Abstract

Large quantities of cement kiln dust (CKD) are produced during the manufacture of cement clinker by the dry process. The technico–economical problems that arise in the transportation of dust from the plant to outside as well as the severe pollution to the surrounding atmosphere show the utmost necessity of utilizing CKD as one of the main objectives during the last decade. CKD is produced as a solid waste from the pre-heater by-pass systems during the manufacture of Portland cement clinker, by using the dry process, as a result of the presence of some minor volatile constituents in the kiln feed and fuel. Actually, the properties of CKD depend on the kind of raw materials and the fuel used, as well as the production method or kiln type. Therefore, due to the high alkali and salt contents of the raw materials for cement production, the dry processes are normally equipped with pre-heater by-pass systems. In these systems, the circulating alkalis are removed through withdrawal of the hot gas stream along with the dust it contains.