Utilization of by-pass cement kiln dust and air-cooled blast-furnace steel slag in the production of some “green” cement products

摘要

By-pass cement kiln dust (CKD) is a fine-grained alkaline particulate material similar in appearance to Portland cement collected in the air-pollution control devices (such as cyclones, bag house or electrostatic precipitators) during the production of cement clinker. The generated CKD during cement production in Egypt reaches about 2.7?million?tons per year (about 4% of the total cement production). In year 2015, according to the quest of the Egyptian Government, a research team has been arranged from the Housing and Building National Research Center (HBNRC) [with the share of the authors of the current work], in association with the Arab Contractors Company and some of the cement companies in Egypt. The assignment given to the team was performing: “A technical and economical feasibility study for establishing a model for a factory for cement products incorporating CKD in the vicinity of every assemblage of cement plants in Egypt”. The feasibility study concluded that: The proposed factory could produce cement bricks having a cement content of 210–250?kg/m3and substituting 20% of the cement by CKD. The factory could, also, produce interlock paving blocks having a cement content of 450?kg/m3or 540?kg/m3(depending on the required strength level) and replacing 20% of the cement by CKD. The current study introduces, in addition to CKD as cement replacement, air-cooled blast-furnace steel slag (ACS) as coarse aggregate in interlock paving units substituting the conventionally used natural dolomite aggregate. The study declared the advantages of air-cooled slag that motivated such utilization.