Application of thermal treatment on cement kiln dust and feldspar to create one-part geopolymer cement

摘要

The objective of this work is to prepare one-part geopolymer (OPG) cement using thermal activation of cement kiln dust (CKD) and feldspar (FS). A homogeneous CKD/FS dry-blend, at weight ratio of 60/40, was exposed to elevated temperature in the presence of soda ash (Na2CO3), yielding smelted glassy material. Rapid air cooling was conducted on the transformed material, followed by grinding to produce OPG-powder. Three main parameters including vitrification temperature (1200 and 1300 degrees C), heat treatment duration (2 h and 3 h), and Na2CO3 content (10 and 20 wt%), were examined. A partial transformation to amorphous structure was recorded after the exposure of CKD/FS to 1200 and 1300 degrees C for 2 h heat treatment duration (in the absence of Na2CO3). With the increase of treatment time (3 h at 1300 degrees C), the sintering of mineral was occurred, leading to the increase in their crystallinity. Thermal treatment in the presence of Na2CO3 has a potential impact on the transformation of CKD/FS to vitreous structure as confirmed by X-ray diffraction (XRD). Where, the use of 20 wt% Na2CO3 leads to produce glassy material, with 100% amorphous content, which can reacts with water to form binding material with 28-days compressive strength of 52 MPa. (C) 2018 Elsevier Ltd. All rights reserved.