Characterization and Activation of Cement Kiln Dust as Heterogeneous Catalyst for Transesterification Process

Abstract

Cement kiln dust (CKD) is a fine, solid material, highly alkaline waste mainly reactive calcium oxide. The characteristic of local CKD is shghtly different to most other CKD in general, especially the absence of sodium oxide, potassium oxide, and sulphite content. Therefore, calcium oxide is the dominant basic oxide (56.52 wt. %) that influence the activity of CKD as catalyst. Analysis of activated CKD with FTIR and XRD showed no chemical reaction occur during activation stages. Furthermore, SEM analysis demonstrated that particle structures of activated CKD are more freely dispersed compared to fresh CKD. Surface area of activated CKD is enhanced, and slightly decrease on longer activation time. In correlation with the later, particle size analysis and density analysis showed swelling process occur that cause a decrease in surface area. Activated CKD performance on transesterification is significant compared to fresh CKD. Results showed that 9.09% methyl ester (ME) conversion were obtained when feedstocks were added simultaneously with fresh CKD, whereas 95.63% ME conversion was obtained when CKD was activated prior to transesterification. This reactivity difference can be attributed to the occurrence of evenly suspended CKD in methanol to provide a high area of contact.