KCl Extracted from Chlorine Bypass Dust as Activator for Plain Concrete

Hong-Beom Choi; Jin-Man Kim; Sun-Mi Choi; Sung-Su Kim

doi:10.3390/ma14206091

KCl Extracted from Chlorine Bypass Dust as Activator for Plain Concrete

Materials (Basel). 2021 Oct 15;14(20):6091. doi: 10.3390/ma14206091.

Authors

Hong-Beom Choi¹, Jin-Man Kim², Sun-Mi Choi³, Sung-Su Kim⁴

Affiliations

¹ Construction Test & Certification Department, Korea Institute of Civil Engineering and Building Technology, Goyang-si 10223, Korea.
² Department of Architectural Engineering, Kongju National University, Cheonan City 31080, Korea.
³ Eco-Friendly Concrete Research Center, Kongju National University, Cheonan City 31080, Korea.
⁴ Department of Environmental Energy Engineering, Kyonggi University, Suwon 16227, Korea.

Abstract

This study demonstrated the use of KCl separated from chlorine bypass dust (CBD) as an activator for plain concrete. The separated KCl was mixed with either ground granulated blast-furnace slag (BFS) alone, or a mixture of BFS and cement. The mixed paste of separated KCl and BFS set within 24 h, and exhibited a compressive strength of 22.6 MPa after 28 d. The separated KCl, cement, and BFS mixture exhibited a more rapid setting and a higher initial activity. Further, the compressive strength at 28 d was 57.7 MPa, which was 26.2% higher than that of the mixture without the activator. Water curing of samples with added separated KCl led to the generation of hydrocalumite, or Friedel's salt. However, this hydrocalumite was decomposed while being cured under autoclave conditions at 180 °C. Overall, KCl was an effective activator for composite materials containing cement, and resulted in superior properties compared to mineral admixtures without an activator.

Keywords: KCl; alkali activator; by-product; chlorine bypass dust; recycling.