title: Effects of compound chemical activators on the hydration of low-carbon ferrochrome slag-based composite cement.
abstract: Low-carbon ferrochrome slag (LCFS), a by-product of the ferrochrome alloy industry, has potential for use as a cementitious material due to its pozzolanic characteristic. The objective of the present study was to determine the optimum compound chemical activators for LCFS-based composite cement using an orthogonal test, in which 7 d and 28 d compressive strengths were used as the evaluating indices. The influences of compound chemical activators on the hydration of a composite cement mix were investigated using X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS) and thermogravimetry-differential scanning calorimetry (TG-DSC). The optimum activator to activate the composite cement was a compound of NaCl (NC) at a dosage of 0.6%, Na2SO4(NS) at a dosage of 1.2%, NaF (NF) at a dosage of 0.6% and Al2(SO4)3(AS) at a dosage of 0.9% or 0.7%. The compressive strengths of the optimum composite cement mix at ages of 3, 28 and 180 d increased by 50.1%, 22.4% and 16.5%, respectively. More hydration products including ettringite and calcium silicate hydrate were formed at an early age of hydration. The compound chemical activators effectively activated the ferrochrome slag (FS), blast-furnace slag (BFS) and fly ash (FA) in the composite cement.
authors.affiliation: Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650500, China; Key Laboratory of Unconventional Metallurgy, Ministry of Education, Kunming, Yunnan 650093, China. Electronic address: zhouxt@kmust.edu.cn.
authors.forename: Xintao
authors.initials: X
authors.lastname: Zhou
authors.affiliation: Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650500, China.
authors.forename: Xutao
authors.initials: X
authors.lastname: Hao
authors.affiliation: Faculty of Civil Engineering and Mechanics, Kunming University of Science and Technology, Kunming, Yunnan 650500, China.
authors.forename: Qianmin
authors.initials: Q
authors.lastname: Ma
authors.affiliation: Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650500, China.
authors.forename: Zhongqiu
authors.initials: Z
authors.lastname: Luo
authors.affiliation: Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650500, China.
authors.forename: Mingqin
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Unconventional Metallurgy, Ministry of Education, Kunming, Yunnan 650093, China. Electronic address: jhpeng@kmust.edu.cn.
authors.forename: Jinhui
authors.initials: J
authors.lastname: Peng
mesh_terms: D002244:Carbon / Q000737:chemistry*; D060729:Coal Ash / Q000737:chemistry; D003252:Construction Materials; D013052:Spectrometry, X-Ray Emission; D014961:X-Ray Diffraction
chemical_list: D060729:Coal Ash; D002244:Carbon
keywords: Chemical activators; Composite cement; Hydration process; Low-carbon ferrochrome slag; Orthogonal test