Title: Solidification characteristics and mechanisms of cement treated Pb/Zn contaminated soils from a mining site in Hunan Province, China

Authors: Mengjia Zhou; Haoliang Wu; Yanjun Du; Yucheng Yi

Addresses: School of Engineering and Technology, China University of Geosciences, Beijing, 100083, China ' Institute of Geotechnical Engineering, Southeast University, Nanjing, 210096, China ' Institute of Geotechnical Engineering, Southeast University, Nanjing, 210096, China ' School of Engineering and Technology, China University of Geosciences, Beijing, 100083, China

Abstract: This paper presents a study on the stabilisation of mine soils from a mining site contaminated with heavy metals through the use of ordinary Portland cement (OPC). The aim of this study was to explore the effects of binder content (%), and the curing age of contaminated soils on the toxicity and strength properties of the contaminated soils using toxicity characteristic leaching procedure (TCLP), acid-neutralising capacity (ANC) test. Sequential extraction procedure (BCR), unconfined compression test (UCT), X-ray diffraction (XRD) and scanning electron microscopy (SEM) procedures were carried out to analyse the solidification mechanisms. The results showed that as the curing time was increased from 0 d to 28 d, OPC stabilised contaminated soil underwent several changes: 1) leaching of Zn and Pb decreased; 2) ANC (β) increased; 3) exchangeable Zn and Pb decreased; 4) residual contents increased; 5) strength improved.

Keywords: cement binder; pollution prevention; heavy metals; solidification; lead leaching; zinc leaching; soil contamination; China; soil stabilisation; mining industry; curing age; toxicity; strength properties; acid-neutralising capacity.

DOI: 10.1504/IJEP.2016.079900

International Journal of Environment and Pollution, 2016 Vol.59 No.2/3/4, pp.269 - 283

Received: 12 Nov 2015
Accepted: 11 Mar 2016
Published online: 20 Oct 2016 *

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