Experimental investigation of synthetic (TOP) soils for mine rehabilitation: Column leaching study

Shashibhushan Biliangadi, Mohan Yellishetty, Vanessa N.L. Wong, Anil Kumar Dikshit, Suman Majumdar

Research output: Chapter in Book/Report/Conference proceedingConference PaperResearch


Linz-Donawitz (LD) slag is one of the major by-products generated in the iron and steel industry. Alternative uses for waste by-products in the iron and steel industry are required due to increasing production, less land for disposal and stringent environmental regulations. Three different synthetic soils (M1 = 30% slag + 70% compost, M2 = 50% slag + 50% compost, and M3 = 70% slag + 30% compost) prepared from LD slag and sewage sludge compost were subjected to continuous column leaching studies for two months. The aim of the leaching study was to understand the variation in pH trends during leaching, mobility of metals and nutrients. Results showed that the pH of M2 and M3 synthetic soil and steel slag leachates remained in alkaline pH ranges. The pH for M1 was circumneutral until the liquid to solid ratio (L/S) = 0.5 and thereafter reached above pH 10. pH generally decreased with increasing percentage of compost. LD slag is a heterogeneous material comprising of 35–40% CaO and 6–8% MgO. Previous studies also suggest that with ageing and in presence of water, steel slag may form new mineral phases. Readily soluble minerals may dissolve in water more quickly however, minerals which are entrapped within complex heterogeneous phase may dissolve slowly. The highly alkaline pH trend during this leaching study may be due to presence of Ca-CO3-OH type ion matrix in leachates. Therefore, when steel slag or synthetic soils are used as an artificial (top) soil, high pH leachates may have some negative ecological impacts.

Original languageEnglish
Title of host publicationLand Reclamation in Ecological Fragile Areas
Subtitle of host publicationProceedings of the 2nd International Symposium on Land Reclamation and Ecological Restoration, LRER 2017
EditorsZhenqi Hu
Place of PublicationLondon UK
PublisherCRC Press
Number of pages4
ISBN (Electronic)9781315166582
ISBN (Print)9781138051034
Publication statusPublished - 20 Jul 2017
EventInternational Symposium on Land Reclamation and Ecological Restoration, 2017 - Holiday Inn Xi'an Big Wild Goose Pagoda, Xi’an, China
Duration: 20 Oct 201723 Oct 2017
Conference number: 2nd


ConferenceInternational Symposium on Land Reclamation and Ecological Restoration, 2017
Abbreviated titleLRER 2017
OtherThe symposium on land reclamation and ecological rehabilitation is a series of international conference, held every three years. The first symposium was held successfully on 16th - 19th October, 2014 in Beijing, China. The effect is remarkable. Nearly 60 foreign scholars from 15 countries and more than 300 domestic scholars to participate the symposium. The deep discussion and communication of mine restoration and land reclamation in China including legislation and practice, technology and theory and so on, promote the development of the mining area ecological environment and land reclamation.
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