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Title: Chemical and mineralogical characterizations of LD converter steel slags: A multi-analytical techniques approach

The use of LD converter steel slags (coming from Linz-Donawitz steelmaking process) as aggregates in road construction can in certain cases lead to dimensional damage due to a macroscopic swelling that is the consequence of chemical reactions. The aim of this study was to couple several analytical techniques in order to carefully undertake chemical and mineralogical characterizations of LD steel slags and identify the phases that are expected to be responsible for their instability. Optical microscopy, scanning electron microscopy and electron probe microanalyses revealed that LD steel slags mainly contain calcium silicates, dicalcium ferrites, iron oxides and lime. However, as a calcium silicate phase is heterogeneous, Raman microspectrometry and transmitted electron microscopy had to be used to characterize it more precisely. Results showed that lime is present under two forms in slag grains: some nodules observed in the matrix whose size ranges from 20 to 100 {mu}m and some micro-inclusions, enclosed in the heterogeneous calcium silicate phase whose size ranges from 1 to 3 {mu}m. It was also established that without the presence of magnesia, lime is expected to be the only phase responsible for LD steel slags instability. Nevertheless, the distribution of lime between nodules and micro-inclusions may playmore » a major role and could explain that similar amounts of lime can induce different instabilities. Thus, it appears that lime content of LD steel slags is not the only parameter to explain their instability.« less
Authors:
 [1] ;  [2] ; ; ;  [1] ;  [2] ;  [1] ;  [2] ;  [3]
  1. Univ Lille Nord de France, F-59000 Lille (France)
  2. (France)
  3. Eiffage Travaux Publics, Recherche et Developpement, 8 rue du Dauphine, B.P. 357, 69960 Corbas (France)
Publication Date:
OSTI Identifier:
22066168
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Characterization; Journal Volume: 61; Journal Issue: 1; Other Information: Copyright (c) 2009 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CALCIUM SILICATES; CHEMICAL REACTIONS; ELECTRON MICROPROBE ANALYSIS; IRON OXIDES; MAGNESIUM OXIDES; MATRIX MATERIALS; OPTICAL MICROSCOPY; PARTICLE SIZE; SCANNING ELECTRON MICROSCOPY; SLAGS; STEELS; SWELLING