Related Experiment Video
Updated: Sep 23, 2025

Two-way Valorization of Blast Furnace Slag: Synthesis of Precipitated Calcium Carbonate and Zeolitic Heavy Metal Adsorbent
Published on: February 21, 2017
Blast furnace slag-Mg(OH)2 cements activated by sodium carbonate
Sam A Walling1, Susan A Bernal1, Laura J Gardner1
1Immobilisation Science Laboratory, Department of Materials Science & Engineering, Sir Robert Hadfield Building, The University of Sheffield S1 3JD UK j.provis@sheffield.ac.uk +44 (0) 114 222 5490.
Abstract:
The structural evolution of a sodium carbonate activated slag cement blended with varying quantities of Mg(OH)2 was assessed. The main reaction products of these blended cements were a calcium-sodium aluminosilicate hydrate type gel, an Mg-Al layered double hydroxide with a hydrotalcite type structure, calcite, and a hydrous calcium aluminate phase (tentatively identified as a carbonate-containing AFm structure), in proportions which varied with Na2O/slag ratios. Particles of Mg(OH)2 do not chemically react within these cements. Instead, Mg(OH)2 acts as a filler accelerating the hardening of sodium carbonate activated slags. Although increased Mg(OH)2 replacement reduced the compressive strength of these cements, pastes with 50 wt% Mg(OH)2 still reached strengths of ∼21 MPa. The chemical and mechanical characteristics of sodium carbonate activated slag/Mg(OH)2 cements makes them a potentially suitable matrix for encapsulation of high loadings of Mg(OH)2-bearing wastes such as Magnox sludge.
Related Concept Videos
Types of Cement II
Pozzolans
Fly ash is...
Hydration of Cement
Portland Cement
Alkali Aggregate Reaction in Concrete
Additives and Fillers in Concrete
The...

