title: Immobilisation of lead smelting slag within spent aluminate-fly ash based geopolymers.
abstract: This study presents the solidification/stabilisation and immobilisation of lead smelting slag (LSS) by its incorporation in coal fly ash - blast furnace slag based geopolymers. It also explores the use of a spent aluminium etching solution (AES) as geopolymer activator instead of the commonly used silicate solutions. The compressive strength of the geopolymers produced with the AES was lower than when applying a K-silicate solution as activator (100MPa versus 80MPa after 28 days). Compressive strength was not affected when up to 10% of the FA was replaced by LSS. NEN 12457-4, TCLP, SPLP and NEN 7375 leaching tests indicated that mobile Pb from LSS was highly immobilised. The diffusion leaching test NEN 7375 revealed exceeding of the Dutch Soil Quality Regulation threshold limits only for Se and Sb. On the condition that the remaining excess leaching can be reduced by further refinement of the mixture recipes, the proposed process will have the potential of producing waste-based construction materials that may be applied under controlled conditions in specific situations.
authors: Delft University of Technology, Department of Chemical Engineering, Product and Process Engineering Group, Julianalaan 136, 2628 BL Delft, The Netherlands. mbogundiran@yahoo.com
authors: M B
authors: MB
authors: Ogundiran
authors: H W
authors: HW
authors: Nugteren
authors: G J
authors: GJ
authors: Witkamp
mesh_terms: D017607:Aluminum Compounds / Q000737:chemistry*; D060729:Coal Ash / Q000737:chemistry*; D019245:Compressive Strength; D052918:Environmental Restoration and Remediation / Q000379:methods; D007220:Industrial Waste; D007854:Lead / Q000737:chemistry*; D008669:Metallurgy; D011108:Polymers / Q000737:chemistry*; D017640:Silicates / Q000737:chemistry; D017670:Sodium Compounds / Q000737:chemistry*
chemical_list: D017607:Aluminum Compounds; D060729:Coal Ash; D007220:Industrial Waste; D011108:Polymers; D017640:Silicates; D017670:Sodium Compounds; D007854:Lead; C539561:sodium aluminate