STABILIZATION OF FLY-ASH CONTAINING HEAVY METALS BY ALKALI ACTIVATION

摘要

The immobilization of waste materials is receiving increasing attention from scientists all over the world. Alkali activation of fly ash or blast furnace slag is a method that successfully stabilizes these waste materials in a solidified matrix. Fly ash (FA) from Czech power plant Po?erady and blast furnace slag (BFS) from Ostrava contain except the mains compounds also small amount of heavy metals – Ba~(2+), Ni~(2+), Zn~(2+), Cu~(2+), Cr. The aim of this work is to find out the ability of aluminosilicate matrix (ASM) and matrix reinforced by wollastonite micro-fibre to stabilize and immobilize heavy metals which originate from raw materials. Amount of heavy metals in raw materials was investigated by XRF. Phase composition was determined by XRD. The ability of matrix to fix and immobilize heavy metals was investigated by leaching tests. These tests were based on the law 383/2001 Sb. and ?SN EN – 12457- 4. The concentration of heavy metals in eluate was analysed by ICP-MS. The addition of wollastonite improved the ability of alkali activated AMSs to fix Ba, Zn and Ni. Fixation of Cu and Cr wasn't influenced by addition of wollastonite.