Stabilisation of heavy metal containing dusts by reaction with phosphoric acid: Study of the reactivity of fly ash

Document Type

Article

Publication Date

12-10-2004

Abstract

Water-washed fly ash was reacted with phosphoric acid in order to transform available heavy metals into insoluble metal phosphate compounds. The temperature, pH and concentration of free phosphate were monitored during the first 80 min of reaction. Phosphoric acid reacted rapidly with second order kinetics and an apparent rate constant of 0.015 l/(mol s m 2). Analysis of the evolution of the concentrations of other major elements of fly ash shows that the reaction follows a dissolution-precipitation type mechanism. The solubility of trace heavy metals tends to increase at low pH values. Various heat and mass transfer coefficients are derived and help understand the phosphate stabilisation procedure and design industrial reactors for this purpose. Calcium phosphates are formed which can trap heavy metals in a stable apatite mineral structure. © 2004 Elsevier B.V. All rights reserved.

Identifier

9344251121 (Scopus)

Publication Title

Journal of Hazardous Materials

External Full Text Location

https://doi.org/10.1016/j.jhazmat.2004.07.021

ISSN

03043894

PubMed ID

15561364

First Page

65

Last Page

74

Issue

1-2

Volume

116

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