Sodalite solids formation at the surface of iron oxide and its impact on flocculation

© The Minerals, Metals & Materials Society 2016. Sodalite represents the main desilication product (DSP) phase formed from reactive silica during alkaline digestion of bauxite in the Bayer Process. Previous studies into DSP effects on bauxite residue flocculation have focused on flocculant sel...

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Main Authors: Senaputra, A., Fawell, P., Jones, Franca, Smith, P.
Format: Conference Paper
Published: 2016
Online Access:http://hdl.handle.net/20.500.11937/68074
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author Senaputra, A.
Fawell, P.
Jones, Franca
Smith, P.
author_facet Senaputra, A.
Fawell, P.
Jones, Franca
Smith, P.
author_sort Senaputra, A.
building Curtin Institutional Repository
collection Online Access
description © The Minerals, Metals & Materials Society 2016. Sodalite represents the main desilication product (DSP) phase formed from reactive silica during alkaline digestion of bauxite in the Bayer Process. Previous studies into DSP effects on bauxite residue flocculation have focused on flocculant selection or digestion optimisation, not answering a fundamental question: does DSP coat the residue and thereby change surface properties? This study sought to answer that question by contrasting the physicochemical properties of hematite slurries (as a model phase for residue) containing DSP where it was either made in-situ or added as a physical mixture. On the basis of differences found in dewatering behaviour, zeta potential, desilication rates and microscopy of the solids, it is proposed that DSP nuclei initially associate with the hematite surface and subsequently affect flocculant adsorption chemistry, resulting in different extents of flocculant adsorption and smaller aggregates. The practical implications for flocculation processes are discussed.
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spelling curtin-20.500.11937-680742018-05-18T08:07:19Z Sodalite solids formation at the surface of iron oxide and its impact on flocculation Senaputra, A. Fawell, P. Jones, Franca Smith, P. © The Minerals, Metals & Materials Society 2016. Sodalite represents the main desilication product (DSP) phase formed from reactive silica during alkaline digestion of bauxite in the Bayer Process. Previous studies into DSP effects on bauxite residue flocculation have focused on flocculant selection or digestion optimisation, not answering a fundamental question: does DSP coat the residue and thereby change surface properties? This study sought to answer that question by contrasting the physicochemical properties of hematite slurries (as a model phase for residue) containing DSP where it was either made in-situ or added as a physical mixture. On the basis of differences found in dewatering behaviour, zeta potential, desilication rates and microscopy of the solids, it is proposed that DSP nuclei initially associate with the hematite surface and subsequently affect flocculant adsorption chemistry, resulting in different extents of flocculant adsorption and smaller aggregates. The practical implications for flocculation processes are discussed. 2016 Conference Paper http://hdl.handle.net/20.500.11937/68074 10.1007/978-3-319-65136-1_13 restricted
spellingShingle Senaputra, A.
Fawell, P.
Jones, Franca
Smith, P.
Sodalite solids formation at the surface of iron oxide and its impact on flocculation
title Sodalite solids formation at the surface of iron oxide and its impact on flocculation
title_full Sodalite solids formation at the surface of iron oxide and its impact on flocculation
title_fullStr Sodalite solids formation at the surface of iron oxide and its impact on flocculation
title_full_unstemmed Sodalite solids formation at the surface of iron oxide and its impact on flocculation
title_short Sodalite solids formation at the surface of iron oxide and its impact on flocculation
title_sort sodalite solids formation at the surface of iron oxide and its impact on flocculation
url http://hdl.handle.net/20.500.11937/68074