Affordable Access

Publisher Website

The effect of calcium and temperature on the transformation of sodalite to cancrinite in Bayer digestion

Authors
Journal
Hydrometallurgy
0304-386X
Publisher
Elsevier
Publication Date
Volume
105
Identifiers
DOI: 10.1016/j.hydromet.2010.07.010
Keywords
  • Avrami Model
  • Bayer Digestion
  • Cancrinite
  • Dsp
  • High Silica Bauxite
  • Lime
  • Soda Reduction
  • Silica In Bayer Liquor
  • Transformation Of Sodalite
  • Xrd Phase Quantification
Disciplines
  • Chemistry

Abstract

Abstract The transformation of sodalite (SOD) to cancrinite (CAN) in Bayer digestion has been studied for a range of temperatures and time intervals relevant to high temperature bauxite refining. The transformation extent was determined by quantifying phases in digestion residues using an XRD method. It has been found that the transformation is slow in the absence of lime but dramatically promoted by three different Ca-containing sources (calcium oxide, calcite and hydrocalumite) commonly found in the Bayer process. The amount of CAN produced, however, is not proportional to the quantity of Ca charged. The transformation process can be modelled by a form of the Avrami equation. The high activation energy (~ 218 kJ/mol) suggests that the transformation is a chemical process controlled by the nucleation and growth of CAN. The advantages of CAN formation include a reduction of soda in digestion residues and better control of silica and carbonate levels in Bayer liquor. The role of Ca, the efficiency of lime charge and the mechanism of the transformation process are discussed, especially within the context of high temperature and high silica bauxite processing.

There are no comments yet on this publication. Be the first to share your thoughts.

Statistics

Seen <100 times
0 Comments

More articles like this

Bayer process plant scale: transformation of sodal...

on Journal of Crystal Growth Jan 01, 1997

The solubility of sodalite and cancrinite in synth...

on Colloids and Surfaces A Physic... Jan 01, 1999

A methodology for quantifying sodalite and cancrin...

on Microporous and Mesoporous Mat... Jan 01, 1999

The kinetics of desilication of synthetic spent Ba...

on Journal of Crystal Growth Jan 01, 1999
More articles like this..