Abstract

Effect of lime causticization on silica, calcium, oxalate and organic carbon levels in Bayer process washer overflow liquor

Author(s): MaxA.Wellington

Inductively coupled plasma (ICP) and Spectrometric analysis of washer overflow liquor (Stage 1-3) from a high temperature JamaicanAlumina refinery revealed significant reductions in liquor calcium (>75%) and Silica (~90%) respectively after causticization using lime (CaO). Reductions were also observed in liquor sulfate (7-14%), fluoride (5-14%), oxalate (2-7%), chloride (6-13%) and Organic Carbon (4-5%) concentrations after causticization.Analysis of the causticization sludge by X-Ray Fluorescence (XRF) and Infra-red thermal analysis confirmed the removal of silica, calcium, phosphorus and organic carbon respectively from the Bayer process liquor.