Authors: Mieke Campforts Evgueni Jak Bart Blanpain Patrick Wollants
Publish Date: 2009/07/22
Volume: 40, Issue: 5, Pages: 632-642
Abstract
Recently freeze linings have been selected more frequently to protect pyrometallurgical reactor walls due to a number of advantages over conventional refractory lining such as a selfregenerating capability and the possibility of operating under highintensity process conditions A freeze lining is formed on a cooled reactor wall in a timedependent temperature gradient To model freezelining behavior input data on several assumptions such as the phase formation and the temperature at the bath–freezelining interface during freezelining formation are needed In order to provide experimental data the freezelining formation of a synthetic lead slag system PbOFeOFe2O3ZnOCaOSiO2 is investigated A labscale freeze lining was produced by submerging an aircooled probe into a liquid slag bath for 120 minutes The temperature evolution during freezelining formation was estimated using the experimentally determined position and composition of the phases the phasetemperature relations predicted with the thermodynamic computer package FactSage and the results of reference experiments For the studied slag system it is concluded that heat transfer is much faster than mass transfer and crystallization As a result the liquid in front of the freeze lining undercools The degree of undercooling depends on the solidification rate It is concluded that the temperature at the bath–freezelining interface varies between the glass transition and liquidus temperatures of the slag bath during freezelining formation
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