• DOI:10.1007/S10973-005-6785-6
• Corpus ID: 96393940

Thermal and XRD analysis of Egyptian galena

@article{AbdelRehim2006ThermalAX,
  title={Thermal
and XRD analysis of Egyptian galena},
  author={Aly M. Abdel-Rehim},
  journal={Journal of Thermal Analysis and Calorimetry},
  year={2006},
  volume={86},
  pages={393-401}
}

• A. Abdel-Rehim
• Published 6 October 2006
• Materials Science
• Journal of Thermal Analysis and Calorimetry

AbstractGalena is the principal ore
mineral for lead industry and the production of lead and its alloys. The industrial
processing of galena includes its oxidized roasting to lead oxide, followed
by reduction smelting of lead oxide agglomerate with coke in the blast furnace
to commercial lead.The present work reports a thermal analysis
study of oxidized roasting of Egyptian galena using a derivatograph. The reaction
products were identified microscopically and by using a Siemens Crystalloflex
diffractometer.On roasting of galena (heating in the air flow),
its oxidation to lead sulphate was shown by a wide and small exothermic DTA
peak at 460°C. The reaction between galena and lead sulphate, produced
PbSO4·PbO at 580°C, is shown by a small
exothermic peak. A large and sharp exothermic tripple maximum at 730, 740
and 765°C was due to the intensive oxidation of galena, accompanied by
an increase in mass (TG). This mass increase is attributed to the formation
of different sulphates. The mass loss is observed at temperature higher than
900°C due to the dissociation of the sulphates to lead oxide and evolution
of sulphur dioxide.The standard free energy (ΔG°) and equilibrium constant (K)
of the reaction of oxidation of galena to lead oxide at 800°C are –167.102
kcal mol–1 and 1.09·1034,
respectively. These values reflect the irreversibility of the reaction.The products of the oxidized roasting of galena are different, depending
upon the temperature of roasting such as anglesite at 300°C, basic lead
sulphates of specified compositions: (PbSO4·PbO
at 600°C, PbSO4·2PbO at 800°C and PbSO4·4PbO
at 900°C) and lead oxide at 1000°C.