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Chemical and mechanical stability of hematite iron-ore in seawater

  • Verhoef P. N. W. 
  • Dalen J. P. J. Van 
Article

Abstract

Hematite ore was considered as a potential high-density rock-fill material for the constuction of a major coastal protection work in The Netherlands (the Storm Surge Barrier in the Eastern Scheldt). Three groups of hematite ore from the Itabira District, Brazil, were investigated for their chemical and mechanical stability in a prefeasibility study. Chemical leaching tests showed only minor chemical activity in one of the three investigated groups of rock samples. The microstructure of the ore was shown by slake durability testing and a sand blast test to be a significant factor influencing mechanical resistance against abrasive processes. The iron ore contains an important volume percentage of cryptocrystalline limonite. The mechaical characteristics of the ore are influenced by the microstructural distribution of the limonite. Redistribution of limonite within the ore and release of limonite from the ore takes place in flowing water, which might lead to visual pollution of the environment if this material is used as rock-fill in coastal protection constructions.

Keywords

Magnetite Hematite Goethite Limonite Sieve Fraction 

La stabilite chimique et mecanique du minerai de fer hematite dans l'eau de mer

Résumé

On examine l'usage du minerai de fer hématite pour réaliser des enrochements pour la construction d'un ouvrage important pour la protection de la côte des Pays-Bas (Digue protectrice contre les tempêtes, Schelde-Est). Trois groupes du minerai hématite provenant du District d'Itabira, au Brésil, ont été examinés quant à la stabilité chimique et mécanique dans une étude de faisabilité. Un essai de lessivage chimique montrait une activité chimique très limitée pour un des trois groupes de roches examinées. La structure microscopique est un facteur important qui contrôle la résistance mécanique contre les processus abrasifs. Le minerai de fer contient un pourcentage important en volume de limonite cryptocrystalline. Les caracteristiques mécaniques du minerai sont influencées par la distribution micostructurale, de la limonite. Il y a redistribution de la limonite dans le minerai et une perte de limonite se produit dans l'eau courante. Cette “perte” peut produire une pollution visuelle de l'environnement si ce matériel est utilisé comme enrochements dans des constructions de protection des côtes.

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References

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Copyright information

© International Association of Engineering Geology 1983

Authors and Affiliations

  • Verhoef P. N. W. 
    • 1
  • Dalen J. P. J. Van 
    • 2
  1. 1.Department of Mining EngineeringDelft University of TechnologyDelftThe Netherlands
  2. 2.Department of Chemical TechnologyDelft University of TechnologyDelftThe Netherlands

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