Multi-scale analysis of uranium-ore agglomerates for heap leaching
Description
Heap leaching allows processing low grade ores. Basically, this industrial mining process consists in percolating a leaching solution slowly down through an ore heap of 6 to 9 meters high to extract the metals of interest. However, fine particles and clays are often the cause of clogging within heaps, leading to a decrease of leaching efficiency. To solve this problem, copper, nickel and uranium industry uses agglomeration of the ore particles. This process allows adjusting the particle size distribution by gathering fine particles. However uranium-ore agglomeration and the impact of the agglomerates structure on heap leaching remains poorly understood. The current thesis allowed characterizing structural and petrophysical properties of agglomerates and its evolution during leaching, studying the influence of agglomeration conditions on agglomerates structures and finally up-scaling there results at the heap scale, using meter scale columns. Clogging phenomena were especially due to the mechanical degradation of agglomerates, causing a decrease of both heap porosity and permeability. (author)
Abstract (French)
La lixiviation en tas est une methode industrielle utilisee pour traiter des minerais a basse teneur consistant en la percolation d'une solution de lixiviation a travers un tas de 6 a 9 metres de haut afin d'en extraire l'element d'interet. Cependant, la presence de nombreuses fines particules et d'argiles au sein du minerai peuvent causer l'apparition de phenomenes de colmatage dans les tas, diminuant l'efficacite de la lixiviation. Afin de resoudre ce probleme, les industries du nickel, du cuivre ou encore de l'uranium agglomerent le minerai, augmentant ainsi sa granulometrie par le rassemblement des fines particules. Neanmoins, l'agglomeration de minerais uraniferes ainsi que l'impact de la structure des agglomerats sur la lixiviation reste peu etudiee. Cette these a permis de caracteriser l'evolution structurale et petro physique des agglomerats de minerais d'uranium au cours de la lixiviation, d'etudier l'influence des conditions d'agglomeration sur la structure des agglomerats resultants et enfin d'etudier la lixiviation des agglomerats a l'echelle du tas, par le biais d'essais en colonnes metriques. De plus, les causes de colmatage ont pu etre identifiees comme provenant d'une degradation mecanique des agglomerats entrainant une reduction de la permeabilite et de la porosite du tas. (auteur)
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Additional details
Additional titles
- Original title (French)
- Etude multi-echelle de l'agglomeration pour la lixiviation en tas de minerais uraniferes
Publishing Information
- Imprint Pagination
- 206 p.
- Report number
- FRNC-TH--10991
INIS
- Country of Publication
- France
- Country of Input or Organization
- France
- INIS RN
- 51079047
- Subject category
- S11: NUCLEAR FUEL CYCLE AND FUEL MATERIALS;
- Resource subtype / Literary indicator
- Thesis
- Descriptors DEI
- AGGLOMERATION; EXTRACTION COLUMNS; FOULING; LEACHING; PERMEABILITY; POROSITY; SATURATION; TOMOGRAPHY; URANIUM ORES
- Descriptors DEC
- DIAGNOSTIC TECHNIQUES; DISSOLUTION; EQUIPMENT; EXTRACTION APPARATUSES; ORES; PHYSICAL PROPERTIES; SEPARATION EQUIPMENT; SEPARATION PROCESSES
Optional Information
- Notes
- 83 refs.; Available from the INIS Liaison Officer for France, see the INIS website for current contact and E-mail addresses