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Title: Hydrometallurgical processing of mixed sulphite-oxide lead and zinc ores
Author: Moradi, Saeid
ISNI:       0000 0004 2718 4196
Awarding Body: Imperial College London
Current Institution: Imperial College London
Date of Award: 2012
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Mixed sulphide-oxide lead and zinc ores are most often found in the transition, and occasionally in the oxidised, zones of lead-zinc ore bodies. They are of great importance because there are numerous unexploited or abandoned reserves of these ores in the world. However, they present difficulties for conventional mineral processing due to complex mineralogy. In this thesis, the specific problems associated with these types of ores are described and methods for solving these problems, combining economic and technical considerations, are discussed. The results of experiments carried out at laboratory scale are presented, in which the dissolution of a mixed ore sample from the Angouran mine in Iran in sulphuric acid in the absence of oxidants and also the dissolution of the sulphide part of sample in ferric sulphate-sulphuric acid solutions in the absence and presence of other oxidants, i.e. oxygen, potassium permanganate, manganese dioxide and hydrogen peroxide. Fractional factorial experimental designs were used to determine which variables are significant and understand how these variables interact and drive the dissolution processes. Mathematical models are derived from the statistical analyses of the results. The kinetic studies indicate the rate controlling steps in non-oxidative and oxidative leaching are: diffusion of products back to the exterior surface of oxidised zinc minerals, and diffusion of ferric ions through the layer of elemental sulphur surrounding the sphalerite particles to the surface of the unreacted core of sphalerite particles, respectively. The dissolution of significant minerals in the ore sample, i.e. smithsonite, hemimorphite, sphalerite, cerussite, mimetite and kehoite during non-oxidative and oxidative leaching at optimal conditions were investigated by the XRD method. The results show the feasibility of zinc recovery from mixed sulphide-oxide lead and zinc ores, which underlines the potential of this approach. A conceptual flow diagram for the hydrometallurgical processing of these ores is proposed.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available