Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369344
Title: The applications of microwave energy to improve grindability and extraction of gold ores.
Author: Huang, Jian Hui.
Awarding Body: University of Birmingham
Current Institution: University of Birmingham
Date of Award: 2000
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Abstract:
Oxidation developed from the surfaces into the cores of the microwaved particles. Metallic particles were also formed during microwave exposure. Lihir gold ore, in which gold was finely disseminated in pyrite and marcasite, was an extremely refractory gold ore. Without pretreatment, only 37-39% of the gold could be extracted with sodium cyanide. However, this was improved after the head ores or floatation concentrates were pretreated by microwave radiation. 74.581.2% of the gold was extracted from the microwave treated head ore. The hydrometallurgical pretreatment of pyrite and marcasite in a microwave field and a conventional heating environment was also investigated.I,n a nitric acid solution, pyrite and marcasite can be rapidly leached. Reaction temperature and the concentration of HNO3 had a significant influence on decomposition rate. Marcasite had a substantially higher i decomposition rate than pyrite. Microwave heating could promote the dissociation of marcasite and pyrite, compared with conventional heating. This was caused by special volumetric heating during microwave exposure that may induce local overheating or improve the interactions between the high dielectric loss minerals and the leaching solution. Kinetic investigations show that the decomposition of both the minerals in a nitric acid medium is controlled by chemical reactions on the surfaces of particles. The decomposition is a second order reaction with respect to nitric acid concentration. Less than 5- 7% of the decomposed sulphur was transformed into elemental sulphur during the leaching of both the minerals
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.369344  DOI: Not available
Keywords: SCANNING ELECTRON MICROSCOPY; X-RAY DIFFRACTION; GOLD ORES; ORE PROCESSING; MICROWAVE RADIATION; HYDROMETALLURGY; DECOMPOSITION Mines and mineral resources Solid state physics Metallurgy
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