The Processing of Double Refractory Gold Ore: Treatment of Alkaline Pox Feed and Alkaline Pox Discharge
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Authors
Lee, Sugyeong
Date
Type
thesis
Language
eng
Keyword
Refractory gold ore , Thiosulfate gold leaching , Carbonaceous matter , Flotation , Alkaline pressure oxidation
Alternative Title
Abstract
This study examined a refractory gold ore containing carbonaceous matter (C-matter) and sulfide minerals from Barrick’s Goldstrike plant; gold is recovered from the ore using pressure oxidation (POX) followed by thiosulfate gold leaching. However, gold recovery is insufficient using the current process, leading to the investigation of poor recovery and possible solutions. Part I and Part II aimed to solve the problem of low gold recovery by taking a divergent approach: Part I determined that the low gold recovery from the alkaline POX discharge was mainly attributed to finely locked gold in the ore. For improved gold liberation and higher gold recovery, treatments were performed: 1) mechanical activation (MA) improved the gold recovery from 59% to 72% as P80 size decreased from 56.5 to 8.54 μm, 2) acid dissolution resulted in an improvement of gold recovery from 59% up to 66% using H2SO4. Part I concluded that the complexity of the ore cannot be fully overcome by the treatments, which motivated the study of pre-treating the ore using flotation to separate C-matter. Part II investigated flotation before POX to produce a C-matter concentrate and a tailings: the C-matter concentrate could be processed in Goldstrike’s roaster, while the tailings could be sent to the alkaline autoclave. Improved gold liberation and higher gold recovery were expected due to the higher efficiency of the roasting process in the treatment of carbonaceous material. Multi-stage flotation using kerosene and MIBC (Methyl isobutyl carbinol) resulted in 70% C-matter recovery and C-matter concentrate grade of 4% using a rougher-scavenger-cleaner flotation circuit. A reagent study demonstrated that 1) higher doses of MIBC increased the flotation rate and reduced the entrainment of gangue minerals, and 2) a kerosene emulsion resulted in higher recovery and faster flotation kinetics than normal kerosene and showed better performance than transformer oil, a novel collector. With the flotation, the overall gold recovery increased from 44% to 60% based on Barrick’s geo-estimation models. Ultimately, this work demonstrated that the main cause of poor performance in thiosulfate gold leaching and flotation was the highly complex nature of Goldstrike’s ore, with very poor liberation of host minerals.
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ProQuest PhD and Master's Theses International Dissemination Agreement
Intellectual Property Guidelines at Queen's University
Copying and Preserving Your Thesis
This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.