Gold Extraction from a High Carbon Low-Grade Refractory Gold Ore by Flotation-Roasting-Leaching Process

Carbonaceous sulfidic gold ores are commonly double refractory and thus require pretreatment before gold extraction. In this paper, the capacity of pre-bio-oxidation can simultaneously decompose sulfides or deactivate carbonaceous matters (CM) from a double refractory gold ore (DRGO) using pure cultures of A. ferrooxidans or L. ferrooxidans, and a mixed culture containing A. ferrooxidans and L. ferrooxidans was investigated. The results showed that direct thiourea leaching of the as-received DRGO yielded only 28.7% gold extraction, which was due to the encapsulation of sulfides on gold and the gold adsorption of CM. After bio-oxidation, thiourea leaching of the DRGO resulted in gold extraction of over 75–80%. Moreover, bio-oxidation can effectively reduce the adsorption of carbon to gold. XRD, SEM-EDS and FTIR analysis showed that many oxygen-containing groups were introduced on the surface of DRGO during bio-oxidation, while the C=C bond was cleaved and the O–C–O and C–N bonds were degraded, causing a decrease in active sites for gold adsorption. Moreover, passivation materials such as jarosite were formed on the surface of DRGO, which might reduce the affinity of CM for gold in solutions. In addition, the cleavage of the S–S band indicated that sulfides were oxidized by bacteria. This work allows us to explain the applicability of pre-bio-oxidation for degrading both sulfides and CM and increasing gold recovery from DRGO in the thiourea system.

Download Full-text

Biooxidation of a Refractory Gold Ore: Implications of Whole-Ore Heap Biooxidation

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.262.65 ◽

2017 ◽

Vol 262 ◽

pp. 65-69 ◽

Cited By ~ 1

Author(s):

Bo Wei Chen ◽

Jian Zhi Sun ◽

He Shang ◽

Biao Wu ◽

Jian Kang Wen

Keyword(s):

Pulp Density ◽

Tianshan Mountain ◽

Gold Mine ◽

Gold Extraction ◽

Gold Leaching ◽

Gold Ore ◽

Refractory Gold ◽

Gold Reserve ◽

Initial Ph ◽

South Tianshan

The Sawayardun Gold Mine, the first Muruntau type gold mine in China, was located in the south Tianshan Mountain, Xinjiang Province. The gold reserve was 127 t with an average gold grade of 2.36 g/t. Due to the high content of arsenic and antimony, the traditional flotation-roasting-cyanidation process was not suitable. The direct cyanidation gold extraction for the raw ore was 44.70 %. Thus, biooxidation experiments in shaker flasks were conducted for this ore. The optimum conditions were obtained as inoculation volume 10 %, initial pH 1.7, pulp density 15 %, temperature 33 °C, leaching time 10 days, with the arsenic oxidation rate of 75.12 %. Then the biooxidation residues were test for gold leaching using NaCN, green gold leaching agent and thiourea. After 24 h leaching rate at pulp density of 33%, gold leaching agent dosage of 2 kg/t ore, the gold extraction for NaCN, green gold leaching agent and thiourea were 91.50 %, 86.23 % and 91.09 %, respectively. The high gold extraction showed a bright future for the whole-ore heap biooxidation of this refractory gold ore.

Download Full-text

Improved recovery of a low-grade refractory gold ore using flotation–preoxidation–cyanidation methods

International Journal of Mining Science and Technology ◽

10.1016/j.ijmst.2014.05.018 ◽

2014 ◽

Vol 24 (4) ◽

pp. 537-542 ◽

Cited By ~ 18

Author(s):

Soltani Faraz ◽

Darabi Hossna ◽

Badri Rezgar ◽

Zamankhan Piroz

Keyword(s):

Low Grade ◽

Gold Ore ◽

Refractory Gold

Download Full-text

Mineralogical Characteristics of a Micro-Fine and Low Grade Refractory Gold Ore

MATEC Web of Conferences ◽

10.1051/matecconf/201714202011 ◽

2018 ◽

Vol 142 ◽

pp. 02011

Author(s):

Yong Chen ◽

Yongsheng Song ◽

Wenjuan Li ◽

Liulu Cai

Keyword(s):

Low Grade ◽

Gold Ore ◽

Mineralogical Characteristics ◽

Refractory Gold

Download Full-text

Mineralogical Characteristics of a Micro-Fine and Low Grade Refractory Gold Ore

MATEC Web of Conferences ◽

10.1051/matecconf/201814202011 ◽

2018 ◽

Vol 142 ◽

pp. 02011

Author(s):

Yong Chen ◽

Yongsheng Song ◽

Wenjuan Li ◽

Liulu Cai

Keyword(s):

Analytical Techniques ◽

Size Analysis ◽

Gangue Mineral ◽

Low Grade ◽

Mineralogical Characterization ◽

Valuable Metal ◽

Gold Ore ◽

Mineralogical Characteristics ◽

Refractory Gold

Detailed characterization of a micro-fine, low-grade refractory gold ore from a beneficiation plant in Yunnan Province, China, was investigated. Different analytical techniques, such as videlicet size analysis, scanning electron microscopy, and mineral analysis by a Mineral Liberation Analyser, were used for mineralogical characterization of the ore. The results show that the most valuable metal is gold. Grain size of pyrites and arsenian pyrites, which are main gold carrying minerals, are mostly 1 ~ 30 μ m. The gangue mineral is composed of quartz, mica, dolomite and feldspar, while the content of easy-to-float and clay gangue minerals is up to 33%.

Download Full-text

Separation Tests of Low-Grade Gold Ore with High Sulfur and Arsenic

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.454.285 ◽

2012 ◽

Vol 454 ◽

pp. 285-291 ◽

Cited By ~ 2

Author(s):

Ying Qiang Ma ◽

Xi Mei Luo ◽

Wan Zhong Yin ◽

Jin Yao ◽

Ming Bao Liu ◽

...

Keyword(s):

Mineral Composition ◽

Chemical Elements ◽

Practical Significance ◽

Low Grade ◽

Preliminary Results ◽

Gold Ore ◽

Refractory Gold

With the rise of gold prices, a large amount of gold resources will be exploited, which leads to more and more refractory gold ore appeared. It has very important practical significance to accelerate the development of refractory gold resources. This paper has done the separation tests of low-grade gold ore with high sulfur and arsenic from Tianmashan, Tong Ling in China. The chemical elements component, mineral composition, and the dissemination of mineral and gold have been analyzed. The separation flowsheet tests have been explored, and the preliminary results and appropriate reagent regime have been obtained.

Download Full-text