scholarly journals The Separation of Carbonaceous Matter from Refractory Gold Ore Using Multi-Stage Flotation: A Case Study

Minerals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1430
Author(s):  
Sugyeong Lee ◽  
Charlotte E. Gibson ◽  
Ahmad Ghahreman
Keyword(s):  
Treatment Method ◽  
Single Stage ◽  
Carbonaceous Matter ◽  
Flotation Concentrate ◽  
Gold Ore ◽  
Fine Grained ◽  
Multi Stage ◽  
Refractory Gold ◽  
Pre Treatment ◽  
Concentrate Grade

As a pre-treatment method of refractory gold ore, carbonaceous matter (C-matter) flotation was investigated with multi-stage flotation by rougher, scavenger, and cleaner stages. Different dosages of kerosene and MIBC (4-Methyl-2-pentanol) were applied and the optimum dosage was selected by testing in each flotation stage. With the combination of each stage, four circuit designs were suggested, which were a single-stage rougher flotation (R), rougher-scavenger flotation (R+S), rougher-scavenger-scavenger cleaner flotation (R+S+SC), and rougher-rougher cleaner-scavenger-scavenger cleaner flotations (R+S+RC+SC). The results indicated that the scavenger flotation increased C-matter recovery but reduced C-matter grade compared with single-stage rougher flotation. Cleaning of the scavenger flotation concentrate improved C-matter grade significantly, but reduced recovery slightly. Cleaning of the rougher flotation concentrate achieved overall improved selectivity in flotation. A combination of rougher-scavenger flotation followed by cleaning of both concentrates (R+S+RC+SC) resulted in 73% C-matter recovery and a combined cleaner concentrate grade of 4%; the final tailings C-matter grade was 0.9%, where the C-matter remaining in the tailings was locked, and fine grained. The results demonstrate the need for the multi-stage flotation of C-matter from refractory gold ore to achieve selective separation and suggested the potential of C-matter flotation as the pre-treatment for efficient gold production.

Simultaneous Removal of S and As from a Refractory Gold Ore in a Single Stage O2-Enriched Roasting Process

2019 ◽  
Vol 50 (4) ◽  
pp. 1588-1596 ◽  
Author(s):  
Xiaoliang Liu ◽  
Qian Li ◽  
Yan Zhang ◽  
Tao Jiang ◽  
Yongbin Yang ◽  
...  
Keyword(s):  
Single Stage ◽  
Simultaneous Removal ◽  
Gold Ore ◽  
Roasting Process ◽  
Refractory Gold

scholarly journals Flotation of Carbonaceous Matter from a Double Refractory Gold Ore: The Effect of MIBC on Flotation Performance and Kinetics

Minerals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1021
Author(s):  
Sugyeong Lee ◽  
Charlotte E. Gibson ◽  
Ahmad Ghahreman
Keyword(s):  
Bubble Size ◽  
Gold Recovery ◽  
Carbonaceous Matter ◽  
Flotation Kinetics ◽  
Pressure Oxidation ◽  
Gold Ore ◽  
Refractory Gold ◽  
Flotation Performance ◽  
Thiosulfate Leaching

The use of alkaline pressure oxidation to pretreat refractory gold ore often results in insufficient gold recovery (<60%) in downstream thiosulfate leaching. To improve gold recovery, flotation was considered for the separation of carbonaceous matter (C-matter). In this study, the effect of MIBC on C-matter flotation was investigated to understand the role of the frother in bubble and froth formation and on flotation kinetics. MIBC dosages between 30 and 150 g/t were used in combination with 500 g/t of kerosene as a collector. The results showed that the recovery and selectivity of C-matter were improved with increasing MIBC dosages. Improved selectivity at higher MIBC dosages was attributed to faster C-matter recovery as bubble size decreased to the critical coalescence concentration (CCC) and to changes to the foam structure. Analysis of flotation kinetics showed that the flotation rate increased as the MIBC dosage increased due to the decreasing bubble size and the reduced induction time caused by the interaction between the collector and the frother. The results of this study explain the role of MIBC in C-matter flotation and can be used as a design basis for scavenger-cleaner flotation testing. Overall, the results show the potential for flotation as a means to improve gold recovery in thiosulfate leaching through the removal of C-matter.

Enzymatic Pre-Treatment of Carbonaceous Matter in Preg-Robbing Gold Ores: Effect of Ferrous Ion Additives

2017 ◽  
Vol 262 ◽  
pp. 43-47
Author(s):  
Kojo T. Konadu ◽  
Keiko Sasaki ◽  
Kwadwo Osseo-Asare ◽  
Takashi Kaneta
Keyword(s):  
Hydrogen Peroxide ◽  
Activated Carbon ◽  
Aromatic Compounds ◽  
Ferrous Ion ◽  
Alkaline Solutions ◽  
Carbonaceous Matter ◽  
Gold Ores ◽  
Refractory Gold Ores ◽  
Refractory Gold ◽  
Pre Treatment

The bio-treatment of double refractory gold ores (DRGO) to reduce preg-robbing needs to account for the heterogeneity of the ore so as to acquire a much more complete picture of the system. To this end, the effects of ferrous ion additives on the degradation of powdered activated carbon (PAC) by cell-free spent medium (CFSM) was studied. Au(CN)2- adsorption and Raman spectrometric results suggest that the ferrous salt could have possibly reacted with some biogenic hydrogen peroxide to aid in the degradation of PAC. The bio-treatment produced mixed solid residues containing some partially degraded aromatic compounds which were soluble in alkaline solutions. Ultimately, biodegradation of PAC using CFSM in the presence of 50 µM FeSO4.7H2O for 7 days followed by washing with 3 mM NaOH reduced Au(CN)2- uptake by 80%.

scholarly journals Significance of Acid Washing after Biooxidation of Sulfides in Sequential Biotreatment of Double Refractory Gold Ore from the Syama Mine, Mali

Minerals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1316
Author(s):  
Cindy Cindy ◽  
Ryotaro Sakai ◽  
Diego M. Mendoza ◽  
Kojo T. Konadu ◽  
Keiko Sasaki
Keyword(s):  
Gold Recovery ◽  
Carbonaceous Matter ◽  
Acid Attack ◽  
Gold Ores ◽  
Gold Ore ◽  
Positive Effects ◽  
Acid Washing ◽  
Washing Process ◽  
Refractory Gold ◽  
Mineralogical Compositions

Environmentally friendly pretreatment of double refractory gold ores (DRGO) to improve gold recovery without emitting pollutant gas is challenging. Sequential biotreatment, including iron-oxidizing microorganisms to decompose sulfides, followed by the enzymatic decomposition of carbonaceous matter, was recently developed. The effect of acid washing by 1 M HCl for 24 h between two bioprocesses was evaluated using a real double refractory gold ore from the Syama mines, Mali, which includes 24 g/t of Au and 5.27 wt % of carbon with a relatively higher graphitic degree. The addition of the acid washing process significantly improved gold recovery by cyanidation to yield to 84.9 ± 0.7% from 64.4 ± 9.2% (n = 2). The positive effects of acid washing can be explained by chemical alteration of carbonaceous matter to facilitate the accessibility for lignin peroxidase (LiP) and manganese peroxidase (MnP) in cell-free spent medium (CFSM), although the agglomeration was enhanced by an acid attack to structural Fe(III) in clay minerals. Sequential treatment of DRGO basically consists of the oxidative dissolution of sulfides and the degradation of carbonaceous matter prior to the extraction of gold; however, the details should be modified depending on the elemental and mineralogical compositions and the graphitic degree of carbonaceous matter.

Sulfide Minerals Bio-Oxidation of a Low-Grade Refractory Gold Ore

2018 ◽  
Vol 921 ◽  
pp. 157-167
Author(s):  
Zeng Ling Wu
Keyword(s):  
Microbial Community ◽  
Mine Drainage ◽  
Sulfide Oxidation ◽  
Dissolution Kinetics ◽  
Mineral Dissolution ◽  
Low Grade ◽  
Gold Ore ◽  
Refractory Gold ◽  
Pre Treatment ◽  
Lower Temperature

This paper describes the oxidative dissolution kinetics of sulfides with gold occlusion within pyrite and arsenopyrite. Shake flasks tests and column leaching of a low grade gold ore from China were carried out with domesticated mixed acidophiles isolated from acid mine drainage. Both test show that the main factors accelerating sulfide oxidation was mainly temperature and redox potential. Column bio-oxidation of mineral with a particle size less than 10 mm at 60°C resulted in higher mineral decomposition, finer fractions and eventually higher sulfide oxidation than that at 30°C. Sulfide-S dissolution increased from 58% to 77% from 30°C to 60°C after 247 ds of bio-oxidation. Further investigation into microbial community attached to the ore surface and in the leachate during the bio-oxidation was done by Real-time PCR assays. Organism of genera Acidithiobacillus was the most dominant species in both leachate and ore surface at lower temperature. For the Archaea, the iron oxidizing microbial Ferroplasma showed its predominance of 60°C. Mineral dissolution kinetics and microbial community in bio-oxidation was lucubrated in this work and suggestions were provided for pre-treatment of refractory gold ore.

EELS characterization of “Smut” layer films on steel surface prepared for chrome plating by anodic etching

1995 ◽  
Vol 53 ◽  
pp. 538-539
Author(s):  
E Y. Wang ◽  
J. T. Cherian ◽  
A. Madsen ◽  
R. M. Fisher
Keyword(s):  
Steel Surface ◽  
Surface Preparation ◽  
Treatment Method ◽  
Chrome Plating ◽  
Transmission Electron ◽  
Alloy Steels ◽  
Pre Treatment ◽  
Hard Chrome ◽  
Electron Energy Loss

Many steel parts are electro-plated with chromium to protect them against corrosion and to improve their wear-resistance. Good adhesion of the chrome plate to the steel surface, which is essential for long term durability of the part, is extremely dependent on surface preparation prior to plating. Recently, McDonnell Douglas developed a new pre-treatment method for chrome plating in which the steel is anodically etched in a sulfuric acid and hydrofluoric acid solution. On carbon steel surfaces, this anodic pre-treatment produces a dark, loosely adhering material that is commonly called the “smut” layer. On stainless steels and nickel alloys, the surface is only darkened by the anodic pre-treatment and little residue is produced. Anodic pre-treatment prior to hard chrome plating results in much better adherence to both carbon and alloy steels.We have characterized the anodic pre-treated steel surface and the resulting “smut” layer using various techniques including electron spectroscopy for chemical analysis (ESCA) on bulk samples and transmission electron microscopy (TEM) and electron energy-loss spectroscopy (EELS) on stripped films.

Arsenic release through refractory gold ore processing. Immobilization and decontamination approaches

2021 ◽  
Vol 20 ◽  
pp. 100236
Author(s):  
Michail Samouhos ◽  
Antoniοs Peppas ◽  
Georgios Bartzas ◽  
Maria Taxiarchou ◽  
Petros E. Tsakiridis
Keyword(s):  
Gold Ore ◽  
Ore Processing ◽  
Refractory Gold
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