Diagnostic pre-treatment procedure for simultaneous cyanide leaching of gold and silver from a refractory gold/silver ore

2011 ◽  
Vol 24 (15) ◽  
pp. 1703-1709 ◽  
Author(s):  
Mojtaba Saba ◽  
Ali MohammadYousefi ◽  
Fereshteh Rashchi ◽  
Javad Moghaddam
Keyword(s):  
Cyanide Leaching ◽  
Treatment Procedure ◽  
Gold Silver ◽  
Refractory Gold ◽  
Pre Treatment

scholarly journals The effect of iron and oxidizing flux addition on the fire assay of low grade pyritic refractory gold ores

2011 ◽  
Vol 47 (2) ◽  
pp. 219-227 ◽  
Author(s):  
A. Turan ◽  
O. Yucel
Keyword(s):  
Precious Metals ◽  
Low Grade ◽  
Fire Assay ◽  
Gold Ores ◽  
Refractory Gold Ores ◽  
Gold Silver ◽  
Refractory Gold ◽  
Pre Treatment ◽  
Comparison Of The Results ◽  
Additional Iron

In this study, experiments were conducted to understand the effects of different quantities of additional iron and oxidizing flux (Na2O2) on the direct fire assay of low grade pyritic refractory gold ores instead of performing any pre-treatment like roasting before fire assay. A portion of the pyritic ore was primarily roasted using a rotary kiln to remove sulphur content for the comparison of the results obtained from direct fire assay of the pyritic ore. Then, fire assay process was performed to the roasted ore and gold and silver content in the ore was determined. Unroasted ore specimens were fused by using fluxes and PbO, which accumulates the precious metals, with various quantities of iron. Correlation between the quantity of additional iron and the recovery of gold-silver were investigated. Various quantities of Na2O2, as an oxidizing flux, were added to the smelting charge with iron additions, from which the highest gold and silver recoveries were obtained from previous experiments. From the results, it was clear that the increase in additional iron and Na2O2 quantities was the reason for the increase in the recovered amounts of lead, gold and silver during the process.

Biooxidation of High-Sulfur Refractory Gold Concentrate by Ferroplasma acidiphilum

2014 ◽  
Vol 997 ◽  
pp. 642-645 ◽  
Author(s):  
He Shang ◽  
Jian Kang Wen ◽  
Biao Wu
Keyword(s):  
Pulp Density ◽  
Cyanide Leaching ◽  
Gold Extraction ◽  
Pressure Oxidation ◽  
Gold Ores ◽  
Refractory Gold Ores ◽  
Refractory Gold ◽  
Initial Ph ◽  
Pre Treatment ◽  
Number Of Bacteria

Gold ores can be categorized into two types-free milling and refractory. Free milling ores are easy to treat. Gold in such ores is recovered by gravity separating techniques or direct cyanidation. Refractory gold ores, on the contrary, are difficult to treat and require pre-treatment prior to cyanidation, such as roasting, pressure oxidation, fine grinding and biooxidation. A number of bacteria are used in biomining but the prominent ones that are known to be involved in the oxidation of sulfide ores include Thiobacillusferrooxidans, Thiobacillus thiooxidans and Leptospirillum ferrooxidans. In this study, the gold concentrate was biooxidized in a reactor at 45°C over a period of 10 days at a pulp density of 15% solids using a culture of already grown Ferroplasma acidiphilum. The initial pH was adjusted to 1.5 with sulfuric acid, resulted in 85.39 % oxidation of sulfur from initial grade of 33.83 %, and the slag rate was 68.52 %. The products of sulfide biooxidation were leached at a pulp density of 20 %(v/w) for 24 h at pH 11. The pH was adjusted using CaO and cyanide strength was 10 kg/t, we got a gold extraction of 90.71 %, which ncreaseed 80.09 % compared with the direct cyanide leaching.

Wet oxidation: a pre-treatment procedure for sludge

2002 ◽  
Vol 22 (6) ◽  
pp. 611-616 ◽  
Author(s):  
Nevim Genç ◽  
Şems Yonsel ◽  
Levent Dağaşan ◽  
A.Nur Onar
Keyword(s):  
Wet Oxidation ◽  
Treatment Procedure ◽  
Pre Treatment

Microwave-Assisted Grinding of Bolkardag (Nigde, Turkey) Gold Ore and Enhanced Cyanide Leachability

2018 ◽  
Vol 115 (5) ◽  
pp. 508 ◽  
Author(s):  
Cemaliye Seflek ◽  
Oktay Bayat
Keyword(s):  
Particle Size ◽  
Power Level ◽  
Microwave Treatment ◽  
Cyanide Leaching ◽  
Gold Ore ◽  
Work Index ◽  
Significant Difference ◽  
Bond Work Index ◽  
Pre Treatment ◽  
Silver Extraction

This experimental work aims at studying the effect of particle size on the microwave pre-treatment for the grindability of Bolkardag (Nigde, Turkey) gold ore for cyanide leaching. Three different particle size batches (−8 + 4.7 mm, −4.75 + 2 mm and −2 + 1 mm) were used for microwave treatment. Each sub-samples were exposed to four different power levels of microwave energy (0.09, 0.18, 0.36 and 0.6 kW) at exposure times of 5, 10, 15 and 30 minutes and then grindability characteristic of the treated samples were investigated with Berry and Bruce comparative grindability method. It was clearly seen that increasing power level and exposure time caused a reduction in comparative Bond Work index. A maximum reduction in Bond Work index (73.54%) was achieved by 0.6 kW at 30 minutes of microwave treatment. Compared to the untreated sample’s results, gold and silver extraction rates increased, using microwave-treated samples, about 7% and 9% after 77 hours cyanide leaching, respectively. Additionally, the hydrated lime added samples (after 0.6 kW at 30 minutes of microwave treatment) were used in the cyanide leaching tests to determine the possible effect. It was observed that there was no significant difference on leaching extraction rates using lime free or lime added samples. Applying microwave pre-treatment before cyanide leaching, the gold and silver extraction rates could be increased and also the cost of communition could be reduced due to easier breakage of the ore due to a significant decrease in Bond Work index.

A simple and rapid method for blood plasma separation driven by capillary force with an application in protein detection

2020 ◽  
Vol 12 (20) ◽  
pp. 2560-2570 ◽  
Author(s):  
Qingxue Gao ◽  
Yongjia Chang ◽  
Qingmei Deng ◽  
Hui You
Keyword(s):  
Blood Plasma ◽  
Rapid Method ◽  
Capillary Force ◽  
Protein Detection ◽  
Microfluidic Devices ◽  
Treatment Procedure ◽  
Plasma Separation ◽  
Pre Treatment ◽  
Blood Plasma Separation

Blood plasma separation is a vital sample pre-treatment procedure for microfluidic devices in blood diagnostics, and it requires reliability and speediness.

An acidic pressure oxidation pre-treatment of refractory gold concentrates from the KweKwe roasting plant, Zimbabwe

1999 ◽  
Vol 12 (8) ◽  
pp. 863-875 ◽  
Author(s):  
F.P. Gudyanga ◽  
T. Mahlangu ◽  
R.J. Roman ◽  
J. Mungoshi ◽  
K. Mbeve
Keyword(s):  
Pressure Oxidation ◽  
Refractory Gold ◽  
Pre Treatment

Effect of Phanerochaete chrysosporium on Graphite Degradation during Pre-Treatment of Simulated Gold Preg-Robbing Ore

2015 ◽  
Vol 1130 ◽  
pp. 169-174
Author(s):  
Qian Liu ◽  
Hong Ying Yang ◽  
Lin Lin Tong ◽  
Li Li Qiao ◽  
Jing Peng ◽  
...  
Keyword(s):  
Phanerochaete Chrysosporium ◽  
Degradation Rate ◽  
Elemental Carbon ◽  
Xrd Analysis ◽  
Optimum Process ◽  
Ftir Analysis ◽  
Carbonaceous Matter ◽  
Cyanide Leaching ◽  
Gold Ores ◽  
Pre Treatment

Abstract. In this study, the effect ofPhanerochaete chrysosporiumon graphite was investigated, and graphite was used as a substitute of elemental carbon in carbonaceous gold ores. Under the condition of optimum process, the fungal degradation rate of graphite reached to 13.49%, and the carbon content of graphite was decreased by 5.13%. XRD analysis indicated thatPhanerochaete chrysosporiumcould destroy the crystal structure of graphite. FTIR analysis indicated thatPhanerochaete chrysosporiumcould increase the number of aliphatic structures and oxygen-containing groups. The cyanide leaching gold tests showed thatPhanerochaete chrysosporiumcan decrease the preg-robbing capacity of graphite, about 9.52%. It indicated thatPhanerochaete chrysosporiumis an available microorganism, which was employed to pre-treat carbonaceous matter in carbonaceous gold ores to reduce the interference of gold cyanidation leaching.

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