2.1 Mineralogy of Gold Ores 8 2.2 Behavior of Arsenic and Antimony Sulfide Minerals in Alkaline Cyanide Solution 13 2.3 Pretreatment of Refractory Sulfidic Gold Ores 15 2.3.1 Pressure Oxidation 18 2.4 Acidic Pressure Oxidation of Iron and Arsenic Sulfide Minerals 29 References 38 CHAPTER 3 FUNDAMENTALS OF OXIDATION 45 3.1 Thermodynamics 45

ABSTRACT It is accepted widely that pressure oxidation (POX) is the most appropriate technology for processing of arsenic containing refractory gold ores.

Feb 06, 2021 · Arsenic (As) has been well documented as toxic and carcinogenic element since 1970. Mining and extraction of Au, Ag, Pb, Zn, Cu and Ni from sulfides o…

Journal of Biomimetics, Biomaterials and Biomedical Engineering Materials Science. Defect and Diffusion Forum

For the gold locked within hematite in the two-stage calcination, which leads to a low gold leaching rate, the present work is aiming at pretreating the calcination to selectively dissolve hematite. The calcination was pretreated by sulfuric acid with cosolvent B. The factors influencing the hematite dissolution rate were studied, and the pretreatment parameters considered were H2SO4 content

Studies on the bioleaching of refractory gold concentrates substrate, and that the bioleaching of pyrite occurs via a multiple sub-process mechanism. Therefore, for the case of pyrite bioleaching the primary role of the bacteria is the oxidation of the ferrous-iron to the ferric form, thereby maintaining a high redox potential within the system and

from realgar and arsenic-bearing refractory gold ore, respectively. A comparative study on arsenic leaching abilities among different treatments was discussed to investigate the efficiency of mixed cultures of four strains of A. ferrooxidans and A. thiooxidans to bio-oxidize and bioleach two kinds of different arsenic-containing sulfide ores.

Biooxidation experiments carried out on a refractory Au ore concentrate containing 2.32 % arsenic and 3 1.04 g/t showed that only about 40% of the Au could be recovered from the concentrate by cyanidation without pretreatment and only 46% recovered after roasting and cyanidation, it was possible to recover 76% of the Au after biooxidation and

The effect of three ore pretreatments on gold recoveries from an ore in which the gold existed in solid solution in an arsenopyrite matrix, as well as being encapsulated in a pyrrhotite phase, was examined. The three pretreatments evaluated included fine grinding, pyrolysis-roast (Pyrox), and an oxidative pressure acid leach (PAL).

Jan 25, 2018 · Results are provided for a study of the substance composition of rebellious gold-copper-arsenic concentrate. The nature of gold dissemination in concentrate mineral components is demonstrated and it is established that gold is associated to a considerable extent with iron sulfides, and less with oxides. Based on results of substance analysis, comparative production schemes are proposed for

Rose and Newman's very comprehensive book, The Metallurgy of Gold, does not even contain the term refractory in its latest, fourth edition (1937). 1 Dorr and Bosqui's Cyanidation and Concentration of Gold and Silver (2d edition, 1950) has a brief chapter (XIII) on "Cyanicides and Refractory Ores," with only four pages devoted to

Mineralogy and Pretreatment of a Refractory Gold Deposit in Zambia study were obtained from an arsenic-containing sulfur-bearing gold. results of mineralogy study, gold partic les had a

Apr 26, 2007 · Abstract. The processing of gold bearing sulphide minerals which contain arsenopyrite and other complex arsenic sulphide minerals results in arsenic containing emissions and effluents which must be given careful consideration in relation to clean air and clean water standards.

The high-sulfur and high-arsenic carbonaceous refractory gold ore used in this study was obtained from Yunnan Gold & Mining Group Co., Ltd., China. The raw gold ore and gold flotation concentrate were ground so that 80% of the particles were finer than 74 μm (200 mesh).

The present invention is directed to recovery of gold from refractory and double refractory ores using a fungal agent and/or culture media. The fungal agent is inoculated in the feed material to either decompose sulfide sulfur or deactivate preg robbing carbon The culture media is applied, m the absence of a microbe, to decompose some sulfide sulfur and release a portion of the gold.

This paper summarizes the result of experiment that was fourced on investigation of oxidation pretreatment on sulfide mineral for leaching of refractory gold concentrate by hydrogen peroxide in sulfuric acid. For a viable option, extraction rate of Fe, Cu was low, but extraction rate of arsenic reached nearly 100%. As the result of oxidation, elemental sulfur was not produced.

Pressure oxidation of gold containing concentrates and ores is an effective pretreatment for liberating refractory gold. This is particularly true when an appreciable portion of the gold is associated with sulfides and is not amenable to conventional cyanidation. A brief review of the literature on pressure oxidation of refractory gold materials is presented.

Biooxidation experiments carried out on a refractory Au ore concentrate containing 2.32 % arsenic and 3 1.04 g/t showed that only about 40% of the Au could be recovered from the concentrate by cyanidation without pretreatment and only 46% recovered after roasting and cyanidation, it was possible to recover 76% of the Au after biooxidation and

DEVELOPMENTS IN THE PRETREATMENT OF REFRACTORY GOLD MINERALS BY NITRIC ACID 149 Feed material is mixed with water and nitric acid to the desired solids concentration in the feed tank and is fed into the fluidized bed via a positive displacement pump.

The problem concerning effective processing of gold ledge ores extremely refractory to loosening has been considered. [1]. Among gold ledge ores in Central Kazakhstan, ores from the Sayak-4 gold-arsenic-cobalt deposit discovered in 1950s have not been processed until the present as they are extremely refractory to loosening and beneficiation. [2, 3]. This papers is devoted to experimental

the kinetics of gold dissolution (Stoychevski and Williams, 1993; Roasting, pressure oxidation, biooxidation, ultrafine grinding and Deschenes and Prud home, 1997). modified cyanidation are the pretreatment methods currently In this study, main cyanidation parameters for two different gold practiced for refractory gold ores and concentrates

The invention discloses a pretreatment method of refractory gold ore, which is characterized by comprising the following steps of: adopting a dry-wet two-level ball grinder activating and impregnation process; carrying out first-level dry grinding by adopting a vibratory ball grinder and efficiently improving the mineral activity on the basis of energy conservation through adjusting the

Sep 28, 2018 · This study investigates the alkaline oxidation pretreatment process of Zarshuran refractory gold ore. Taguchi method-orthogonal array design (OAD) is applied to evaluate and optimize the influence of five main factors including solution pH, …

A "refractory" gold ore is an ore that has ultra fine gold particles disseminated throughout its gold occluded minerals. These ores are naturally resistant to recovery by standard cyanidation and carbon adsorption processes. These refractory ores require pre-treatment in order for cyanidation to be effective in recovery of the gold.

oxidation process of arsenic-pyrite refractory gold material prior to cyanidation [21, 23]. To date, there are few reports on bio-oxidation pretreatment regarding arsenic-containing concentrate. Therefore, in this work, the pretreatment of one high arsenic gold-bearing concentrate by the two-step bio-oxidation

Fizykochemiczne Problemy Mineralurgii, 32 (1998), 173–181 Alper ÖZKAN*, Salih AYDOGAN*, Ünal AKDEMIR* BACTERIAL LEACHING AS A PRE-TREATMENT STEP FOR GOLD RECOVERY FROM REFRACTORY ORES In this article, pre-treatment such as bio-leaching before cyanidation is discussed as an alternative technique to treat refractory gold ores containing pyrite and arsenopyrite.

The bacterial pre-oxidation process of arsenic-containing gold concentrates and the bacterial activity under different chloride ion concentrations were studied by using a mixture of thermophilic strains TCJ domesticated in production. The experimental result shows that with different samples and leaching systems, the adaptability and Cl− tolerance of bacteria are different, and that

Jun 01, 2016 · Pretreatment of arsenic-bearing gold ore with microwave-assisted alkaline leaching Pretreatment of arsenic-bearing gold ore with microwave-assisted alkaline leaching Ma, Hongzhou; Yan, Chao; Wang, Yaoning 2016-06-01 00:00:00 In this paper, the removal of arsenic from arsenic-bearing gold ore through air oxidation and sodium hydroxide leaching with microwave irradiation was studied.

According to the results of process mineralogy, the reasons for the low efficiency of beneficiation and the possibility of removing arsenic from gold concentrate are analyzed, and a suitable pretreatment process is proposed to recover the refractory gold ore reasonably and efficiently. Table 1. Chemical analysis of the raw ore (mass fraction, %).

The invention relates to a method for recovering gold from a sulphidic concentrate, particularly one containing arsenopyrite and/or pyrite, hydro- metallurgically. The concentrate is first subjected to leaching with a concentrated solution of alkali chloride and copper (II) chloride, by means of which the copper minerals and some of the gold in the concentrate are made to dissolve.

Roasting is a pretreatment method with many years of industrial experimental experience in the industry, especially for removing sulfur and carbon, producing porous calcine material suitable for cyanidation and recovering arsenic. However, the production of gold mines containing arsenic, antimony, mercury, and tellurium is highly successful and

It is necessary to apply a pretreatment to obtain high gold recovery (>80%) from such refractory ores by cyanide leaching. There have been many studies on the oxidation of refractory gold ores for

According to the results of process mineralogy, the reasons for the low efficiency of beneficiation and the possibility of removing arsenic from gold concentrate are analyzed, and a suitable pretreatment process is proposed to recover the refractory gold ore reasonably and efficiently. Table 1. Chemical analysis of the raw ore (mass fraction, %).

Being the most common sulfide minerals, Arsenopyrite and pyrite under oxidizing conditions breaks down to release acids of As and S into the environment, leading to acid mine drainage with high concentrations of dissolved As. In this research, the dissolution of gold ore (with FeS2 and FeAsS as the main sulfides) from Tianli gold mine, Liaoning province, China was investigated.

Gold-Ore Roasting Conclusions Roasting of As-bearing sufide ores and concentrates is a pyro-metallurgical pre-treatment process that was commonly utilized in the extraction of refractory gold and some smelting operations (especially Cu). The product of roasting is referred to as calcine.