oxidation of refractory minerals

Factors affecting bio‐oxidation of sulfide minerals at ...

Bio‐oxidation has proved to be a viable process for the oxidative pretreatment of refractory gold‐bearing sulfides. Generally, the oxidation rate is maximal at 20% …

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Redox effects on the microbial degradation of refractory ...

Redox effects on the microbial degradation of refractory organic matter in marine sediments Clare E. Reimersa,⇑, Yvan Alleaua, James E. Bauerb, Jennifer Delaneyc, Peter R. Girguisc, Paul S. Schradera, Hilmar A. Stecher IIIa,1 aCollege of Earth, Ocean and Atmospheric Sciences, Oregon State University, 104 CEOAS Administration Building, Corvallis, OR 5503, United States

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The reasons of gold refractory, Gold ore classification ...

 · The reason of the gold mineral refractory There are so many types of reasons that caused the difficulty of gold ore processing, including physical element, chemical element, and mineralogical element.

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Tistarite, Ti2O3, a new refractory mineral from the ...

, a new refractory mineral from the Allende meteorite Chi Ma* and Geor G e r. ross M an Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, Califor, U.S.A. abstra C t Tistarite, ideally Ti 2 O 3, is a new member of …

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[PDF] OXIDATION OF REFRACTORY GOLD CONCENTRATES AND ...

 · The oxidation of refractory gold concentrates containing arsenopyrite and pyrite and the simultaneous dissolution of gold in aerated alkaline solutions at ambient temperatures and pressures without the addition of cyanide has been studied.

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Microbial oxidation of gold ores and gold bioleaching ...

This paper reviews recent progress in the use of microorganisms tooxidize the sulfidic matrix in refractory gold ores (bio-oxidation) and to solubilize elemental gold (bioleaching). Arsenopyrite oxidation, ... Acidophilic bacteria and their activity in mineral sulfide oxidation. In .

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MULCOA - Imerys Refractory Minerals - The global benchmark ...

Imerys Refractory Minerals is the world’s leading producer of calcined products for the refractory industry. Our Mulcoa® range of materials is recognized as the global benchmark. Clays are mined from the South Georgia kaolin belt in the US, and blended to obtain chemistries between 45 and 70% alumina.

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PRESSURE OXIDATION OF REFRACTORY GOLD ORES: THE …

The refractory nature of the concentrate requires a pressure oxidation (POX) step to oxidise the sulfide minerals and unlock the value metals. The oxidation of sulfides is a highly exothermic reaction. The energy generated by the reaction of the sulfide minerals is such that the autoclave temperature can exceed the 210 – 230°C operating

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Pressure Oxidation of a Refractory Sulfide Concentrate and ...

Pressure oxidation of the refractory sulfide/carbonaceous ores has gained world-wide acceptance. Compared with roasting, pressure oxidation yields higher gold extractions from ores or concentrates and enables better handling of environmentally sensitive impurities. Normally, gold is extracted from neutralized autoclave leach residue by cyanidation.

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Biooxidation of Refractory Gold Ores (The Geobiotics ...

As free-milling oxide deposits are depleted on a world-wide scale, the mining companies capable of efficiently mining and processing both low- and high-grade refractory sulfide deposits will become industry leaders. This chapter addresses a new process for the biooxidation of refractory gold ores developed by GeoBiotics, Inc.

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FR2713242A1 - Process for rendering more sensitive to the ...

The invention relates to a method for rendering more sensitive to the biological oxidation of ores based on refractory sulfides. The process comprises the steps of separating clays and fines from a milled refractory sulfide ore, deforming a pile from this ore, and biologically leaching the ore to oxidize iron sulphides. present there, and hydrometallurgical treatment of biologically leached ...

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Effect of Pretreatment of Sulfide Refractory Concentrate ...

For extraction of gold from refractory ores or concen- trate, in which gold is surrounded or covered by iron sul- fide minerals, mainly arsenopyrite and pyrite, mineral oxidative pretreatment is essential to oxidize sulfides and to expose gold to the leaching solution. Pyrometallurgi- cal oxidation by roasting is under environmental restric-

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Oxidation studies of some refractory metals

Oxidation studies of some refractory metals Abstract Samples of niobium, tantalum, molybdenum and tungsten metals have been given phosphided cases by heating in a phosphorous atmosphere. The samples were subsequently exposed to air at an elevated temperature. In tests at 800°C, the phosphided samples resisted air oxidation markedly compared to ...

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On the oxidation mechanism of refractory high entropy ...

The high-temperature oxidation mechanism of a series of refractory high entropy alloys: TaMoCrTiAl, NbMoCrTiAl, NbMoCrAl and TaMoCrAl at 1000 °C in air was studied. A complex protective oxide layer consisting of Al 2 O 3, Cr 2 O 3 and CrTaO 4 oxides was observed for the quinary Ta-containing alloy.

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Autoclave Technology - Hatch

Solutions. Every autoclave and preleach circuit is a custom design, based on the experience and expertise of the design team. With the right innovative and proprietary equipment designs, your pressure-oxidation needs can be effectively met.

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Oxidation | chemical reaction

Oxidation of organic compounds generally… Read More; In oxidation-reduction reaction: Major classifications, in any oxidation reaction a reciprocal reduction occurs, and (2) they involve a characteristic net chemical change—i.e., an atom or electron goes from one unit of matter to another.

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Recovery Refractory Resources

host minerals in refractory gold deposits. “Recent introduction of hydrometallurgi-cal pre-treatment processes, such as pressure oxidation and bacterial leaching (bio-oxidation), has given mining companies more options for treating refractory ores,” says Dr Fleming. “In many cases, these new technologies have found

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CHLORIDE HYPOCHLORITE OXIDATION AND LEACHING …

Chloride–hypochlorite oxidation and leaching of refractory sulfide gold concentrate 63 Fig. 1. The Pourbaix diagram of Fe–S at [Fe] –= 10 4 M, [S] = 10– M and 25 C (the chlorine species regions are also marked) (Marsden and House, 2005) Fig. 2.

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Basic Iron Sulphate in Pressure Oxidation Processing

PRESSURE OXIDATION PROCESSING . OF REFRACTORY GOLD CONCENTRATES IF NOT HANDLED APPROPRIATELY. C.A. FLEMING –– SGS MINERALS. ABSTRACT. Refractory gold concentrates often contain sub-microscopic gold that is encapsulated within the crystal matrix of iron sulphide minerals such as pyrite, pyrrhotite and arsenopyrite.

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Types of Refractory Materials and Their Applications

 · Various refractory bricks in different sizes and shapes are now available for diverse applications. The typical refractory materials include fireclay refractories, high alumina refractories ...

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Bacterial Oxidation – An Economic Alternative for the ...

Bacterial oxidation technology was successfully applied in a mine site pilot plant for the treatment of refractory gold concentrates. The bacterial culture was proven capable of selectively breaking down the refractory sulphide minerals to release the gold. Gold extractions greater than 90 per cent were possible when oxidised concentrate was leached with cyanide solution.

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Atmospheric Oxidation Of Refractory Gold-Containing ...

The theoretical justification of atmospheric oxidation was carried out, in the result of this the mechanism and the degree of sulphide minerals? oxidation was found out, the dependence of gold dissolution speed on the slurry content in liquid phase produced by grinding and oxidation was identified.

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Bio-oxidation of refractory gold ores containing stibnite ...

Arsenic and antimony are environmental pollutants associated with several diseases, including skin cancer. One of the main sources of both elements is the oxidation of sulphide minerals, particularly arsenopyrite and therefore any of both elements is a concern in gold mining operations because arsenic- and antimony-bearing sulphides may contain significant gold contents.

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Oxidation of refractory gold concentrates and simultaneous ...

The oxidation of refractory gold concentrates containing arsenopyrite and pyrite and the simultaneous dissolution of gold in aerated alkaline solutions at ambient temperatures and pressures without the addition of cyanide has been studied. It involves the following aspects: the chemistry of the oxidation of pure arsenopyrite and pyrite minerals in aerated alkaline solutions; the kinetics of ...

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Fusion Techniques for the Oxidation of Refractory Actinide ...

Small-scale experiments were performed to demonstrate the feasibility of fusing refractory actinide oxides with a series of materials commonly used to decompose minerals, glasses, and other refractories as a pretreatment to dissolution and subsequent recovery operations. In these experiments, 2 g of plutonium or neptunium oxide (PuO 2 > or NpO<sub>2</sub>) were calcined at 900 degrees ...

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John T. Boyd Company – Refractory Ore Specialist ...

John T. Boyd Company – Mining and Geological Consultant is a prominent international metals mining consultant providing Refractory Ore consulting services relative to Gold and other minerals to a diverse client base with locations in United States, Australia, China, Colombia.

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Atmospheric Alkaline Pre-Oxidation of Refractory Sulphide ...

Atmospheric Alkaline Pre-Oxidation of Refractory Sulphide Gold Ores by Alan Joseph Rego B.A.Sc., The University of British Columbia, 2012 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF

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Ultra Fine Grinding - A Practical Alternative to Oxidative ...

Ultra Fine Grinding - A Practical Alternative to Oxidative Treatment of Refractory Gold Ores S. Ellis Kalgoorlie Consolidated Gold Mines Kalgoorlie, WA. Abstract Since early 2001, Kalgoorlie Consolidated Gold Mines (KCGM) has successfully operated an ultra fine grinding (UFG) circuit to supplement its roaster capacity for the

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OXIDATION OF REFRACTORY GOLD CONCENTRATES AND …

OXIDATION OF REFRACTORY GOLD CONCENTRATES AND SIMULTANEOUS DISSOLUTION OF GOLD IN AERATED ALKALINE SOLUTIONS By Suchun Zhang B. Eng. (Appl. Chem.), Tsinghua University, Beijing, China This thesis is presented for the degree of Doctor of Philosophy of Murdoch University Western Australia March 2004

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Effect of Pretreatment of Sulfide Refractory Concentrate ...

For extraction of gold from refractory ores or concen- trate, in which gold is surrounded or covered by iron sul- fide minerals, mainly arsenopyrite and pyrite, mineral oxidative pretreatment is essential to oxidize sulfides and to expose gold to the leaching solution. Pyrometallurgi- cal oxidation by roasting is under environmental restric-

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Science and Technology bCritical Reviews in Environmental

of Refractory Mineral Ores for Gold Extraction: A Review ... addition, the role of the microbial community in the bio-oxidation of refractory ores for removal of base metal impurities and in the

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Developments in the pretreatment of refractory gold ...

processing refractory gold ores, especially development in the pretreatment of refractory gold minerals by nitric acid. These processes include the high-pressure and the atmospheric-pressure oxidation methods. High-pressure oxidation processes are difficult …

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