Effect of Power and Exposure Time on the Microwave …
Gold in refractory ores occurs as fine-size gold-bearing sulfide minerals. In this study, the microwave-assisted roasting method has been investigated as a pretreatment for a refractory gold ore. This method can provide rapid heating radiation, cause micro-cracks, and trigger the decomposition of sulfide minerals.
Removal of arsenic and sulfur from a refractory gold …
The R&D results demonstrate that microwave energy has potential in mineral treatment and metal recovery operations such as heating, drying, carbothermic reduction of oxide minerals, leaching ...
Leaching of Refractory Gold Ores by Microwave Irradiation …
The present paper attempts to assess the effects of microwave irradiation on the leachability of refractory gold ores. Characteristics of the crystal structure and microstructure of the ores were determined by x-ray structural analysis (XRD) and scanning electron microscopy (SEM) before and after microwave irradiation. Compared to …
Removal of arsenic and sulfur from a refractory gold …
Microwave heating is being developed as a potential thermal pretreatment process, because of its unique advantages over conventional heating and the differences of ore minerals in absorbing microwaves ... The main minerals in the refractory gold concentrate were arsenopyrite, pyrite, pyrrhotite and quartz. ...
Microwave energy for mineral treatment processes—a brief …
This review is a brief account of R&D results generated from microwave-assisted mineral treatments tests. The R&D results demonstrate that microwave energy has potential in mineral treatment and metal recovery operations such as heating, drying, carbothermic reduction of oxide minerals, leaching, roasting/smelting, pretreatment of …
Microwave heating of magnesium silicate minerals
Microwave-assisted metallurgy. Z. Peng Jiann-Yang Hwang. Materials Science, Engineering. 2015. Microwave heating has been extensively explored in various fields of materials processing. This technology exhibits unique characteristics including volumetric and selective heating, which eventually…. Expand.
Effect of Power and Exposure Time on the Microwave
Microwave power between 300 - 600 watts significantly affected the increase in roasting temperature and weight loss of refractory gold ore. The highest temperature reached 567°C in roasting at ...
Microwave treatment for gold minerals used in small-scale …
The microwave effect is an effective pretreatment in refractory minerals for the extraction of gold. With a permanence of four minutes of the gold mineral in the microwave, it is possible to reach a temperature of 640ºC in which the transformation of the chemical composition to oxides occurs, making the leaching of gold with thiourea more ...
Materials Processing by Microwave Heating | SpringerLink
As a relatively new energy source, microwave radiation has considerable potential in minerals processing and extractive metallurgy—that is hydrometallurgy and pyrometallurgy. ... A.J. Berteaud, J.C. Badot, High temperature microwave heating in refractory materials. J. Microwave Power 11, 315–320 (1976) Article Google Scholar
Extraction of Gold from a Low-Grade Double Refractory …
After roasting, microwave heating or alkaline pressure oxidation, the gold cyanidation ratio reached 82.37%, 81.26% and 71.09% respectively. Roasting was an effective, reliable and mature technique to oxidize sulfide minerals and carbonaceous matters. ... "Microwave pretreatment of a double refractory gold ore," Minerals Engineering, 20 (11 ...
Alumina-enhanced valorization of ferronickel slag into refractory …
For further assessment of the influence of Al 2 O 3 on the preparation of the refractory materials by microwave sintering, the SEM-EDS analyses of the resulting materials prepared with different Al 2 O 3 additions (0, 2, 4 ... Microwave heating of magnesium silicate minerals. Powder Technol., 339 (2018), pp. 1-7. View PDF View …
Conventional versus microwave-assisted roasting of sulfidic …
In this regard, the current research focuses on the pretreatment of refractory gold ore and investigates the effect of microwave power, the role of additives, and water on the oxidation and decomposition of sulfide minerals. Pretreatment using microwave-assisted roasting with NaClO 3 as an additive to the oxidizing agent is a new …
Microwave energy for gold ore processing | Request PDF
This paper provides a brief overview of microwave energy used for gold ore and concentrate processing and describes the behaviour of minerals in the microwave field, as well as the results of a ...
Microwave heating applications in environmental engineering—a review
It has been demonstrated that microwave energy has many potential applications in mineral treatment and metal recovery operations, these include heating, drying, carbothermic reduction of oxide minerals, leaching, roasting/smelting and pre-treatment of refractory gold ores and concentrates (Haque, 1999).
microwave heating of refractory minerals – Grinding Mill …
Unique microwave heating characteristics are the main driver for potential … refractory gold ore. Minerals Engineering, 2007. 20(11): p. 1109-1119. 12. » Free Online Chat. Microwave heating characteristics of selected … Microwave Assisted Leaching of Refractory Gold Concentrates : SUMMARY… Microwave heating characteristics of …
Alumina-enhanced valorization of ferronickel slag into refractory …
This study presents a new approach to enhance preparation of superior-quality refractory materials by microwave sintering of the mixture of ferronickel slag and sintered magnesia with addition of alumina up to 10 wt %. It was shown that in the process of microwave sintering, the proper addition of alumina could contribute to formation of …
Concentrate Using Microwave Assisted Leaching
2.2.2. Microwave-Assisted Leaching: Recovery of Gold. Microwave-assisted leaching was performed by heating a 500 mL Pyrex glass containing 200 mL of nitric acid (1.0, 3.0, and 5.0 M) and 20 g of ...
Microwave Pyrolysis Pretreatment of High Arsenic Refractory …
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Microwave-assisted leaching—a review
Microwave-assisted leaching has been investigated in an attempt to improve the yield of extracted metal and to reduce process time, especially with the increasing demand for more environmental friendly processes. Unique microwave heating characteristics are the main driver for potential implementation in metal extraction.
Microwave treatment of minerals-a review
THEORETICAL STUDIES IN THE MICROWAVE TREATMENT OF MINERALS Little research has been instigated in the theoretical aspects of microwave …
Microwave heating of magnesium silicate minerals
Compared with conventional heating methods, microwave heat minerals selectively, efficiently, and automated [9][10] [11] [12][13]. Considering the advantages of microwave heating and the pressure ...
Microwave roasting of flash flotation concentrate …
3.3. Conventional roasting of flotation concentrate. Roasting in the auriferous industry involves the heating of complex or refractory gold concentrates containing sulphides (mainly pyrite and arsenopyrite) and carbonaceous materials in air to produce volatile arsenic xide (As 2 O 3), sulphur dioxide (SO 2) and carbon dioxide (CO …
Recovery of Gold from the Refractory Gold Concentrate …
the sulfide minerals in a refractory gold concentrate react to form a harmful gas during roasting and the iron oxide produced during roasting encapsulates invisible or fine gold [7]. Pyrite is the most ... Microwave heating has also been applied by Choi et al. [17] to perform pre-treatment,
The Application of Microwave Digestion in Decomposing Some Refractory
A digestion time of 15 min for 3.0g solid fusion agent mixture of sodium peroxide/sodium carbonate (Na2O2/Na2CO3) in a corundum crucible via microwave heating is sufficient to decompose 0.1 g ...
Microwave heating of magnesium silicate minerals
Conclusions. 1. The microwave heating of the magnesium silicate minerals serpentine and olivine was investigated. Upon exposure to microwave radiation, serpentine heated to a maximum temperature of 216 °C after 19 min of microwave heating time and olivine heated to a maximum temperature of 56.6 °C after a microwave heating time of …
The Application of Microwave Energy in Mineral Processing …
Refractory gold ore contains sulfide minerals such as pyrite (FeS 2 ), chalcopyrite (CuFeS 2 ), galena (PbS), and sphalerite (ZnS). ... Microwave heating is an attractive method to improve the ...
(PDF) Microwave Heating Applications in Mineral …
Effect of microwave heating on the temperature of various minerals (500 W, 2450 MHz, 4min. radiation) Microwave Heating Applications in Mineral Processing 85. Thus, a fundamental. understanding of ...
Microwave treatment of minerals-a review
It was felt that microwaves offered most potential in roasting refractory concentrates. Haque [16] applied high power microwave energy to typical refractory gold concentrates. ... Walkiewicz, J.W., Kazonich, G. & McGill, S.L., Microwave heating characteristics of minerals and compounds, Minerals and Metallurgical Processing, 39, …
Microwave Heating Applications in Mineral Processing
The information compiled in this chapter demonstrates that microwave energy has the potential for application in mineral treatment and metal recovery processes such as heating, drying, grinding, leaching, roasting, smelting, carbothermic reduction of …
Microwave heating of magnesium silicate minerals
Serpentine (Mg 3 Si 2 O 5 (OH) 4 ), and olivine (Mg 2 SiO 4 ), from Ward's Natural Science (Rochester, New York, USA), were used for all experiments. The samples were crushed and ground to <45 μm. For the microwave heating behaviour tests, the ground samples were compressed into briquettes using a pressure of 20.7 MPa.