The refractory metals tungsten, tantalum and niobium are considered critical raw materials in Europe. ... As the water solubilities of typical tungsten ore minerals scheelite (CaWO 4) and ferberite (FeWO 4) ... niobium and tantalum from intermediate and low-grade primary and secondary ore materials via alkaline fusion using microwave heating ...
One such area which has shown particular promise over a period of several years is the use of microwave heating technologies to improve the efficiency of various mineral processing unit operations including: leaching, refractory gold ore treatment, grindability and liberation and coal grinding. ... Kashyap S., (1984) 'The relative ...
of extracting 93.10% of gold in 180 minutes from a refractory mineral of pyritic origin with economic and environmentally friendly techniques such as the use of pretreatment with microwave waves,
Semantic Scholar extracted view of "MICROWAVE IRRADIATION PRETREATMENT OF A REFRACTORY GOLD CONCENTRATE" by K. E. Haque. ... The influence of microwave radiation on the liberation of the valuable minerals in a massive sulfide ore is presented. ... Heating in a microwave oven in the presence of acid mixtures dissolves the metals from powdered ...
Research into heating of minerals by microwave energy started in 1996 when Connell and Moe (1966) obtained a US patent for apparatus for treatment of ore. Ford and Pei (1967) applied microwaves to several oxides and sulphides. ... pre-treatment of refractory gold ores, coal desulphurisation, leaching, roasting, carbon reactivation, carbothermic ...
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, …
Abstract: The application of microwave technology in mineral metallurgy is a transformative ap-proach to ore processing that offers new ideas about the current progressive depletion of …
Microwave energy was applied in the pretreatment of a typical refractory arsenopyritic gold concentrate. More than 80% of As and S were volatilized off as As 2 O 3 and SO 2; whereas iron was oxidized mostly to hematite (Fe 2 O 3).All the gold was present in the calcine which responded favourably to the conventional alkaline cyanidation process and …
In this research, microwave roasting of a double refractory gold ore was investigated as an alternative method and the results were compared to those obtained by …
The use of microwave heating in primary metallurgy is gaining an increasing interest due to the possibility to selectively process ores and to volumetrically heat large amounts of low-thermal conductivity minerals. In this paper the study, development and testing of a new applicator combining the use of microwave and induction heating for rapid reduction of metal containing …
Moreover, the rate of microwave heating of minerals, effect of microwaves on coal desulphurisation and the extraction of diterpanes from coal were investigated. ... Refractory gold ore contains ...
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 refractory gold ore and …
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, (Feb. 1988) pp ...
Microwave heating of gold ores for enhanced grindability and cyanide amenability. ... Fig. 1 shows the sample temperature of the various minerals after heating for 5 ... Both refractory and non-refractory ores were considered, with cyanidation extraction followed by carbon in pulp (CIP) recovery assumed for non-refractory ore processing. ...
Some minerals such as pyrite, magnetite and manganese oxides readily absorb microwaves and are considered as hyperactive. Hematite may be classified as active while silica would be inactive (Haque, 1999, Amankwah and Pickles, 2005, Amankwah et al., 2005b, Kingman, 2006). ... Research has confirmed that microwave heating of refractory ores and ...
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 ...
11.1.1 Sintering and Drying of Ceramics. The calcination and sintering of ceramics by microwaves was reported as early as 1972 by Shimomura et al. []; fundamental and application studies followed thereafter around 1980.Even so, much of the theory and some of the relevant data on microwave-material interactions, which provided a valuable background for microwave …
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 ...
understanding of how microwave energy interacts with minerals is the key to unlocking the technology for use in mineral processing industries. To shed more light on the subject of the
The exploration of microwave-heating principles has revealed its capacity for rapid, uniform, and selective heating, translating into enhanced processing efficiencies across various stages of mineral metallurgy.
refractory gold sulfide resources, mainly containing minerals of elemental sulfur, dense pyrite, and arsenopyrite. The decomposability was evaluated using thermodynamic and thermogravimetric analyses. Faster microwave heating characteristics were confirmed under a nitrogen atmosphere. The
The microwave-assisted reduction behaviours of two low-grade iron ores having a similar Fe content of 49wt% but distinctly different mineralogical and liberation characteristics were studied. Their performances in terms of the iron grade and recovery as obtained from statistically designed microwave (MW) roasting followed by low-intensity magnetic separation …
Most geological materials often contain refractory minerals (Table 1) that are resistant to acid attack and may require several hours of heating with acids, a fusion process, or a microwave digestion for satisfactory dissolution. Chromite is an example of a mineral phase that is very difficult to digest.
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.
The microwave heating of serpentine and olivine, the two primary components of the ultramafic nickel ores studied by Bobicki et al. [15], is explored in the present study.The microwave heating of serpentine has been investigated in a limited capacity by Chunpeng et al. [25] and White et al. [26].Chunpeng et al. [25] found that serpentine heated to >200 °C upon …
Some minerals such as pyrite, magnetite and manganese oxides readily absorb microwaves and are considered as hyperactive. ... 2006). Research has confirmed that microwave heating of refractory ores and concentrates effectively oxidises sulphides and carbonaceous matter and liberate gold particles. ... Microwave heating and roasting tests were ...
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 (Al-Harahsheh and Kingman, 2004, Haque, 1999, Huang and Rowson, 2000, Kingman, 2006, Nanthakumar et al., 2007).It has been demonstrated that microwave …
The vast majority of refractory gold occurs in sulphidic minerals such as py rite ... evolved during microwave heating of this mixt ure; instead water soluble products such as;
Microwave technology has been confirmed to be suitable for use in a wide range of mineral leaching processes. Compared to conventional leaching, microwave-assisted leaching has significant advantages. It is a proven process, because of its short processing time and reduced energy. The purpose of this study was to enhance the gold content in a refractory gold …
suitable for refractory use. The mechanism is explained by the ability ofthe microwave radiation to heat specificpoints within the bauxite. These heat-specific points are at the location ofiron minerals. In a reduced atmosphere, the microwaves promotefaster conversion ofthe iron minerals to a magnetic phase, which improves the magnetic-separa ...
The microwave heating behaviour studies showed that the sample temperature increased with increasing incident microwave power, processing time and sample mass. Due to the hyperactive response of the concentrate to the microwaves, a low incident power of 600 W was found to be suitable for roasting, as higher powers resulted in sintering and ...
Professor of Minerals/Metallurgical Engineering - Cited by 981 - Gold hydrometallurgy - mycohydrometallurgy - bioprocessing of minerals - mine wastewater ... Microwave heating of gold ores for enhanced grindability and cyanide amenability. ... Fungal pretreatment of sulfides in refractory gold ores. G ...