Effect of microwave system location on floatability of chalcopyrite and pyrite in a copper ore processing circuit (original) (raw)
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Influence of microwave pre-treatment on the flotation of low-grade sulphide ore
Sulphide ores are always difficult to process because of the complication in their mineralogical associations and the intergrown nature of their constituent minerals. These complexities usually result in a poor liberation of the associated minerals. Hence, full determination of comminution parameters relevant to the crushing and milling of these minerals will enhance higher recovery of the concentrate minerals as well as enable proper plant design to take place. Meanwhile, most high-grade deposits of the world have been depleted which give rise to the need to process low-grade ores. The conventional methods of mineral processing are also no longer effective for the processing of these low-grade ores. This work centres on understanding the effects of microwave pre-treatment on the flotation characteristics of the low grade-sulphide ores. The ore was characterized using JEOL JSM. 7600 SEM-EDX, Qurum150TE XRD-Ultima IV and XRF-ZSX Primus II. Microwave treatment was also carried out using 2.45 GHZ intellowave microwave oven at a power output of 750W. Comminution and particle size analysis of the ore shows that P 80 for microwave treated sample is equal to -212µm +150µm while for the untreated sample P 80 corresponds to -250 µm +212µm. Sodium Ethyl Xanthate, SEX was used as the collector, Methyl Isobutyl Carbinol, MIBC as the frother and three different depressants (Starch, sodium silicate and potassium dichromate). Particle sizes 150µm, 106µm, 75µm and 53µm were used for flotation experiment. The trend of the recoveries of both microwave treated and untreated samples shows that recoveries are higher for the microwave treated samples.
The Microwave Irradiation Effect on the Floatability of Mixed Sulphide/Oxide Copper Ores
Rudarsko-geološko-naftni zbornik, 2021
Pre-treatment of copper sulphide and oxide ores using microwave radiation causes a difference in their floatability through change in the surface properties of the minerals. The aim of this study is to investigate the behaviour of Sungun porphyry copper ore under the influence of microwave radiation. In this regard, the feed sample of Sungun copper flotation circuit has been subjected to microwave irradiation for 0-120 s and a radiation power of 0-600 W. The prepared samples were then subjected to flotation experiments. According to the results, the grade of sulphide and oxide Cu minerals, as well as the grade of Fe, increased by microwave irradiation in all experiments compared to the non-irradiated samples. At the same time, recovery rate has a reversed trend and decreased in all cases. Variations in the recovery rates of copper oxides and sulphides due to microwave irradiation are different. Increasing the power of irradiation resulted in a greater reduction in the recovery of co...
Effect of microwave pretreatment on grinding and flotation kinetics of copper complex ore
International Journal of Minerals, Metallurgy and Materials
The present study initially investigates the kinetics of microwave-assisted grinding and flotation in a porphyry copper deposit. Kinetic tests were conducted on untreated and microwave-irradiated samples by varying the exposure time from 15 to 150 s. Optical microscopy, energy-dispersive X-ray spectroscopy, and scanning electron microscopy were conducted to determine the mineral liberation and particle surface properties, and to perform mineralogical analyses. Results showed that the ore breakage rate constant monotonically increased by increasing the exposure time, particularly for the coarsest fraction size (400 µm) due to the creation of thermal stress fractures alongside grain boundaries. Excessive irradiation time (>60 s) led to the creation of oxidized and porous surfaces along with a dramatic change in particle morphologies that result in a substantial reduction of chalcopyrite and pyrite flotation rate constants and ultimate recoveries. We concluded that MW-pretreated copper ore was ground faster than the untreated variety, but the two types have slightly similar floatabilities.
Recent developments in microwave-assisted comminution
International Journal of Mineral Processing, 2004
The influence of high electric field strength microwave energy on copper carbonatite ore has been elucidated. It has been shown that very short exposures times can lead to significant reductions in ore strength as determined by point load tests. Comparative drop weight tests were carried out to determine any potential change in required comminution energy for microwave-treated material. It was shown that reductions in required comminution energy of over 30% could be achieved for microwave energy inputs of less than 1 kW h t À 1. Comparative specific rate of breakage grinding studies showed that significant increases in grindability could also be achieved after short microwave exposure times, changes being related to particle size. QEM * SEM liberation studies showed that the amount of locked and middling copper sulphides was reduced from 69.2% to 31.8% in the + 500 Am size fraction. Conclusions are made regarding the potential future development of this technology.
Mining, metallurgy & exploration, 2007
The effects of microwave treatment on the floatabilities and magnetic susceptibilities of some sulfide minerals, namely, pyrite, chalcopyrite, galena and sphalerite, were studied. Pure mineral samples were prepared in-425+212f.lm,-212+106-f.lm and-106+38-f.lm size fractions. Microflotation and magnetic separation tests were carried out on the samples after microwave treatment at 600,950 and 1,300 Watts for 5,20,60,90,120 and 240 seconds. The maximum temperature values of the samples were measured during the microwave treatment, and possible alterations on the mineral surfaces were determined by X-ray diffraction (XRD) analysis. The effects of microwave treatment are discussed based on the result of microflotation and magnetic separation tests. The results revealed that pyrite, chalcopyrite and galena were heated very quickly and that their surface temperatures reached _700° to 900°C, while the temperature of sphalerite reached only-J30°c. The floatability of pyrite, chalcopyrite and galena were decreased when microwave energy and the duration of treatment were increased, owing to oxidation of the mineral surfaces caused by relatively high temperature. As expected, there was no change in the floatability of sphalerite. The magnetic properties of pyrite and chalcopyrite were improved by the increase in microwave energy and the duration of treatment to such an extent that 90% of the feed separated as magnetic product. But no change was observed in the magnetic properties of galena and sphalerite.
The effect of microwave pretreatment on the liberation of a copper carbonatite ore after milling
International Journal of Mineral Processing, 2008
The influence of microwave radiation on the liberation of the valuable minerals in a massive sulfide ore is presented. In general, sphalerite shows the highest degree of liberation with a maximum value of 84%. Sphalerite is followed by galena with 73% liberation and chalcopyrite with 63% liberation. Afine feed size and a high microwave power are the two common requirements for the liberation of the valuable metalbearing minerals in the are. Some of the valuable base-metal minerals show slightly different degrees of sensitivity to microwave irradiation. Therefore, process efficiency and economics should be considered in deciding the applicable level of heating. Chalcopyrite and galena, which are readily affected by microwave radiation, show a tendency to generate high amounts of locked particles, due presumably to randomfracture, partial (non-uniform) particle transformation and irregular particle shape.
Minerals Engineering, 2020
Refractory gold ores are difficult to treat, and several techniques have been proposed with the aim of increasing gold extraction. A necessary prerequisite for processing such ores is to remove the refractoriness through oxidation of sulphides and carbonaceous matter, which are the key components for the refractoriness. Roasting is one of the methods utilised in dealing with refractoriness. In this study, flash flotation concentrate containing sulphides and carbonaceous matter was investigated to ascertain its susceptibility to roasting under microwave irradiation. The major minerals present in the concentrate were quartz, pyrite, arsenopyrite and muscovite. The concentrates responded strongly to microwave irradiation. Temperatures above 1200°C could be attained after heating 50 g samples for 10 mins. Removal of sulphur, arsenic and carbonaceous matter during the microwave roasting process was above 92%. Volatilisation of organic carbonaceous matter from 4.4% to 0.2% resulted in 72% reduction in preg-robbing activity. The rapid removal of the volatile components led to cracking and foliation of the residual calcine particles, thus eliminating the need for regrinding of the pretreated concentrate prior to cyanidation. Direct cyanidation of the calcine extracted over 95% of the gold content while samples roasted in an electrical resistance furnace at 650°C and 750°C gave gold recoveries of 84% and 91% respectively.
ENERGY SOURCES, PART A: RECOVERY, UTILIZATION, AND ENVIRONMENTAL EFFECTS, 2020
The present work initially studies the impact of a laboratory microwave (MW)’s location (before and after a jaw crusher) on grindability of a copper ore. Additionally, the role of MW’s radiation time (15–150 sec) and grinding time (13, 15 and 17 min) on the produced particle size distribution (PSD), mineral liberation degree (LD) and energy consumption are investigated. relative work index (RWI), standard Bond work index (Wi), and grindability index (GI) together with the breakage and selection functions were utilized to assess the grinding efficiency and its kinetics of the untreated and MWpretreated (at a constant power of 0.9 kW) samples. Bond work indices were obtained 13.70, 13.04 and 10.86 kWh/t for the untreated, MW-treated uncrushed and MW-treated crushed samples, respectively. Besides, the results confirmed that the microwave pretreatment was comparatively effective at the shortest grinding time (13 min). Furthermore, locating the microwave after the crushing stage indicated substantial improvements in the sample’s grindability and its kinetics rate. The product size (P80) of the MW-treated crushed sample (13 min, 0.9 kW, 150 sec) showed enhancements of 27% and 17% in comparison with the un-microwaved and MWtreated uncrushed samples. Finally, the comparative GIs acquired in the entire spectrum of the particle range were reasonably higher if the microwave was located after the jaw crusher, particularly for the coarse fraction sizes
Comminution behaviour of microwave heated two sulphide copper ores
Indian Journal of Chemical Technology
The effect of microwave irradiation on the comminution of two sulphide copper ores with different mineralogy were investigated to enhance the milling processes. Each ore was subjected to microwave radiation for varying time periods to determine their heating profiles. Changes in breakage characteristics with the microwave exposure time were quantified by sieving breakage, standard Bond work index grindability and single particle drop weight comminution tests. The results of the sieving breakage tests with the untreated and microwaved samples indicated significant improvements in the size reduction due to microwave energy induced macro fracturing. Differing ore mineralogy has been shown to affect the effectiveness of microwave assisted size reduction. The results of the standard Bond work index grindability tests performed with both the microwave treated copper ores, on the other hand, suggested no significant improvements in grindability. The single particle fracture experiments per...