The Experts below are selected from a list of 25428 Experts worldwide ranked by ideXlab platform
S W Kingman - One of the best experts on this subject based on the ideXlab platform.
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Microwave Treatment of electric arc furnace dust with tetrabromobisphenol a dielectric characterization and pyrolysis leaching
Journal of Analytical and Applied Pyrolysis, 2017Co-Authors: Mohammad Alharahsheh, S W Kingman, Ian S HamiltonAbstract:In the present work Microwave Treatment of electric arc furnace dust (EAFD) mixed with tetrabromobisphenol A (TBBPA) was investigated. A range of characterization techniques were used to understand the thermal behaviour of TBBPA-EAFD mixtures under Microwave pyrolysis conditions. Dielectric and thermal properties of EAFD, TBBPA and their mixtures were determined. Both the dielectric constant and loss factor of the mixture were found to vary considerably with temperature and subsequently it was found that the mixtures of these materials absorbed Microwaves effectively, especially at temperatures above 170 °C. The high loss tangent of EAFD-TBBPA mixture above 170 °C resulted in fast heating and high temperatures (above 700 °C) resulting in reduction of Fe, Pb and Zn to their metallic form. This resulted in low recoveries of both Zn and Pb when the residue was leached in water. The recovery of Zn varied between 14 and 52 wt,%, while Pb recovery varied between 3 and 31 wt.% depending on Microwave Treatment efficiency. The low recovery of Zn and Pb could be ascribed by the reduction of metal oxides into their metallic form. More importantly this work has shown great selectivity in the leachability of both zinc and iron; with iron being left in the solid residue.
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towards large scale Microwave Treatment of ores part 1 basis of design construction and commissioning
Minerals Engineering, 2017Co-Authors: A J Buttress, A R Batchelor, D A Jones, Juliano Katrib, D A Craig, T A Royal, Chris Dodds, S W KingmanAbstract:Despite over thirty years of work, Microwave pre-Treatment processes for beneficiation of ores have not progressed much further than laboratory testing. In this paper we present a scaleable pilot-scale system for the Microwave Treatment of ores capable of operating at throughputs of up to 150tph. This has been achieved by confining the electric field produced from two 100kW generators operating at 896MHz in a gravity fed vertical flow system using circular choking structures yielding power densities of at least 6x108 W/m3 in the heated mineral phases. Measured S11 scattering parameters for a quartzite ore (-3.69±0.4dB) in the as-built applicator correlated well with the simulation (-3.25dB), thereby validating our design approach. We then show that by fully integrating the applicator with a materials handling system based on the concept of mass flow, we achieve a reliable, continuous process. The system was used to treat a range of porphyry copper ores.
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increasing the grind size for effective liberation and flotation of a porphyry copper ore by Microwave Treatment
Minerals Engineering, 2016Co-Authors: A R Batchelor, D A Jones, S Plint, S W KingmanAbstract:In this paper, mineralogy, grain size, dissemination, textural consistency and mineral associations were determined for a commercially exploited porphyry copper ore using a Mineral Liberation Analyser (MLA). The ore was subjected to high power density Microwave Treatments in a single mode cavity at 15 kW and approximately 2 kW h/t. The untreated and Microwave-treated samples were subsequently milled to two grind sizes near the nominal plant grind size and a size-by-liberation analysis performed. The analysis revealed that equivalent liberation could be obtained at a grind size approximately 50–60 μm coarser than the nominal plant grind due to the Microwave Treatment. Flotation testing indicated that an increase in copper recovery of approximately 1% could be achieved, or that a grind size increase of approximately 30 μm may potentially yield equivalent copper recovery due to the Microwave-enhanced liberation observed. However, statistical analyses demonstrated that it is difficult to attain confidence in recovery increases of approximately 1% even when conducting batch flotation tests in triplicate. The ore under investigation had previously been shown to produce only modest average reductions in strength (∼8%) under similar Microwave Treatment conditions due to a prevalence of many unfavourable textures. However, the preferential association of copper minerals with a hard matrix mineral (quartz) and a hard Microwave-absorbent mineral (pyrite) resulted in a significant change in liberation behaviour.
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Microwave Treatment of electric arc furnace dust with pvc dielectric characterization and pyrolysis leaching
Journal of Hazardous Materials, 2014Co-Authors: Mohammad Alharahsheh, S W Kingman, Leema Almakhadmah, Ian E HamiltonAbstract:Microwave Treatment of electric arc furnace dust (EAFD) with poly(vinyl chloride) (PVC) was studied in this work. A comprehensive characterization of the dust as well as assessing the suitability of using the thermal de-chlorination of the common plastic (PVC) under inert atmosphere was carried out to assess the possibility of Zn and other heavy metals extraction (Pb and Cd) from EAFD. The dielectric and thermal properties of EAFD, PVC and their mixtures were measured. Once combined and heated the metal oxides present in the dust reacted with HCl released from PVC during thermal de-chlorination, forming metal chlorides which were subsequently recovered by leaching with water. It was found that zinc chloride could be almost completely recovered in the leaching stage, with the overall recovery of Zn reaching 97% when the EAFD:PVC ratio was 1:2. The investigation highlighted that franklinite, the most refractory mineral to leaching, was completely destroyed. The leaching residue was found to compose mainly of magnetite and hematite.
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scale up and design of a continuous Microwave Treatment system for the processing of oil contaminated drill cuttings
Chemical Engineering Research & Design, 2010Co-Authors: John P Robinson, S W Kingman, Colin E Snape, S M Bradshaw, M S A Bradley, H Shang, Richelieu BarrancoAbstract:A continuous Microwave Treatment system has been developed for the remediation of contaminated drill cuttings at pilot scale. Using the mechanisms of oil removal as a basis, a design was produced using electromagnetic simulations to find the optimum Microwave applicator geometry which yielded the most favourable power density distribution. Bulk materials handling and process engineering principles were systematically integrated with the electromagnetic design to produce a system capable of treating 500 kg/h of material. The effects of the key design parameters are simulated, and a number of the simulations are verified with experimental data. It is shown that the environmental discharge threshold of 1% oil can be achieved in continuous operation, and the sensitivity of the system to changing feedstock properties is also highlighted. The parity between the simulations and experimental results in this paper highlights the necessity of electromagnetic modelling in the design and scale-up Microwave processing equipment.
Ian S Hamilton - One of the best experts on this subject based on the ideXlab platform.
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Microwave Treatment of electric arc furnace dust with tetrabromobisphenol a dielectric characterization and pyrolysis leaching
Journal of Analytical and Applied Pyrolysis, 2017Co-Authors: Mohammad Alharahsheh, S W Kingman, Ian S HamiltonAbstract:In the present work Microwave Treatment of electric arc furnace dust (EAFD) mixed with tetrabromobisphenol A (TBBPA) was investigated. A range of characterization techniques were used to understand the thermal behaviour of TBBPA-EAFD mixtures under Microwave pyrolysis conditions. Dielectric and thermal properties of EAFD, TBBPA and their mixtures were determined. Both the dielectric constant and loss factor of the mixture were found to vary considerably with temperature and subsequently it was found that the mixtures of these materials absorbed Microwaves effectively, especially at temperatures above 170 °C. The high loss tangent of EAFD-TBBPA mixture above 170 °C resulted in fast heating and high temperatures (above 700 °C) resulting in reduction of Fe, Pb and Zn to their metallic form. This resulted in low recoveries of both Zn and Pb when the residue was leached in water. The recovery of Zn varied between 14 and 52 wt,%, while Pb recovery varied between 3 and 31 wt.% depending on Microwave Treatment efficiency. The low recovery of Zn and Pb could be ascribed by the reduction of metal oxides into their metallic form. More importantly this work has shown great selectivity in the leachability of both zinc and iron; with iron being left in the solid residue.
Khizar Hayat - One of the best experts on this subject based on the ideXlab platform.
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effect of Microwave Treatment on phenolic content and antioxidant activity of citrus mandarin pomace
Food Chemistry, 2010Co-Authors: Khizar Hayat, Xiaoming Zhang, Shuqin Xia, Chengsheng Jia, Fang Zhong, Umar Farooq, Shabbar Abbas, Jing ZhangAbstract:The effects of Microwave Treatment on the phenolic compounds and antioxidant capacity of citrus mandarin pomace were evaluated. After Treatment, methanol extracts of citrus pomace were prepared and the contents of phenolic acids (free and bound) and flavanol, flavanone and flavonol compounds (FCs) were determined by HPLC. Antioxidant capacity of pomace extracts was measured using DPPH radical-scavenging assay, hydroxyl radical-scavenging assay and reducing power. After Microwave Treatment, the free fraction of phenolic acids increased, whereas the bound fractions decreased and antioxidant activity was increased. The content of total FCs increased with power but, at longer irradiation time, it declined which meant that some FCs might be degraded. The results indicated that appropriate Microwave Treatment could be an efficient process to liberate and activate the bound phenolic compounds and to enhance the antioxidant activity of citrus mandarin pomace.
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liberation and separation of phenolic compounds from citrus mandarin peels by Microwave heating and its effect on antioxidant activity
Separation and Purification Technology, 2010Co-Authors: Khizar Hayat, Xiaoming Zhang, Hanqing Chen, Shuqin Xia, Chengsheng Jia, Fang ZhongAbstract:The effect of Microwave Treatment on the phenolic compounds and antioxidant capacity of citrus mandarin peels was evaluated. After Microwave Treatment, methanol extracts of citrus peels were prepared and the contents of phenolic acids (free and bound) and flavanol, flavanone and flavonol compounds (FCs) were determined by HPLC. Antioxidant capacity of peel extracts was measured using DPPH radical scavenging assay, hydroxyl radical scavenging assay and reducing power. After Microwave Treatment, the free fraction of phenolic acids increased, whereas the bound fractions decreased and antioxidant activity was increased. The content of total FCs increased with power but at longer irradiation time it was declined which meant that some FCs might be degraded. The results indicated that appropriate Microwave Treatment could be an efficient process to liberate and activate the bound phenolic compounds and to increase the antioxidant capacity of citrus mandarin peels.
John P Robinson - One of the best experts on this subject based on the ideXlab platform.
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scale up and design of a continuous Microwave Treatment system for the processing of oil contaminated drill cuttings
Chemical Engineering Research & Design, 2010Co-Authors: John P Robinson, S W Kingman, Colin E Snape, S M Bradshaw, M S A Bradley, H Shang, Richelieu BarrancoAbstract:A continuous Microwave Treatment system has been developed for the remediation of contaminated drill cuttings at pilot scale. Using the mechanisms of oil removal as a basis, a design was produced using electromagnetic simulations to find the optimum Microwave applicator geometry which yielded the most favourable power density distribution. Bulk materials handling and process engineering principles were systematically integrated with the electromagnetic design to produce a system capable of treating 500 kg/h of material. The effects of the key design parameters are simulated, and a number of the simulations are verified with experimental data. It is shown that the environmental discharge threshold of 1% oil can be achieved in continuous operation, and the sensitivity of the system to changing feedstock properties is also highlighted. The parity between the simulations and experimental results in this paper highlights the necessity of electromagnetic modelling in the design and scale-up Microwave processing equipment.
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Microwave Treatment of oil contaminated north sea drill cuttings in a high power multimode cavity
Separation and Purification Technology, 2006Co-Authors: H Shang, S W Kingman, Colin E Snape, John P RobinsonAbstract:Abstract This paper describes a Microwave heating technique as a new method for the Treatment of oil-contaminated drill cuttings (OCDC). The effects of power, Treatment time and moisture content on the thermal desorption of oil were studied, and it was found that under certain operating conditions the oil levels could be reduced to below the current environmental discharge limit of 1%. For a sample mass of 40 g, it is shown that approximately 20 s of Microwave Treatment is required in order to reduce the residual oil levels close to or below the 1% threshold. The major limitation in the minimum achievable residual oil levels appears to be the moisture content, however, it is shown that increasing the amount of water in the samples can potentially overcome such limitations.
Mohammad Alharahsheh - One of the best experts on this subject based on the ideXlab platform.
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Microwave Treatment of electric arc furnace dust with tetrabromobisphenol a dielectric characterization and pyrolysis leaching
Journal of Analytical and Applied Pyrolysis, 2017Co-Authors: Mohammad Alharahsheh, S W Kingman, Ian S HamiltonAbstract:In the present work Microwave Treatment of electric arc furnace dust (EAFD) mixed with tetrabromobisphenol A (TBBPA) was investigated. A range of characterization techniques were used to understand the thermal behaviour of TBBPA-EAFD mixtures under Microwave pyrolysis conditions. Dielectric and thermal properties of EAFD, TBBPA and their mixtures were determined. Both the dielectric constant and loss factor of the mixture were found to vary considerably with temperature and subsequently it was found that the mixtures of these materials absorbed Microwaves effectively, especially at temperatures above 170 °C. The high loss tangent of EAFD-TBBPA mixture above 170 °C resulted in fast heating and high temperatures (above 700 °C) resulting in reduction of Fe, Pb and Zn to their metallic form. This resulted in low recoveries of both Zn and Pb when the residue was leached in water. The recovery of Zn varied between 14 and 52 wt,%, while Pb recovery varied between 3 and 31 wt.% depending on Microwave Treatment efficiency. The low recovery of Zn and Pb could be ascribed by the reduction of metal oxides into their metallic form. More importantly this work has shown great selectivity in the leachability of both zinc and iron; with iron being left in the solid residue.
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Microwave Treatment of electric arc furnace dust with pvc dielectric characterization and pyrolysis leaching
Journal of Hazardous Materials, 2014Co-Authors: Mohammad Alharahsheh, S W Kingman, Leema Almakhadmah, Ian E HamiltonAbstract:Microwave Treatment of electric arc furnace dust (EAFD) with poly(vinyl chloride) (PVC) was studied in this work. A comprehensive characterization of the dust as well as assessing the suitability of using the thermal de-chlorination of the common plastic (PVC) under inert atmosphere was carried out to assess the possibility of Zn and other heavy metals extraction (Pb and Cd) from EAFD. The dielectric and thermal properties of EAFD, PVC and their mixtures were measured. Once combined and heated the metal oxides present in the dust reacted with HCl released from PVC during thermal de-chlorination, forming metal chlorides which were subsequently recovered by leaching with water. It was found that zinc chloride could be almost completely recovered in the leaching stage, with the overall recovery of Zn reaching 97% when the EAFD:PVC ratio was 1:2. The investigation highlighted that franklinite, the most refractory mineral to leaching, was completely destroyed. The leaching residue was found to compose mainly of magnetite and hematite.
