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Annsofi Jonsson - One of the best experts on this subject based on the ideXlab platform.
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Characterization of Irreversible Fouling after Ultrafiltration of Thermomechanical Pulp Mill Process Water
Journal of Wood Chemistry and Technology, 2018Co-Authors: Johan Thuvander, Agata Zarebska, Claus Hélix-nielsen, Annsofi JonssonAbstract:Large volumes of wasteWater with dissolved wood components are treated in wasteWater treatment plants at thermomechanical pulp mills. It has been shown previously that hemicelluloses in these wasteWater streams can be recovered by membrane filtration. A serious obstacle when treating lignocellulose Process streams is fouling of the membranes. Fouling not only increases operating costs but also reduces the operating time of the membrane plant. When optimizing the membrane cleaning method, it is important to know which compounds cause the fouling. In this work fouling of an ultrafiltration membrane was studied. The fouling propensity of untreated Process Water and microfiltrated Process Water was compared. Fouled membranes were analyzed using scanning electron microscopy and attenuated total reflection Fourier transform infrared spectrometry. Acid hydrolysis of membranes exposed to untreated Process Water and microfiltration permeate revealed that 508 mg/m2 and 37 mg/m2 of polysaccharides, respectively, rem...
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Enzymatic treatment of hemicelluloses and lignin isolated from thermomechanical pulp mill Process Water
Chemical Engineering Journal, 2016Co-Authors: Johan Thuvander, Petri Oinonen, Annsofi JonssonAbstract:Hemicelluloses dissolved in thermomechanical pulp (TMP) mill Process streams can be used to manufacture high-value-added products. The molecular mass of the dissolved hemicelluloses is about 10 kDa. In some applications, it would be beneficial with larger molecules. It was therefore investigated whether it is possible to increase the size of hemicelluloses isolated by microfiltration and ultrafiltration from TMP Process Water using enzymatic treatment with laccase. No significant increase of the size of hemicelluloses was achieved, probably due to only a small percentage of lignin carbohydrate complexes in the Process Water. The molecular mass of lignin increased however markedly from a peak molecular mass of 1 kDa to about 60 kDa. Diafiltration was used to purify large molecules after the enzymatic treatment. Low-molecular-mass sugar and lignin molecules in the diafiltration permeate were concentrated by nanofiltration. The retention of sugars and lignin was about 98% during nanofiltration to a volume reduction of 80%. Average flux during nanofiltration was 49 l/m2 h.
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separation of dispersed substances and galactoglucomannan in thermomechanical pulp Process Water by microfiltration
Separation and Purification Technology, 2011Co-Authors: Holger Krawczyk, Annsofi JonssonAbstract:Several valuable substances are released from wood during the production of thermomechanical pulp. These substances can be isolated and purified for use as value-added chemicals. The hemicellulose galactoglucomannan (GGM) has attracted a great deal of interest because of its possible applications as an oxygen barrier film in packaging materials, as a hydrogel in biomedical products and as an emulsion stabilizer in food and feed. In order to exploit GGM in pulp mill Process Water, it must be recovered at a high concentration and high purity. The first step in the purification Process is the separation of GGM and dispersed substances. In this work, the influence of membrane pore size, cross-flow velocity and backpulsing on membrane performance during the microfiltration of thermomechanical pulp Process Water was investigated. The flux of 0.4 and 0.8 μm membranes was lower than the flux of a 0.2 μm membrane, and it was not possible to recover the pure Water flux of the 0.4 and 0.8 μm membranes. Increased cross-flow velocity and backpulsing had a positive effect on the flux, but only a minor influence on the retention. The mean molecular mass of GGM in the Process Water was 9 kg/mol. The retention was therefore expected to be 50%, irrespective of the operating conditions.
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isolation of hemicelluloses by ultrafiltration of thermomechanical pulp mill Process Water influence of operating conditions
Chemical Engineering Research & Design, 2010Co-Authors: Tobias Persson, Annsofi JonssonAbstract:Hemicelluloses could be used to replace fossil-based materials in several high-value-added products. Today, vast amounts of hemicelluloses are discharged from pulp mills all over the world as waste, but these could be isolated by membrane filtration, and utilized in various applications. In this study, the hemicellulose galactoglucomannan was isolated from Process Water from a thermomechanical pulp mill using ultrafiltration. The retention of hemicelluloses and lignin, and the flux and fouling of three ultrafiltration membranes (ETNA01, ETNA10 and UFX5) were studied at various operating conditions. One of the membranes (UFX5) was found to have a high hemicellulose retention (above 90%) independent of flux and pressure. With the ETNA01 membrane it was impossible to combine a high flux with high hemicellulose retention, while with the ETNA10 membrane the hemicellulose retention could be increased above 90% by running at transmembrane pressures above the critical flux. The UFX5 membrane could be used at the temperature of the Process Water in the pulp mill (75-85 degrees C), while the ETNA10 membrane could only withstand temperatures below 60 degrees C, increasing the cost due to the need to cool the Process Water. However, the susceptibility of UFX5 to fouling was much greater than for ETNA10, which would increase the cleaning cost of the UFX5 membrane. (C) 2010 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved. (Less)
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Fractionation of Process Water in thermomechanical pulp mills.
Bioresource Technology, 2010Co-Authors: Tobias Persson, Holger Krawczyk, Anna-karin Nordin, Annsofi JonssonAbstract:In this work Process Water from a thermomechanical pulp mill was divided into five fractions by filtration and membrane filtration. Suspended matter was mainly isolated in the retentate from the drum filter, extractives in the microfiltration retentate, hemicelluloses in the ultrafiltration retentate and lignin in the nanofiltration retentate. The final Water fraction was of fresh Water quality. For each tonne of pulp produced, about 10kg of suspended matter, more than 0.3kg of extractives, 11kg of hemicelluloses and 8kg of aromatic compounds (lignin) could be recovered from the drum filtration retentate, the microfiltration retentate, the ultrafiltration retentate and the nanofiltration retentate, respectively. About 40% of the treated Process Water could be recovered as fresh Water.
Tobias Persson - One of the best experts on this subject based on the ideXlab platform.
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isolation of hemicelluloses by ultrafiltration of thermomechanical pulp mill Process Water influence of operating conditions
Chemical Engineering Research & Design, 2010Co-Authors: Tobias Persson, Annsofi JonssonAbstract:Hemicelluloses could be used to replace fossil-based materials in several high-value-added products. Today, vast amounts of hemicelluloses are discharged from pulp mills all over the world as waste, but these could be isolated by membrane filtration, and utilized in various applications. In this study, the hemicellulose galactoglucomannan was isolated from Process Water from a thermomechanical pulp mill using ultrafiltration. The retention of hemicelluloses and lignin, and the flux and fouling of three ultrafiltration membranes (ETNA01, ETNA10 and UFX5) were studied at various operating conditions. One of the membranes (UFX5) was found to have a high hemicellulose retention (above 90%) independent of flux and pressure. With the ETNA01 membrane it was impossible to combine a high flux with high hemicellulose retention, while with the ETNA10 membrane the hemicellulose retention could be increased above 90% by running at transmembrane pressures above the critical flux. The UFX5 membrane could be used at the temperature of the Process Water in the pulp mill (75-85 degrees C), while the ETNA10 membrane could only withstand temperatures below 60 degrees C, increasing the cost due to the need to cool the Process Water. However, the susceptibility of UFX5 to fouling was much greater than for ETNA10, which would increase the cleaning cost of the UFX5 membrane. (C) 2010 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved. (Less)
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Fractionation of Process Water in thermomechanical pulp mills.
Bioresource Technology, 2010Co-Authors: Tobias Persson, Holger Krawczyk, Anna-karin Nordin, Annsofi JonssonAbstract:In this work Process Water from a thermomechanical pulp mill was divided into five fractions by filtration and membrane filtration. Suspended matter was mainly isolated in the retentate from the drum filter, extractives in the microfiltration retentate, hemicelluloses in the ultrafiltration retentate and lignin in the nanofiltration retentate. The final Water fraction was of fresh Water quality. For each tonne of pulp produced, about 10kg of suspended matter, more than 0.3kg of extractives, 11kg of hemicelluloses and 8kg of aromatic compounds (lignin) could be recovered from the drum filtration retentate, the microfiltration retentate, the ultrafiltration retentate and the nanofiltration retentate, respectively. About 40% of the treated Process Water could be recovered as fresh Water.
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Purification of Process Water in a thermomechanical pulp mill by nanofiltration
2009Co-Authors: Tobias Persson, Jun-li Ren, Annsofi JonssonAbstract:Process Water from a Swedish thermomechanical pulp mill was purified by consecutive treatment by microfiltration, ultrafiltration and nanofiltration. In the present study the nanofiltration step was studied. The flux and retention of four nanofiltration membranes were compared. The NF99HF membrane (Alfa Laval, Lund, Sweden), had significantly higher flux and higher retention of lignin and charged compounds (measured as conductivity) compared to the others. The flux was 220 l/m2 h and the retention of calcium ions was 99% at 20 bar transmembrane pressure and a temperature of 50°C. At the same conditions, the conductivity (measured at 20°C) was decreased from 1 500 µS/cm in the feed solution to 150 µS/cm in the nanofiltration permeate.
Fatai Ikumapayi - One of the best experts on this subject based on the ideXlab platform.
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Recycling Process Water in complex sulphide ore flotation
2016Co-Authors: Fatai Ikumapayi, Maria Mäkitalo, Björn Johansson, Hanumantha Rao KotaAbstract:An approach to environmental sustainability and improved Process economy in sulphide minerals production is recycling of Process Water in flotation of complex sulphide ores. However Process Water c ...
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Recycling of Process Water : effect of calcium and sulphate ions in sulphides flotation
2016Co-Authors: Fatai Ikumapayi, Björn Johansson, Hanumantha Rao KotaAbstract:The effects of major components of calcium and sulphate ions in Process Water on sulphide mineral flotation has been investigated through Hallimond flotation of pure sulphide minerals using tapwate ...
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recycling of Process Water in sulphide flotation effect of calcium and sulphate ions on flotation of galena
Minerals Engineering, 2012Co-Authors: Fatai Ikumapayi, Maria Mäkitalo, Björn JohanssonAbstract:Abstract The effects of major components of calcium and sulphate species present in recycled Process Water on galena flotation has been investigated through Hallimond flotation, zeta-potential, diffuse reflectance FTIR spectroscopy and XPS measurements using pure galena mineral. The significance of Process Water species in flotation has been understood using deionised Water, Process Water and simulated tap Water containing equivalent calcium and sulphate ions concentration as in Process Water. Hallimond flotation indicated marginally lower recoveries of galena in the presence of calcium and sulphate ions using potassium amyl xanthate as collector. Zeta-potential shows the adsorption of calcium ions whereby the potential are seen to increase while sulphate ions have no significant effect. FTIR and XPS studies revealed surface calcium carbonate and/or calcium sulphate species in Process Water which affected xanthate adsorption. Presence of surface oxidised species such as sulfoxy, hydroxyl species on galena at pH 10.5 in deionised and Process Water was also revealed.
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Recycling Process Water in sulfide flotation : Part B: Effect of H2O2 and Process Water components on sphalerite flotation from complex sulfide
Minerals & Metallurgical Processing, 2012Co-Authors: Fatai Ikumapayi, Hikmet Sis, B. Johansson, K. Hanumantha RaoAbstract:Hydrogen peroxide production was measured during the grinding of a complex sulfide ore, and its oxidizing effect on solid surfaces was investigated using Fourier transform infrared spectroscopy (FTIR) with diffuse reflectance attachment measurement. In turn, an attempt was made to correlate the formation of hydrogen peroxide, surface oxidation and sphalerite flotation. Additionally, in order to predict and minimize detrimental production problems due to the recycling of Process Water in sulfide ore Processing, the effects of major components of calcium and sulfate species present in recycled Process Water and the effect of temperature on sphalerite flotation were investigated through bench-scale flotation tests using complex sulfide ores. The significance of Process Water species in flotation was studied using tap Water, Process Water and simulated Water containing calcium and sulfate ions. Formation of hydrogen peroxide was revealed during the grinding of the complex sulfide ore, and its formation was counteracted by diethylenetriamine (DETA). The FTIR spectrum of the pulp solid fraction showed varying degrees of oxidized surface species, which are related to the concentration of H2O2 analyzed in pulp liquid. Bench-scale flotation using two different complex sulfide ores showed that sphalerite recovery is better in Process Water than in tap Water. Flotation results also indicated a varied recovery of sphalerite at different temperatures in either tap Water or Process Water.
Holger Krawczyk - One of the best experts on this subject based on the ideXlab platform.
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separation of dispersed substances and galactoglucomannan in thermomechanical pulp Process Water by microfiltration
Separation and Purification Technology, 2011Co-Authors: Holger Krawczyk, Annsofi JonssonAbstract:Several valuable substances are released from wood during the production of thermomechanical pulp. These substances can be isolated and purified for use as value-added chemicals. The hemicellulose galactoglucomannan (GGM) has attracted a great deal of interest because of its possible applications as an oxygen barrier film in packaging materials, as a hydrogel in biomedical products and as an emulsion stabilizer in food and feed. In order to exploit GGM in pulp mill Process Water, it must be recovered at a high concentration and high purity. The first step in the purification Process is the separation of GGM and dispersed substances. In this work, the influence of membrane pore size, cross-flow velocity and backpulsing on membrane performance during the microfiltration of thermomechanical pulp Process Water was investigated. The flux of 0.4 and 0.8 μm membranes was lower than the flux of a 0.2 μm membrane, and it was not possible to recover the pure Water flux of the 0.4 and 0.8 μm membranes. Increased cross-flow velocity and backpulsing had a positive effect on the flux, but only a minor influence on the retention. The mean molecular mass of GGM in the Process Water was 9 kg/mol. The retention was therefore expected to be 50%, irrespective of the operating conditions.
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Fractionation of Process Water in thermomechanical pulp mills.
Bioresource Technology, 2010Co-Authors: Tobias Persson, Holger Krawczyk, Anna-karin Nordin, Annsofi JonssonAbstract:In this work Process Water from a thermomechanical pulp mill was divided into five fractions by filtration and membrane filtration. Suspended matter was mainly isolated in the retentate from the drum filter, extractives in the microfiltration retentate, hemicelluloses in the ultrafiltration retentate and lignin in the nanofiltration retentate. The final Water fraction was of fresh Water quality. For each tonne of pulp produced, about 10kg of suspended matter, more than 0.3kg of extractives, 11kg of hemicelluloses and 8kg of aromatic compounds (lignin) could be recovered from the drum filtration retentate, the microfiltration retentate, the ultrafiltration retentate and the nanofiltration retentate, respectively. About 40% of the treated Process Water could be recovered as fresh Water.
Wenheng Li - One of the best experts on this subject based on the ideXlab platform.
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minimizing beneficiation wasteWater through internal reuse of Process Water in flotation circuit
Journal of Cleaner Production, 2020Co-Authors: Meirong Wu, Yuehua Hu, Wenheng LiAbstract:Abstract Cost-effective methods for reducing freshWater requirement and wasteWater emission in beneficiation Processes (particularly in flotation Process) are greatly important in the modern mining industry. This study aims to minimize Water consumption and wasteWater generation in dressing plants by internally reusing Process Water at certain stages of flotation circuit. Laboratory scale tests demonstrated that locked cycle recycling of Process Water built up chemical reagents in Water, which in turn influenced the flotation performance of valuable minerals and significantly decreased the grade and recovery of concentrates. Changing flotation reagent regimes in response to flotation fluctuations can reliably and feasibly maintain mineral recovery efficiency during the reuse Process. Industrial scale tests validated that the quality of concentrates obtained with and without Process Water reuse did not show any considerable difference and satisfied the product specifications by carefully adjusting the dosage of flotation reagent. The required reagent dosages in the flotation circuit were reduced by more than 10% after using recycled Water. Among the required reagent dosages, sodium sulfide (Na2S) was sharply reduced by 18.56%. Most importantly, the internal reuse of Process Water in the flotation circuit minimized freshWater consumption by 34.62% (i.e., from 5.2 t/d to 3.4 t/d), indicating that 525.6 tons of wasteWater would no longer be generated every year. Overall, the proposed internal reuse Process is a cost-effective and eco-friendly alternative for greening flotation Process.
