Chloride is one of the effective medium in which platinum group metals (PGMs) can be brought into a solution, thus chlorocomplexes are particularly important in the process chemistry of PGMs separations. Ru(III) chlorocomplexes are poorly extracted into organic solvents, which is due to the charge of the complex as well as those inert character in a solution, that is, formation of RuCl6–n(H2O)n (n = 1–6). The problem of solvent extraction of Ru from chloride solutions has not yet been solved and there is no effective industrial extractant for Ru. PGMs are traditionally separated from one another and the other metals by a complex series of selective precipitation techniques and distillation. These are generally inefficient in terms of the degree of separation achieved. Solvent extraction applied to refining process for PGMs offers several advantages over the traditional precipitation methods and distillation. Adding Sn(II) to a Rh(III) feed is a good procedure which can be used to make Rh react more easily to extraction. However, the effect of addition of Sn(II) on extraction of Ru(III) from chloride solution is not clarified. In the present study, the extraction of Ru from hydrochloric acid solutions with tri-n-octylamine (TOA) and trioctyl methyl ammonium chloride (TOMAC) were tested to clarify the effect of addition of Sn(II) on the extraction of Ru and stripping of Ru. The addition of Sn(II) was effective for the extraction of Ru, however, the stripping effeciency of Ru was not sufficient.
{"title":"Solvent Extraction Characteristics of Ruthenium from Chloride Solutions added Tin(II) with TOA and TOMAC","authors":"Takeshi Tanishige, Koudai Nagano, Tasuma Suzuki, Masakazu Niinae","doi":"10.4144/rpsj.66.133","DOIUrl":"https://doi.org/10.4144/rpsj.66.133","url":null,"abstract":"Chloride is one of the effective medium in which platinum group metals (PGMs) can be brought into a solution, thus chlorocomplexes are particularly important in the process chemistry of PGMs separations. Ru(III) chlorocomplexes are poorly extracted into organic solvents, which is due to the charge of the complex as well as those inert character in a solution, that is, formation of RuCl6–n(H2O)n (n = 1–6). The problem of solvent extraction of Ru from chloride solutions has not yet been solved and there is no effective industrial extractant for Ru. PGMs are traditionally separated from one another and the other metals by a complex series of selective precipitation techniques and distillation. These are generally inefficient in terms of the degree of separation achieved. Solvent extraction applied to refining process for PGMs offers several advantages over the traditional precipitation methods and distillation. Adding Sn(II) to a Rh(III) feed is a good procedure which can be used to make Rh react more easily to extraction. However, the effect of addition of Sn(II) on extraction of Ru(III) from chloride solution is not clarified. In the present study, the extraction of Ru from hydrochloric acid solutions with tri-n-octylamine (TOA) and trioctyl methyl ammonium chloride (TOMAC) were tested to clarify the effect of addition of Sn(II) on the extraction of Ru and stripping of Ru. The addition of Sn(II) was effective for the extraction of Ru, however, the stripping effeciency of Ru was not sufficient.","PeriodicalId":20971,"journal":{"name":"Resources Processing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76484604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tomoyuki Tawara, H. Ohya, Akiyoshi Yatsugi, Kinya Hirabayashi, K. Oda
“Art Clay Silver (Silver Clay)”, developed as a silver recycled product, is a mixture of fine powdered silver and binder for easily making silver accessories after sintering at 650°C. In this study, in order to find the optimum binder amount to maximize the strength of the sintered product, the filling structure of sintered Silver Clay was analyzed at various binder amounts under three particle size fractions (fine, coarse, and their equal weight mixture) on the basis of the measurements of porosity, shrinkage rate, strength, and pore size distribution together with SEM observation. As a result, we found that the filling structure was controlled by changing the particle size and the binder amount, and that the binder addition of 5–8% to fine particle fraction yielded the minimum porosity and maximum strength.
{"title":"Study on Improvement of Filling Structure and Functionality of Silver Clay Sintering Body","authors":"Tomoyuki Tawara, H. Ohya, Akiyoshi Yatsugi, Kinya Hirabayashi, K. Oda","doi":"10.4144/rpsj.66.128","DOIUrl":"https://doi.org/10.4144/rpsj.66.128","url":null,"abstract":"“Art Clay Silver (Silver Clay)”, developed as a silver recycled product, is a mixture of fine powdered silver and binder for easily making silver accessories after sintering at 650°C. In this study, in order to find the optimum binder amount to maximize the strength of the sintered product, the filling structure of sintered Silver Clay was analyzed at various binder amounts under three particle size fractions (fine, coarse, and their equal weight mixture) on the basis of the measurements of porosity, shrinkage rate, strength, and pore size distribution together with SEM observation. As a result, we found that the filling structure was controlled by changing the particle size and the binder amount, and that the binder addition of 5–8% to fine particle fraction yielded the minimum porosity and maximum strength.","PeriodicalId":20971,"journal":{"name":"Resources Processing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79194588","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zn-Al composite hydroxide by a co-precipitation method and its calcined products were prepared in different chemical composition. For the purpose of lowering calcination temperature and controlling particle morphology for ZnAl2O4 (spinel) synthesis, the obtained Zn-Al composite hydroxide was used as a precursor before a calcination operation. Zn-Al-CO3 LDH (Layered Double Hydroxide) is produced as a crystalline material in both chemical composition of spinel formation ([Zn2+]:[Al3+] = 1:2) and LDH formation ([Zn2+]:[Al3+] = 2:1). ZnAl2O4 is synthesized at lower calcination temperature of 700°C in the case of [Zn2+]:[Al3+] = 1:2. Zn-Al composite hydroxide with large plate-like particles is produced by applying a solvothermal treatment using ethylene glycol as a solvent to the Zn-Al composite hydroxide. When they are calcined, the composite oxide keeping the plate-like particle morphology of the precursor (Zn-Al LDH) is produced. It is clarified that ZnAl2O4 is synthesized at low temperature and the particle morphology is controlled by using Zn-Al LDH as a precursor.
{"title":"Particle Shape Control of Zn-Al Composite Oxides by Using Composite Hydroxides as a Precursor","authors":"Kohei Yamazaki, Mitsuaki Matsuoka, N. Murayama","doi":"10.4144/RPSJ.67.73","DOIUrl":"https://doi.org/10.4144/RPSJ.67.73","url":null,"abstract":"Zn-Al composite hydroxide by a co-precipitation method and its calcined products were prepared in different chemical composition. For the purpose of lowering calcination temperature and controlling particle morphology for ZnAl2O4 (spinel) synthesis, the obtained Zn-Al composite hydroxide was used as a precursor before a calcination operation. Zn-Al-CO3 LDH (Layered Double Hydroxide) is produced as a crystalline material in both chemical composition of spinel formation ([Zn2+]:[Al3+] = 1:2) and LDH formation ([Zn2+]:[Al3+] = 2:1). ZnAl2O4 is synthesized at lower calcination temperature of 700°C in the case of [Zn2+]:[Al3+] = 1:2. Zn-Al composite hydroxide with large plate-like particles is produced by applying a solvothermal treatment using ethylene glycol as a solvent to the Zn-Al composite hydroxide. When they are calcined, the composite oxide keeping the plate-like particle morphology of the precursor (Zn-Al LDH) is produced. It is clarified that ZnAl2O4 is synthesized at low temperature and the particle morphology is controlled by using Zn-Al LDH as a precursor.","PeriodicalId":20971,"journal":{"name":"Resources Processing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85785144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Gjergj Dodbiba, Hiroki Oshikawa, Josiane Ponou, Yonggu Kim, Kazutoshi Haga, A. Shibayama, T. Fujita
Recently, the demand for LED light bulbs is rapidly increasing due to an increasing demand for energy saving lightning options. In this work, the elemental composition of LED light bulbs is first analyzed, and then a flowsheet for recovering LED chips and other valuable metals from spent LED light bulbs is put forward. The suggested flowsheet includes eddy current separation (ECS) and air tabling, in addition to several refining processes. The experimental results indicated that the eddy current separation and the air tabling are useful techniques for sorting components of LED bulbs, enabling the recycling of aluminium, plastics, and precious metals, such as gold and silver. Next, five different scenarios for treatment of spent LED light bulbs were considered and a combined life cycle assessment (LCA) and cost-benefit analysis was carried out to find out the most suitable alternative. The results of the combined assessment suggested that the recycling of mainly Al and plastics from spent LED bulbs is an environmentally friendly and cost-effective alternative.
{"title":"Treatment of Spent LED Light Bulbs for Recycling of Its Components: A Combined Assessment in the Context of LCA and Cost-Benefit Analysis","authors":"Gjergj Dodbiba, Hiroki Oshikawa, Josiane Ponou, Yonggu Kim, Kazutoshi Haga, A. Shibayama, T. Fujita","doi":"10.4144/RPSJ.66.15","DOIUrl":"https://doi.org/10.4144/RPSJ.66.15","url":null,"abstract":"Recently, the demand for LED light bulbs is rapidly increasing due to an increasing demand for energy saving lightning options. In this work, the elemental composition of LED light bulbs is first analyzed, and then a flowsheet for recovering LED chips and other valuable metals from spent LED light bulbs is put forward. The suggested flowsheet includes eddy current separation (ECS) and air tabling, in addition to several refining processes. The experimental results indicated that the eddy current separation and the air tabling are useful techniques for sorting components of LED bulbs, enabling the recycling of aluminium, plastics, and precious metals, such as gold and silver. Next, five different scenarios for treatment of spent LED light bulbs were considered and a combined life cycle assessment (LCA) and cost-benefit analysis was carried out to find out the most suitable alternative. The results of the combined assessment suggested that the recycling of mainly Al and plastics from spent LED bulbs is an environmentally friendly and cost-effective alternative.","PeriodicalId":20971,"journal":{"name":"Resources Processing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83937187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Ishikawa, Takeshi Tanishige, Tasuma Suzuki, Masakazu Niinae
Chloride is one of the effective medium in which platinum group metals (PGMs) can be brought into a solution, thus chlorocomplexes are particularly important in the process chemistry of PGMs separations. Rh(III) chlorocomplexes are poorly extracted into organic solvents, which is due to the charge of the complex as well as those inert character in a solution, that is, formation of RhCl 6–n (H 2 O) n(3–n)– (n = 1–6). The problem of solvent extraction of Rh from chloride solutions has not yet been solved and there is no effective industrial extractant for Rh. Adding Sn(II) to a Rh(III) feed is a good procedure which can be used to make Rh react more easily to extraction. However, the impurities such as Fe(III) and Al(III) are also leached together from spent automobile catalysts with chlo- ride solutions. Therefore, the investigation of effect of Sn(II) on extraction of Fe(III) and Al(III) as impurities is important for the extraction of Rh from chloride solutions added Sn(II). In the present study, the effect of Sn(II) on extraction of Fe(III) and Al(III) from chloride solutions contained Sn(II) with tri-n-octylamine (TOA) was investigated for the separation from Rh(III). Al(III) was not extracted with TOA, either with or without Sn(II). Meanwhile, the extraction of Fe(III) decreased with increase in the concentration of Sn(II) and the separation of Rh(III) from Fe(III) was possible by concentrating Rh(III) and Sn(II) in the organic pahse.
{"title":"Solvent Extraction of Iron(III) and Aluminum(III) and Separation from Rhodium(III) in Chloride Solutions Added Tin(II) with Tri-n-octylamine","authors":"A. Ishikawa, Takeshi Tanishige, Tasuma Suzuki, Masakazu Niinae","doi":"10.4144/RPSJ.66.9","DOIUrl":"https://doi.org/10.4144/RPSJ.66.9","url":null,"abstract":"Chloride is one of the effective medium in which platinum group metals (PGMs) can be brought into a solution, thus chlorocomplexes are particularly important in the process chemistry of PGMs separations. Rh(III) chlorocomplexes are poorly extracted into organic solvents, which is due to the charge of the complex as well as those inert character in a solution, that is, formation of RhCl 6–n (H 2 O) n(3–n)– (n = 1–6). The problem of solvent extraction of Rh from chloride solutions has not yet been solved and there is no effective industrial extractant for Rh. Adding Sn(II) to a Rh(III) feed is a good procedure which can be used to make Rh react more easily to extraction. However, the impurities such as Fe(III) and Al(III) are also leached together from spent automobile catalysts with chlo- ride solutions. Therefore, the investigation of effect of Sn(II) on extraction of Fe(III) and Al(III) as impurities is important for the extraction of Rh from chloride solutions added Sn(II). In the present study, the effect of Sn(II) on extraction of Fe(III) and Al(III) from chloride solutions contained Sn(II) with tri-n-octylamine (TOA) was investigated for the separation from Rh(III). Al(III) was not extracted with TOA, either with or without Sn(II). Meanwhile, the extraction of Fe(III) decreased with increase in the concentration of Sn(II) and the separation of Rh(III) from Fe(III) was possible by concentrating Rh(III) and Sn(II) in the organic pahse.","PeriodicalId":20971,"journal":{"name":"Resources Processing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72996182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hiroshi Takahashi, Tomoaki Kameyama, T. Shoji, Keisuke Chiba, H. Saito, Kou Amano, Katsuo Kyogoku, M. Okuda, K. Narita
Production of γ-aminobutyric acid (GABA) was investigated using rice-bran extract for effective utilization of agricultural resources. In the experiments using L-glutamic acid as substrate and rice bran extract as an additive including enzyme, the GABA production reaction stoichiometrically proceeded. The optimum conditions of pH and temperature for GABA production were at pH 5.5 and 30~40°C. The kinetic parameters of rice-bran extract using L-glutamic acid as a substrate were also evaluated by a mathematical model that considered the material balances of L-glutamic acid and GABA, and reaction rate expressed by Michaelis-Menten’s equation. The model successfully explained the concentration profiles of experimental data.
{"title":"Fundamental Study on Production of γ-Aminobutyric Acid using Rice-bran Extract","authors":"Hiroshi Takahashi, Tomoaki Kameyama, T. Shoji, Keisuke Chiba, H. Saito, Kou Amano, Katsuo Kyogoku, M. Okuda, K. Narita","doi":"10.4144/rpsj.66.99","DOIUrl":"https://doi.org/10.4144/rpsj.66.99","url":null,"abstract":"Production of γ-aminobutyric acid (GABA) was investigated using rice-bran extract for effective utilization of agricultural resources. In the experiments using L-glutamic acid as substrate and rice bran extract as an additive including enzyme, the GABA production reaction stoichiometrically proceeded. The optimum conditions of pH and temperature for GABA production were at pH 5.5 and 30~40°C. The kinetic parameters of rice-bran extract using L-glutamic acid as a substrate were also evaluated by a mathematical model that considered the material balances of L-glutamic acid and GABA, and reaction rate expressed by Michaelis-Menten’s equation. The model successfully explained the concentration profiles of experimental data.","PeriodicalId":20971,"journal":{"name":"Resources Processing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77765672","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kohei Isoi, Fumika Shirasugi, Mitsuaki Matsuoka, J. Hayashi, N. Murayama
Mg-Fe composite oxides with various mixing ratios were synthesized at different calcination temperature, to use them as anion removal agents. Crystal structure and specific surface area of the Mg-Fe composite oxides were evaluat - ed. The B and As(III) removal tests from dilute aqueous solution (initial concentration: 20 mg/dm 3 ) were conducted by using the Mg-Fe composite oxides. The predominant factors for removing them efficiently were considered. The Mg-Fe composite oxides having various specific surface area and different crystal structure are obtained, de pending on the chemical composition and the calcination temperature. When the mixing ratios are set to Mg:Fe = 1:1, 2:1 and 3:1, respectively, Mg-Fe type LDH is mainly formed as a precursor before calcination. Amorphous composite oxide is obtained by the calcination of Mg-Fe type LDH at 400°C. Approximately, the specific surface area of Mg-Fe composite oxides is increasing with an increase in the mixing ratio of Fe. On the other hand, the specific surface area of them also tends to decrease as the calcination temperature increases over 600°C. As the B removal mechanism from dilute aqueous solution, it is considered that (1) the formation of Mg(OH) 2 on the particle surface by the hydration of Mg-Fe composite oxides during removal operation and (2) the reconstruction of LDH structure by the partial hydration of Mg-Fe composite oxides are predominant. It is also found that (1) the hydration on the surface of MgO particles, (2) the reconstruction of LDH structure by the partial hydration, (3) the affinity with As(III) due to Fe and (4) the high specific surface area are effective for the As(III) removal.
{"title":"Removal of Borate and Arsenite in Dilute Aqueous Solution with Various Mg-Fe Composite Oxides","authors":"Kohei Isoi, Fumika Shirasugi, Mitsuaki Matsuoka, J. Hayashi, N. Murayama","doi":"10.4144/RPSJ.66.29","DOIUrl":"https://doi.org/10.4144/RPSJ.66.29","url":null,"abstract":"Mg-Fe composite oxides with various mixing ratios were synthesized at different calcination temperature, to use them as anion removal agents. Crystal structure and specific surface area of the Mg-Fe composite oxides were evaluat - ed. The B and As(III) removal tests from dilute aqueous solution (initial concentration: 20 mg/dm 3 ) were conducted by using the Mg-Fe composite oxides. The predominant factors for removing them efficiently were considered. The Mg-Fe composite oxides having various specific surface area and different crystal structure are obtained, de pending on the chemical composition and the calcination temperature. When the mixing ratios are set to Mg:Fe = 1:1, 2:1 and 3:1, respectively, Mg-Fe type LDH is mainly formed as a precursor before calcination. Amorphous composite oxide is obtained by the calcination of Mg-Fe type LDH at 400°C. Approximately, the specific surface area of Mg-Fe composite oxides is increasing with an increase in the mixing ratio of Fe. On the other hand, the specific surface area of them also tends to decrease as the calcination temperature increases over 600°C. As the B removal mechanism from dilute aqueous solution, it is considered that (1) the formation of Mg(OH) 2 on the particle surface by the hydration of Mg-Fe composite oxides during removal operation and (2) the reconstruction of LDH structure by the partial hydration of Mg-Fe composite oxides are predominant. It is also found that (1) the hydration on the surface of MgO particles, (2) the reconstruction of LDH structure by the partial hydration, (3) the affinity with As(III) due to Fe and (4) the high specific surface area are effective for the As(III) removal.","PeriodicalId":20971,"journal":{"name":"Resources Processing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80136972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The objective of this study was to evaluate the role of anatase impurities in sediments and the NaCl concentrations in the leaching solutions during the Cd(II) leaching from artificially contaminated sediments. It was found that the leaching of Cd(II) increased with increasing NaCl concentrations but this trend was less significant for the sediments containing higher amount of anatase. Based on the modeling analyses considering surface complexation and ion exchange reactions, the observed experimental results were explained by the difference between kaolinite and anatase in the Cd(II) adsorption mechanisms. At pH 5.9, which was the pH during the preparation of artificially contaminated sediments, kaolinite absorbs Cd(II) mainly via outer-sphere complex formation and that is why the absorbed Cd(II) was easily desorbed by the Na+ containing in the leaching solutions. On the other hand, the dominant Cd(II) adsorption mechanism for anatase was inner-sphere complex formation which was not hindered by the presence of NaCl. These experimental and modeling analyses results consistently showed that the content of anatase in sediments was one of the factors controlling the leaching level of Cd(II) from sediments when exposed to leaching solutions with high NaCl concentration.
{"title":"Influence of Anatase Content in Sediment and NaCl Concentration in the Leaching Solution in the Leaching of Cd(II) from Artificially Contaminated Sediment","authors":"Tasuma Suzuki, Kisyo Nakase, Masakazu Niinae","doi":"10.4144/rpsj.66.105","DOIUrl":"https://doi.org/10.4144/rpsj.66.105","url":null,"abstract":"The objective of this study was to evaluate the role of anatase impurities in sediments and the NaCl concentrations in the leaching solutions during the Cd(II) leaching from artificially contaminated sediments. It was found that the leaching of Cd(II) increased with increasing NaCl concentrations but this trend was less significant for the sediments containing higher amount of anatase. Based on the modeling analyses considering surface complexation and ion exchange reactions, the observed experimental results were explained by the difference between kaolinite and anatase in the Cd(II) adsorption mechanisms. At pH 5.9, which was the pH during the preparation of artificially contaminated sediments, kaolinite absorbs Cd(II) mainly via outer-sphere complex formation and that is why the absorbed Cd(II) was easily desorbed by the Na+ containing in the leaching solutions. On the other hand, the dominant Cd(II) adsorption mechanism for anatase was inner-sphere complex formation which was not hindered by the presence of NaCl. These experimental and modeling analyses results consistently showed that the content of anatase in sediments was one of the factors controlling the leaching level of Cd(II) from sediments when exposed to leaching solutions with high NaCl concentration.","PeriodicalId":20971,"journal":{"name":"Resources Processing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85692239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Gjergj Dodbiba, Kouji Yabui, Josiane Ponou, T. Fujita
cost-benefit analysis. Abstract Japan is a major consumer of precious metals. Nevertheless, it imports most of its required amount of precious metals. In order to ensure a stable supply of precious metals as well as deal with the increasing global demand, it is important to develop cost effective and environmental-friendly technologies that are able to recover the precious metals from electronic waste, known as e-waste. Generally speaking the conventional method for recovering gold (Au) from printed circuit boards (PCB) involves the incineration of scarp, followed by acid leaching. In an attempt to improve the Au extraction process, the authors are putting forward a new method. The sample was first subject to carbonization in N 2 atmosphere, followed by flotation in order to reduce the amount of sample subject to acid leaching as well as reduce the acid consumption. The sample recovered by flotation was then treated with aqua regia to dissolve Au. After investigating the effect of the carbonization temperature, a Cost-Benefit Analysis and a Life Cycle Assessment (LCA) were carried out in order to compare the efficiency of both conventional and suggested methods.
{"title":"Extracting Gold from Obsolete Printed Circuit Boards","authors":"Gjergj Dodbiba, Kouji Yabui, Josiane Ponou, T. Fujita","doi":"10.4144/RPSJ.65.3","DOIUrl":"https://doi.org/10.4144/RPSJ.65.3","url":null,"abstract":"cost-benefit analysis. Abstract Japan is a major consumer of precious metals. Nevertheless, it imports most of its required amount of precious metals. In order to ensure a stable supply of precious metals as well as deal with the increasing global demand, it is important to develop cost effective and environmental-friendly technologies that are able to recover the precious metals from electronic waste, known as e-waste. Generally speaking the conventional method for recovering gold (Au) from printed circuit boards (PCB) involves the incineration of scarp, followed by acid leaching. In an attempt to improve the Au extraction process, the authors are putting forward a new method. The sample was first subject to carbonization in N 2 atmosphere, followed by flotation in order to reduce the amount of sample subject to acid leaching as well as reduce the acid consumption. The sample recovered by flotation was then treated with aqua regia to dissolve Au. After investigating the effect of the carbonization temperature, a Cost-Benefit Analysis and a Life Cycle Assessment (LCA) were carried out in order to compare the efficiency of both conventional and suggested methods.","PeriodicalId":20971,"journal":{"name":"Resources Processing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78646553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Polishing glass components using a cerium oxide abrasive produces an abrasive–glass polishing powder waste. This study investigated the feasibility of applying the liquid-liquid extraction method for separating cerium oxide abrasive from an abrasive–glass polishing powder waste. Isooctane and water served as the two liquids, and sodium oleate (NaOL) served as the surfactant collector. First of all, the extracted fraction of individual cerium oxide abrasive and glass powder from the water phase to the isooctane phase was investigated separately. Subsequently, the cerium oxide abrasive was separated from an abrasive–glass powder mixture. The results indicated that the extracted fraction of the cerium oxide abrasive reached nearly 100% at a pH of 7 when more than 2.5 kg/ton of NaOL was added, whereas that of the glass powder was approximately 10%. Optimal separation of the cerium oxide abrasive from an abrasive–glass powder mixture was achieved at a pH of 7 with the addition of 7.5 kg/ton of NaOL; the grade of cerium oxide abrasive in the solid of isooctane phase reached 96.0%, with the recovery being 94.5%. After this method was applied to a real abrasive–glass polishing powder waste under optimal separation conditions, the grade and recovery of cerium oxide abrasive in the solid of isooctane phase reached 96.4% and 88.1%, respectively.
{"title":"Separation of Cerium Oxide Abrasive from an Abrasive–Glass Polishing Powder Waste by Means of Liquid-Liquid Extraction Method","authors":"Li Pang Wang, Yan Jhang Chen, Y. Tso, Y. Jiang","doi":"10.4144/RPSJ.65.93","DOIUrl":"https://doi.org/10.4144/RPSJ.65.93","url":null,"abstract":"Polishing glass components using a cerium oxide abrasive produces an abrasive–glass polishing powder waste. This study investigated the feasibility of applying the liquid-liquid extraction method for separating cerium oxide abrasive from an abrasive–glass polishing powder waste. Isooctane and water served as the two liquids, and sodium oleate (NaOL) served as the surfactant collector. First of all, the extracted fraction of individual cerium oxide abrasive and glass powder from the water phase to the isooctane phase was investigated separately. Subsequently, the cerium oxide abrasive was separated from an abrasive–glass powder mixture. The results indicated that the extracted fraction of the cerium oxide abrasive reached nearly 100% at a pH of 7 when more than 2.5 kg/ton of NaOL was added, whereas that of the glass powder was approximately 10%. Optimal separation of the cerium oxide abrasive from an abrasive–glass powder mixture was achieved at a pH of 7 with the addition of 7.5 kg/ton of NaOL; the grade of cerium oxide abrasive in the solid of isooctane phase reached 96.0%, with the recovery being 94.5%. After this method was applied to a real abrasive–glass polishing powder waste under optimal separation conditions, the grade and recovery of cerium oxide abrasive in the solid of isooctane phase reached 96.4% and 88.1%, respectively.","PeriodicalId":20971,"journal":{"name":"Resources Processing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91388064","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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