start-ver=1.4 cd-journal=joma no-vol=5 cd-vols= no-issue=4 article-no= start-page=551 end-page=560 dt-received= dt-revised= dt-accepted= dt-pub-year=2019 dt-pub=20190923 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Separation Between Silicon and Aluminum Powders Contained Within Pulverized Scraped Silicon-Based Waste Solar Cells by Flotation Method en-subtitle= kn-subtitle= en-abstract= kn-abstract= There are few study examples on the separation of metals by floating method. In this study, separation of silicon and aluminum, which are the main components of silicon-based solar cell module, was carried out by floating method in order to purify silicon from waste solar cell module. The selection of surfactant, control of electric charge, wettability of the solid particles, surface tensions, and bubble surface area are important for separation of solids by floating method. Sodium dodecyl sulfate (SDS) can increase the hydrophobicity of aluminum powder due to the difference of surface potentials between silicon and aluminum. SDS behaves as a collector of aluminum as well as a frothing agent to decrease the bubble size. At a SDS concentration of 2 g/L and sample dipping time of 10 min, 80.1 mass% of aluminum was floated and separated, and the sedimentary silicon reached a purity of 90.7% from a mixture of 50 mass% aluminum and 50 mass% silicon. Finally, at a pH value of 7.0, SDS concentration between 1.0 and 2.5 g/L and air flow rate of 2.5 L/min (STP) were suitable experimental conditions to purify silicon from a mixture of silicon and aluminum by flotation separation method. en-copyright= kn-copyright= en-aut-name=HaradaSho en-aut-sei=Harada en-aut-mei=Sho kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=UddinMd. Azhar en-aut-sei=Uddin en-aut-mei=Md. Azhar kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KatoYoshiei en-aut-sei=Kato en-aut-mei=Yoshiei kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=KawanishiTakanori en-aut-sei=Kawanishi en-aut-mei=Takanori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=HayashiYoshiaki en-aut-sei=Hayashi en-aut-mei=Yoshiaki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil=Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=2 en-affil=Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=3 en-affil=Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=4 en-affil=Wet Process Division, Toho Kasei Co., Ltd kn-affil= affil-num=5 en-affil=Wet Process Division, Toho Kasei Co., Ltd kn-affil= en-keyword=Flotation kn-keyword=Flotation en-keyword=Floating separation kn-keyword=Floating separation en-keyword=Waste solar cell module kn-keyword=Waste solar cell module en-keyword=Silicon kn-keyword=Silicon en-keyword=Sodium dodecyl sulfate kn-keyword=Sodium dodecyl sulfate END start-ver=1.4 cd-journal=joma no-vol=179 cd-vols= no-issue= article-no= start-page=109225 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2020 dt-pub=20200526 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Simultaneous degradation and dechlorination of poly (vinyl chloride) by a combination of superheated steam and CaO catalyst/adsorbent en-subtitle= kn-subtitle= en-abstract= kn-abstract=In order to explore the possibility of efficient chlorine removal from the poly (vinyl chloride) (PVC) containing waste plastics, simultaneous degradation and dechlorination of PVC at a relatively low temperature was investigated by changing the atmosphere gas and metal oxide as catalyst and/or adsorbent (catalyst/adsorbent). 5.0 g of PVC and various metallic oxides such as CaO, Fe3O4, SiO2, Al2O, Ca(OH)2, MgO were used under the superheated steam and nitrogen atmosphere of 473 K. The degradation rate of the PVC sample was small and the chlorine conversion to inorganic chloride was not observed without catalyst/adsorbent in the presence of either superheated steam or nitrogen atmosphere. Under the superheated steam atmosphere, the CaO catalyst/adsorbent resulted in much larger rates of degradation and dechlorination than any other metal oxides such as Fe3O4, SiO2, Al2O, Ca(OH)2, MgO compared with nitrogen atmosphere. The calcium compounds such as CaCl?, CaClOH and Ca(OH)? were formed in the sample by the combination of CaO catalyst/adsorbent and superheated steam. The rates of PVC degradation and chlorine conversion to inorganic chlorides were dramatically enhanced beyond the stoichiometric CaO amount for the CaCl? formation reaction with PVC under the superheated steam atmosphere. The CaO addition contributed to both of the PVC degradation as a catalyst and the reactant with HCl as an adsorbent, whereas the superheated steam played a role of the sample temperature increase to promote the PVC degradation through the exothermic reaction with CaO. en-copyright= kn-copyright= en-aut-name=NishibataHaruka en-aut-sei=Nishibata en-aut-mei=Haruka kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=UddinMd. Azhar en-aut-sei=Uddin en-aut-mei=Md. Azhar kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KatoYoshiei en-aut-sei=Kato en-aut-mei=Yoshiei kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= affil-num=1 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= en-keyword=Dechloriation kn-keyword=Dechloriation en-keyword=Waste plastics kn-keyword=Waste plastics en-keyword=PVC kn-keyword=PVC en-keyword=Superheated steam kn-keyword=Superheated steam en-keyword=CaO kn-keyword=CaO en-keyword=Adsorbent kn-keyword=Adsorbent en-keyword=Catalyst kn-keyword=Catalyst END start-ver=1.4 cd-journal=joma no-vol=99 cd-vols= no-issue=1 article-no= start-page=410 end-page=420 dt-received= dt-revised= dt-accepted= dt-pub-year=2020 dt-pub=20200712 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Suspension pattern and rising height of sedimentary particles with low concentration in a mechanically stirred vessel en-subtitle= kn-subtitle= en-abstract= kn-abstract=In this study, the effects of impeller rotation speed, off]bottom clearance, blade angle, types of solid and liquid, etc., on the suspension pattern of sedimentary particles and particle rise height in liquid were investigated with a hemispherical vessel without baffles under low particle concentration. The transition conditions of suspension pattern between regimes I and II, and regimes II and III, were observed visually, and their non]dimensional equations were expressed with an acceptable correlation by varying the above operation factors a great deal. Here, regime I is stagnation of particles on a vessel bottom, II is partial suspension, and III is complete suspension in liquid. The non]dimensional equation of the maximum particle rise height was also successfully obtained. The combination of the non]dimensional equations of transition and maximum particle rise height permitted us to determine the adequate solid/liquid mixing operation conditions without collision of particles with device parts. en-copyright= kn-copyright= en-aut-name=TokuraYuichiro en-aut-sei=Tokura en-aut-mei=Yuichiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=MiyagawaKeita en-aut-sei=Miyagawa en-aut-mei=Keita kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=UddinMd. Azhar en-aut-sei=Uddin en-aut-mei=Md. Azhar kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=KatoYoshiei en-aut-sei=Kato en-aut-mei=Yoshiei kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil=Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=2 en-affil=Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=3 en-affil=Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=4 en-affil=Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University kn-affil= en-keyword=mechanical stirring kn-keyword=mechanical stirring en-keyword=PIV kn-keyword=PIV en-keyword=sedimentary particle kn-keyword=sedimentary particle en-keyword=solid/liquid mixing kn-keyword=solid/liquid mixing en-keyword=suspension kn-keyword=suspension END start-ver=1.4 cd-journal=joma no-vol=232 cd-vols= no-issue=1 article-no= start-page=17 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2021 dt-pub=20210106 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Enhancement of Zinc Ion Removal from Water by Physically Mixed Particles of Iron/Iron Sulfide en-subtitle= kn-subtitle= en-abstract= kn-abstract=Zinc (Zn) removal by physically mixed particles of zero-valent iron (Fe) and iron sulfide (FeS) was investigated as one technology for Zn removal from waste groundwater. The effects of the Fe/FeS mass ratio, including a single Fe and FeS particles, and pH on changes in the concentrations of Zn, Fe, and S were examined by a batch test and column tests, and the mechanism of Zn elimination was discussed. Among all the mixing fractions of Fe and FeS, Zn was eliminated most effectively by 3Fe/7FeS (mass ratio of Fe/FeS?=?3/7). The Zn removal rate decreased in the order of 3Fe/7FeS, FeS, and Fe, whereas the Fe concentration decreased in the order of Fe, FeS, and 3Fe/7FeS. The S concentration of FeS was larger than that of 3Fe/7FeS. The Zn removal rate by physically mixed 3Fe/7FeS particles was enhanced by a local cell reaction between the Fe and FeS particles. The electrons caused by Fe corrosion moved to the FeS surface and reduced the dissolved oxygen in the solution. Zn2+, Fe2+, and OH? ions in the solution were then coprecipitated on the particles as ZnFe2(OH)6 and oxidized to ZnFe2O4. Moreover, Zn2+ was sulfurized as ZnS by both the Fe/FeS mixture and the simple FeS particles. The Zn removal rate increased with increasing pH in the range from pH 3 to 7. From a kinetic analysis of Zn removal, the rate constant of anode (Fe)/cathode (FeS) reaction was almost the same as that of ZnS formation and slightly larger than that of Fe alone. en-copyright= kn-copyright= en-aut-name=KambaYuya en-aut-sei=Kamba en-aut-mei=Yuya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=UetaMiharu en-aut-sei=Ueta en-aut-mei=Miharu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=UddinMd. Azhar en-aut-sei=Uddin en-aut-mei=Md. Azhar kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=KatoYoshiei en-aut-sei=Kato en-aut-mei=Yoshiei kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil=Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=2 en-affil=Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=3 en-affil=Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=4 en-affil=Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University kn-affil= en-keyword=Zero-valent iron kn-keyword=Zero-valent iron en-keyword=Iron sulfide kn-keyword=Iron sulfide en-keyword=Zinc ion kn-keyword=Zinc ion en-keyword=Zinc removal kn-keyword=Zinc removal en-keyword=Groundwater treatment kn-keyword=Groundwater treatment END start-ver=1.4 cd-journal=joma no-vol=124 cd-vols= no-issue= article-no= start-page=108400 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2021 dt-pub=202102 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Effect of ultrasonic irradiation on -Fe2O3 formation by co-precipitation method with Fe3+ salt and alkaline solution en-subtitle= kn-subtitle= en-abstract= kn-abstract=The effect of ultrasonic irradiation on direct maghemite (-Fe2O3) preparation by a co-precipitation method with Fe3+ salt (Fe(NO3)3) and an excess amount of alkaline (KOH) solution without going through the conventional magnetite (Fe3O4) formation route was explored in comparison with impeller stirring. The preparation procedure for obtaining iron oxide nanoparticles was designed using the sequential processes of precipitation, decantation, drying and thermal dehydration, and ultrasonic irradiation or impeller stirring was done during the precipitation process. -ferric oxyhydroxide (-FeOOH) was partially formed in addition to -ferric oxyhydroxide (-FeOOH) and thermally dehydrated to -Fe2O3 and hematite (-Fe2O3) by ultrasonic-assisted co-precipitation of Fe3+ salt and the excess KOH solution, whereas only -FeOOH and -Fe2O3 were synthesized by impeller stirring. The difference between the products of the two methods was explained by the Lamer model associated with the nucleation and growth of FeOOH. Magnetization increased as the crystallite diameter decreased, which is estimated to facilitate partial formation of magnetic -Fe2O3. Magnetization was enhanced by a lower ultrasonic frequency due to the stronger shock wave induced by the cavitation effect. en-copyright= kn-copyright= en-aut-name=KoizumiHayato en-aut-sei=Koizumi en-aut-mei=Hayato kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=UddinMd. Azhar en-aut-sei=Uddin en-aut-mei=Md. Azhar kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KatoYoshiei en-aut-sei=Kato en-aut-mei=Yoshiei kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= affil-num=1 en-affil=Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=2 en-affil=Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=3 en-affil=Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University kn-affil= en-keyword=-Fe2O3 kn-keyword=-Fe2O3 en-keyword=Ultrasonic irradiation kn-keyword=Ultrasonic irradiation en-keyword=Impeller stirring kn-keyword=Impeller stirring en-keyword=-FeOOH kn-keyword=-FeOOH en-keyword=Co-precipitation method kn-keyword=Co-precipitation method END start-ver=1.4 cd-journal=joma no-vol=61 cd-vols= no-issue=6 article-no= start-page=1775 end-page=1783 dt-received= dt-revised= dt-accepted= dt-pub-year=2021 dt-pub=20210615 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Effect of Impeller and Gas Stirring on Agglomeration Behavior of Polydisperse Fine Particles in Liquid en-subtitle= kn-subtitle= en-abstract= kn-abstract=Agglomeration, coalescence and flotation of non-metallic inclusions in steel melt are effective for obtaining gclean steel.h In this study, the agglomeration and breakup behaviors of particles with a primary particle size distribution (hereinafter, polydisperse particles) in a liquid under impeller and gas stirring were compared by numerical calculations and model experiments. The particle-size-grouping (PSG) method in the numerical agglomeration model of particles was combined with a breakup term of agglomeration due to bubble bursting at the free surface. Polydisperse and monodisperse polymethylmethacrylate (PMMA) particles were used in the agglomeration experiments. The agglomeration rate of the polydisperse particles under impeller stirring was increased by an increasing energy input rate, whereas the agglomeration rate under gas stirring decreased under this condition due to the larger contribution of the breakup of agglomerated particles during bubble bursting in gas stirring. At the same energy input rate, agglomeration of polydisperse particles was larger under impeller stirring than under gas stirring. The agglomeration rate of polydisperse particles was larger than that of monodisperse particles under both impeller and gas stirring at the same energy input rate. The computational temporal changes in the total number of particles were in good agreement with the experimental results. This means that the difference in the agglomeration behaviors observed in impeller and gas stirring can be explained by the turbulent coagulation and subsequent agglomerated particle breakup in gas stirring. The computational temporal change in the number of each group approximately agreed with the experimental change in both impeller and gas stirring. en-copyright= kn-copyright= en-aut-name=YamaguchiAkito en-aut-sei=Yamaguchi en-aut-mei=Akito kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=OkanoHitoshi en-aut-sei=Okano en-aut-mei=Hitoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=SumitomoSyunsuke en-aut-sei=Sumitomo en-aut-mei=Syunsuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=UddinMd. Azhar en-aut-sei=Uddin en-aut-mei=Md. Azhar kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=KatoYoshiei en-aut-sei=Kato en-aut-mei=Yoshiei kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil=Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=2 en-affil=Department of Material and Energy Science, Graduate School of Environmental Science kn-affil= affil-num=3 en-affil=Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=4 en-affil=Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=5 en-affil=Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University kn-affil= en-keyword=agglomeration kn-keyword=agglomeration en-keyword=breakup kn-keyword=breakup en-keyword=particle kn-keyword=particle en-keyword=impeller stirring kn-keyword=impeller stirring en-keyword=gas agitation kn-keyword=gas agitation en-keyword=particle-size-grouping method kn-keyword=particle-size-grouping method END start-ver=1.4 cd-journal=joma no-vol= cd-vols= no-issue= article-no= start-page= end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2023 dt-pub=2023530 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Sequential flotation of 4 components in silicon-based waste solar cells en-subtitle= kn-subtitle= en-abstract= kn-abstract=Si, Al, Cu, and Ag particlesf mixture which mainly composes pulverized silicon-based waste solar cells were individually separated by the batch flotation experiments with high recovery and content, and then a general flow chart of the sequential flotation procedure of n-component was postulated including 2-, 3-, and 4-components. The n-component mixture was separated to 1: n-1 or i: j (i?+?j?=?n) by a flotation procedure and n-1 times operation was necessary to divide into the individual component. The first flotation process to separate Al into the froth layer was carried out with a collector of SDS solution after dipping Si, Al, Cu, and Ag mixture into the SDS solution. Si was separated in the froth by the second flotation with a collector of a commercial neutral detergent after Al etching by HCl, and Si, Cu and Ag mixture dipped in the detergent. The Cu and Ag mixture was calcinated at 673 or 773 K and dipped into the detergent, and the third flotation with the collector of the detergent led to Cu in the froth and Ag in the sediment. The 4-component mixture was successfully separated into each component by the 3-consecutive flotation processes. en-copyright= kn-copyright= en-aut-name=MizukawaMami en-aut-sei=Mizukawa en-aut-mei=Mami kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=NishimuraNoriko en-aut-sei=Nishimura en-aut-mei=Noriko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=UddinMd. Azhar en-aut-sei=Uddin en-aut-mei=Md. Azhar kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=KatoYoshiei en-aut-sei=Kato en-aut-mei=Yoshiei kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=UchidaYu-ichi en-aut-sei=Uchida en-aut-mei=Yu-ichi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil=Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=2 en-affil=Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=3 en-affil=Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=4 en-affil=Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=5 en-affil=Department of Applied Chemistry, Faculty of Fundamental Engineering, Nippon Institute of Technology kn-affil= en-keyword=Flotation kn-keyword=Flotation en-keyword=Multicomponent kn-keyword=Multicomponent en-keyword=Waste solar cell kn-keyword=Waste solar cell en-keyword=Silicon kn-keyword=Silicon en-keyword=Recovery kn-keyword=Recovery END start-ver=1.4 cd-journal=joma no-vol=25 cd-vols= no-issue=2 article-no= start-page=826 end-page=834 dt-received= dt-revised= dt-accepted= dt-pub-year=2022 dt-pub=20221210 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Flotation kinetics of aluminum powders derived from waste crystalline silicon solar cells and its comparison between batch, continuous and column flotation practices en-subtitle= kn-subtitle= en-abstract= kn-abstract=In this study, floatability rate of aluminum (Al) powders was analyzed for the purpose of separating valuable resources from residual materials in waste photovoltaic (PV) solar cells, and equations for flotation recovery were developed for various flotation types according to the rate-determining steps of the gas flowrate and feed rate. The flotation rate became a zero-order reaction at the rate-determining step of the gas flow rate and had the same form between a batch and continuous typed practices by substituting residence time with real time. Under the rate-determining step of the feed rate, the flotation rate was expressed by the linear combination of the first-order reaction of an even group material. The flotation recovery rate of Al powders was analyzed by the data of a batch floatability experiment and indicated by the linear expression of the first-order reaction of two groups due to the rate-determining step of the feed rate. The calculated separation recovery of n-cell type device increased as the number of cells increased and approached that of the batch and column types. en-copyright= kn-copyright= en-aut-name=KatoYoshiei en-aut-sei=Kato en-aut-mei=Yoshiei kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=HaradaSho en-aut-sei=Harada en-aut-mei=Sho kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=NishimuraNoriko en-aut-sei=Nishimura en-aut-mei=Noriko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=UddinMd. Azhar en-aut-sei=Uddin en-aut-mei=Md. Azhar kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=UchidaYu-ichi en-aut-sei=Uchida en-aut-mei=Yu-ichi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil=Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=2 en-affil=Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=3 en-affil=Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=4 en-affil=Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=5 en-affil=Department of Applied Chemistry, Faculty of Fundamental Engineering, Nippon Institute of Technology kn-affil= en-keyword=Flotation kn-keyword=Flotation en-keyword=Recovery kn-keyword=Recovery en-keyword=Waste solar cell kn-keyword=Waste solar cell en-keyword=Column flotation kn-keyword=Column flotation en-keyword=Cell-to-cell flotation kn-keyword=Cell-to-cell flotation END start-ver=1.4 cd-journal=joma no-vol=6 cd-vols= no-issue= article-no= start-page=132 end-page=141 dt-received= dt-revised= dt-accepted= dt-pub-year=2020 dt-pub=20200203 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Alkali Elution Behavior of Steelmaking Slag Packed in an Open Channel Vessel in Seawater en-subtitle= kn-subtitle= en-abstract= kn-abstract=The alkali elution behavior of steelmaking slag in seawater was kinetically investigated and simulated under continuous flow in an open channel vessel with packed bed of steelmaking slag. Two types of steelmaking slags, viz. decarburization slag and dephosphorization slag, were used in this study. The alkali elution rate of decarburization slag was larger than that of dephosphorization slag due to larger free CaO content. The pH value for dephosphorization slag was almost the same as the seawater pH value in 3?4 days, whereas that for decarburization slag was stabilized in 3 days although the pH value was slightly larger than that of seawater. The capacity coefficients of alkali elution for dephosphorization and decarburization slags decreased together in an exponential manner with time. Based on a regression equation on the mass transfer capacity coefficient change with time, the alkali elution behavior was simulated and the calculated results agreed well with the experimental ones. The temporal pH change was predicted by changing slag surface area and seawater flow rate as a parameter. According to the simulation results for dephosphorization slag, the seawater pH value did not reach a high level in the ocean area. en-copyright= kn-copyright= en-aut-name=MatsudaYamato en-aut-sei=Matsuda en-aut-mei=Yamato kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=UddinMd. Azhar en-aut-sei=Uddin en-aut-mei=Md. Azhar kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KatoYoshiei en-aut-sei=Kato en-aut-mei=Yoshiei kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=MiyataYasuhito en-aut-sei=Miyata en-aut-mei=Yasuhito kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=KisoEiji en-aut-sei=Kiso en-aut-mei=Eiji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil=Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=2 en-affil=Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=4 en-affil=Slag & Refractories Research Department, Steel Research Laboratory, JFE Steel Corporation kn-affil= affil-num=5 en-affil=Marketing Development, Slag & Cement Division, Nippon Steel Corporation kn-affil= en-keyword=Steelmaking slag kn-keyword=Steelmaking slag en-keyword=Alkali elution kn-keyword=Alkali elution en-keyword=Seawater kn-keyword=Seawater en-keyword=Open channel kn-keyword=Open channel en-keyword=Packed bed kn-keyword=Packed bed END