With BrazeTec BlueBraze the manufacturers in HVACR industry have an alternative filler metal with 10 weight-% less silver but same brazing temperatures. The performance of these new alloys has been evaluated in severa...With BrazeTec BlueBraze the manufacturers in HVACR industry have an alternative filler metal with 10 weight-% less silver but same brazing temperatures. The performance of these new alloys has been evaluated in several tests. The evaluation included wetting investigations, metallographic examinations, joint strength at different temperatures and pulsation and corrosion resistance. The results of these tests will be presented in this paper.展开更多
Metal droplets sticking to spinel solids, present in metallurgical slag systems, play an important role in hindering the sedimentation of copper in slags. To understand this phenomenon, the interaction between spinel ...Metal droplets sticking to spinel solids, present in metallurgical slag systems, play an important role in hindering the sedimentation of copper in slags. To understand this phenomenon, the interaction between spinel particles with Cu on one handand with slag, on the other hand,wasevaluated. A dedicated approach was applied, using an industrially relevant synthetic slag system PbO-FeO-SiO2-CaO-Al2O3-Cu2O-ZnO, pure copper and MgAl2O4substrates to represent the industrial slag, the entrained copper droplets and the spinel solids, respectively. Both the copper-MgAl2O4and the slag-MgAl2O4interaction were studied using sessile drop measurements, combined with an extensive microstructural analysis. Additionally, the effectoftimeon the slag-MgAl2O4 interaction was studied using immersion experiments. Copper displayed a non-wetting behaviour on MgAl2O4, whereas slag displayed a reactive wetting and an interaction layer of （Mg,Fe,Zn）（Al,Fe）2O4spinelwas formed at the interface, which was also observed in the immersion experiments. Moreover, the diffusion of MgO and Al2O3from the spinel substrate into the slag droplets was noted.展开更多
Metallurgical wastewaters contain high concentrations of sulfate,up to 15 g L^(-1).Sulfate-reducing bioreactors are employed to treat these wastewaters,reducing sulfates to sulfides which subsequently coprecipitate me...Metallurgical wastewaters contain high concentrations of sulfate,up to 15 g L^(-1).Sulfate-reducing bioreactors are employed to treat these wastewaters,reducing sulfates to sulfides which subsequently coprecipitate metals.Sulfate loading and reduction rates are typically restricted by the total H2S concentration.Sulfide stripping,sulfide precipitation and dilution are the main strategies employed to minimize inhibition by H2S,but can be adversely compromised by suboptimal sulfate reduction,clogging and additional energy costs.Here,metallurgical wastewater was treated for over 250 days using two hydrogenotrophic granular activated carbon expanded bed bioreactors without additional removal of sulfides.H2S toxicity was minimized by operating at pH 8±0.15,resulting in an average sulfate removal of 7.08±0.08 g L^(-1),sulfide concentrations of 2.1±0.2 g L^(-1) and peaks up to 2.3±0.2 g L^(-1).A sulfate reduction rate of 20.6±0.9 g L^(-1)d^(-1) was achieved,with maxima up to 27.2 g L^(-1)d^(-1),which is among the highest reported considering a literature review of 39 studies.The rates reported here are 6e8 times higher than those reported for other reactors without active sulfide removal and the only reported for expanded bed sulfate-reducing bioreactors using H2.By increasing the influent sulfate concentration and maintaining high sulfide concentrations,sulfate reducers were promoted while fermenters and methanogens were suppressed.Industrial wastewater containing 4.4 g L^(-1) sulfate,0.036 g L^(-1) nitrate and various metals(As,Fe,Tl,Zn,Ni,Sb,Co and Cd)was successfully treated with all metal(loid)s,nitrates and sulfates removed below discharge limits.展开更多
Brazing is a suitable technology to join different materials such as cemented carbides and steel. Even though this technology has been investigated for many years, insufficient joints can occur easily, as the brazing ...Brazing is a suitable technology to join different materials such as cemented carbides and steel. Even though this technology has been investigated for many years, insufficient joints can occur easily, as the brazing process is very sensitive concerning the handling parameters. Defects such as voids and cracks are hard to detect by commonly used visual inspection methods. Other nondestructive methods such as radiography or ultrasonic testing are usually not economical for the examination of these joints. Studies proved that the electrical resistance has the potential to serve as an effective alternative for the evaluation of brazed joints. In this study, the authors have compared the electrical resistance and the shear strength. For this, cemented carbides were brazed to steel by means of induction heating at an ambient atmosphere. A silver-based filler metal （ BrazeTec 4900 / Ag 449 ） and a flux （ BrazeTec spezial h / FH12） were selected to enable the brazing process. The brazing time and the temperature were varied in order to produce different joint qualities. After brazing, the resistance was measured on each joint with the 4-point probe method to facilitate a high accuracy. The results underline the possibility to use electrical resistance measurements as an effective tool for a quality control of brazed joints.展开更多
We will highlight the values Umicore's unique Process Excellence Model is based upon and how these do correlate with the overall culture of Umicore. Besides, we are going to explain about the benefits for the targ...We will highlight the values Umicore's unique Process Excellence Model is based upon and how these do correlate with the overall culture of Umicore. Besides, we are going to explain about the benefits for the target industries that come along with our approach. Here, we will not mainly focus on the usually mentioned cost saving potential, but how also other aspects do create substantial value for the industries.展开更多
文摘With BrazeTec BlueBraze the manufacturers in HVACR industry have an alternative filler metal with 10 weight-% less silver but same brazing temperatures. The performance of these new alloys has been evaluated in several tests. The evaluation included wetting investigations, metallographic examinations, joint strength at different temperatures and pulsation and corrosion resistance. The results of these tests will be presented in this paper.
基金science and technology in Flanders(IWT,project 110541)
文摘Metal droplets sticking to spinel solids, present in metallurgical slag systems, play an important role in hindering the sedimentation of copper in slags. To understand this phenomenon, the interaction between spinel particles with Cu on one handand with slag, on the other hand,wasevaluated. A dedicated approach was applied, using an industrially relevant synthetic slag system PbO-FeO-SiO2-CaO-Al2O3-Cu2O-ZnO, pure copper and MgAl2O4substrates to represent the industrial slag, the entrained copper droplets and the spinel solids, respectively. Both the copper-MgAl2O4and the slag-MgAl2O4interaction were studied using sessile drop measurements, combined with an extensive microstructural analysis. Additionally, the effectoftimeon the slag-MgAl2O4 interaction was studied using immersion experiments. Copper displayed a non-wetting behaviour on MgAl2O4, whereas slag displayed a reactive wetting and an interaction layer of （Mg,Fe,Zn）（Al,Fe）2O4spinelwas formed at the interface, which was also observed in the immersion experiments. Moreover, the diffusion of MgO and Al2O3from the spinel substrate into the slag droplets was noted.
基金This research was supported by Flanders Innovation&Entrepreneurship(VLAIO,HBC.217.000)the Research&Development Umicore Group.JVL is supported by Ghent University Bijzonder Onderzoeksfonds(BOF)BOF.GOA.2015.0002.01 and BOF15/GOA/006,while KF is supported by BOF/PDO/2020/0020+1 种基金KR is supported by a BOF GOA grant(BOF19/GOA/026)LB is supported by Ghent University Bijzonder Onderzoeksfonds BOF20/PDO/025.
文摘Metallurgical wastewaters contain high concentrations of sulfate,up to 15 g L^(-1).Sulfate-reducing bioreactors are employed to treat these wastewaters,reducing sulfates to sulfides which subsequently coprecipitate metals.Sulfate loading and reduction rates are typically restricted by the total H2S concentration.Sulfide stripping,sulfide precipitation and dilution are the main strategies employed to minimize inhibition by H2S,but can be adversely compromised by suboptimal sulfate reduction,clogging and additional energy costs.Here,metallurgical wastewater was treated for over 250 days using two hydrogenotrophic granular activated carbon expanded bed bioreactors without additional removal of sulfides.H2S toxicity was minimized by operating at pH 8±0.15,resulting in an average sulfate removal of 7.08±0.08 g L^(-1),sulfide concentrations of 2.1±0.2 g L^(-1) and peaks up to 2.3±0.2 g L^(-1).A sulfate reduction rate of 20.6±0.9 g L^(-1)d^(-1) was achieved,with maxima up to 27.2 g L^(-1)d^(-1),which is among the highest reported considering a literature review of 39 studies.The rates reported here are 6e8 times higher than those reported for other reactors without active sulfide removal and the only reported for expanded bed sulfate-reducing bioreactors using H2.By increasing the influent sulfate concentration and maintaining high sulfide concentrations,sulfate reducers were promoted while fermenters and methanogens were suppressed.Industrial wastewater containing 4.4 g L^(-1) sulfate,0.036 g L^(-1) nitrate and various metals(As,Fe,Tl,Zn,Ni,Sb,Co and Cd)was successfully treated with all metal(loid)s,nitrates and sulfates removed below discharge limits.
文摘Brazing is a suitable technology to join different materials such as cemented carbides and steel. Even though this technology has been investigated for many years, insufficient joints can occur easily, as the brazing process is very sensitive concerning the handling parameters. Defects such as voids and cracks are hard to detect by commonly used visual inspection methods. Other nondestructive methods such as radiography or ultrasonic testing are usually not economical for the examination of these joints. Studies proved that the electrical resistance has the potential to serve as an effective alternative for the evaluation of brazed joints. In this study, the authors have compared the electrical resistance and the shear strength. For this, cemented carbides were brazed to steel by means of induction heating at an ambient atmosphere. A silver-based filler metal （ BrazeTec 4900 / Ag 449 ） and a flux （ BrazeTec spezial h / FH12） were selected to enable the brazing process. The brazing time and the temperature were varied in order to produce different joint qualities. After brazing, the resistance was measured on each joint with the 4-point probe method to facilitate a high accuracy. The results underline the possibility to use electrical resistance measurements as an effective tool for a quality control of brazed joints.
文摘We will highlight the values Umicore's unique Process Excellence Model is based upon and how these do correlate with the overall culture of Umicore. Besides, we are going to explain about the benefits for the target industries that come along with our approach. Here, we will not mainly focus on the usually mentioned cost saving potential, but how also other aspects do create substantial value for the industries.
