The effects of the acid leaching and alkali fusion on the leaching efficiency of Y,Eu,Ce,and Tb from the waste rare earth fluorescent powders were investigated in this paper.The results show that hydrochloric acid is ...The effects of the acid leaching and alkali fusion on the leaching efficiency of Y,Eu,Ce,and Tb from the waste rare earth fluorescent powders were investigated in this paper.The results show that hydrochloric acid is better than sulfuric acid in the first acid leaching,and NaOH is better than Na2CO3in the alkali fusion.In the first acid leaching,the Wloss is 20.94%when the waste rare earth fluorescent powders are acid leached in H?concentration 3 mol L-1and S/L ratio 1:3 for 4 h due to red powders dissolved.The better results of the alkali fusion can be got at 800℃ for 2 h when the NaOH is used.The blue powders and the green powders can be dissolved into NaAlO2and oxides such as rare earth oxide(REO).The REO can be dissolved in H?concentration 5 mol L-1,S/L1:10 for 3 h in the second acid leaching.The leaching rates of the Y,Eu,Ce,and Tb are 99.06%,97.38%,98.22%,and 98.15%,respectively.The leaching rate of the total rare earth is 98.60%.展开更多
The electromagnetic and microwave absorbing properties of FeCoB powder composites prepared by sin- gle-roller melt-spinning and mechanical milling processes were investigated in this paper. The result indicates that t...The electromagnetic and microwave absorbing properties of FeCoB powder composites prepared by sin- gle-roller melt-spinning and mechanical milling processes were investigated in this paper. The result indicates that the flake-like powders are obtained. As milling time increases, the flake-like powder particles tend to agglomerate, causing the flake-like powders decrease gradually. The milling time plays an important role in the electromagnetic parameters which relates to the shape and size of the powder particles. The calculation shows that the sample milled for 6 h could achieve an optimal reflection loss of -11.5 dB at 5.8 GHz, with mass fraction of 83 % and a matching thickness of 1.8 mm. The result also indicates that the microwave absorbing properties of the FeCoB powder composites are adjustable by changing their thickness, and can be applied as a thinner microwave absorbing material in the range of 2-8 GHz.展开更多
Oily cold rolling mill (CRM) sludge contains lots of iron and alloying elements along with plenty of hazardous organic components, which makes it as an attractive secondary source and an environmental contaminant at...Oily cold rolling mill (CRM) sludge contains lots of iron and alloying elements along with plenty of hazardous organic components, which makes it as an attractive secondary source and an environmental contaminant at the same time. The compound methods of "vacuum distillation + oxidizing roasting" and "vacuum distillation + hydrogen reduction" were employed for the recycle of oily cold rolling mill sludge. First, the sludge was dynamically vacuum distilled in a rotating furnace at 50 r/rain and 600℃ for 3 h, which removed almost hazardous organic components, obtaining 89.2wt% ferrous resultant. Then, high purity ferric oxide powders (99.2wt%) and reduced iron powders (98.9wt%) were obtained when the distillation residues were oxidized and reduced, respectively. The distillation oil can be used for fuel or chemical feedstock, and the distillation gases can be collected and reused as a fuel.展开更多
Oily cold rolling mill (CRM) sludge is one of the pollutants emitted by iron and steel plants. Recycling oily CRM sludge can not only reduce pollution but also bring social and environmental benefits. In this study,...Oily cold rolling mill (CRM) sludge is one of the pollutants emitted by iron and steel plants. Recycling oily CRM sludge can not only reduce pollution but also bring social and environmental benefits. In this study, using oily CRM sludge as sources of iron oxide, the strontium ferrite powders were synthesized in multiple steps including vacuum distillation, magnetic separation, oxidizing roasting, and solidstate reaction. The optimal technological conditions of vacuum distillation and oxidizing roasting were studied carefully. To consider the effects of Fe203/ SrCO3 tool ratio, calcination temperature, milling time and calcination time on magnetic properties of prepared strontium ferrite powders, the orthogonal experimental method was adopted. The maximum saturation magneti- zation (62.6 mA-m2.g-1) of the synthesized strontium ferrite powders was achieved at the Fe203/SrCO3 mol ratio of 6, 5 h milling time, 1250 ~C calcination temperature, and 1 h calcination time. Strontium ferrite powders syn- thesis method not only provides a cheap, high quality raw material for the production of strontium ferrite powders, but also effectively prevents the environmental pollution.展开更多
Oily cold rolling mill (CRM) sludge is one of metallurgical industry solid wastes. The recycle of these wastes can not only protect the environment but also permit their reutilization. In this research, a new proces...Oily cold rolling mill (CRM) sludge is one of metallurgical industry solid wastes. The recycle of these wastes can not only protect the environment but also permit their reutilization. In this research, a new process of "hydrometallurgical treatment + hydrothermal synthesis" was investigated for the combined recovery of iron and organic materials from oily CRM sludge. Hydrometallurgical treatment, mainly including acid leaching, centrifugal separation, neutralization reaction, oxidizing, and preparation of hydrothermal reaction precursor, was first utilized for processing the sludge. Then, micaceous iron oxide (MIO) pigment powders were prepared through hydrothermal reaction of the obtained precursor in alkaline media. The separated organic materials can be used for fuel or chemical feedstock. The quality of the prepared MIO pigments is in accordance with the standards of MIO pigments for paints (ISO 10601-2007). This clean, effective, and economical technology offers a new way to recycle oily CRM sludge.展开更多
In this paper, the method of recycling copper and tin by constant-current and constant-voltage electrolysis from the stripping tin solution of tinned copper wastes was studied. The experimental results show that the e...In this paper, the method of recycling copper and tin by constant-current and constant-voltage electrolysis from the stripping tin solution of tinned copper wastes was studied. The experimental results show that the elements could be deposited on the cathode in turn by different deposition potentials, therefore, the copper and tin were separated by constant-voltage electrolysis but not constant-current electrolysis. In this study, the influence of anode materials was also investigated. Graphite anode is stable without impurities dissolved into the stripping tin solution, while 316 stainless steel anode is dissolved into Fe2?and Fe3?as anodic corrosion, which could decrease the deposition efficiency of tin. The copper and tin in the stripping tin solution are separated orderly by electrodeposition at different voltages using the graphite anode. The recovery rate of copper is up to 100 % at 2.00 V, while that of tin is 80 % at 3.00 V.展开更多
Comprehensive CeMgA111O19: Tb3+ (CTMA) disintegration via alkaline fusion was discussed. The rare earth (RE) elements in CTMA were dissolved by HC1 completely after alkaline fusion. Relationships between the alk...Comprehensive CeMgA111O19: Tb3+ (CTMA) disintegration via alkaline fusion was discussed. The rare earth (RE) elements in CTMA were dissolved by HC1 completely after alkaline fusion. Relationships between the alkaline fusion temperature and various properties of the compounds were examined by various techniques to elu- cidate their roles in the expected CTMA disintegration. X-ray diffraction (XRD) analysis indicates the phase transformation sequence. A scientific hypothesis of crystal structure disintegration presents that sodium ions substitute for the europium and barium ions in the mirror plane and magnesium ions in the spinel block successively, resulting in that more oxygen vacancies and interstitial sodium ions appear. The unit cell [P63/mmc (194)] breaks from the mirror plane. Then it is decomposed into NaA102, and magnesium, cerium, and terbium ions combine with free OH- into MgO, Tb2O3 and CeO2; Tb2O3 and CeO2 change into Ceo.6Tbo.O2-x. In the end, the rare earth oxide is recycled easily by the acidolysis. The mechanism provides fundamental basis for recycling of REEs from waste phosphors.展开更多
The recycling method and principle of SnO2 from the tin slag of printed circuit boards(PCB) waste were investigated. In this study, pure SnO2 powders were obtained through a multi-step process including ball-milling...The recycling method and principle of SnO2 from the tin slag of printed circuit boards(PCB) waste were investigated. In this study, pure SnO2 powders were obtained through a multi-step process including ball-milling, roasting, dissolving, precipitating, and pickling. The total recovery rate of tin can be up to 91 %. The SnO2 powders obtained is the single phase, and the content of SnO2 is up to 99.9 %. However, the SnO2 particles are easier to agglomerate during the precipitation process. The agglomerate SnO2 particles are about 7.778 lm in mean particle size(D50). This preparation method presents a viable alternative for the tin slag recycling. The tin is not only recycled, but also reused directly to prepare pure SnO2 powders.展开更多
This study aimed to find an efficient way to recover Sb from the SbC15 acid solution obtained by the chloride leaching process of the tin-depleted residue. Sb was recovered in the form of hydrated antimony pentoxide t...This study aimed to find an efficient way to recover Sb from the SbC15 acid solution obtained by the chloride leaching process of the tin-depleted residue. Sb was recovered in the form of hydrated antimony pentoxide through the hydrolysis process. The effects of hydrolysis ratio and aging time on the Sb recovery process were studied, and the corresponding trends were established. The experimental results show that the amount of the antimony free ions increases with the hydrolysis ratio and aging time. This decreases the concentration quotient of the hydrolysis reaction and thus facilitates the reaction. Product crystallinity is affected by the solution supersaturation, which varies at different stages with aging time. As a result, the optimal conditions of recovering Sb correspond to the hydrolysis ratio of 1.5 and aging time of 7 days with the recovery rate of 97 %.展开更多
The effect of height on performance of the PZT/Ni cylindrical bilayered magnetoelectric (ME) com- posites was studied in situ in this paper. Multiple resonant peaks appear between 1 and 300 kHz frequency for cyl- in...The effect of height on performance of the PZT/Ni cylindrical bilayered magnetoelectric (ME) com- posites was studied in situ in this paper. Multiple resonant peaks appear between 1 and 300 kHz frequency for cyl- inders of different heights. The first resonance frequency does not change with the cylinder height decreasing, but the second and the third resonant frequencies increase. The first three resonant modes radial, first-order height are attributed to the cylinder resonance, and second-order height resonance, respectively. The appropriate size and resonance frequency were chosen to obtain the highest ME voltage coefficient when designing cylindrical bilayered magnetoelectric devices. This article provides reference to design cylindrical magnetoelectric devices.展开更多
In this study, Pb was separated and used to prepare BaPbO3 conductive ceramics from leaded waste.The experimental results show that BaPbO3 powder synthesized at 700 °C has particle size of 2–5 lm. The powders we...In this study, Pb was separated and used to prepare BaPbO3 conductive ceramics from leaded waste.The experimental results show that BaPbO3 powder synthesized at 700 °C has particle size of 2–5 lm. The powders were densified by sintering at 1,000 °C for 2 h in the air.Synthesized BaPbO3 ceramics have high Curie temperature and high-temperature positive temperature coefficient(PTC) resistivity characteristics. Electrical resistivity of BaPbO3 compact increases from 5 × 10^-6Ω·m at room temperature to 4 × 10^-4Ω·m at 750 °C. Compared with the one prepared by pure chemical reagents, the BaPbO3 prepared from leaded waste has the similar characteristics of high Curie temperature and PTC resistivity.展开更多
基金supported by the National Hi-Tech R&D Program of China (No. 2012AA063202)National Key Project of Scientific and Technical Support Program of China (Nos. 2011BAE13B07, 2012BAC02B01, and 2011BAC10B02)National Natural Science Foundation of China (Nos. 51174247 and 50972013)
文摘The effects of the acid leaching and alkali fusion on the leaching efficiency of Y,Eu,Ce,and Tb from the waste rare earth fluorescent powders were investigated in this paper.The results show that hydrochloric acid is better than sulfuric acid in the first acid leaching,and NaOH is better than Na2CO3in the alkali fusion.In the first acid leaching,the Wloss is 20.94%when the waste rare earth fluorescent powders are acid leached in H?concentration 3 mol L-1and S/L ratio 1:3 for 4 h due to red powders dissolved.The better results of the alkali fusion can be got at 800℃ for 2 h when the NaOH is used.The blue powders and the green powders can be dissolved into NaAlO2and oxides such as rare earth oxide(REO).The REO can be dissolved in H?concentration 5 mol L-1,S/L1:10 for 3 h in the second acid leaching.The leaching rates of the Y,Eu,Ce,and Tb are 99.06%,97.38%,98.22%,and 98.15%,respectively.The leaching rate of the total rare earth is 98.60%.
基金financially supported by the National Hi-tech R&D Project Supporting Programs Funded by Ministry of Science&Technology of China(No.2012AA063202)the National Natural Science Foundation of China(Nos.50972013,50802008,and 51004011)+1 种基金the National Key Project of Scientific and Technical Supporting Programs Funded by Ministry of Science&Technology of China(Nos.2012BAC02B01,2012BAC12B05,2011BAE13B07,and 2011BAC10B02)the Guangdong Province&Ministry of Education Industry-Study-Research United Project(No.2009A090100017)
文摘The electromagnetic and microwave absorbing properties of FeCoB powder composites prepared by sin- gle-roller melt-spinning and mechanical milling processes were investigated in this paper. The result indicates that the flake-like powders are obtained. As milling time increases, the flake-like powder particles tend to agglomerate, causing the flake-like powders decrease gradually. The milling time plays an important role in the electromagnetic parameters which relates to the shape and size of the powder particles. The calculation shows that the sample milled for 6 h could achieve an optimal reflection loss of -11.5 dB at 5.8 GHz, with mass fraction of 83 % and a matching thickness of 1.8 mm. The result also indicates that the microwave absorbing properties of the FeCoB powder composites are adjustable by changing their thickness, and can be applied as a thinner microwave absorbing material in the range of 2-8 GHz.
基金financially supported by the National Key Technology R&D Program(Nos.2012BAC02B01,2012BAC12B05,2011BAE13B07,and 2011BAC10B02)the National High-Tech Research and Development Program of China(No.2012AA063202)+2 种基金the National Natural Science Foundation of China(Nos.51174247 and51004011)the Science and Technology Program of Guangdong Province,China(No.2010A030200003)the Ph.D.Programs Foundation of the Ministry of Education of China(No.2010000612003)
文摘Oily cold rolling mill (CRM) sludge contains lots of iron and alloying elements along with plenty of hazardous organic components, which makes it as an attractive secondary source and an environmental contaminant at the same time. The compound methods of "vacuum distillation + oxidizing roasting" and "vacuum distillation + hydrogen reduction" were employed for the recycle of oily cold rolling mill sludge. First, the sludge was dynamically vacuum distilled in a rotating furnace at 50 r/rain and 600℃ for 3 h, which removed almost hazardous organic components, obtaining 89.2wt% ferrous resultant. Then, high purity ferric oxide powders (99.2wt%) and reduced iron powders (98.9wt%) were obtained when the distillation residues were oxidized and reduced, respectively. The distillation oil can be used for fuel or chemical feedstock, and the distillation gases can be collected and reused as a fuel.
基金supported by the National Key Technology R&D Program (Nos. 2012BAC02B01, 2012BAC12B05, 2011BAE13B07, and 2011BAC10B02)the National High Technology Research and Development Program of China (No. 2012AA063202)+2 种基金the National Natural Science Foundation of China (Nos. 51174247 and 51004011)the Science and Technology Program of Guangdong Province, China (No. 2010A030200003)the Ph.D. Programs Foundation of the Ministry of Education of China (No. 2010000612003)
文摘Oily cold rolling mill (CRM) sludge is one of the pollutants emitted by iron and steel plants. Recycling oily CRM sludge can not only reduce pollution but also bring social and environmental benefits. In this study, using oily CRM sludge as sources of iron oxide, the strontium ferrite powders were synthesized in multiple steps including vacuum distillation, magnetic separation, oxidizing roasting, and solidstate reaction. The optimal technological conditions of vacuum distillation and oxidizing roasting were studied carefully. To consider the effects of Fe203/ SrCO3 tool ratio, calcination temperature, milling time and calcination time on magnetic properties of prepared strontium ferrite powders, the orthogonal experimental method was adopted. The maximum saturation magneti- zation (62.6 mA-m2.g-1) of the synthesized strontium ferrite powders was achieved at the Fe203/SrCO3 mol ratio of 6, 5 h milling time, 1250 ~C calcination temperature, and 1 h calcination time. Strontium ferrite powders syn- thesis method not only provides a cheap, high quality raw material for the production of strontium ferrite powders, but also effectively prevents the environmental pollution.
基金financially supported by the National Key Technology R&D Program of China (Nos.2012BAC02B01,2012BAC12B05,2011BAE13B07,and 2011BAC10B02)the National High-Tech Research and Development Program of China (No.2012AA063202)+2 种基金the National Natural Science Foundation of China (Nos.51174247 and 51004011)the Science and Technology Program of Guangdong Province,China (No.2010A030200003)the Ph.D. Programs Foundation of the Ministry of Education of China (No.2010000612003)
文摘Oily cold rolling mill (CRM) sludge is one of metallurgical industry solid wastes. The recycle of these wastes can not only protect the environment but also permit their reutilization. In this research, a new process of "hydrometallurgical treatment + hydrothermal synthesis" was investigated for the combined recovery of iron and organic materials from oily CRM sludge. Hydrometallurgical treatment, mainly including acid leaching, centrifugal separation, neutralization reaction, oxidizing, and preparation of hydrothermal reaction precursor, was first utilized for processing the sludge. Then, micaceous iron oxide (MIO) pigment powders were prepared through hydrothermal reaction of the obtained precursor in alkaline media. The separated organic materials can be used for fuel or chemical feedstock. The quality of the prepared MIO pigments is in accordance with the standards of MIO pigments for paints (ISO 10601-2007). This clean, effective, and economical technology offers a new way to recycle oily CRM sludge.
基金financially supported by National Hi-Tech R&D Program of China (No. 2012AA063202)National Key Project of Scientific and Technical Support Program of China (Nos. 2011BAE13B07, 2012BAC02B01, and 2011BAC10B02)+1 种基金the National Natural Science Foundation of China (Nos. 51174247 and 50972013)the Guangdong Province Science and Technology Project (No. 2010A030200003)
文摘In this paper, the method of recycling copper and tin by constant-current and constant-voltage electrolysis from the stripping tin solution of tinned copper wastes was studied. The experimental results show that the elements could be deposited on the cathode in turn by different deposition potentials, therefore, the copper and tin were separated by constant-voltage electrolysis but not constant-current electrolysis. In this study, the influence of anode materials was also investigated. Graphite anode is stable without impurities dissolved into the stripping tin solution, while 316 stainless steel anode is dissolved into Fe2?and Fe3?as anodic corrosion, which could decrease the deposition efficiency of tin. The copper and tin in the stripping tin solution are separated orderly by electrodeposition at different voltages using the graphite anode. The recovery rate of copper is up to 100 % at 2.00 V, while that of tin is 80 % at 3.00 V.
基金financially supported by the National Key Project of the Scientific and Technical Support Program of China(No.2012BAC02B01)the National Hi-Tech R&D Program of China(No.2012AA063202)+2 种基金the National Natural Science Foundation of China(No.51472030)the Fundamental Research Funds for the Central Universities(Project No.FRF-TP-14-043A1)the China Postdoctoral Science Foundation Funded Project(No.2014M560885)
文摘Comprehensive CeMgA111O19: Tb3+ (CTMA) disintegration via alkaline fusion was discussed. The rare earth (RE) elements in CTMA were dissolved by HC1 completely after alkaline fusion. Relationships between the alkaline fusion temperature and various properties of the compounds were examined by various techniques to elu- cidate their roles in the expected CTMA disintegration. X-ray diffraction (XRD) analysis indicates the phase transformation sequence. A scientific hypothesis of crystal structure disintegration presents that sodium ions substitute for the europium and barium ions in the mirror plane and magnesium ions in the spinel block successively, resulting in that more oxygen vacancies and interstitial sodium ions appear. The unit cell [P63/mmc (194)] breaks from the mirror plane. Then it is decomposed into NaA102, and magnesium, cerium, and terbium ions combine with free OH- into MgO, Tb2O3 and CeO2; Tb2O3 and CeO2 change into Ceo.6Tbo.O2-x. In the end, the rare earth oxide is recycled easily by the acidolysis. The mechanism provides fundamental basis for recycling of REEs from waste phosphors.
基金financially supported by the Beijing Nova Program (No. Z141103001814006)the National Key Technology R&D Program (Nos. 2012BAC12B05 and 2012BAC02B01)+1 种基金the National Natural Science Foundation of China (Nos. 51174247 and U1360202)the National High-Tech Research and the Development Program of China (No. 2012AA063202)
文摘The recycling method and principle of SnO2 from the tin slag of printed circuit boards(PCB) waste were investigated. In this study, pure SnO2 powders were obtained through a multi-step process including ball-milling, roasting, dissolving, precipitating, and pickling. The total recovery rate of tin can be up to 91 %. The SnO2 powders obtained is the single phase, and the content of SnO2 is up to 99.9 %. However, the SnO2 particles are easier to agglomerate during the precipitation process. The agglomerate SnO2 particles are about 7.778 lm in mean particle size(D50). This preparation method presents a viable alternative for the tin slag recycling. The tin is not only recycled, but also reused directly to prepare pure SnO2 powders.
基金financially supported by the National Natural Science Foundation of China(Nos.U1360202 and51472030)the National Key Project of the Scientific and Technical Support Program of China(Nos.2011BAE13B07,2012BAC02B01and 2011BAC10B02)+3 种基金the National Hi-Tech R&D Program of China(No.2012AA063202)the Fundamental Research Funds for the Central Universities(No.FRF-TP-14-043A1)the China Postdoctoral Science Foundation Funded Project(No.2014M560885)the Beijing Nova Program(No.Z141103001814006)
文摘This study aimed to find an efficient way to recover Sb from the SbC15 acid solution obtained by the chloride leaching process of the tin-depleted residue. Sb was recovered in the form of hydrated antimony pentoxide through the hydrolysis process. The effects of hydrolysis ratio and aging time on the Sb recovery process were studied, and the corresponding trends were established. The experimental results show that the amount of the antimony free ions increases with the hydrolysis ratio and aging time. This decreases the concentration quotient of the hydrolysis reaction and thus facilitates the reaction. Product crystallinity is affected by the solution supersaturation, which varies at different stages with aging time. As a result, the optimal conditions of recovering Sb correspond to the hydrolysis ratio of 1.5 and aging time of 7 days with the recovery rate of 97 %.
基金supported by the Beijing Nova Program(No.Z141103001814006)the National Key Technology R&D Program(Nos.2012BAC12B05 and 2012BAC02B01)+1 种基金the National Natural Science Foundation of China(Nos.51174247 and U1360202)the National High-Tech Research and the Development Program of China(No.2012AA063202)
文摘The effect of height on performance of the PZT/Ni cylindrical bilayered magnetoelectric (ME) com- posites was studied in situ in this paper. Multiple resonant peaks appear between 1 and 300 kHz frequency for cyl- inders of different heights. The first resonance frequency does not change with the cylinder height decreasing, but the second and the third resonant frequencies increase. The first three resonant modes radial, first-order height are attributed to the cylinder resonance, and second-order height resonance, respectively. The appropriate size and resonance frequency were chosen to obtain the highest ME voltage coefficient when designing cylindrical bilayered magnetoelectric devices. This article provides reference to design cylindrical magnetoelectric devices.
基金financially supported by the Beijing Nova Program (No.Z141103001814006)the National Key Technology R&D Program (Nos. 2012BAC12B05 and 2012BAC02B01)+1 种基金the National Natural Science Foundation of China (Nos. 51174247 and U1360202)the National High-Tech Research and the Development Program of China (No. 2012AA063202)
文摘In this study, Pb was separated and used to prepare BaPbO3 conductive ceramics from leaded waste.The experimental results show that BaPbO3 powder synthesized at 700 °C has particle size of 2–5 lm. The powders were densified by sintering at 1,000 °C for 2 h in the air.Synthesized BaPbO3 ceramics have high Curie temperature and high-temperature positive temperature coefficient(PTC) resistivity characteristics. Electrical resistivity of BaPbO3 compact increases from 5 × 10^-6Ω·m at room temperature to 4 × 10^-4Ω·m at 750 °C. Compared with the one prepared by pure chemical reagents, the BaPbO3 prepared from leaded waste has the similar characteristics of high Curie temperature and PTC resistivity.