Iron-rich electrolytic manganese residue(IREMR)is an industrial waste produced during the processing of electrolytic metal manganese,and it contains certain amounts of Fe and Mn resources and other heavy metals.In thi...Iron-rich electrolytic manganese residue(IREMR)is an industrial waste produced during the processing of electrolytic metal manganese,and it contains certain amounts of Fe and Mn resources and other heavy metals.In this study,the slurry electrolysis technique was used to recover high-purity Fe powder from IREMR.The effects of IREMR and H2SO4 mass ratio,current density,reaction temper-ature,and electrolytic time on the leaching and current efficiencies of Fe were studied.According to the results,high-purity Fe powder can be recovered from the cathode plate,and the slurry electrolyte can be recycled.The leaching efficiency,current efficiency,and purity of Fe reached 92.58%,80.65%,and 98.72wt%,respectively,at a 1:2.5 mass ratio of H2SO4 and IREMR,reaction temperature of 60℃,electric current density of 30 mA/cm^(2),and reaction time of 8 h.In addition,vibrating sample magnetometer(VSM)analysis showed that the coercivity of electrolytic iron powder was 54.5 A/m,which reached the advanced magnetic grade of electrical pure-iron powder(DT4A coercivity standard).The slurry electrolytic method provides fundamental support for the industrial application of Fe resource recovery in IRMER.展开更多
In this study, a method for preparing pure manganese sulfate from low-grade ores with a granule mean size of 0.47 mm by direct acid leaching was developed. The effects of the types of leaching agents, sulfitric acid c...In this study, a method for preparing pure manganese sulfate from low-grade ores with a granule mean size of 0.47 mm by direct acid leaching was developed. The effects of the types of leaching agents, sulfitric acid concentration, reaction temperature, and agitation rate on the leaching efficiency of manganese were investigated. We observed that sulfuric acid used as a leaching agent provides a similar leach- ing efficiency of manganese and superior selectivity against calcium compared to hydrochloric acid. The optimal leaching conditions in sul- furic acid media were determined; under the optimal conditions, the leaching efficiencies of Mn and Ca were 92.42% and 9.61%, respec- tively. Moreover, the kinetics of manganese leaching indicated that the leaching follows the diffusion-controlled model with an apparent ac- tivation energy of 12.28 kJ·mol-l. The purification conditions of the leaching solution were also discussed. The results show that manganese dioxide is a suitable oxidant of ferrous ions and sodium dimethyldithiocarbamate is an effective precipitant of heavy metals. Finally, through chemical analysis and X-ray diffraction analysis, the obtained product was determined to contain 98% of MnSOa4·H20.展开更多
The effect of sulfate on Fischer-Tropsch synthesis performance was investigated in a slurryphase continuously stirred tank reactor (CSTR) over a Fe-Mn catalyst. The physiochemical properties of the catalyst impregna...The effect of sulfate on Fischer-Tropsch synthesis performance was investigated in a slurryphase continuously stirred tank reactor (CSTR) over a Fe-Mn catalyst. The physiochemical properties of the catalyst impregnated with different levels of sulfate were characterized by N2 physisorption, X-ray photoelectron spectroscopy (XPS), H2 (or CO) temperature-programmed reduction (TPR), Mossbauer spectroscopy, and CO2 temperature-programmed desorption (TPD). The characterization results indicated that the impregnated sulfate slightly decreased the BET surface area and pore volume of the catalyst, suppressed the catalyst reduction and carburization in CO and syngas, and decreased the catalyst surface basicity. At the same time, the addition of small amounts of sulfate improved the activities of FischerTropsch synthesis (FTS) and water gas shift (WGS), shifted the product to light hydrocarbons (C1-C11) and suppressed the formation of heavy products (C12+). Addition of SO4^2- to the catalyst improved the FTS activity at a sulfur loading of 0.05-0.80 g per 100 g Fe, and S-05 catalyst gave the highest CO conversion (62.3%), and beyond this sulfur level the activity of the catalyst decreased.展开更多
Refractory antibiotics in domestic wastewater are hard to be completely eliminated by conventional methods,and then lead to severe environmental contamination and adverse effects on public health.In present work,advan...Refractory antibiotics in domestic wastewater are hard to be completely eliminated by conventional methods,and then lead to severe environmental contamination and adverse effects on public health.In present work,advanced oxidation processes(AOPs)are adopted to remove the antibiotic of sul-fachloropyridazine(SCP).Nanosized Mn_(2)O_(3) was fabricated on the SBA-15 material to catalytically acti-vate potassium peroxydisulfate(PDS)to generate reactive oxygen radicals of.OH and SO_(4).for SCP degradation.The effects of location and size of Mn_(2)O_(3) were explored through choosing either the as-made or template free SBA-15 as the precursor of substrate.Great influences from the site and size of Mn_(2)O_(3) on the oxidation activity were discovered.It was found that Mn_(2)O_(3) with a large size at the exterior of SBA-15(Mn-tfSBA)was slightly easier to degrade SCP at a low manganese loading of 1.0-2.0 mmol.g;however,complete SCP removal could only be achieved on the catalyst of Mn_(2)O_(3) with a refined size at the interior of SBA-15(Mn-asSBA).Moreover,the SO_(4).species were revealed to be the decisive radicals in the SCP degradation processes.Exploring the as-made mesoporous silica as a support provides a new idea for the further development of environmentally friendly catalysts.展开更多
基金supported by the Key Research and Development Program of Guangxi Province,China (No.AB23075174)the National Natural Science Foundation of China (No.52174386)the Science and Technology Plan Project of Sichuan Province,China (No.2022YFS0459).
文摘Iron-rich electrolytic manganese residue(IREMR)is an industrial waste produced during the processing of electrolytic metal manganese,and it contains certain amounts of Fe and Mn resources and other heavy metals.In this study,the slurry electrolysis technique was used to recover high-purity Fe powder from IREMR.The effects of IREMR and H2SO4 mass ratio,current density,reaction temper-ature,and electrolytic time on the leaching and current efficiencies of Fe were studied.According to the results,high-purity Fe powder can be recovered from the cathode plate,and the slurry electrolyte can be recycled.The leaching efficiency,current efficiency,and purity of Fe reached 92.58%,80.65%,and 98.72wt%,respectively,at a 1:2.5 mass ratio of H2SO4 and IREMR,reaction temperature of 60℃,electric current density of 30 mA/cm^(2),and reaction time of 8 h.In addition,vibrating sample magnetometer(VSM)analysis showed that the coercivity of electrolytic iron powder was 54.5 A/m,which reached the advanced magnetic grade of electrical pure-iron powder(DT4A coercivity standard).The slurry electrolytic method provides fundamental support for the industrial application of Fe resource recovery in IRMER.
基金supported by the National Natural Science Foundation of China (51374249)
文摘In this study, a method for preparing pure manganese sulfate from low-grade ores with a granule mean size of 0.47 mm by direct acid leaching was developed. The effects of the types of leaching agents, sulfitric acid concentration, reaction temperature, and agitation rate on the leaching efficiency of manganese were investigated. We observed that sulfuric acid used as a leaching agent provides a similar leach- ing efficiency of manganese and superior selectivity against calcium compared to hydrochloric acid. The optimal leaching conditions in sul- furic acid media were determined; under the optimal conditions, the leaching efficiencies of Mn and Ca were 92.42% and 9.61%, respec- tively. Moreover, the kinetics of manganese leaching indicated that the leaching follows the diffusion-controlled model with an apparent ac- tivation energy of 12.28 kJ·mol-l. The purification conditions of the leaching solution were also discussed. The results show that manganese dioxide is a suitable oxidant of ferrous ions and sodium dimethyldithiocarbamate is an effective precipitant of heavy metals. Finally, through chemical analysis and X-ray diffraction analysis, the obtained product was determined to contain 98% of MnSOa4·H20.
基金the National Natural Science Foundation of China(20590360)and the Natural Science Foundation of Shanxi Province(2006021014).
文摘The effect of sulfate on Fischer-Tropsch synthesis performance was investigated in a slurryphase continuously stirred tank reactor (CSTR) over a Fe-Mn catalyst. The physiochemical properties of the catalyst impregnated with different levels of sulfate were characterized by N2 physisorption, X-ray photoelectron spectroscopy (XPS), H2 (or CO) temperature-programmed reduction (TPR), Mossbauer spectroscopy, and CO2 temperature-programmed desorption (TPD). The characterization results indicated that the impregnated sulfate slightly decreased the BET surface area and pore volume of the catalyst, suppressed the catalyst reduction and carburization in CO and syngas, and decreased the catalyst surface basicity. At the same time, the addition of small amounts of sulfate improved the activities of FischerTropsch synthesis (FTS) and water gas shift (WGS), shifted the product to light hydrocarbons (C1-C11) and suppressed the formation of heavy products (C12+). Addition of SO4^2- to the catalyst improved the FTS activity at a sulfur loading of 0.05-0.80 g per 100 g Fe, and S-05 catalyst gave the highest CO conversion (62.3%), and beyond this sulfur level the activity of the catalyst decreased.
基金funding support from National Natural Science Foundation of China (51602133)State Key Laboratory of Materials-Oriented Chemical Engineering (KL19-05)
文摘Refractory antibiotics in domestic wastewater are hard to be completely eliminated by conventional methods,and then lead to severe environmental contamination and adverse effects on public health.In present work,advanced oxidation processes(AOPs)are adopted to remove the antibiotic of sul-fachloropyridazine(SCP).Nanosized Mn_(2)O_(3) was fabricated on the SBA-15 material to catalytically acti-vate potassium peroxydisulfate(PDS)to generate reactive oxygen radicals of.OH and SO_(4).for SCP degradation.The effects of location and size of Mn_(2)O_(3) were explored through choosing either the as-made or template free SBA-15 as the precursor of substrate.Great influences from the site and size of Mn_(2)O_(3) on the oxidation activity were discovered.It was found that Mn_(2)O_(3) with a large size at the exterior of SBA-15(Mn-tfSBA)was slightly easier to degrade SCP at a low manganese loading of 1.0-2.0 mmol.g;however,complete SCP removal could only be achieved on the catalyst of Mn_(2)O_(3) with a refined size at the interior of SBA-15(Mn-asSBA).Moreover,the SO_(4).species were revealed to be the decisive radicals in the SCP degradation processes.Exploring the as-made mesoporous silica as a support provides a new idea for the further development of environmentally friendly catalysts.