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
Electrolytic manganese residue(EMR)can cause serious environmental and biological hazards.In order to solve the problem,zeolite A(EMRZA)and zeolite X(EMRZX)were synthesized by EMR.The pure phase zeolites were synthesi...Electrolytic manganese residue(EMR)can cause serious environmental and biological hazards.In order to solve the problem,zeolite A(EMRZA)and zeolite X(EMRZX)were synthesized by EMR.The pure phase zeolites were synthesized by alkaline melting and hydrothermal two-step process,which had high crystallinity and excellent crystal control.And the optimum conditions for synthesis of zeolite were investigated:NaOH-EMR mass ratio=1.2,L/S=10,hydrothermal temperature=90℃,and hydrothermal time=6 h.Then,EMRZA and EMRZX showed excellent adsorption of Cd^(2+).When T=25℃,time=120min,pH=6,C0=518 mg·L^(-1),and quantity of absorbent=1.5 g·L^(-1),the adsorption capacities of EMRZA and EMRZX reached 314.2 and 289,5 mg·g^(-1),respectively,In addition,after three repeated adsorption-desorption cycles,EMRZA and EMRZX retained 80%and 74%of the initial zeolites removal rates,respectively.Moreover,adsorption results followed quasi-second-order kinetics and monolayer adsorption,which was regulated by a combination of chemisorption and intra-particle diffusion mechanisms.The adsorption mechanism was ions exchange between Cd^(2+)and Na+.In summary,it has been confirmed that EMRZA and EMRZX can be reused as highly efficient adsorbents to treat Cd^(2+)-contaminated wastewater.展开更多
An environmentally friendly and resource-conserving route to the clean production of electrolytic manganese was developed,in which the electrolytic manganese residue(EMR)was initially calcined for cement buffering;the...An environmentally friendly and resource-conserving route to the clean production of electrolytic manganese was developed,in which the electrolytic manganese residue(EMR)was initially calcined for cement buffering;then the generated SO2-containing flue gas was managed using manganese oxide ore and anolyte(MOOA)desulfurization;at last,the desulfurized slurry was introduced to the electrolytic manganese production(EMP).Results showed that 4.0 wt%coke addition reduced the sulfur of calcined EMR to 0.9%,thereby satisfying the cement-buffer requirement.Pilot-scale desulfurization showed that about 7.5 vol%of high SO2 containing flue gas can be cleaned to less than 0.1 vol%through a five-stage countercurrent MOOA desulfurization.The desulfurized slurry had 42.44 g·L-Mn2+and 1.92 g·L-1 S2 O62-,which was suitable for electrowinning after purification,and the purity of manganese product was 99.93%,satisfy the National Standard of China YB/T051-2015.This new integrated technology fulfilled 99.7%of sulfur reutilization from the EMR and 94.1%was effectively used to the EMP.The MOOA desulfurization linked the EMP a closed cycle without any pollutant discharge,which promoted the cleaner production of EMP industry.展开更多
Electrolytic manganese metal residue(EMMR)harmless treatment has always lacked a low-cost and quick processing technology.In this study,surfactants,namely tetradecyl trimethylammonium chloride(TTC),sodium dodecyl benz...Electrolytic manganese metal residue(EMMR)harmless treatment has always lacked a low-cost and quick processing technology.In this study,surfactants,namely tetradecyl trimethylammonium chloride(TTC),sodium dodecyl benzene sulfonate(SDBS),sodium lignin sulfonate(SLS),and octadecyl trimethylammonium chloride(OTC),were used in the solidification of Mn^(2+)and removal of NH_(4)^(+)-N from EMMR.The Mn^(2+)and NH_(4)^(+)-N concentrations under different reaction conditions,Mn^(2+)solidification and NH_(4)^(+)-N removal mechanisms,and leaching behavior were studied.The results revealed that the surfactants could enhance the Mn^(2+)solidification and NH_(4)^(+)-N removal from EMMR,and the order of enhancement was as follows:TTC>SDBS>OTC>SLS.The NH_(4)^(+)-N and Mn^(2+)concentrations were 12.3 and 0.05 mg·L^(-1)with the use of 60.0 mg·kg^(-1)TTC under optimum conditions(solid–liquid ratio of 1.5:1,EMMR to BRM mass ratio of 100:8,temperature of 20℃,and reaction duration of 12 h),which met the integrated wastewater discharge standard(GB8978-1996).Mn^(2+)was mainly solidified as Mn(OH)_(2),MnOOH and MnSiO_(3),and NH_(4)^(+)-N in EMMR was mostly removed in the form of ammonia.The results of this study could provide a new idea for cost-effective EMMR harmless treatment.展开更多
According to the statistic analysis,the reserve of manganese in electrolytic manganese residue deposit is over 780 kt. The average contents of available manganese and ammonium reach 3.90% and 1.68% (mass fraction),res...According to the statistic analysis,the reserve of manganese in electrolytic manganese residue deposit is over 780 kt. The average contents of available manganese and ammonium reach 3.90% and 1.68% (mass fraction),respectively. Large amount of manganese compounds and ammonium sulfate are detruded without any treatment or recovery. The compositions of the main elements in electrolytic manganese residue were analyzed comprehensively based on the extensive research data. According to the new development of electrolytic manganese residue comprehensively used in recent years,a water washing residue-twice precipitation process was also proposed. The experimental results indicate that manganese dioxide silicon dioxide and calcium sulfate are presented as amorphous state in the manganese residues. The recovery rates of manganese and nitrogen reach up to 99.5% and 94.5 %,respectively. The recovery process can be easily implemented,environment-friendly and fitting for industrial production.展开更多
Electrolytic manganese residue(EMR), a high volume byproduct resulting from the electrolytic manganese industry, was used as a cheap and abundant chemical source for preparing MnO2 and EMR-made calcium silicate hydrat...Electrolytic manganese residue(EMR), a high volume byproduct resulting from the electrolytic manganese industry, was used as a cheap and abundant chemical source for preparing MnO2 and EMR-made calcium silicate hydrate(EMR-CSH). The MnO2 is successfully synthesized from the metal cations extracted from EMR, which can effectively recycle the manganese in the EMR. By the combination of XRD, SEM and EDX analysis, the as-prepared MnO2 is found to exhibit a single-phase with the purity of 90.3%. Furthermore, EMR-CSH is synthesized from EMR via hydrothermal method. Based on the detailed analyses using XRD, FT-IR, FE-SEM, EDX and BET surface area measurement, the product synthesized under the optimum conditions(p H 12.0 and 100 °C) is identified to be a calcium silicate hydrate with a specific surface area of 205 m2/g incorporating the slag-derived metals(Al and Mg) in its structure. The as-synthesized material shows good adsorption properties for removal of Mn2+ and phosphate ions diluted in water, making it a promising candidate for efficient bulk wastewater treatment. This conversion process, which enables us to fabricate two different kinds of valuable materials from EMR at low cost and through convenient preparation steps, is surely beneficial from the viewpoint of the chemical and economical use of EMR.展开更多
Electrolytic manganese residue (EMR) is a waste from electrolytic manganese industry that contains high concentration of toxic substances. Since the EMR disposal in landfill sites has a serious environmental impact, n...Electrolytic manganese residue (EMR) is a waste from electrolytic manganese industry that contains high concentration of toxic substances. Since the EMR disposal in landfill sites has a serious environmental impact, new ways of EMR utilization are being sought. Considering the melting of EMR to a glass at high temperature was a relatively less energy-intensive process, EMR was first made into a base glass and then the ground base glass was heat-treated in a certain procedure to make a glass-ceramic and the crystallization process was studied. It was determined by X-ray diffraction (XRD) that the primary crystalline phases of the EMR glass-ceramic were diopside and anorthite, which formed the surface crystallization mechanism with a crystallization activation energy of 429 kJ/mol. Scanning electron microscopy (SEM) observation showed that a layer of small spherical particles with an average size of about 0.5 μm were covered on the glass matrix surface, and among them there were some big particles. The low melting temperature and crystallization activation energy make it promising to reuse EMR for glass-ceramic production.展开更多
The online flow injection preconcentration and electrothermal atomic absorption spectrometry method were used for the determination of trace nickel in electrolytic manganese samples by sorption on a conical minicolumn...The online flow injection preconcentration and electrothermal atomic absorption spectrometry method were used for the determination of trace nickel in electrolytic manganese samples by sorption on a conical minicolumn packed with activated carbon at pH 9.0. The nickel was eluted from the minicolumn with 10%(v/v) nitric acid. An enrichment factor of 190-fold for a sample volume of 10mL was obtained. The detection limit (DL) of nickel with the use of the preconcentration method was 13ng·g -1in the original solid sample. The precision for 10 replicate determinations at 150ng·g -1 nickel concentration was 5.2% relative standard deviation (RSD). The calibration graph was linear with a correlation coefficient of r=0.9996 up to concentration of 660ng·g -1 nickel.展开更多
An analytical method, using sector field inductively coupled plasma mass spectrometry(SF-ICP-MS) for rapid simultaneous determination of Be, Na, Mg, Si, Ca, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, As, Sn, Sb, Pb and Bi in elec...An analytical method, using sector field inductively coupled plasma mass spectrometry(SF-ICP-MS) for rapid simultaneous determination of Be, Na, Mg, Si, Ca, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, As, Sn, Sb, Pb and Bi in electrolytic manganese metal, was described. At the beginning, the samples were decomposed by HNO3 and H2 SO4, and then analyzed by SF-ICP-MS. Most of the spectral interferences could be avoided by measuring in different mass resolution modes. The matrix effects due to the excess of sulfuric acid and Mn were evaluated. Correction of matrix effects was conducted by using the internal standard elements. The optimum condition for the determination was investigated and discussed. The detection limit is in the range of 0.001 0.169 μg/L. The current method is applied to the determination of trace impurities in electrolytic manganese metal. And experiments show that good results can be obtained much faster, more accurately and conveniently by current method.展开更多
The effects of four types of graphite tube and five matrix modifiers on the determination of selenium by graphite furnace atomic absorption spectrometry were compared.The results show that platform thermolysis coat gr...The effects of four types of graphite tube and five matrix modifiers on the determination of selenium by graphite furnace atomic absorption spectrometry were compared.The results show that platform thermolysis coat graphite tube and magnesium nitrate and cobaltco as matrix modifer can get a high sensitivity and a good recovery.The optimized working conditions and interference in the determination were invesigated.This result is consistent with that of XRF.The recovery is from 100.8 % to102.2 %,the relative standard deviation is from 3.47% to 5.56 % (n=9),and the detection limit of selenium is 378 pg (C=44.5μg/g to 97.3μg/g.).The proposed method can be applied to the rapid determination of selenium in electrolytic manganese.展开更多
Grainy electrolytic manganese dioxide was prepared by electrodeposition in a 0.9 mol/L MnSO4 and 2.5 mol/LH2SO4 solution. The structure, particle size and appearance of the grainy electrolytic manganese dioxide were d...Grainy electrolytic manganese dioxide was prepared by electrodeposition in a 0.9 mol/L MnSO4 and 2.5 mol/LH2SO4 solution. The structure, particle size and appearance of the grainy electrolytic manganese dioxide were determined by powder X-ray diffraction, laser particle size analysis and scanning electron micrographs measurements. Current density has important effects on cell voltage, anodic current efficiency and particle size of the grainy electrolytic manganese dioxide, and the optimum current density is 30 A/dm2. The grainy electrolytic manganese dioxide electrodeposited under the optimum conditions consists of γ-MnO2 with an orthorhombic lattice structure; the grainy electrolytic manganese dioxide has a spherical or sphere-like appearance and a narrow particle size distribution with an average particle diameter of 7.237 μm.展开更多
The effects of temperature and the concentration of sulfuric acid on the cell voltage, the anode current efficiency of elec- trodeposition and the particle size of grainy electrolytic manganese dioxide (EMD) were inve...The effects of temperature and the concentration of sulfuric acid on the cell voltage, the anode current efficiency of elec- trodeposition and the particle size of grainy electrolytic manganese dioxide (EMD) were investigated. The structure, particle size and appearance of grainy EMD were determined by powder X-ray diffraction, laser particle size analysis and scanning electron mi- crograph measurements. As the concentration of sulfuric acid increases, both the cell voltage and the average anode current efficien- cy decrease. With the increase of electrolysis temperature in the range of 30-60°C, the cell voltage, average anode current efficiency and particle size decrease. The optimum temperature of 30°C and concentration of sulfuric acid of 2.5 mol/L for electrodeposition of the grainy EMD were obtained. XRD patterns show that the grainy EMD electrodeposited under the optimum conditions consists of γ-MnO2 and has an orthorhombic lattice structure. According to the results of SEM, the grainy EMD has a spherical or sphere-like appearance and a narrow particle size distribution with an average size of about 7 μm. The grainy EMD is a promising cathode of rechargeable alkaline batteries for high energy density and a prospective precursor for production of the LiMn2O4 cathode of lithium ion batteries.展开更多
Remelting rejected electrolytic manganese metal (EMM) scrap was investigated by electroslag remelting (ESR) process through industrial experiment. The results indicated that the ANF-6 slag (70 wt.% CaF_(2) + 30 wt.% A...Remelting rejected electrolytic manganese metal (EMM) scrap was investigated by electroslag remelting (ESR) process through industrial experiment. The results indicated that the ANF-6 slag (70 wt.% CaF_(2) + 30 wt.% Al_(2)O_(3)) and deoxidizer could promote the desulfurization of ESR manganese in an air atmosphere. Under an air atmosphere, the sulfur in the ingot decreased to 0.0534 wt.% with a desulfurization ratio of ESR manganese of 53.2% by using ANF-6 slag and water-cooled copper electrode electroslag remelting rejected EMM scrap, suggesting its efficient removal. The electroslag ingots exhibited uneven chemical composition in an air atmosphere and cooling condition of the ESR process. The metal manganese could be oxidized by electroslag remelting of rejected EMM scrap in an air atmosphere with MnO content in the final slag of 21.9 wt.%. Besides, the activity of MnO in slag increased with increasing remelting temperature, resulting in a reduction in the slag–manganese sulfur partition ratio and desulfurization ratio. Moreover, with the accumulation of sulfur in slag and the oxidation of metallic manganese liquid, the slag showed a lower cleanliness and more oxidation, leading to an increase in sulfur and oxygen content in the electroslag ingot with the increase in ingot height.展开更多
Electrolytic aqueous zinc-manganese(Zn–Mn) batteries have the advantage of high discharge voltage and high capacity due to two-electron reactions. However, the pitfall of electrolytic Zn–Mn batteries is the sluggish...Electrolytic aqueous zinc-manganese(Zn–Mn) batteries have the advantage of high discharge voltage and high capacity due to two-electron reactions. However, the pitfall of electrolytic Zn–Mn batteries is the sluggish deposition reaction kinetics of manganese oxide during the charge process and short cycle life. We show that, incorporating ZnO electrolyte additive can form a neutral and highly viscous gel-like electrolyte and render a new form of electrolytic Zn–Mn batteries with significantly improved charging capabilities. Specifically, the ZnO gel-like electrolyte activates the zinc sulfate hydroxide hydrate assisted Mn^(2+) deposition reaction and induces phase and structure change of the deposited manganese oxide(Zn_(2)Mn_(3)O_8·H_(2)O nanorods array), resulting in a significant enhancement of the charge capability and discharge efficiency. The charge capacity increases to 2.5 mAh cm^(-2) after 1 h constant-voltage charging at 2.0 V vs. Zn/Zn^(2+), and the capacity can retain for up to 2000 cycles with negligible attenuation. This research lays the foundation for the advancement of electrolytic Zn–Mn batteries with enhanced charging capability.展开更多
The anti-freezing strategy of hydrogels and their self-healing structure are often contradictory,it is vital to break through the molecular structure to design and construct hydrogels with intrinsic anti-freezing/self...The anti-freezing strategy of hydrogels and their self-healing structure are often contradictory,it is vital to break through the molecular structure to design and construct hydrogels with intrinsic anti-freezing/self-healing for meeting the rapid development of flexible and wearable devices in diverse service conditions.Herein,we design a new hydrogel electrolyte(AF/SH-Hydrogel)with intrinsic anti-freezing/self-healing capabilities by introducing ethylene glycol molecules,dynamic chemical bonding(disulfide bond),and supramolecular interaction(multi-hydrogen bond)into the polyacrylamide molecular chain.Thanks to the exceptional freeze resistance(84%capacity retention at-20℃)and intrinsic self-healing capabilities(95%capacity retention after 5 cutting/self-healing cycles),the obtained AF/SH-Hydrogel makes the zinc||manganese dioxide cell an economically feasible battery for the state-of-the-art applications.The Zn||AF/SH-Hydrogel||MnO_(2)device offers a near-theoretical specific capacity of 285 m A h g^(-1)at 0.1 A g^(-1)(Coulombic efficiency≈100%),as well as good self-healing capability and mechanical flexibility in an ice bath.This work provides insight that can be utilized to develop multifunctional hydrogel electrolytes for application in next generation of self-healable and freeze-resistance smart aqueous energy storage devices.展开更多
The recycling rate of rejected electrolytic manganese metal(EMM)scrap can be increased by inhibiting the manganese metal(MM)vaporization during the remelting process with electroslag.However,if the latter is achieved ...The recycling rate of rejected electrolytic manganese metal(EMM)scrap can be increased by inhibiting the manganese metal(MM)vaporization during the remelting process with electroslag.However,if the latter is achieved by reducing the remelting temperature,the desulfurization behavior will deteriorate.Therefore,Na_(2)O-containing electroslag and metallic additive were used to increase the rejected EMM scrap recovery ratio.The respective high-temperature experiment was conducted in a MoSi_(2) electrical resistance furnace filled with fluid argon at 1673 K using five different types of electroslag with the Na_(2)O content ranging from 5.81%to 15.71%.High-purity metallic magnesium and magnesium calcium alloy additives were used as deoxidizers.The addition of Na_(2)O and metallic additives effectively promoted the desulfurization and deoxidization of MM.The removal of sulfur and oxygen by the interaction between Na_(2)O-containing electroslag melt and molten MM with metallic additive was analyzed from the thermodynamic and kinetic standpoints.The effect of Na_(2)O-containing electroslag volatilization on desulfurization and deoxidization was considered.With an increase in Na_(2)O content in the slag,the mass loss rates of Na_(2)O and electroslag rose,as well as the final sulfur partition ratio.If the Na_(2)O content volatilized in the slag melt did not exceed 10.44%,the sulfur removal ratio was increased by high sulfide capacity and CaO activity in all slags due to the addition of Na_(2)O.The rejected EMM scrap deoxidization ratio grew with the increased activity of CaO and reduced activity of Al_(2)O_(3) in the molten slag,caused by the increased Na_(2)O content in the molten slag.The addition of metallic Mg and Mg-Ca alloy indirectly promoted desulfurization and deoxidization by reducing the MnO content in the rejected EMM scrap and growing slag oxidability.The Mg-Ca alloy could also react with dissolved sulfur and oxygen,directly promoting desulfurization and deoxidization processes.The Na_(2)O content in slag should not exceed 10.44%to ensure the high desulfurization and deoxidization abilities,fluidity and low volatilization of slag.展开更多
Electrolytic manganese residue（EMR） is generated from electrolytic manganese metal（EMM） industry, and its disposal is currently a serious problem in China.The EMR were calcined in the interval 100—900℃to enhance...Electrolytic manganese residue（EMR） is generated from electrolytic manganese metal（EMM） industry, and its disposal is currently a serious problem in China.The EMR were calcined in the interval 100—900℃to enhance their pozzolanic activity and characterized by the differential thermal analysis-thermogravimetry（TGDTA）, X-ray diffraction（XRD）,infra-red（IR） and chemical analysis techniques with the aim to correlate phase transitions and structural features with the pozzolanic activity of calcined EMR.Prom the phase analysis and compressive strength results,it is found that the EMR calcined within 700—800℃had the best pozzolanic activity due to the decomposition of poorly-crystallized CaSO4 under the reducing ambient created by the decomposition of（NH4）2SO4.The appearance of reactive CaO mainly contributes to the good pozzolanic activity of EMR calcined within 700—800℃.The crystallinity of Mn3CO4 increases leading an unfavourable effect on the pozzolanic behaviour of EMR calcined at 900℃.The developed pozzolanic material containing 30%（mass fraction） EMR possesses compressive strength properties at a level similar to 42.5# normal Portland cement,in the range of 41.5—50.5 MPa.Besides,leaching results show that EMR blend cement pastes have excellent effect on the solidification of heavy metals.展开更多
CO_(2) electrolysis with solid oxide electrolytic cells(SOECs)using intermittently available renewable energy has potential applications for carbon neutrality and energy storage.In this study,a pulsed current strategy...CO_(2) electrolysis with solid oxide electrolytic cells(SOECs)using intermittently available renewable energy has potential applications for carbon neutrality and energy storage.In this study,a pulsed current strategy is used to replicate intermittent energy availability,and the stability and conversion rate of the cyclic operation by a large-scale flat-tube SOEC are studied.One hundred cycles under pulsed current ranging from -100 to -300 mA/cm^(2) with a total operating time of about 800 h were carried out.The results show that after 100 cycles,the cell voltage attenuates by 0.041%/cycle in the high current stage of−300 mA/cm^(2),indicating that the lifetime of the cell can reach up to about 500 cycles.The total CO_(2) conversion rate reached 52%,which is close to the theoretical value of 54.3% at -300 mA/cm^(2),and the calculated efficiency approached 98.2%,assuming heat recycling.This study illustrates the significant advantages of SOEC in efficient electrochemical energy conversion,carbon emission mitigation,and seasonal energy storage.展开更多
Here we prepared PEO coatings on Mg alloys in silicate-NaOH-phosphate electrolyte containing different concentrations of NaF addition.The detailed microstructural characterizations combining with potentiodynamic polar...Here we prepared PEO coatings on Mg alloys in silicate-NaOH-phosphate electrolyte containing different concentrations of NaF addition.The detailed microstructural characterizations combining with potentiodynamic polarization and electrochemical impedance spectra(EIS)were employed to investigate the roles of fluoride in the growth and corrosion properties of PEO coating on Mg.The result shows the introduction of NaF led to a fluoride-containing nanolayer(FNL)formed at the Mg/coating interface.The FNL consists of MgO nanoparticles and insoluble MgF_(2)nanoparticles(containing rutile phase and cubic phase).The increase in the NaF concentration of the electrolyte increases the thickness and the MgF_(2)content in the FNL.When anodized in the electrolyte containing 2 g/L NaF,the formed FNL has the highest thickness of 100-200 nm along with the highest value of x of∼0.6 in(MgO)_(1-x)(MgF_(2))x resulted in the highest corrosion performance of PEO coating.In addition,when anodized in the electrolyte containing a low NaF concentration(0.4-0.8 g/L),the formed FNL was thin and discontinuous,which would decrease the pore density and increase the coating's uniformness simultaneously.展开更多
A roaring price of nickel and a shortage of the raw material of electrolytic manganese have intensified the demand for electrolytic manganese in China. As an alternative to nickel, electrolytic manganese has been cons...A roaring price of nickel and a shortage of the raw material of electrolytic manganese have intensified the demand for electrolytic manganese in China. As an alternative to nickel, electrolytic manganese has been consumed at a quickened speed, which boosts the continuous increase in export quotation. On the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(52164036,U1960201,51764007)the Guizhou Province Graduate Research Fund(YJSKYJJ(2021)003).
文摘Electrolytic manganese residue(EMR)can cause serious environmental and biological hazards.In order to solve the problem,zeolite A(EMRZA)and zeolite X(EMRZX)were synthesized by EMR.The pure phase zeolites were synthesized by alkaline melting and hydrothermal two-step process,which had high crystallinity and excellent crystal control.And the optimum conditions for synthesis of zeolite were investigated:NaOH-EMR mass ratio=1.2,L/S=10,hydrothermal temperature=90℃,and hydrothermal time=6 h.Then,EMRZA and EMRZX showed excellent adsorption of Cd^(2+).When T=25℃,time=120min,pH=6,C0=518 mg·L^(-1),and quantity of absorbent=1.5 g·L^(-1),the adsorption capacities of EMRZA and EMRZX reached 314.2 and 289,5 mg·g^(-1),respectively,In addition,after three repeated adsorption-desorption cycles,EMRZA and EMRZX retained 80%and 74%of the initial zeolites removal rates,respectively.Moreover,adsorption results followed quasi-second-order kinetics and monolayer adsorption,which was regulated by a combination of chemisorption and intra-particle diffusion mechanisms.The adsorption mechanism was ions exchange between Cd^(2+)and Na+.In summary,it has been confirmed that EMRZA and EMRZX can be reused as highly efficient adsorbents to treat Cd^(2+)-contaminated wastewater.
基金supported by the National Key R&D Program of China(No.2018YFC0213405)。
文摘An environmentally friendly and resource-conserving route to the clean production of electrolytic manganese was developed,in which the electrolytic manganese residue(EMR)was initially calcined for cement buffering;then the generated SO2-containing flue gas was managed using manganese oxide ore and anolyte(MOOA)desulfurization;at last,the desulfurized slurry was introduced to the electrolytic manganese production(EMP).Results showed that 4.0 wt%coke addition reduced the sulfur of calcined EMR to 0.9%,thereby satisfying the cement-buffer requirement.Pilot-scale desulfurization showed that about 7.5 vol%of high SO2 containing flue gas can be cleaned to less than 0.1 vol%through a five-stage countercurrent MOOA desulfurization.The desulfurized slurry had 42.44 g·L-Mn2+and 1.92 g·L-1 S2 O62-,which was suitable for electrowinning after purification,and the purity of manganese product was 99.93%,satisfy the National Standard of China YB/T051-2015.This new integrated technology fulfilled 99.7%of sulfur reutilization from the EMR and 94.1%was effectively used to the EMP.The MOOA desulfurization linked the EMP a closed cycle without any pollutant discharge,which promoted the cleaner production of EMP industry.
基金supported by National Natural Science Foundation of China(52174386,21806132)the National Key Research and Development Program of China(2018YFC1903500)+1 种基金the Science and Technology Plan Project of Sichuan Province(2021YFH0058)the Key Research and Development Program of Guangxi Province(AB18126088)。
文摘Electrolytic manganese metal residue(EMMR)harmless treatment has always lacked a low-cost and quick processing technology.In this study,surfactants,namely tetradecyl trimethylammonium chloride(TTC),sodium dodecyl benzene sulfonate(SDBS),sodium lignin sulfonate(SLS),and octadecyl trimethylammonium chloride(OTC),were used in the solidification of Mn^(2+)and removal of NH_(4)^(+)-N from EMMR.The Mn^(2+)and NH_(4)^(+)-N concentrations under different reaction conditions,Mn^(2+)solidification and NH_(4)^(+)-N removal mechanisms,and leaching behavior were studied.The results revealed that the surfactants could enhance the Mn^(2+)solidification and NH_(4)^(+)-N removal from EMMR,and the order of enhancement was as follows:TTC>SDBS>OTC>SLS.The NH_(4)^(+)-N and Mn^(2+)concentrations were 12.3 and 0.05 mg·L^(-1)with the use of 60.0 mg·kg^(-1)TTC under optimum conditions(solid–liquid ratio of 1.5:1,EMMR to BRM mass ratio of 100:8,temperature of 20℃,and reaction duration of 12 h),which met the integrated wastewater discharge standard(GB8978-1996).Mn^(2+)was mainly solidified as Mn(OH)_(2),MnOOH and MnSiO_(3),and NH_(4)^(+)-N in EMMR was mostly removed in the form of ammonia.The results of this study could provide a new idea for cost-effective EMMR harmless treatment.
基金Project(2008AA031202) supported by the National High Technology Research and Development Program of ChinaProject(0992007-6) supported by Major Science & Technology of Guangxi ProvinceProject(CSTC2008AB7127) supported by Major Science & Technology of Chongqing
文摘According to the statistic analysis,the reserve of manganese in electrolytic manganese residue deposit is over 780 kt. The average contents of available manganese and ammonium reach 3.90% and 1.68% (mass fraction),respectively. Large amount of manganese compounds and ammonium sulfate are detruded without any treatment or recovery. The compositions of the main elements in electrolytic manganese residue were analyzed comprehensively based on the extensive research data. According to the new development of electrolytic manganese residue comprehensively used in recent years,a water washing residue-twice precipitation process was also proposed. The experimental results indicate that manganese dioxide silicon dioxide and calcium sulfate are presented as amorphous state in the manganese residues. The recovery rates of manganese and nitrogen reach up to 99.5% and 94.5 %,respectively. The recovery process can be easily implemented,environment-friendly and fitting for industrial production.
基金Project(21376273)supported by the National Natural Science Foundation of ChinaProject(2010FJ1011)supported by the Research Fund of Science and Technology of Hunan Province,China
文摘Electrolytic manganese residue(EMR), a high volume byproduct resulting from the electrolytic manganese industry, was used as a cheap and abundant chemical source for preparing MnO2 and EMR-made calcium silicate hydrate(EMR-CSH). The MnO2 is successfully synthesized from the metal cations extracted from EMR, which can effectively recycle the manganese in the EMR. By the combination of XRD, SEM and EDX analysis, the as-prepared MnO2 is found to exhibit a single-phase with the purity of 90.3%. Furthermore, EMR-CSH is synthesized from EMR via hydrothermal method. Based on the detailed analyses using XRD, FT-IR, FE-SEM, EDX and BET surface area measurement, the product synthesized under the optimum conditions(p H 12.0 and 100 °C) is identified to be a calcium silicate hydrate with a specific surface area of 205 m2/g incorporating the slag-derived metals(Al and Mg) in its structure. The as-synthesized material shows good adsorption properties for removal of Mn2+ and phosphate ions diluted in water, making it a promising candidate for efficient bulk wastewater treatment. This conversion process, which enables us to fabricate two different kinds of valuable materials from EMR at low cost and through convenient preparation steps, is surely beneficial from the viewpoint of the chemical and economical use of EMR.
基金the National High Technology Research and Development Program (‘863’ Program) of China (No. 2008AA031206)Key Scientific and Technological Projects of Chongqing (No. CSTC2007AB4019)
文摘Electrolytic manganese residue (EMR) is a waste from electrolytic manganese industry that contains high concentration of toxic substances. Since the EMR disposal in landfill sites has a serious environmental impact, new ways of EMR utilization are being sought. Considering the melting of EMR to a glass at high temperature was a relatively less energy-intensive process, EMR was first made into a base glass and then the ground base glass was heat-treated in a certain procedure to make a glass-ceramic and the crystallization process was studied. It was determined by X-ray diffraction (XRD) that the primary crystalline phases of the EMR glass-ceramic were diopside and anorthite, which formed the surface crystallization mechanism with a crystallization activation energy of 429 kJ/mol. Scanning electron microscopy (SEM) observation showed that a layer of small spherical particles with an average size of about 0.5 μm were covered on the glass matrix surface, and among them there were some big particles. The low melting temperature and crystallization activation energy make it promising to reuse EMR for glass-ceramic production.
文摘The online flow injection preconcentration and electrothermal atomic absorption spectrometry method were used for the determination of trace nickel in electrolytic manganese samples by sorption on a conical minicolumn packed with activated carbon at pH 9.0. The nickel was eluted from the minicolumn with 10%(v/v) nitric acid. An enrichment factor of 190-fold for a sample volume of 10mL was obtained. The detection limit (DL) of nickel with the use of the preconcentration method was 13ng·g -1in the original solid sample. The precision for 10 replicate determinations at 150ng·g -1 nickel concentration was 5.2% relative standard deviation (RSD). The calibration graph was linear with a correlation coefficient of r=0.9996 up to concentration of 660ng·g -1 nickel.
基金Project(21075138)supported by the National Natural Science Foundation of ChinaProject(cstc2013jcyjA10088)supported by Chongqing Natural Science Foundation,ChinaProject(KJ121311)supported by Scientific and Technological Research Program of Chongqing Municipal Education Commission,China
文摘An analytical method, using sector field inductively coupled plasma mass spectrometry(SF-ICP-MS) for rapid simultaneous determination of Be, Na, Mg, Si, Ca, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, As, Sn, Sb, Pb and Bi in electrolytic manganese metal, was described. At the beginning, the samples were decomposed by HNO3 and H2 SO4, and then analyzed by SF-ICP-MS. Most of the spectral interferences could be avoided by measuring in different mass resolution modes. The matrix effects due to the excess of sulfuric acid and Mn were evaluated. Correction of matrix effects was conducted by using the internal standard elements. The optimum condition for the determination was investigated and discussed. The detection limit is in the range of 0.001 0.169 μg/L. The current method is applied to the determination of trace impurities in electrolytic manganese metal. And experiments show that good results can be obtained much faster, more accurately and conveniently by current method.
文摘The effects of four types of graphite tube and five matrix modifiers on the determination of selenium by graphite furnace atomic absorption spectrometry were compared.The results show that platform thermolysis coat graphite tube and magnesium nitrate and cobaltco as matrix modifer can get a high sensitivity and a good recovery.The optimized working conditions and interference in the determination were invesigated.This result is consistent with that of XRF.The recovery is from 100.8 % to102.2 %,the relative standard deviation is from 3.47% to 5.56 % (n=9),and the detection limit of selenium is 378 pg (C=44.5μg/g to 97.3μg/g.).The proposed method can be applied to the rapid determination of selenium in electrolytic manganese.
文摘Grainy electrolytic manganese dioxide was prepared by electrodeposition in a 0.9 mol/L MnSO4 and 2.5 mol/LH2SO4 solution. The structure, particle size and appearance of the grainy electrolytic manganese dioxide were determined by powder X-ray diffraction, laser particle size analysis and scanning electron micrographs measurements. Current density has important effects on cell voltage, anodic current efficiency and particle size of the grainy electrolytic manganese dioxide, and the optimum current density is 30 A/dm2. The grainy electrolytic manganese dioxide electrodeposited under the optimum conditions consists of γ-MnO2 with an orthorhombic lattice structure; the grainy electrolytic manganese dioxide has a spherical or sphere-like appearance and a narrow particle size distribution with an average particle diameter of 7.237 μm.
基金This work was financially supported by the National Natural Science Foundation of China (No. 50302016) and the PostdoctoralScience Foundation of Central South University.
文摘The effects of temperature and the concentration of sulfuric acid on the cell voltage, the anode current efficiency of elec- trodeposition and the particle size of grainy electrolytic manganese dioxide (EMD) were investigated. The structure, particle size and appearance of grainy EMD were determined by powder X-ray diffraction, laser particle size analysis and scanning electron mi- crograph measurements. As the concentration of sulfuric acid increases, both the cell voltage and the average anode current efficien- cy decrease. With the increase of electrolysis temperature in the range of 30-60°C, the cell voltage, average anode current efficiency and particle size decrease. The optimum temperature of 30°C and concentration of sulfuric acid of 2.5 mol/L for electrodeposition of the grainy EMD were obtained. XRD patterns show that the grainy EMD electrodeposited under the optimum conditions consists of γ-MnO2 and has an orthorhombic lattice structure. According to the results of SEM, the grainy EMD has a spherical or sphere-like appearance and a narrow particle size distribution with an average size of about 7 μm. The grainy EMD is a promising cathode of rechargeable alkaline batteries for high energy density and a prospective precursor for production of the LiMn2O4 cathode of lithium ion batteries.
基金support from the National Natural Science Foundation of China(Grant No.51804227).
文摘Remelting rejected electrolytic manganese metal (EMM) scrap was investigated by electroslag remelting (ESR) process through industrial experiment. The results indicated that the ANF-6 slag (70 wt.% CaF_(2) + 30 wt.% Al_(2)O_(3)) and deoxidizer could promote the desulfurization of ESR manganese in an air atmosphere. Under an air atmosphere, the sulfur in the ingot decreased to 0.0534 wt.% with a desulfurization ratio of ESR manganese of 53.2% by using ANF-6 slag and water-cooled copper electrode electroslag remelting rejected EMM scrap, suggesting its efficient removal. The electroslag ingots exhibited uneven chemical composition in an air atmosphere and cooling condition of the ESR process. The metal manganese could be oxidized by electroslag remelting of rejected EMM scrap in an air atmosphere with MnO content in the final slag of 21.9 wt.%. Besides, the activity of MnO in slag increased with increasing remelting temperature, resulting in a reduction in the slag–manganese sulfur partition ratio and desulfurization ratio. Moreover, with the accumulation of sulfur in slag and the oxidation of metallic manganese liquid, the slag showed a lower cleanliness and more oxidation, leading to an increase in sulfur and oxygen content in the electroslag ingot with the increase in ingot height.
基金financially supported by National Natural Science Foundation of China (22209133, 22272131, 21972111, 22211540712)Natural Science Foundation of Chongqing (CSTB2022NSCQ-MSX1411)+1 种基金Chongqing Engineering Research Center for Micro-Nano Biomedical Materials and DevicesChongqing Key Laboratory for Advanced Materials and Technologies。
文摘Electrolytic aqueous zinc-manganese(Zn–Mn) batteries have the advantage of high discharge voltage and high capacity due to two-electron reactions. However, the pitfall of electrolytic Zn–Mn batteries is the sluggish deposition reaction kinetics of manganese oxide during the charge process and short cycle life. We show that, incorporating ZnO electrolyte additive can form a neutral and highly viscous gel-like electrolyte and render a new form of electrolytic Zn–Mn batteries with significantly improved charging capabilities. Specifically, the ZnO gel-like electrolyte activates the zinc sulfate hydroxide hydrate assisted Mn^(2+) deposition reaction and induces phase and structure change of the deposited manganese oxide(Zn_(2)Mn_(3)O_8·H_(2)O nanorods array), resulting in a significant enhancement of the charge capability and discharge efficiency. The charge capacity increases to 2.5 mAh cm^(-2) after 1 h constant-voltage charging at 2.0 V vs. Zn/Zn^(2+), and the capacity can retain for up to 2000 cycles with negligible attenuation. This research lays the foundation for the advancement of electrolytic Zn–Mn batteries with enhanced charging capability.
基金supported by the link project of the National Natural Science Foundation of China(52002052 and 22209020)the Key Research and Development Project of Science and Technology Department of Sichuan Province(2022YFSY0004)+2 种基金the Opening project of the State Key Laboratory of New Textile Materials and Advanced Processing Technology(FZ2021009)the Natural Science Foundation of Sichuan Province(2023NSFSC0995)the Natural Science Foundation of Hunan Province(2022JJ30227)。
文摘The anti-freezing strategy of hydrogels and their self-healing structure are often contradictory,it is vital to break through the molecular structure to design and construct hydrogels with intrinsic anti-freezing/self-healing for meeting the rapid development of flexible and wearable devices in diverse service conditions.Herein,we design a new hydrogel electrolyte(AF/SH-Hydrogel)with intrinsic anti-freezing/self-healing capabilities by introducing ethylene glycol molecules,dynamic chemical bonding(disulfide bond),and supramolecular interaction(multi-hydrogen bond)into the polyacrylamide molecular chain.Thanks to the exceptional freeze resistance(84%capacity retention at-20℃)and intrinsic self-healing capabilities(95%capacity retention after 5 cutting/self-healing cycles),the obtained AF/SH-Hydrogel makes the zinc||manganese dioxide cell an economically feasible battery for the state-of-the-art applications.The Zn||AF/SH-Hydrogel||MnO_(2)device offers a near-theoretical specific capacity of 285 m A h g^(-1)at 0.1 A g^(-1)(Coulombic efficiency≈100%),as well as good self-healing capability and mechanical flexibility in an ice bath.This work provides insight that can be utilized to develop multifunctional hydrogel electrolytes for application in next generation of self-healable and freeze-resistance smart aqueous energy storage devices.
基金The authors appreciate the financial support from the National Natural Science Foundation of China(Grant No.51804227).
文摘The recycling rate of rejected electrolytic manganese metal(EMM)scrap can be increased by inhibiting the manganese metal(MM)vaporization during the remelting process with electroslag.However,if the latter is achieved by reducing the remelting temperature,the desulfurization behavior will deteriorate.Therefore,Na_(2)O-containing electroslag and metallic additive were used to increase the rejected EMM scrap recovery ratio.The respective high-temperature experiment was conducted in a MoSi_(2) electrical resistance furnace filled with fluid argon at 1673 K using five different types of electroslag with the Na_(2)O content ranging from 5.81%to 15.71%.High-purity metallic magnesium and magnesium calcium alloy additives were used as deoxidizers.The addition of Na_(2)O and metallic additives effectively promoted the desulfurization and deoxidization of MM.The removal of sulfur and oxygen by the interaction between Na_(2)O-containing electroslag melt and molten MM with metallic additive was analyzed from the thermodynamic and kinetic standpoints.The effect of Na_(2)O-containing electroslag volatilization on desulfurization and deoxidization was considered.With an increase in Na_(2)O content in the slag,the mass loss rates of Na_(2)O and electroslag rose,as well as the final sulfur partition ratio.If the Na_(2)O content volatilized in the slag melt did not exceed 10.44%,the sulfur removal ratio was increased by high sulfide capacity and CaO activity in all slags due to the addition of Na_(2)O.The rejected EMM scrap deoxidization ratio grew with the increased activity of CaO and reduced activity of Al_(2)O_(3) in the molten slag,caused by the increased Na_(2)O content in the molten slag.The addition of metallic Mg and Mg-Ca alloy indirectly promoted desulfurization and deoxidization by reducing the MnO content in the rejected EMM scrap and growing slag oxidability.The Mg-Ca alloy could also react with dissolved sulfur and oxygen,directly promoting desulfurization and deoxidization processes.The Na_(2)O content in slag should not exceed 10.44%to ensure the high desulfurization and deoxidization abilities,fluidity and low volatilization of slag.
基金the National Natural Science Foundation of China(Nos.51104008 and 51034008)China Postdoctoral Science Foundation Funded Project(No.20100480202)+1 种基金the Research Fund for the Doctoral Program of Higher Education of China (No.20100006120010)the Fundamental Research Funds for the Central Universities(No.FRF-TP-12- 026A)
文摘Electrolytic manganese residue（EMR） is generated from electrolytic manganese metal（EMM） industry, and its disposal is currently a serious problem in China.The EMR were calcined in the interval 100—900℃to enhance their pozzolanic activity and characterized by the differential thermal analysis-thermogravimetry（TGDTA）, X-ray diffraction（XRD）,infra-red（IR） and chemical analysis techniques with the aim to correlate phase transitions and structural features with the pozzolanic activity of calcined EMR.Prom the phase analysis and compressive strength results,it is found that the EMR calcined within 700—800℃had the best pozzolanic activity due to the decomposition of poorly-crystallized CaSO4 under the reducing ambient created by the decomposition of（NH4）2SO4.The appearance of reactive CaO mainly contributes to the good pozzolanic activity of EMR calcined within 700—800℃.The crystallinity of Mn3CO4 increases leading an unfavourable effect on the pozzolanic behaviour of EMR calcined at 900℃.The developed pozzolanic material containing 30%（mass fraction） EMR possesses compressive strength properties at a level similar to 42.5# normal Portland cement,in the range of 41.5—50.5 MPa.Besides,leaching results show that EMR blend cement pastes have excellent effect on the solidification of heavy metals.
基金National Key Research&Development Project,Grant/Award Number:2017YFE0129300Ningbo Science and Technology Innovation 2025 Major Project,Grant/Award Numbers:2019B10046,2020Z107+2 种基金Zhejiang Provincial Key R&D Program,Grant/Award Number:2021C01101National Natural Science Foundation of China,Grant/Award Numbers:U20A20251,11932005The from 0 to 1 Innovative Program of CAS,Grant/Award Number:ZDBS-LY-JSC021。
文摘CO_(2) electrolysis with solid oxide electrolytic cells(SOECs)using intermittently available renewable energy has potential applications for carbon neutrality and energy storage.In this study,a pulsed current strategy is used to replicate intermittent energy availability,and the stability and conversion rate of the cyclic operation by a large-scale flat-tube SOEC are studied.One hundred cycles under pulsed current ranging from -100 to -300 mA/cm^(2) with a total operating time of about 800 h were carried out.The results show that after 100 cycles,the cell voltage attenuates by 0.041%/cycle in the high current stage of−300 mA/cm^(2),indicating that the lifetime of the cell can reach up to about 500 cycles.The total CO_(2) conversion rate reached 52%,which is close to the theoretical value of 54.3% at -300 mA/cm^(2),and the calculated efficiency approached 98.2%,assuming heat recycling.This study illustrates the significant advantages of SOEC in efficient electrochemical energy conversion,carbon emission mitigation,and seasonal energy storage.
基金Zhu.L.and Li.H.contributed equally to this work.This work is supported by the National Natural Science Foundation of China(Grant No.51901121)the Natural Science Foundation of Shaanxi Province(Grant No.2021JM-203,2019JQ-433,2020zdzx04-03-02)the Fundamental Research Funds for the Central Universities(Grant No.GK202103022).
文摘Here we prepared PEO coatings on Mg alloys in silicate-NaOH-phosphate electrolyte containing different concentrations of NaF addition.The detailed microstructural characterizations combining with potentiodynamic polarization and electrochemical impedance spectra(EIS)were employed to investigate the roles of fluoride in the growth and corrosion properties of PEO coating on Mg.The result shows the introduction of NaF led to a fluoride-containing nanolayer(FNL)formed at the Mg/coating interface.The FNL consists of MgO nanoparticles and insoluble MgF_(2)nanoparticles(containing rutile phase and cubic phase).The increase in the NaF concentration of the electrolyte increases the thickness and the MgF_(2)content in the FNL.When anodized in the electrolyte containing 2 g/L NaF,the formed FNL has the highest thickness of 100-200 nm along with the highest value of x of∼0.6 in(MgO)_(1-x)(MgF_(2))x resulted in the highest corrosion performance of PEO coating.In addition,when anodized in the electrolyte containing a low NaF concentration(0.4-0.8 g/L),the formed FNL was thin and discontinuous,which would decrease the pore density and increase the coating's uniformness simultaneously.
文摘A roaring price of nickel and a shortage of the raw material of electrolytic manganese have intensified the demand for electrolytic manganese in China. As an alternative to nickel, electrolytic manganese has been consumed at a quickened speed, which boosts the continuous increase in export quotation. On the
