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
A new method for producing higher density PM parts, high velocity compaction （HVC）, was presented in the paper. Using water atomized pure iron powder without lubricant admixed as the staring material, ring samples w...A new method for producing higher density PM parts, high velocity compaction （HVC）, was presented in the paper. Using water atomized pure iron powder without lubricant admixed as the staring material, ring samples were compacted by the technique. Scanning electron microscopy （SEM） and a computer controlled universal testing machine were used to investigate the morphologies and the mechanical properties of samples, respectively. The relationships among the impact velocity, the green density, the sintered density, the bending strength and the tensile strength were discussed, The results show that with increasing impact velocity, the green density and the bending strength increase gradually, so the sintered density does. In addition, the tensile strength of sintered material is improved continuously with the sintered density enhancing. In the study, the sintered density of 7.545 g/cm^3 and the tensile strength of 190 MPa are achieved at the optimal impact velocity of 9.8 m/s.展开更多
Recent studies revealed that in eutectic to slightly hypereutectic grey irons(CE = 4.3%-4.5%) the presence of austenite dendrites provides an opportunity to improve the cast iron properties,as a high number of eutecti...Recent studies revealed that in eutectic to slightly hypereutectic grey irons(CE = 4.3%-4.5%) the presence of austenite dendrites provides an opportunity to improve the cast iron properties,as a high number of eutectic cells are "reinforced" by austenite dendrites.An iron powder addition proved to be important by promoting dendritic austenite in hypereutectic irons,but was accompanied by adverse effect on the characteristics of potential nuclei for graphite.The purpose of the present paper is to investigate the solidification pattern of these irons.Chill wedges with different cooling moduli(CM = 0.11-0.43 cm) were poured in resin bonded sand and metal moulds.Relative clear /mottled /total chill measurement criteria were applied.Iron powder additions led to a higher chill tendency,while single inoculation showed the strongest graphitizing effect.The various double treatments show an intermediate position,but the inoculant added after iron powder appears to be the most effective in reducing base iron chill tendency,for all cooling moduli and chill evaluation parameters.This performance reflects the improved properties of(Mn,X)S polygonal compounds as nucleation sites for graphite,especially in resin bonded sand mould castings.Both austenite and graphite nucleation benefit from a double addition of iron powder + inoculant,with positive effect on the final structure and chill tendency.展开更多
The using of the iron to extract reduced iron with T Fe ≥ 69.5% Al 2O 3+SiO 2<0.3% was studied. Preparation of reduced iron powder in this experimental research can produce ultra pure magnetite concentrate...The using of the iron to extract reduced iron with T Fe ≥ 69.5% Al 2O 3+SiO 2<0.3% was studied. Preparation of reduced iron powder in this experimental research can produce ultra pure magnetite concentrate. The quality of the final product reaches the product standard of SC 100.26 and NC 100.24.展开更多
A new model for describing the compaction process of iron powder was proposed based on the continuum hypothesis and elliptical yield criterion.To simulate the densification behaviour,the constitutive model was impleme...A new model for describing the compaction process of iron powder was proposed based on the continuum hypothesis and elliptical yield criterion.To simulate the densification behaviour,the constitutive model was implemented in Marc computer program.For the relationship between load and displacement,different models were compared and the influence of the parameters in the constitutive equations was determined by means of simulation and experiments.The density distribution of a balancer was measured and simulated.The results show that the parameterηadopted plays a modification role for the load-displacement curve,and compared with other models the present model fits better with the experimental data in the later stage of the compaction process mainly due to the different parameters A and B.The friction on the contact surface contributes to the inhomogeneous density distribution under large deformation of the workpiece.The comparison between the simulation and experimental data indicates that this model can be used to predict the powder compact process precisely and effectively.展开更多
In this study, the effect of iron powder (Fe2O3) on the compressive strength, tensile strength, workability, and porosity of the binary blended concrete were experimentally investigated. For this purpose, Portland cem...In this study, the effect of iron powder (Fe2O3) on the compressive strength, tensile strength, workability, and porosity of the binary blended concrete were experimentally investigated. For this purpose, Portland cement was partially replaced by 1.5%, 2.5%, 3.5%, and 5% by weighing of iron powder. The amount of water-binder-ratio was considered constant. The workability of the fresh composite concrete was determined using cone Abrams method;mechanical properties were determined included compressive and tensile strengths at 7, 14, and 28 days and durability evaluated by water absorption and permeable porosity. It was observed that the compressive and tensile strengths change with the replacement of iron powder by up to 5%. However, the maximum improvement was gained at 2.5 wt% for compressive strength and 1.5 wt% for tensile strength. The workability of the fresh mixtures decreased when iron powder amount increased. It was observed that the porosity decreased respectively by 21.88% and 26.77% at 1.5 wt% and 2.5 wt% replacement. Moreover, this present study shows the importance and benefits to improve concrete properties by using micro-particles materials.展开更多
A new cement free iron trough castable was prepared with dense corundum and silicon carbide as the main raw materials and submicron SiO_(2) powder(d_(50)=0.242μm,SiO_(2)=99.9 mass%)as the binder.The effect of the sub...A new cement free iron trough castable was prepared with dense corundum and silicon carbide as the main raw materials and submicron SiO_(2) powder(d_(50)=0.242μm,SiO_(2)=99.9 mass%)as the binder.The effect of the submicron SiO_(2) powder addition(3%,4%,5%,6%,7%,8%,and 9%,by mass,respectively)on the properties of the prepared castables was studied.The working mechanism of submicron SiO_(2) powder was analyzed from the perspective of the particle size distribution and infrared absorption spectrum.The results show that:(1)cement free iron trough castables can be prepared using submicron SiO_(2) powder alone as the binder;(2)compared with traditional castables,the cement free castables have made a breakthrough in the water addition and hot modulus of rupture.The optimal submicron SiO_(2) powder addition is 4%-6%.展开更多
Lubricant is harmful to the mechanical properties of the sintered materials. Die wall lubrication was applied on warm compaction powder metallurgy in the hope of reducing the concentration level of the admixed lubrica...Lubricant is harmful to the mechanical properties of the sintered materials. Die wall lubrication was applied on warm compaction powder metallurgy in the hope of reducing the concentration level of the admixed lubricant. Iron based samples were prepared by die wall lubricated warm compaction at 175 ℃, using a compacting pressure of 550 MPa. Emulsified polytetrafluoroethylene(PTFE) was used as die wall lubricant. Admixed lubricant concentration ranging from 0 to 0.5% was tested. Extremely low admixed lubricant contents were used. Results show that in addition to the decrease in ejection forces, the green density of the compacts increases with the decrease of admixed lubricant content until it reaches the maximum at 0.06% of lubricant content, then decreases with the decrease of admixed lubricant content. The mechanical properties of the sintered compacts that contain more than 0.06% admixed lubricant are better than those of the samples that contain lesser lubricant. No scoring was observed in all die wall lubricated experiments.展开更多
Infant formula provides the largest, if not sole, source of nutrition for an extended interval;the nutritional adequacy of the formula must be confirmed and the indications for its use were well understood. Both iron ...Infant formula provides the largest, if not sole, source of nutrition for an extended interval;the nutritional adequacy of the formula must be confirmed and the indications for its use were well understood. Both iron deficiency and iron excess during the fetal and neonatal period bode poorly for developing organ systems. Voltammetry is analytical method based on current potential measurements in electrochemical cells. In this study the concentration of iron in four brands of powder milk and baby food (based on rice and based on wheat) was analyzed with DPASV and voltammeter device. Total Means ± SE of Iron in baby foods and powder milk (n = 40) were 8.55 ± 1.18 mg/100g, 5.21 ± 0.66 respectively. Iron level in baby food type I and II was lower than labeled value (p p < 0.05).展开更多
A new process was used for producing FeAl alloy pow de rs with double consumable rotating electrodes and the powders made in this appar atus were analyzed. In this new technology, tungsten rod serves as a cathode ele ...A new process was used for producing FeAl alloy pow de rs with double consumable rotating electrodes and the powders made in this appar atus were analyzed. In this new technology, tungsten rod serves as a cathode ele ctrode, while the alloy rod as an anode electrode. The conventional rotating ele ctrode process must have an anode with pre-melting alloys; however, in this new process, using pure iron as cathode electrode and pure aluminum as anode electr ode can eliminate the step of pre-melting. The effects of process variables, which include electrode rotational speed, a nd electrode diameter of the mean particle diameter were determined. Results showed that both the rotational speed and diameter of electrodes would a ffect the mean diameter of particles. There are three kinds of powders with diff erent composition produced in this study and the possible mechanisms are discuss ed. The process parameters and volume mean diameter of the powders have been cor related to find an experimental equation. The results show that when the rotational speed and the diameter of the anode el ectrode are increased, the powders size will decrease. However, the powders size will increase with cathode electrode.展开更多
Warm compaction behaviors and their affecting factors such as compaction temperature, compaction pressure and lubricant concentration were studied. Effect of die wall lubrication on the powder’s warm compaction behav...Warm compaction behaviors and their affecting factors such as compaction temperature, compaction pressure and lubricant concentration were studied. Effect of die wall lubrication on the powder’s warm compaction behavior was also studied. The use of smaller size colloidal graphite investigated can give a higher compact density and lesser spring back effect than the use of flake graphite.展开更多
Mechanical properties of the warm compacted alumina particulate reinforced powder metallurgy composite materials was compared with those of the materials obtained by conventional cold compaction. Factors affecting the...Mechanical properties of the warm compacted alumina particulate reinforced powder metallurgy composite materials was compared with those of the materials obtained by conventional cold compaction. Factors affecting the properties of the warm compacted material such as compaction temperature, lubricant content and alumina content were studied. A 3%(mass fraction) alumina particulate reinforced iron-base composite with a green density of 7.0 g/cm 3 can be obtained by pressing the powder with a pressure of 700 MPa at 175 ℃. The sintered materials have a density of 6.88 g/cm 3, a tensile strength of 512 MPa and an elongation of 1.3%. Results show that as alumina content increases, density and mechanical properties of the composite decrease.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 National 973 Program (No.2006CB605207)MOE Program for Changjiang Scholars and Innovative Research Team in Universityof China (No.I2P407)
文摘A new method for producing higher density PM parts, high velocity compaction （HVC）, was presented in the paper. Using water atomized pure iron powder without lubricant admixed as the staring material, ring samples were compacted by the technique. Scanning electron microscopy （SEM） and a computer controlled universal testing machine were used to investigate the morphologies and the mechanical properties of samples, respectively. The relationships among the impact velocity, the green density, the sintered density, the bending strength and the tensile strength were discussed, The results show that with increasing impact velocity, the green density and the bending strength increase gradually, so the sintered density does. In addition, the tensile strength of sintered material is improved continuously with the sintered density enhancing. In the study, the sintered density of 7.545 g/cm^3 and the tensile strength of 190 MPa are achieved at the optimal impact velocity of 9.8 m/s.
文摘Recent studies revealed that in eutectic to slightly hypereutectic grey irons(CE = 4.3%-4.5%) the presence of austenite dendrites provides an opportunity to improve the cast iron properties,as a high number of eutectic cells are "reinforced" by austenite dendrites.An iron powder addition proved to be important by promoting dendritic austenite in hypereutectic irons,but was accompanied by adverse effect on the characteristics of potential nuclei for graphite.The purpose of the present paper is to investigate the solidification pattern of these irons.Chill wedges with different cooling moduli(CM = 0.11-0.43 cm) were poured in resin bonded sand and metal moulds.Relative clear /mottled /total chill measurement criteria were applied.Iron powder additions led to a higher chill tendency,while single inoculation showed the strongest graphitizing effect.The various double treatments show an intermediate position,but the inoculant added after iron powder appears to be the most effective in reducing base iron chill tendency,for all cooling moduli and chill evaluation parameters.This performance reflects the improved properties of(Mn,X)S polygonal compounds as nucleation sites for graphite,especially in resin bonded sand mould castings.Both austenite and graphite nucleation benefit from a double addition of iron powder + inoculant,with positive effect on the final structure and chill tendency.
文摘The using of the iron to extract reduced iron with T Fe ≥ 69.5% Al 2O 3+SiO 2<0.3% was studied. Preparation of reduced iron powder in this experimental research can produce ultra pure magnetite concentrate. The quality of the final product reaches the product standard of SC 100.26 and NC 100.24.
基金Project(50325516) supported by the National Natural Science Foundation of ChinaProject(CG2003-GA005) supported by China Education and Research Grid(China Grid)+1 种基金Project(003019) supported by the Natural Science Foundation of Guangdong Province,ChinaProject(2009ZM0290) supported by the Fundamental Research Funds for the Central Universities,China
文摘A new model for describing the compaction process of iron powder was proposed based on the continuum hypothesis and elliptical yield criterion.To simulate the densification behaviour,the constitutive model was implemented in Marc computer program.For the relationship between load and displacement,different models were compared and the influence of the parameters in the constitutive equations was determined by means of simulation and experiments.The density distribution of a balancer was measured and simulated.The results show that the parameterηadopted plays a modification role for the load-displacement curve,and compared with other models the present model fits better with the experimental data in the later stage of the compaction process mainly due to the different parameters A and B.The friction on the contact surface contributes to the inhomogeneous density distribution under large deformation of the workpiece.The comparison between the simulation and experimental data indicates that this model can be used to predict the powder compact process precisely and effectively.
文摘In this study, the effect of iron powder (Fe2O3) on the compressive strength, tensile strength, workability, and porosity of the binary blended concrete were experimentally investigated. For this purpose, Portland cement was partially replaced by 1.5%, 2.5%, 3.5%, and 5% by weighing of iron powder. The amount of water-binder-ratio was considered constant. The workability of the fresh composite concrete was determined using cone Abrams method;mechanical properties were determined included compressive and tensile strengths at 7, 14, and 28 days and durability evaluated by water absorption and permeable porosity. It was observed that the compressive and tensile strengths change with the replacement of iron powder by up to 5%. However, the maximum improvement was gained at 2.5 wt% for compressive strength and 1.5 wt% for tensile strength. The workability of the fresh mixtures decreased when iron powder amount increased. It was observed that the porosity decreased respectively by 21.88% and 26.77% at 1.5 wt% and 2.5 wt% replacement. Moreover, this present study shows the importance and benefits to improve concrete properties by using micro-particles materials.
基金support from the National Natural Science Foundation of China(NSFC,No.51804233)。
文摘A new cement free iron trough castable was prepared with dense corundum and silicon carbide as the main raw materials and submicron SiO_(2) powder(d_(50)=0.242μm,SiO_(2)=99.9 mass%)as the binder.The effect of the submicron SiO_(2) powder addition(3%,4%,5%,6%,7%,8%,and 9%,by mass,respectively)on the properties of the prepared castables was studied.The working mechanism of submicron SiO_(2) powder was analyzed from the perspective of the particle size distribution and infrared absorption spectrum.The results show that:(1)cement free iron trough castables can be prepared using submicron SiO_(2) powder alone as the binder;(2)compared with traditional castables,the cement free castables have made a breakthrough in the water addition and hot modulus of rupture.The optimal submicron SiO_(2) powder addition is 4%-6%.
文摘Lubricant is harmful to the mechanical properties of the sintered materials. Die wall lubrication was applied on warm compaction powder metallurgy in the hope of reducing the concentration level of the admixed lubricant. Iron based samples were prepared by die wall lubricated warm compaction at 175 ℃, using a compacting pressure of 550 MPa. Emulsified polytetrafluoroethylene(PTFE) was used as die wall lubricant. Admixed lubricant concentration ranging from 0 to 0.5% was tested. Extremely low admixed lubricant contents were used. Results show that in addition to the decrease in ejection forces, the green density of the compacts increases with the decrease of admixed lubricant content until it reaches the maximum at 0.06% of lubricant content, then decreases with the decrease of admixed lubricant content. The mechanical properties of the sintered compacts that contain more than 0.06% admixed lubricant are better than those of the samples that contain lesser lubricant. No scoring was observed in all die wall lubricated experiments.
文摘Infant formula provides the largest, if not sole, source of nutrition for an extended interval;the nutritional adequacy of the formula must be confirmed and the indications for its use were well understood. Both iron deficiency and iron excess during the fetal and neonatal period bode poorly for developing organ systems. Voltammetry is analytical method based on current potential measurements in electrochemical cells. In this study the concentration of iron in four brands of powder milk and baby food (based on rice and based on wheat) was analyzed with DPASV and voltammeter device. Total Means ± SE of Iron in baby foods and powder milk (n = 40) were 8.55 ± 1.18 mg/100g, 5.21 ± 0.66 respectively. Iron level in baby food type I and II was lower than labeled value (p p < 0.05).
文摘A new process was used for producing FeAl alloy pow de rs with double consumable rotating electrodes and the powders made in this appar atus were analyzed. In this new technology, tungsten rod serves as a cathode ele ctrode, while the alloy rod as an anode electrode. The conventional rotating ele ctrode process must have an anode with pre-melting alloys; however, in this new process, using pure iron as cathode electrode and pure aluminum as anode electr ode can eliminate the step of pre-melting. The effects of process variables, which include electrode rotational speed, a nd electrode diameter of the mean particle diameter were determined. Results showed that both the rotational speed and diameter of electrodes would a ffect the mean diameter of particles. There are three kinds of powders with diff erent composition produced in this study and the possible mechanisms are discuss ed. The process parameters and volume mean diameter of the powders have been cor related to find an experimental equation. The results show that when the rotational speed and the diameter of the anode el ectrode are increased, the powders size will decrease. However, the powders size will increase with cathode electrode.
文摘Warm compaction behaviors and their affecting factors such as compaction temperature, compaction pressure and lubricant concentration were studied. Effect of die wall lubrication on the powder’s warm compaction behavior was also studied. The use of smaller size colloidal graphite investigated can give a higher compact density and lesser spring back effect than the use of flake graphite.
文摘Mechanical properties of the warm compacted alumina particulate reinforced powder metallurgy composite materials was compared with those of the materials obtained by conventional cold compaction. Factors affecting the properties of the warm compacted material such as compaction temperature, lubricant content and alumina content were studied. A 3%(mass fraction) alumina particulate reinforced iron-base composite with a green density of 7.0 g/cm 3 can be obtained by pressing the powder with a pressure of 700 MPa at 175 ℃. The sintered materials have a density of 6.88 g/cm 3, a tensile strength of 512 MPa and an elongation of 1.3%. Results show that as alumina content increases, density and mechanical properties of the composite decrease.
