The arsenic extraction from the arsenic-containing cobalt and nickel slag,which came from the purification process of zinc sulfate solution in a zinc smelting factory,was investigated.The alkaline leaching method was ...The arsenic extraction from the arsenic-containing cobalt and nickel slag,which came from the purification process of zinc sulfate solution in a zinc smelting factory,was investigated.The alkaline leaching method was proposed according to the mode of occurrence of arsenic in the slag and its amphoteric characteristic.The leaching experiments were conducted in the alkaline aqueous medium,with bubbling of oxygen into the solution,and the optimal conditions for leaching arsenic were determined.The results showed that the extraction rate of arsenic was maximized at 99.10%under the optimal conditions of temperature 140 ℃,NaOH concentration 150 g/L,oxygen partial pressure 0.5 MPa,and a liquid-to-solid ratio 5：1.Based on the solubilities of As2O5,ZnO and PbO in NaOH solution at 25 ℃,a method for the separation of As in the form of sodium arsenate salt from the arsenic-rich leachate via cooling crystallization was established,and the reaction medium could be fully recycled.The crystallization rate was confirmed to reach 88.9%（calculated on the basis of Na3AsO4） upon a direct cooling of the hot leachate down to room temperature.On the basis of redox potentials,the sodium arsenate solution could be further reduced by sulfur dioxide（SO2） gas to arsenite,at a reduction yield of 92%under the suitable conditions.Arsenic trioxide with regular octahedron shape could be prepared successfully from the reduced solution,and further recycled to the purification process to purify the zinc sulfate solution.Also,sodium arsenite solution obtained after the reduction of arsenate could be directly used to purify the zinc sulfate solution.Therefore,the technical scheme of alkaline leaching with pressured oxygen,cooling crystallization,arsenate reduction by SO2 gas,and arsenic trioxide preparation,provides an attractive approach to realize the resource utilization of arsenic-containing cobalt and nickel slag.展开更多
In order to utilize slag discarded by nickel plants, the selective recovery of nickel and copper versus iron was investigated by selective reduction, which was achieved by controlling the reduction parameters and magn...In order to utilize slag discarded by nickel plants, the selective recovery of nickel and copper versus iron was investigated by selective reduction, which was achieved by controlling the reduction parameters and magnetic separation process on bench scale. The results show that increasing the basicity （mass ratio of CaO to SIO2） of nickel slag facilitates the enrichment of nickel and copper The process parameters for selective reduction were optimized as follows： basicity of 0.15, reducing at 1200 ~C for 20 min, 5% coal on a dried slag mass base. The grinding-magnetic separation results of reduced briquettes show that concentrate containing 3.25%Ni, 1.20%Cu and 75.26%Fe is obtained and selective enrichment is achieved with a recovery of 82.20%, 80.00% for nickel and copper respectively, while the recovery of iron is only 42.17%. The S and P contents are not reduced obviously and further research may be needed to examine the behaviors of S and P in the process.展开更多
The effect of CaCO3 addition on the carbothermic reduction of nickel slag was studied,and the mechanism of CaCO3 in improving the reduction was analyzed.The results showed that when the CaCO3 content added to the slag...The effect of CaCO3 addition on the carbothermic reduction of nickel slag was studied,and the mechanism of CaCO3 in improving the reduction was analyzed.The results showed that when the CaCO3 content added to the slag was increased from 0 to 8 wt.%,initiation temperature of the carbothermic reaction decreased from 1100 to 1000℃,the temperature reaching the maximum reduction rate decreased from 1150 to 1100℃,and the reduction degree of the nickel slag increased from 58%to 88%.The iron particles in the reduced nickel slag were coarsened and the X-ray diffraction intensity of metallic iron peaks increased,confirming that the addition of CaCO3 was beneficial to the reduction of nickel slag and recovery of iron.展开更多
Al（OH）_3 modified nickel slag adsorbent was prepared by sintering technology. The structure of the sample was characterized by BET, XRD, IR, SEM and EDAX. The sample＇s adsorption performance of Pb^（2＋） and Cu^（...Al（OH）_3 modified nickel slag adsorbent was prepared by sintering technology. The structure of the sample was characterized by BET, XRD, IR, SEM and EDAX. The sample＇s adsorption performance of Pb^（2＋） and Cu^（2＋） from aqueous solution was studied. Results indicated that the adsorbent is a loose and porous mesoporous material. Its surface had mass aluminosilicate, high-activity γ-Al_2O_3 and its p H ranges from 4 to 12 that all have negative charges. The BET surface of the adsorbent is 23.90 m^2/g. Furthermore, its surface contains rich oxygenic functional groups, which could not only provide abundant adsorption sites for Pb^（2＋） and Cu^（2＋）, but also improve the adsorption performance of Pb^（2＋） and Cu^（2＋） from waste water through the complexation of heavy metal ions. The best p H values selected in the adsorption of Pb^（2＋） and Cu^（2＋） are 6 and 5, respectively. With the increase of the initial concentration of simulated solution, the adsorption capacities of Pb^（2＋） and Cu^（2＋） gradually increased but the removal rates showed a downward trend. The competitive adsorption results of Pb^（2＋） and Cu^（2＋） showed that Pb^（2＋） has better preferential adsorption than Cu^（2＋）.展开更多
Desulphurization slag modified nickel slag adsorbent was prepared by unburned forming technology. The structure of the sample was characterized by BET,XRD,IR,SEM and EDAX. The adsorption performance of Pb^2＋ and Cu^2...Desulphurization slag modified nickel slag adsorbent was prepared by unburned forming technology. The structure of the sample was characterized by BET,XRD,IR,SEM and EDAX. The adsorption performance of Pb^2＋ and Cu^2＋ onto the resultant adsorbent from aqueous solution was studied. Results indicated that the adsorbent possesses a network pore structure formed by the AFt and C–S–H through cross lapping; the adsorbent contains a large number of Si–OH and Al–OH functional groups. The presence of functional groups not only provides abundant adsorption sites for Pb^2＋ and Cu^2＋,but also improves the adsorption performance of Pb^2＋ and Cu^2＋ from waste water through the complexation of heavy metal ions. The result of specific surface area analysis showed that the adsorbent sample possesses mesoporous structure and the BET specific surface area is 27.15 m^2/g. The solution p H values for the adsorption of Pb^2＋ and Cu^2＋ were optimized to be 6 and 5.5,respectively. The adsorption capacities of Pb^2＋ and Cu^2＋ gradually increase,whereas the removal rates of the two metal ions decrease with increasing the initial concentration of simulated solution. The resultant adsorbent gives a higher adsorption capacity for Cu^2＋ than for Pb^2＋ in the single ion solution. However,it shows preferential adsorption of Pb^2＋ rather than that of Cu^2＋. Meanwhile,results of recyclability indicate the remarkable regeneration capacity,re-adsorption ability and reusability performance of the adsorbent sample.展开更多
The effects of mechanical activation on particle size distribution,crystalline phase,morphology,and mechanical energy storage of nickel slag were studied.Then,the direct reduction experiments of mechanically activated...The effects of mechanical activation on particle size distribution,crystalline phase,morphology,and mechanical energy storage of nickel slag were studied.Then,the direct reduction experiments of mechanically activated nickel slag mixed with reducing agent graphite powder were performed under conditions of 873-1273 K and reduction for 30-70 min.The results show that after 12 h of activation,90%of the nickel slag has a particle diameter less than 1.05 pm,and the total energy storage is 1790.4 kJ mol^(-1).With the extension of the mechanical activation duration,the intensity of the dift'raction peaks of the main crystalline phases Fe_(2)SiO_(4) and Mg2SiO4 in the nickel slag decreases.Mechanical activation is also an effective means to enhance the reduction of nickel slag.With the extension of the activation time,the reduction effect of the nickel slag and metallization degree increase.After 12 h of mechanical activation,the nickel slag was reduced at 1273 K for 70 min,and the metallization degree of the reduced product could reach 83.12%.展开更多
The slag cleaning(or matte settling) process was experimentally investigated at 1573 K using a fayalitic nickel converter slag containing spinel and matte/alloy particles.The addition of various amounts of spent potli...The slag cleaning(or matte settling) process was experimentally investigated at 1573 K using a fayalitic nickel converter slag containing spinel and matte/alloy particles.The addition of various amounts of spent potlining(SPL) was studied in terms of its influence on matte settling and the overall metal recoveries.The slags produced were characterized by scanning electron microscopy,energy-dispersive spectroscopy,and wet chemical analysis using inductively coupled plasma optical emission spectrometry.The presence of solid spinel particles in the molten slag hindered coalescence and settling of matte/alloy droplets.Matte settling was effectively promoted with the addition of as little as 2 wt% SPL because of the reduction of spinel by the carbonaceous component of the SPL.The reduced viscosity of the molten slag in the presence of SPL also contributed to the accelerated matte settling.Greater metal recoveries were achieved with larger amounts of added SPL.Fast reduction of the molten slag at 1573 K promoted the formation of highly dispersed metal particles/clusters via accelerated nucleation in the molten slag,which increased the overall slag viscosity.This increase in viscosity,when combined with rapid gas evolution from accelerated reduction reactions,led to slag foaming.展开更多
The leaching of magnesium from desiliconization slag of nickel laterite ores by carbonation process was studied.The influence of various parameters was investigated to optimize the conditions and determine the kinetic...The leaching of magnesium from desiliconization slag of nickel laterite ores by carbonation process was studied.The influence of various parameters was investigated to optimize the conditions and determine the kinetics of the reaction.The results show that with increasing stirring speed,liquid-to-solid ratio and reaction time,and decreasing temperature,the leaching rate of magnesium enhances.The leaching process of the desiliconization slag in the range of 288-298 K is controlled by the surface chemical reaction model.The apparent activation energy is-20.45 kJ/mol,and the kinetics model is obtained.展开更多
基金Project (2012BAC12B01) supported by the National Key Technologies R&D Program of ChinaProject (2012FJ1010) supported by Science and Technology Major Project of Hunan Province,China
文摘The arsenic extraction from the arsenic-containing cobalt and nickel slag,which came from the purification process of zinc sulfate solution in a zinc smelting factory,was investigated.The alkaline leaching method was proposed according to the mode of occurrence of arsenic in the slag and its amphoteric characteristic.The leaching experiments were conducted in the alkaline aqueous medium,with bubbling of oxygen into the solution,and the optimal conditions for leaching arsenic were determined.The results showed that the extraction rate of arsenic was maximized at 99.10%under the optimal conditions of temperature 140 ℃,NaOH concentration 150 g/L,oxygen partial pressure 0.5 MPa,and a liquid-to-solid ratio 5：1.Based on the solubilities of As2O5,ZnO and PbO in NaOH solution at 25 ℃,a method for the separation of As in the form of sodium arsenate salt from the arsenic-rich leachate via cooling crystallization was established,and the reaction medium could be fully recycled.The crystallization rate was confirmed to reach 88.9%（calculated on the basis of Na3AsO4） upon a direct cooling of the hot leachate down to room temperature.On the basis of redox potentials,the sodium arsenate solution could be further reduced by sulfur dioxide（SO2） gas to arsenite,at a reduction yield of 92%under the suitable conditions.Arsenic trioxide with regular octahedron shape could be prepared successfully from the reduced solution,and further recycled to the purification process to purify the zinc sulfate solution.Also,sodium arsenite solution obtained after the reduction of arsenate could be directly used to purify the zinc sulfate solution.Therefore,the technical scheme of alkaline leaching with pressured oxygen,cooling crystallization,arsenate reduction by SO2 gas,and arsenic trioxide preparation,provides an attractive approach to realize the resource utilization of arsenic-containing cobalt and nickel slag.
基金Project([2009]606)supported by the National Development and Reform Commission of ChinaProject(50974135)supported by the National Natural Science Foundation of China
文摘In order to utilize slag discarded by nickel plants, the selective recovery of nickel and copper versus iron was investigated by selective reduction, which was achieved by controlling the reduction parameters and magnetic separation process on bench scale. The results show that increasing the basicity （mass ratio of CaO to SIO2） of nickel slag facilitates the enrichment of nickel and copper The process parameters for selective reduction were optimized as follows： basicity of 0.15, reducing at 1200 ~C for 20 min, 5% coal on a dried slag mass base. The grinding-magnetic separation results of reduced briquettes show that concentrate containing 3.25%Ni, 1.20%Cu and 75.26%Fe is obtained and selective enrichment is achieved with a recovery of 82.20%, 80.00% for nickel and copper respectively, while the recovery of iron is only 42.17%. The S and P contents are not reduced obviously and further research may be needed to examine the behaviors of S and P in the process.
基金Projects(51774224,51574189) supported by the National Natural Science Foundation of China
文摘The effect of CaCO3 addition on the carbothermic reduction of nickel slag was studied,and the mechanism of CaCO3 in improving the reduction was analyzed.The results showed that when the CaCO3 content added to the slag was increased from 0 to 8 wt.%,initiation temperature of the carbothermic reaction decreased from 1100 to 1000℃,the temperature reaching the maximum reduction rate decreased from 1150 to 1100℃,and the reduction degree of the nickel slag increased from 58%to 88%.The iron particles in the reduced nickel slag were coarsened and the X-ray diffraction intensity of metallic iron peaks increased,confirming that the addition of CaCO3 was beneficial to the reduction of nickel slag and recovery of iron.
基金Supported by the National Natural Science Foundation of China(Nos.51102047&51472050)
文摘Al（OH）_3 modified nickel slag adsorbent was prepared by sintering technology. The structure of the sample was characterized by BET, XRD, IR, SEM and EDAX. The sample＇s adsorption performance of Pb^（2＋） and Cu^（2＋） from aqueous solution was studied. Results indicated that the adsorbent is a loose and porous mesoporous material. Its surface had mass aluminosilicate, high-activity γ-Al_2O_3 and its p H ranges from 4 to 12 that all have negative charges. The BET surface of the adsorbent is 23.90 m^2/g. Furthermore, its surface contains rich oxygenic functional groups, which could not only provide abundant adsorption sites for Pb^（2＋） and Cu^（2＋）, but also improve the adsorption performance of Pb^（2＋） and Cu^（2＋） from waste water through the complexation of heavy metal ions. The best p H values selected in the adsorption of Pb^（2＋） and Cu^（2＋） are 6 and 5, respectively. With the increase of the initial concentration of simulated solution, the adsorption capacities of Pb^（2＋） and Cu^（2＋） gradually increased but the removal rates showed a downward trend. The competitive adsorption results of Pb^（2＋） and Cu^（2＋） showed that Pb^（2＋） has better preferential adsorption than Cu^（2＋）.
基金Supported by the National Natural Science Foundation of China(Nos.51472050,51402295 and 51672046)
文摘Desulphurization slag modified nickel slag adsorbent was prepared by unburned forming technology. The structure of the sample was characterized by BET,XRD,IR,SEM and EDAX. The adsorption performance of Pb^2＋ and Cu^2＋ onto the resultant adsorbent from aqueous solution was studied. Results indicated that the adsorbent possesses a network pore structure formed by the AFt and C–S–H through cross lapping; the adsorbent contains a large number of Si–OH and Al–OH functional groups. The presence of functional groups not only provides abundant adsorption sites for Pb^2＋ and Cu^2＋,but also improves the adsorption performance of Pb^2＋ and Cu^2＋ from waste water through the complexation of heavy metal ions. The result of specific surface area analysis showed that the adsorbent sample possesses mesoporous structure and the BET specific surface area is 27.15 m^2/g. The solution p H values for the adsorption of Pb^2＋ and Cu^2＋ were optimized to be 6 and 5.5,respectively. The adsorption capacities of Pb^2＋ and Cu^2＋ gradually increase,whereas the removal rates of the two metal ions decrease with increasing the initial concentration of simulated solution. The resultant adsorbent gives a higher adsorption capacity for Cu^2＋ than for Pb^2＋ in the single ion solution. However,it shows preferential adsorption of Pb^2＋ rather than that of Cu^2＋. Meanwhile,results of recyclability indicate the remarkable regeneration capacity,re-adsorption ability and reusability performance of the adsorbent sample.
基金the National Natural Science Foundation of China(No.51774224)for the funding of this research.
文摘The effects of mechanical activation on particle size distribution,crystalline phase,morphology,and mechanical energy storage of nickel slag were studied.Then,the direct reduction experiments of mechanically activated nickel slag mixed with reducing agent graphite powder were performed under conditions of 873-1273 K and reduction for 30-70 min.The results show that after 12 h of activation,90%of the nickel slag has a particle diameter less than 1.05 pm,and the total energy storage is 1790.4 kJ mol^(-1).With the extension of the mechanical activation duration,the intensity of the dift'raction peaks of the main crystalline phases Fe_(2)SiO_(4) and Mg2SiO4 in the nickel slag decreases.Mechanical activation is also an effective means to enhance the reduction of nickel slag.With the extension of the activation time,the reduction effect of the nickel slag and metallization degree increase.After 12 h of mechanical activation,the nickel slag was reduced at 1273 K for 70 min,and the metallization degree of the reduced product could reach 83.12%.
文摘The slag cleaning(or matte settling) process was experimentally investigated at 1573 K using a fayalitic nickel converter slag containing spinel and matte/alloy particles.The addition of various amounts of spent potlining(SPL) was studied in terms of its influence on matte settling and the overall metal recoveries.The slags produced were characterized by scanning electron microscopy,energy-dispersive spectroscopy,and wet chemical analysis using inductively coupled plasma optical emission spectrometry.The presence of solid spinel particles in the molten slag hindered coalescence and settling of matte/alloy droplets.Matte settling was effectively promoted with the addition of as little as 2 wt% SPL because of the reduction of spinel by the carbonaceous component of the SPL.The reduced viscosity of the molten slag in the presence of SPL also contributed to the accelerated matte settling.Greater metal recoveries were achieved with larger amounts of added SPL.Fast reduction of the molten slag at 1573 K promoted the formation of highly dispersed metal particles/clusters via accelerated nucleation in the molten slag,which increased the overall slag viscosity.This increase in viscosity,when combined with rapid gas evolution from accelerated reduction reactions,led to slag foaming.
基金Project(2007CB613603)supported by the National Basic Research Program of China
文摘The leaching of magnesium from desiliconization slag of nickel laterite ores by carbonation process was studied.The influence of various parameters was investigated to optimize the conditions and determine the kinetics of the reaction.The results show that with increasing stirring speed,liquid-to-solid ratio and reaction time,and decreasing temperature,the leaching rate of magnesium enhances.The leaching process of the desiliconization slag in the range of 288-298 K is controlled by the surface chemical reaction model.The apparent activation energy is-20.45 kJ/mol,and the kinetics model is obtained.
