Decomposition of sodium aluminate solution is the key step for alumina production;however,approximately only 55% alumina yield is obtained by seeded precipitation.So,it is difficult to obtain sodium aluminate solution...Decomposition of sodium aluminate solution is the key step for alumina production;however,approximately only 55% alumina yield is obtained by seeded precipitation.So,it is difficult to obtain sodium aluminate solution with high caustic ratio.In this study,a method was explored to recover alumina from spent Bayer liquor by deep decomposition with methanol.A variety of conditions,including reaction temperature,reaction time,methanol amount and seed coefficient were elaborately investigated.The results showed that the appropriate conditions were 1:1 in volume ratio of methanol to spent Bayer liquor,more than 1.0 seed coefficient and in a 40℃water bath for 24 h.By characterizing through XRD,the crystal products were found to be Al(OH)3.With this method,the molar ratio of Na2O to Al2O3 of the spent liquor can be increased from about 3.0 to 10.0 due to the recovery of alumina,which is beneficial for the treatment of red mud.展开更多
The assignments of the absorption peaks in the Fourier transform infrared (FTIR)spectra of the Bayer liquors were established in this study, which provided the basis for the study of Bayer liquors by FTIR techniques. ...The assignments of the absorption peaks in the Fourier transform infrared (FTIR)spectra of the Bayer liquors were established in this study, which provided the basis for the study of Bayer liquors by FTIR techniques. The FTIR study of the Bayer liquors from two alumina refineries indicated that both liquors contained carbonate, humate and A1(OH); ions. The existence of sulphate ions in one of the liquors was also discovered.展开更多
A method for the simultaneous separation and determination of organic acids and inorganic anions in Bayer liquors was developed by gradient ion chromatography with suppressed conductivity detection. Formate, acetate, ...A method for the simultaneous separation and determination of organic acids and inorganic anions in Bayer liquors was developed by gradient ion chromatography with suppressed conductivity detection. Formate, acetate, propionate, oxalate, succinate, glutarate, fluoride, chloride and sulfate were separated and determined in 33 min. The samples were pretreated with solid-phase extraction, which has high selectivity for removing a large number of metallic ions in the Bayer liquors, and filtered with a 0.45 μm filter membrane before being injected into the ion chromatographic system. The separation of six organic acids and three inorganic anions was achieved on an IonPac AS11-HC column with KOH as the eluent, and the detection was performed by a conductivity detection mode. No interference is found in the presence of fluorate, chlorate and sulphate when organic acids are determined. The calibration graphs of peak area for all the analytes are linear over a wide range. The relative standard derivation of the peak area of analytes is less than 2.14%. Under optimum conditions the detection ranges from 0.2 to 100.0 mg/L. The average recoveries of the added standards are between 94.3% and 102.8%.展开更多
A new technology was developed to recover V2O5 from Bayer spent liquor by ion exchange.The experimental results show that in the conditions of 105℃ and 0.20-0.25 mass ratios between CaO in lime and Al2O3 in spent liq...A new technology was developed to recover V2O5 from Bayer spent liquor by ion exchange.The experimental results show that in the conditions of 105℃ and 0.20-0.25 mass ratios between CaO in lime and Al2O3 in spent liquor, the precipitation rate of vanadium in Bayer liquor is more than 85%.The vanadium-bearing precipitation is leached by NaHCO3 solution.The leaching rate of vanadium can reach 85% in the conditions of 95℃, 40 g·L-1 of NaHCO3 concentration, and ventilating of CO2.The 201 × 7 type of resin has good adsorption effect on vanadium in the leaching solution.The adsorption rate is more than 94% with the flow rate of 0.09 mL·min-1·g-1 of leaching solution and the temperature of 40-50℃.By using 3 mol·L-1 of NaOH to desorb the saturated resin after adsorption at 40-50℃, a solution with more than 5 g·L-1 of V2O5 can be obtained.After roasting ammonium metavanadate that precipitates from the desorption solution when NH4Cl is added at the temperature of 500-550℃ for 2 h, V2O5 with more than 99% of purity is obtained.展开更多
High purity ammonium metavanadate(NH_(4)VO_(3))is the most vital chemical to produce V2O5,VO2,VN alloy,VFe alloy and VOSO4,which have some prospective applications for high strength steel,smart window,infrared detecto...High purity ammonium metavanadate(NH_(4)VO_(3))is the most vital chemical to produce V2O5,VO2,VN alloy,VFe alloy and VOSO4,which have some prospective applications for high strength steel,smart window,infrared detector and imaging,large scale energy storage system.NH_(4)VO_(3)is usually produced by spontaneous crystallization from the aqueous solution due to its sharp dependence of solubility on the temperature.However,hazardous chemicals in industrial effluent,include phosphorate,silicate and arsenate,causing severe damage to the environment.In this work,these impurities are selectively precipitated onto inorganic flocculants,while the vanadate dissolved in an aqueous solution keeps almost undisturbed.Therefore,high purity NH_(4)VO_(3)is produced by the crystallization from the purified solution.By screening various flocculants and precipitating parameters,polyaluminum sulfate with an optimal amount of 50 g/L,is demonstrated to selectively remove phosphorate,silicate and arsenate,corresponding to the removing efficiency of 93.39%,97.11%and 88.31%,respectively.NH_(4)VO_(3)from the purified solution holds a purity of 99.21%,in comparison with 98.33%in the product from the crude solution.This purifying technology cannot only produce NH_(4)VO_(3)with high added value,but also reduce the environmental pollution of waste liquid.展开更多
基金Project(50874099)supported by the National Natural Science Foundation of ChinaProject(2006AA06Z129)supported by the National Hi-tech Research and Development Program of China+2 种基金Projects(2009CB219901,2007CB613501)supported by the National BasicResearch Program of ChinaProject(KGCX2-YW-321-2)supported by Knowledge Innovation Program of Chinese Academy of SciencesProject supported by the Scientific Research Foundation of State Education Ministry for the Returned Overseas Chinese Scholars,China
文摘Decomposition of sodium aluminate solution is the key step for alumina production;however,approximately only 55% alumina yield is obtained by seeded precipitation.So,it is difficult to obtain sodium aluminate solution with high caustic ratio.In this study,a method was explored to recover alumina from spent Bayer liquor by deep decomposition with methanol.A variety of conditions,including reaction temperature,reaction time,methanol amount and seed coefficient were elaborately investigated.The results showed that the appropriate conditions were 1:1 in volume ratio of methanol to spent Bayer liquor,more than 1.0 seed coefficient and in a 40℃water bath for 24 h.By characterizing through XRD,the crystal products were found to be Al(OH)3.With this method,the molar ratio of Na2O to Al2O3 of the spent liquor can be increased from about 3.0 to 10.0 due to the recovery of alumina,which is beneficial for the treatment of red mud.
文摘The assignments of the absorption peaks in the Fourier transform infrared (FTIR)spectra of the Bayer liquors were established in this study, which provided the basis for the study of Bayer liquors by FTIR techniques. The FTIR study of the Bayer liquors from two alumina refineries indicated that both liquors contained carbonate, humate and A1(OH); ions. The existence of sulphate ions in one of the liquors was also discovered.
基金Project(2005CB623702) supported by the National Key Basic Research Program of China
文摘A method for the simultaneous separation and determination of organic acids and inorganic anions in Bayer liquors was developed by gradient ion chromatography with suppressed conductivity detection. Formate, acetate, propionate, oxalate, succinate, glutarate, fluoride, chloride and sulfate were separated and determined in 33 min. The samples were pretreated with solid-phase extraction, which has high selectivity for removing a large number of metallic ions in the Bayer liquors, and filtered with a 0.45 μm filter membrane before being injected into the ion chromatographic system. The separation of six organic acids and three inorganic anions was achieved on an IonPac AS11-HC column with KOH as the eluent, and the detection was performed by a conductivity detection mode. No interference is found in the presence of fluorate, chlorate and sulphate when organic acids are determined. The calibration graphs of peak area for all the analytes are linear over a wide range. The relative standard derivation of the peak area of analytes is less than 2.14%. Under optimum conditions the detection ranges from 0.2 to 100.0 mg/L. The average recoveries of the added standards are between 94.3% and 102.8%.
文摘A new technology was developed to recover V2O5 from Bayer spent liquor by ion exchange.The experimental results show that in the conditions of 105℃ and 0.20-0.25 mass ratios between CaO in lime and Al2O3 in spent liquor, the precipitation rate of vanadium in Bayer liquor is more than 85%.The vanadium-bearing precipitation is leached by NaHCO3 solution.The leaching rate of vanadium can reach 85% in the conditions of 95℃, 40 g·L-1 of NaHCO3 concentration, and ventilating of CO2.The 201 × 7 type of resin has good adsorption effect on vanadium in the leaching solution.The adsorption rate is more than 94% with the flow rate of 0.09 mL·min-1·g-1 of leaching solution and the temperature of 40-50℃.By using 3 mol·L-1 of NaOH to desorb the saturated resin after adsorption at 40-50℃, a solution with more than 5 g·L-1 of V2O5 can be obtained.After roasting ammonium metavanadate that precipitates from the desorption solution when NH4Cl is added at the temperature of 500-550℃ for 2 h, V2O5 with more than 99% of purity is obtained.
基金support from the Natural Science Foundation of Hubei Province(2020BED011)XPS characterizations and ICP-OES were carried out in the Analytical and Testing Center in HUST.
文摘High purity ammonium metavanadate(NH_(4)VO_(3))is the most vital chemical to produce V2O5,VO2,VN alloy,VFe alloy and VOSO4,which have some prospective applications for high strength steel,smart window,infrared detector and imaging,large scale energy storage system.NH_(4)VO_(3)is usually produced by spontaneous crystallization from the aqueous solution due to its sharp dependence of solubility on the temperature.However,hazardous chemicals in industrial effluent,include phosphorate,silicate and arsenate,causing severe damage to the environment.In this work,these impurities are selectively precipitated onto inorganic flocculants,while the vanadate dissolved in an aqueous solution keeps almost undisturbed.Therefore,high purity NH_(4)VO_(3)is produced by the crystallization from the purified solution.By screening various flocculants and precipitating parameters,polyaluminum sulfate with an optimal amount of 50 g/L,is demonstrated to selectively remove phosphorate,silicate and arsenate,corresponding to the removing efficiency of 93.39%,97.11%and 88.31%,respectively.NH_(4)VO_(3)from the purified solution holds a purity of 99.21%,in comparison with 98.33%in the product from the crude solution.This purifying technology cannot only produce NH_(4)VO_(3)with high added value,but also reduce the environmental pollution of waste liquid.
