It has been found that samples of sodium aluminate solutions with the same composition but different preparative history may have difTerent structure and physico-chemical properties.The structure of sodium-bearing alu...It has been found that samples of sodium aluminate solutions with the same composition but different preparative history may have difTerent structure and physico-chemical properties.The structure of sodium-bearing aluminate solutions change very slowly during the storage after preparation.Sodium aluminate solutions contain several ammunium-bearing anisons such as Al(OH)^(-)_(4),Al(OH)^(3-)_(6)and[(HO)_(3)Al-O-Al(OH)_(3)]^(2-),etc.These anions can convert to each other but the reactions are very slow owing to the formation or breakage of covalent Al-O bond.Hence the ratio between these anions approaches equilibrium very slowly after the preparation,and the structure or properties of these solution samples before equilibrium is reached depend on their preparative histosive.展开更多
1.IntroductionSodium aluminate solutions are veryimportant intermediate products in alumin-ium metallurgy.The physico-chemicalproperties of sodium aluminate solutions areconcerned by metallurgists and engineersdealing...1.IntroductionSodium aluminate solutions are veryimportant intermediate products in alumin-ium metallurgy.The physico-chemicalproperties of sodium aluminate solutions areconcerned by metallurgists and engineersdealing with alumina production[1].Thedata of viscosity,electroconductivity,UV展开更多
The constitution of high-caustic ratio and highly concentrated sodium aluminate solutions has been investigated by Raman spectra method.By comparison with the Raman spectra of crystalline solids of Ca_3[Al(OH)_6]_2 an...The constitution of high-caustic ratio and highly concentrated sodium aluminate solutions has been investigated by Raman spectra method.By comparison with the Raman spectra of crystalline solids of Ca_3[Al(OH)_6]_2 and Ba_2[Al_2(OH)_(10)],it can be concluded that AI(OH)_6^(3-)ion and perhaps its polymers may be formed in these solutions.展开更多
Na4EDTA and EDTA were adopted as new additives to intensify the seeded precipitation process of sodium aluminate solution. The effects of the two additives at certain concentrations on the seeded precipitation rate of...Na4EDTA and EDTA were adopted as new additives to intensify the seeded precipitation process of sodium aluminate solution. The effects of the two additives at certain concentrations on the seeded precipitation rate of sodium aluminate solution, particle size distribution (PSD) and morphology of precipitated gibbsite were investigated using titration method, particle size analyzer and scanning electron microscope (SEM), respectively. The results show that the two additives can accelerate the seeded precipitation rate of sodium aluminate solution. At relatively high concentration, the facilitative effect of EDTA on sodium aluminate solution is more obvious than that of Na4EDTA. EDTA makes gibbsite particles thinner than Na4EDTA. The Na+ and H+ result in the different effects on the seeded precipitation rate of sodium aluminate solution in spite of the same EDTA anion in the two additives.展开更多
The anionic species of the SiO_2-containing sodium aluminate solutions prepared by different methods have been investigated by Raman spectra and ultraviolet spectra.It was found that these solutions have different SiO...The anionic species of the SiO_2-containing sodium aluminate solutions prepared by different methods have been investigated by Raman spectra and ultraviolet spectra.It was found that these solutions have different SiO_2-containing anions.The solution prepared by leaching in- dustrial sinter of soda-lime sintering process contains polvsilicate ions with Si-O-Si radicals.展开更多
The electronic structure and the energy of various aluminate anions possibly existed in sodium aluminate solutions have been calculated by ah inilio and DV-Xct methods of quantum chemistry.The calculation results are ...The electronic structure and the energy of various aluminate anions possibly existed in sodium aluminate solutions have been calculated by ah inilio and DV-Xct methods of quantum chemistry.The calculation results are used to explain the experimental results of the spectroscopic study of sodium aluminate solutions.It has been found that Al(OH)4^(-)may be more stable than AlO_(2)in solutions,and that[(H0)3Al-O-Al(OH)_(3)]^(2-)may be more stable than[(HO)_(3)Al<H■H>Al(OH)_(3)]^(2-)anions.The ultraviolet spectra of sodium aluminate solutions are also interpreted by quantum chemical method.展开更多
基金supported by the National Natural Science Foundation of China
文摘It has been found that samples of sodium aluminate solutions with the same composition but different preparative history may have difTerent structure and physico-chemical properties.The structure of sodium-bearing aluminate solutions change very slowly during the storage after preparation.Sodium aluminate solutions contain several ammunium-bearing anisons such as Al(OH)^(-)_(4),Al(OH)^(3-)_(6)and[(HO)_(3)Al-O-Al(OH)_(3)]^(2-),etc.These anions can convert to each other but the reactions are very slow owing to the formation or breakage of covalent Al-O bond.Hence the ratio between these anions approaches equilibrium very slowly after the preparation,and the structure or properties of these solution samples before equilibrium is reached depend on their preparative histosive.
文摘1.IntroductionSodium aluminate solutions are veryimportant intermediate products in alumin-ium metallurgy.The physico-chemicalproperties of sodium aluminate solutions areconcerned by metallurgists and engineersdealing with alumina production[1].Thedata of viscosity,electroconductivity,UV
文摘The constitution of high-caustic ratio and highly concentrated sodium aluminate solutions has been investigated by Raman spectra method.By comparison with the Raman spectra of crystalline solids of Ca_3[Al(OH)_6]_2 and Ba_2[Al_2(OH)_(10)],it can be concluded that AI(OH)_6^(3-)ion and perhaps its polymers may be formed in these solutions.
基金Project(20476107) supported by the National Natural Science Foundation of ChinaProject(2005CB623702) supported by the National Basic Research Program of China
文摘Na4EDTA and EDTA were adopted as new additives to intensify the seeded precipitation process of sodium aluminate solution. The effects of the two additives at certain concentrations on the seeded precipitation rate of sodium aluminate solution, particle size distribution (PSD) and morphology of precipitated gibbsite were investigated using titration method, particle size analyzer and scanning electron microscope (SEM), respectively. The results show that the two additives can accelerate the seeded precipitation rate of sodium aluminate solution. At relatively high concentration, the facilitative effect of EDTA on sodium aluminate solution is more obvious than that of Na4EDTA. EDTA makes gibbsite particles thinner than Na4EDTA. The Na+ and H+ result in the different effects on the seeded precipitation rate of sodium aluminate solution in spite of the same EDTA anion in the two additives.
文摘The anionic species of the SiO_2-containing sodium aluminate solutions prepared by different methods have been investigated by Raman spectra and ultraviolet spectra.It was found that these solutions have different SiO_2-containing anions.The solution prepared by leaching in- dustrial sinter of soda-lime sintering process contains polvsilicate ions with Si-O-Si radicals.
基金supported by the National Natural Science Foundation of China。
文摘The electronic structure and the energy of various aluminate anions possibly existed in sodium aluminate solutions have been calculated by ah inilio and DV-Xct methods of quantum chemistry.The calculation results are used to explain the experimental results of the spectroscopic study of sodium aluminate solutions.It has been found that Al(OH)4^(-)may be more stable than AlO_(2)in solutions,and that[(H0)3Al-O-Al(OH)_(3)]^(2-)may be more stable than[(HO)_(3)Al<H■H>Al(OH)_(3)]^(2-)anions.The ultraviolet spectra of sodium aluminate solutions are also interpreted by quantum chemical method.
