INFLUENCE OF PREPARATIVE HISTORY ON STRUCTURE AND PROPERTIES OF SODIUM ALUMINATE SOLUTIONS
(1.Shanghai Institute of Metallurgy, Academia Sinica Shanghai 200056, China;
2.Shanghai University of ,Science and Technology;
3.Shandong Aluminium Factory)
2.Shanghai University of ,Science and Technology;
3.Shandong Aluminium Factory)
Abstract: It has been found that samples of sodium aluminate solutions with the same composition but different preparative history may have different structure and physico-chemical properties. The structure of sodium aluminate solutions change very slowly during the storage after preparation. Sodium aluminate solutions contain several aluminium-bearing anions such as Al(OH)4-,. Al(OH)63- and [(HO)3Al-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 histories.
Key words: sodium aluminate solutions physico-chemical properties structure preparative history