Bauxite Dissolution Conditions On The Structural Effects Of Sodium Aluminate Solution

Supersaturated sodium solution decomposition is an important process of alumina production. Research on the structures of sodium aluminum solution may provide basic data for the process of alumina production.Based on the IR, UV, Raman, XRD, SEM analysis and other modern analytical testing methods, the effects of concentration, alkali ratio on the structure of sodium aluminate solution as approximate industrial ingredients were investigated. Moreover, the influence of the dissolving-out temperature, bauxite type and time on the structure of sodium aluminate solution was studied. The influence of dissolving-out temperature on the structure and morphology of precipitation was also investigated.Conclusions are as follows:(1) When certain ak is involved, Al(OH)4 is the main ion at lower sodium aluminate concentration, while Al(OH)4-, [(HO)3Al-O-Al(OH)3]2-or more complex homopolymers exist at higher sodium aluminate concentration.(2) At a certain alumina concentration, polymers and ion pairs exists at lowerαk sodium aluminate solution; while main anion is Al(OH)4 at higherαk solution. At higher ak and higher concentration, Al(OH)63- and Al(OH)4 are the main species connected by hydrogen bonding.(3)The main species of Al(OH)4- in aluminate sodium solution combines with water hydration to form aluminate ions, which turns into various polymer aluminum metal ions and ion pairs after preparation a short time. The liquid structures of Shate bauxite and JinNan bauxite after precipitation are the same as those before precipitation. Liquid structure of YinNi bauxite is present as various polymers before precipitation, but turns into other ingredient or simplex polymer after precipitation.(4)The main anion of sodium aluminate solution is Al(OH)4 at lower dissolving-out temperature, while the anions are Al(OH)4- and [(HO)3Al-O-Al(OH)3]2- at higher dissolving-out temperature. Bauxite types have effect on the structure of sodium aluminate solution. Liquid structure of YinNi bauxite appears more complicate aluminate ions than JinNan bauxite.(5)Dissoving-out temperature have no obvious influence on the structure of sediment products ofα-Al(OH)3. The product is loose at higher dissoving-out temperature, while it is compact at lower dissoving-out temperature.