Anhydrous Preparation Of Sodium Metaaluminate
May 19, 2023
Sodium metaaluminate does not exist in the solution, solid state high temperature reaction can generate sodium metaaluminate
The compound produced by the reaction of metal aluminum and sodium hydroxide solution was once considered to be NaAlO2, but scientific research has proved that the product is actually Na[Al(OH)4] (sodium tetrahydroxyaluminate), which belongs to the coordination compound.
To prepare sodium metaaluminate with molecular formula NaAlO2, the method is to add activated alumina to molten sodium hydroxide, the product is sodium metaaluminate and water, and water evaporates in the form of gas, the equation is:
Al2O3+2NaOH=high temperature=2NaAlO2+H2O(g)↑(water vapor)
Sodium metaaluminate is formed when dry alumina is melted with sodium carbonate [2]. The reaction equation is as follows:
Al2O3+Na2CO3=2NaAlO2+CO2
Hydrated alumina and sodium carbonate are heated to 950 ° C, that is, sodium metaaluminate and sodium aluminate are formed (a)
(a) 2Al2O3·H2O+2Na2CO3→NaAlO2+Na3AlO3+Al2O3+2H2O↑+2CO2↑;
The latter generates sodium metaaluminate (b) when heated to 1200°C.
(b) NaAlO2+Na3AlO3+Al2O3═4NaAlO2
