Experimental Study of Pollutant Removal Chemical Techniques in the Bayer Process

In this work, carbonate and oxalate creating factors were determined in the Bayer process. In the chemical removal of carbonate and sodium oxalate soluble in sodium aluminate liquor, barium aluminate with structures of Ba2Al2O5, Ba2Al4(OH)16 and BaAl2O4, calcium aluminate (Ca3Al2(OH)12), sodium phosphate (Na3PO4) and lime were separately used. Investigation of temperature, concentration of caustic soda, Al2O3 and sodium carbonate revealed that using barium aluminate with the structure of Ba2Al4(OH)16 with the removal efficiency of carbonate equal to 80.2% and sodium phosphate (Na3PO4) and lime with the removal efficiency equal to 66.9% in oxalate removal, have maximum efficiency. The results also showed that lime and bauxite lead to 66.9 and 99.9% of carbonate and oxalate pollutions in Bayer process liquor, respectively.