DIAO Runli 1, LIU Dandan 2
(1. Henan Quality Polytechnic, Pingdingshan 467001, Henan, China; 2.Key Laboratory of Ecological Restoration in Hilly Area, Pingdingshan University, Pingdingshan 467000, Henan, China)
Abstract: In order to overcome the shortcoming of the chemical method of removing iron, refined kaolin was obtained by purifying with sodium citrate and NaOH mixed to 2:1, de-ironing with Na2S2O4and calcination. The influences of the dosages of the purification agents,Na2S2O4, and oxalic acid, calcination temperature, etc. on the iron removal and bleaching result of Pingdingshan kaolin were investigated.The best iron removal and bleaching solution was discovered. When the concentration of the mineral slurry was 10%, the dosage of the purification agents was 0.5wt.%, the dosage of Na2S2O4 was 3wt.%, the dosage of oxalic acid was 1.5wt.%, and the calcinations temperature was 800 ℃, the mass fraction of Fe2O3 in kaolin dropped from1.08% to 0.31%, and the kaolin whiteness increased from 59.3° to 85.7°.
Key words: kaolin; Pingdingshan; iron removal; bleaching