Surface charge properties of red mud particles generated from Chinese diaspore bauxite

• Published in: Transactions of Nonferrous Metals Society of China Vol. 18; no. 5; pp. 1285 - 1289
• Main Author: 张琨瑜 胡慧萍 张丽娟 陈启元
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.10.2008; School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China
• Subjects: bauxite; point of zero charge; potentiometric titration; red mud; surface charge; 表面炉料; 金属学; 铝土矿; surface charge; bauxite; red mud; potentiometric titration; point of zero charge
• ISSN: 1003-6326
• DOI: 10.1016/S1003-6326(08)60218-6

Acid/basic potentiometric titration can be used to quantify the red mud surface charge properties. The amount of surface active --OH groups and surface charge density on the red mud particles generated from Chinese diaspore bauxite were evaluated from the acid/basic potentiometric titration data in 0.1 mol/L or 0.5 mol/L NaCl solution. The results show that the adsorption of sodium polyacrylate（SPA） on the red mud surface causes the increase of the surface active --OH groups, which makes the point of zero charge（PZC） shift to a lower pH value. However, the adsorption of polyacrylamide（PAM） causes little change. As the concentration of NaCl solution increases, the surface charge becomes more positive in acidic solution and more negative in alkaline solution, which can be attributed to the presence of a porous surface gel coating on the red mud particles.