The adsorption of polysaccharides onto mineral surfaces: an acid/base interaction

Natural polysaccharides such as starch, dextrin, guar gum, cellulose and th eir derivatives are promising non-toxic organic depressants. Although gener ally perceived as non-selective, these polymers have found use in commercia l processes or have been tested in laboratories in practically all flotatio n systems involving every type of minerals. In this communication, the adso rption mechanisms of natural polysaccharides are reviewed, with the objecti ve of promoting the wider applications of the polymers. While it seems gene rally accepted that natural polysaccharides interact with minerals via surf ace metal-hydroxylated species, an acid/base interaction model between the natural polysaccharides and mineral surfaces is proposed to explain many ob served adsorption and flotation phenomena. (C) 2000 Elsevier Science B.V. A ll rights reserved.