INFLUENCE OF IRON ON THE COMPLEXATION AND OXIDATION OF QUEBRACHO: AN INVESTIGATION ON THE STABILITY OF SULFUR DISPERSING AGENT

摘要

The oxidation of Quebracho was evaluated by acid-butanol assay, which indicates de-polymerization of Quebracho. Anthocyanidin, an oxidation product of Quebracho, is stable at 95°C for up to 2 h. The ionization, complexation, and oxidation properties of Quebracho were discussed. Complexation of metal-Quebracho occurs at ambient temperature. The formation of complex precipitates is influenced by the acidity of the solution. Temperature is another important parameter that influences the oxidation and the complexation of Quebracho. Quebracho-ferric complex precipitate forms at 90°C, 0.1 mol/L H_2SO_4. The formation of Quebracho-metal complex in the leach solution is a possible reason for the consumption of Quebracho. Quebracho molecules adsorption on the mineral surface is reduced by consumption of Quebracho, resulting in poor sulfur dispersing effect in the leaching process.