Bleaching kaolin with organic acid and fermentation medium

PTMS magnetic separation

How does a magnetic frum separator work?

Kaolin used in coatings and filler applications in the paper industry requires a high level of brightness and therefore requires a treatment for the removal of iron, which adds color to the mineral to reduce its commercial value. The bleaching of kaolin is usually carried out by reduction leaching of iron, which produces effluents of considerable environmental problems. Although there are not many investigations, the use of organic acids appears to be a good alternative to iron removal and has the advantage of producing less polluted wastewater.

This paper describes the bleaching treatment of different Brazilian kaolin samples using organic acids and fermentation media. Aspergillus niger is used as a leaching agent. Studies have shown to be more effective when using oxalic acid and fermentation media. When a fermentation medium and oxalic acid were used as the bleaching agent, the brightness of the kaolin sample reached the level of the filler clay (the sample was not magnetically separated) and the coated clay (the sample subjected to magnetic separation). These results cannot be obtained by more traditional methods.