80 Years Activated Bleaching Earth

Abstract

Fuller's Earth, as bleaching earth has been called, was used for thousands of yearsin thecleaningofwoolandclothes.Itsdecolourisationabilitywasdetectedinmoderntimesby David Wessoninabout 187X-XO.Itisnow8Oyearsthat a small company "Erdwerke Kronwinkl Franz Schmid & Co. GmbH" was founded.This company was the root of the today's activated bleaching earth. The paper reports on the development of this company and the early history of acid activated bleaching earth. Fahn,Fette . Seifen . Anstrichmittel 75,77 [ 19731. 'I W Zschu, What is Bleaching Clay, AOCS Short Course, Lake 32 R. Fahn, La Filtration dam le Raffinage et le Fractionnement des 33 H. Eicke, Der gegenw,irtigeStand der Bleichung im Rainations-prozeB pflanzlicher Ole und tierischer Fette, Fette . Seifen . Anstrichmittel 87,355 [ 19851.

Palm oil refining

“…It was assumed that the rise in refined oil red color could be due to color formation caused by both oxidized fatty acids and oxidized carotenoids: elevated temperatures would increase the formation of the color bodies. Although the refined oil color rose with increasing bleach temperature, the oxidative stability index (OSI) values indicated an optimum around 120 7C, in agreement with other work [13,32]. It may be argued that by increasing the bleaching earth dosage or by altering other refining parameters, oil of any DOBI value could be adequately refined.…”

“…If instead of phosphoric or citric acid, pure water (up to 1.5%) is added at the same time as the clays at atmospheric pressure (wet bleaching), phosphorus removal is very efficient; the data correlate with the quantity of water (Tab. 4) [32]. Indeed, the clays have also acidic properties and ion exchange capacity and could take the role of phosphoric and citric acids.…”

“…Compared to the normal bleaching earths, these materials have a much higher adsorption capacity for phosphatides, soaps and metal traces and can partially replace the bleaching earths. However, pigments (chlorophyll, carotenoids) are weakly adsorbed by these silical gels [32].…”

“…Savings of up to 30% are reported. Pre-treatment with silica is particularly interest- (7) filter [32].…”