Development of Tonsil®-bleaching earths – historical background

Naturally-active bleaching earths have been used under the name of “fuller’s earth” since about 1880. The discovery goes back to information which indicated that, in the orient, the colour of olive oil was sometimes improved by the addition of clay.

Manufacturing oil
Manufacturing oil about 1580 (copperplate by Galle, after Jan van der Straet)

Clay Silicates, “Tonsilikate” in German, such as bentonite, can be transformed into
highly active bleaching earths by treatment with acid. This discovery was made at the beginning of the last century, when the acidic activation of bentonite – the main constituent of which is montmorillonite – was invented independently in two laboratories. The process was then improved, and a new facility was built at Moosburg, which to this day is still our main plant for the production of Tonsil® bleaching earths. The original use as a colour reduction agent to lighten dark oils has undergone some major changes in the course of the years, thanks to new modern technologies. Bleaching earths have been developed into adsorption earths,
in which context not only the high adsorption capacity of colour bodies and other undesirable oil constituents are of major importance, but also their acidic and catalytic properties, as well as their ionexchanging capability. Tonsil® is the brand name of our highly-active bleaching earths, which are created from natural bentonites by acid activation. Thanks to persistent research and development, we are in a position today to offer a wide range of tailor-made Tonsil® grades.
Their properties are especially adapted to suit the requirements of our customers, requirements which often differ very widely. The consistently high quality of our products over decades, and our intensive co-operation with customers all over the world, have made Tonsil® bleaching earths a name which is recognised and appreciated all over the globe as a leader in its field.

We have taken account of this major significance of our bleaching earths, for the manufacture of vegetable and animal oils and fats as a basic foodstuff, by the establishment of production facilities in a variety of different regions. Our “Adsorbents and Additives” Division today operates state-of-the-art plants in Germany, Indonesia, Mexico, Spain, Peru, South Africa and Brazil.