Fuller's earth
Bleaching earth (also Walker earth or fuller's earth ) is the collective term for a mixture of various swellable layered silicates from the group of smectites , which the clay minerals belong. The main component is the montmorillonite .
Bleaching earth is mainly used as an adsorbent in the refining of edible oil (decolorization, cleaning and stabilization).
In the food industry, bleaching earth is used for fining wine, must and juice, for stabilizing beer and for cleaning sugar juice and syrup.
In the paper industry, bleaching earth is used as a pigment and color developer.
Fuller's earth can also be used as a binder for fat / oil on water.
To separate off dyes , hydroperoxides or heavy metals , fuller's earth ( aluminum silicate ) is added at 90 ° C. Often this happens in combination with activated charcoal .
Other fields of application were in cloth production . The soil was the substance when walking (engl fulling. Fullerene = Walker) of felt added to promote the entanglement of the fibers.
At Weilburg , Aachen and Roßwein as well as in Silesia and Styria , fuller earth deposits were mined in the 19th century.
See also
literature
- Entry to fuller's earth. In: Römpp Online . Georg Thieme Verlag, accessed on September 25, 2014.
- K. Jasmund, G. Lagaly, Tonminerale und Tone , Steinkopff Verlag, Darmstadt, ( 1993 ).
Individual evidence
- ^ Brockhaus ABC Chemie , VEB FA Brockhaus Verlag Leipzig 1965, p. 187.