Verfahren zur Regenerierung von gebrauchten ölhaltigen Bleicherden

摘要

A process for regenerating used oil-containing clays is characterised by a combination of the following steps; (a) de-oiling the used clay by extraction with an oil solvent down to a maximum 25% by weight (of C) residual content of carbonated substances; (b) thermal treatment of the de-oiled clay in an oxidising atmosphere at a temperature from 500 to 650 DEG C until the clay is practically free from organic carbonated substances, whereas the structure of the clay remains largely intact and the montmorillonite content of the clay is practically not reduced; (c) admixture to the thus obtained product of an aqueous acid in an amount, concentration and temperature selected so that practically no inorganic components are dissolved out of the product and the water content of the product lies between 2 and 10, preferably between 5 and 8% by weight.