GB474504A - Improvements relating to processes for the purification and/or decolourisation of oils and fats - Google Patents

Abstract

Oils, fats, and fatty acids, especially of animal or vegetable origin, are purified and decolorized by dehydrating and freeing the oil from solid impurities, then suspending in it in the absence of water and at normal temperatures, a small amount (between 0,1 and ,5 per cent) of a metal, metal oxide or salt in the form of a dry powder, and stirring the mixture until colour disappears, thereupon adding a small amount of an acid and heating to a temperature not exceeding 90 DEG C., and adding a powdered adsorbent. The oil is then filtered. The purification may be effected in a vacuum. The decolorized and filtered oil may be further treated at elevated temperatures and in vacuo with fuller's earth. Metal, metal oxides and salts specified are, pulverized nickel, cobalt, zinc, manganese or copper, oxides of copper, cobalt, manganese or nickel, or salts of these metals, e.g. manganate, benzoate, bichromate or chlorate. In an example, peanut, olive or palm oil is freed from solid impurities and 0,4 per cent by weight of manganese dioxide is stirred in. When free from colour, 0,2 per cent of sulphuric acid is added, and slowly heated to 90 DEG C. with addition of 3 to 4 per cent of fuller's earth and charcoal. The mixture is then filtered. The oil is free from colour, albumins and mucins, and soaps formed therefrom do not develop any colour. Petroleum oils may also be treated.