GB184473A - A process for purifying liquids - Google Patents

Abstract

Liquids are purified by treatment with a precipitate of an insoluble material formed outside the liquid with the aid of heat and afterwards removed by filtration. The precipitates are especially effective in removing substances that have a chemical similarity to them, e.g. calcium phosphate will remove calcium compounds and phosphates, calcium carbonate will remove calcium compounds and organic compounds. The precipitate can be produced in any known way and at a higher or lower temperature as a coarser or finer precipitate is required. The process may be used in combination with other known processes, e.g. decolorizing substances, such as decolorizing carbon or bleaching earth, may be employed along with the precipitate. The precipitate is preferably used when freshly precipitated, but it may be revivified after use and reused. When this is to be done the material treated is preferably first freed from coarse impurities by filtration, decantation, or washing with dilute acid or alkali. The precipitate is then dissolved wholly or in part and reprecipitated. It may first be ignited, or washed with a dilute acid or alkali, or these methods may be used in combination. The liquid may be treated with an electric current during purification, or catalysts or electrolytes may be added. When this process is used for treating oils and fats the precipitate is first washed with alcohol or alkali. The Specification as open to inspection under Sect 91 (3) (a) mentions the application of the invention to mineral oils and greases, benzine and glycerine. This subject-matter does not appear in the Specification as accepted.