GB409278A - Improvements in the manufacture and production of high quality asphalts - Google Patents

Abstract

Asphalts are recovered from oily substances containing them by precipitation in stages with different substances having successively increasing precipitating power. The precipitating agents consecutively used preferably consist of hydrocarbons of decreasing molecular weight, for example heavy oil, middle oil, benzine and liquefied gaseous hydrocarbons such as pentane, butane, propane or ethane. The liquefied saturated hydrocarbons may be mixed with or replaced by liquefied unsaturated hydrocarbons. The asphalt-containing raw materials may consist of crude petroleum, or distillation, cracking or destructive hydrogenation residues obtained from coal, tars or mineral oils. In examples: (1) a petroleum residue is heated to 50 DEG C. under pressure with liquefied butane. After standing the precipitated asphalt is separated off and the mixture of butane and oil is mingled with a mixture of propane and ethane, when a further amount of asphalt is precipitated; (2) a residue obtained in the destructive hydrogenation of brown coal is treated in successive stages with illuminating oil, benzine and liquefied propane, the asphalt precipitates and the precipitating agent being separated from the oil at each stage. The asphalts obtained differ in physical properties and may be used in the preparation of electrical insulations, anti-rust agents and road surfacing compositions. The oils may be purified simultaneously by adding to the precipitating agents sulphur dioxide, phenol, aniline, nitrobenzene, furfurol, ketones, dichlorethane, aceto-nitrile or benzo nitrile or these reagents may be used with the asphalt-free oil. The purified oil may be used as a lubricating oil and improved by treatment with hydrogen under elevated temperatures and pressures in the presence of a catalyst. Specification 365,046 is referred to.