GB379710A - Process for the emulsification of bituminous and like substances, especially for theproduction of road-surfaces - Google Patents

Abstract

Comparatively unstable aqueous emulsions of bitumen and the like, employed particularly for road surfacing, are prepared by introducing the material, heated to a temperature considerably above the boiling-point of water, say, 130-160 DEG C., and preferably in fine streams, into the water or aqueous emulsifying agent, at a speed predetermined as that required to produce spontaneous dispersion, without the necessity of stirring, by the action of the steam produced. A coagulating agent such as acid petroleum pitch may be added to the materials before dispersion, or such an agent, or inorganic salts, may be added for the same purpose to the prepared emulsion. Mixtures of tar with 15-23 per cent of natural asphalt may be emulsified as above, although tar itself, or mixtures outside the stated proportions are stated to produce reversed emulsions. Mixtures of up to 15 parts of natural bitumen with up to 85 parts of tar-petroleum-pitch mixtures containing at least 15 parts of tar are stated, when treated according to the invention, to produce stable jelly-like emulsions which revert to mobile form on stirring. Examples of the invention are as follows: (1) 100 kgs. of bitumen, which may contain about 0,7 per cent of fats, fatty or naphthenic acids or solvents, are heated to 140 DEG C. and added to 100 kgs. of water, at 95-100 DEG C. and containing if desired 0,3 per cent of alkali, the addition taking \ba1/2\be-8 minutes as predetermined; (2) the bitumen in (1) may contain 0,7 per cent of acid pitch as coagulant; (3) the bitumen of (1) may be replaced by 78 kgs. of tar, 4 kgs. of petroleum pitch and 17 kgs. of natural asphalt, and 1 kg. of soap may be added; (4) a jelly-like emulsion is prepared as in (1) from 60 kgs. of natural bitumen, 30 kgs. of petroleum pitch and 20 kgs. of tar; (5) to an emulsion made as in (1) and comprising 50 parts of Trinidad asphalt, 30 parts petroleum pitch and 20 parts of tar, up to 0,5 per cent of solid common salt is added as coagulant while hot and immediately before use on the road.