GB343427A - A process for the production of aqueous dispersions of bituminous materials - Google Patents

Abstract

Aqueous dispersions of asphalt, pitch and other bituminous materials, having melting points of about 100 DEG to 220 DEG F., the dispersed particles of which will remain in suspension over indefinite periods of time without any noticeable settling, are made with the use, as dispersing agents, of argillaceous materials such as bentonite and clay, or mixtures thereof, with or without the addition of protective colloids, in an amount not exceeding 10 per cent by weight of the dispersed phase, the temperature of dispersion being not substantially higher than the melting point of the material dispersed so that the average size of the dispersed particles is not substantially greater than 10 microns, the water content of the dispersion being kept below the point (about 40 per cent) where further dilution substantially decreases the suspendability of the dispersed particles, and the dispersion on leaving the dispersing apparatus being subjected, without addition of water, to a rapid beating or whipping action, which may be performed in the beating apparatus described in Specification 334,100, [Class 81 (i), Disinfecting &c.]. By using not more than 10 per cent of dispersing agent, a dispersion is obtained which, when once freed from water, will not redisperse. Bentonite and clay mixtures containing from about 10 to 75 per cent of the former may be used, or bentonite with a protective colloid, e.g. upwards of 5 per cent of alkali casein may be employed. New Jersey ball clay and casein, swollen with ammonia or sodium borate solution, may be used to give a dispersion containing 1,4 per cent clay, 0,7 per cent casein, and about 70 per cent asphalt, the remainder being water. The suspendability of the dispersed particles is conveniently tested by centrifuging. In an example, Mexican asphalt, melting point 105 DEG F., heated to about 165 DEG F., and a suspension containing about 5 per cent of bentonite in water, having a viscosity above 45 seconds and preferably a pH of about 7,5, are fed simultaneously, in proportions of 1\ba1/2\be-2 to 1 respectively, to a dispersing apparatus the contents of which are maintained at 105 to 110 DEG F. The dispersion obtained is beaten to reduce its viscosity, and has a water content of 30-40 per cent. Specifications 244,135, [Class 81 (i), Disinfecting &c.] and 341,443 also are referred to.