GB506300A - Improved process for the emulsification of tars and like substances - Google Patents

Abstract

506,300. Bituminous emulsions. WOODALL - DUCKHAM (1920), Ltd., and ARNOLD, E. March 2, 1938, No. 6514. Addition to 465,589. [Class 1 (i)] In the process described in the parent Specification wherein a water-in-oil emulsion is first made from the whole of the tar, pitch, or bitumen, &c., and a part of the water and an emulsifying agent, and this emulsion is then reversed by dispersion in a concentrated aqueous solution of an emulsifying agent, the emulsifying agent employed for the preparation of the water-in-oil emulsion consists of a solution containing farinaceous matter, e.g. starch, and an alkali or alkaline salt, e.g. caustic soda or trisodium phosphate or a mixture of such a solution with an alkali alginate, and the emulsifying agent used for reversing the water-in-oil emulsion consists of an alkalisoluble protein and a small amount of free alkali together with either an alkaline farinaceous solution or a mixture of such a solution and an alkali alginate. The viscosity of the final emulsion may be increased by decreasing the amount of water used in the first stage, and conversely, and the rate of breaking may bedecreased by increasing the proportion of alkali alginate used in the second or both stages, and conversely. The use of trisodium phosphate tends to increase stability. Formaldehyde may be added as a preservative. According to examples: (1) a water-in-oil emulsion of road tar is obtained with the aid of a starch solution containing either caustic soda or trisodium phosphate and a little formaldehyde. This emulsion is then reversed by stirring into a solution containing starch, casein and ammonia. The product may be diluted as required ; (2) an emulsion of road tar is prepared using a starch solution as above, and sodium alginate in the first stage and starch solution, sodium alginate, casein and ammonia in the second stage. This emulsion 'breaks less rapidly than that described in example 1 ; (3) an emulsion of coke-oven tar is made using starch solution containing trisodium phosphate and a little formaldehyde. In this case, it is necessary to use sodium alginate in addition to starch, casein and alkali in the second stage.