GB259889A - Process of deflocculating solids - Google Patents

Abstract

259,889. Acheson, G. W. March 8, 1926, [Convention date]. Colloidal sols.-Solid bodies, such as graphite, carbon black, clay, pigments, lead arsenate, sulphur &c., are brought into the colloidal state by deflocculating and reflocculating them by attrition with an organic agent, such as tannin, cutch, or extracts from cereals or starchy bodies, and peptizing the reflocculated aggregates, preferably by means of an infusion of a grass such as hay or straw, though other suitable vegetable infusions may be used, or inorganic peptizing agents such as sodium silicate. For example, graphite in the form of a heavy paste is treated in a mill with 6 per cent of tannin, to which a small amount of ammonia has been added, until all the tannin has been absorbed. The operation is repeated, with further additions of tannin, until most or all of the deflocculated graphite is reflocculated. In the case of electric furnace graphite, for instance, 80 per cent of the charge was deflocculated and reflocculated after a total addition of tannin equal to 18 per cent of the weight of dry graphite. The reflocculated aggregates are then treated in the same or a second mill with the peptizing agent.