Process for the treatment of a colloidal suspension

DETAILED DESCRIPTION Generally speaking, a solid-liquid separation process is provided for separating colloidally-suspended solids such as clay, metal minerals and hydroxides, color materials, BOD, COD, organic and inorganic materials and like substances from a mother liquor wherein the solids concentration is less than 10 g/l and for yielding a clarified effluent of low impurity content.
The conversion involves the addition of an inorganic metal salt flocculating agent to destabilize and coagulate the colloidal suspension followed by the addition of an organic, high molecular weight flocculating agent after a suitable time interval and subjection of the resultant suspension to shear within a critical range of energy input.
The suspended solids are agglomerated to a coagulum of substantially spherical particles characterized by a high density, large particle size and generally exhibit different properties from the flocs thereof, said flocs being formed by the addition of the inorganic metal salt flocculating agent.
The coagulum separates from a supernatant at about 5 to about 10 times the precipitation rate of a floc treated according to a conventional flocculation-precipitation method.
The resulting sludge exhibits superior condensability and is extremely suitable for treatment by a known hydroextraction technique.
It is, therefore, a principal object of the invention to provide a method for separating a substantially low concentration of suspended solids from a colloidal suspension.
It is another object of the invention to provide a method for separating colloidally-suspended solids from the mother liquor of a suspension wherein the solids concentration is below 10 g/l.
Yet another object of the invention is to provide a process for the separation of colloidally-suspended solids from the mother liquor of a suspension by a process which proceeds at about 5 to 10 times the separation rate of a conventional flocculation-precipitation process, and provides a highly condensable sludge which may be treated by any known hydroextraction technique with excellent results