Abstract Aqueous suspensions of solids with a wide particle size range having comparatively coarse materials including some larger than 65 mesh and very fine materials including some smaller than 325 mesh settle out with the solids in unclassified and in resuspendable form, when settling in the hindered state under non-Stokes conditions, is effected in the presence of a polymer of the acrylamide-acrylic acid-acrylonitrile type which causes the fines to remain with the large particles and settle out comparatively homogeneously. This aids in preventing deposits of coarse materials in settling tanks, leach tanks, internal combustion engines and their radiators, heat exchangers, cooling towers, flowing streams in natural or man-made water courses, and mine operations, and the polymer in solution can penetrate into coarse material with fines so that settled material can be resuspended, even if the polymer is introduced after at least some settling has occurred.
The process of claim 1 in which the polyelectrolyte is
Claim 2
Dependent Claim
35 words
The method of claim 1 in which silt and mud in tanks is fluidized and maintained in a readily resuspendable condition by adding said polymer to induce a thixotropic readily resuspendable character to settling solids.
Claim 3
Dependent Claim
193 words
In the method of manipulating sub-divided solids suspended in water in which the suspended solids include a substantial fraction of comparatively coarse materials larger than 65 mesh, and also a substantial fraction of very fine materials smaller than 325 mesh, the improvement which comprises: agitating said sub-divided solids with water and a small but effective amount of a suspending agent, from 0.005 to 5 pounds per ton of suspended solids, of a water soluble polyelectrolyte which is an ampholytic linear carbon chain vinyl polymer consisting essentially of recurring carbamylethylene and carboxyethylene linkages and not more than a minor amount of nitriloethylene linkages, and salts thereof, having a weight average molecular weight in excess Of 100,000, and uniformly dispersing the polyelectrolyte throughout the suspension, thereby forming a homogeneous suspension which is of uniform characteristics and from which the solids settle out in an unclassified readily resuspendable form, and transferring said suspension to a desired location, said polymer increasing the viscosity of the aqueous phase, insuring laminar flow at higher velocities, thereby reducing pumping power requirements, and simultaneously stabilizing the suspension, so that during interruptions in agitation, the suspension remains fluidized, and in pumpable condition.