Process for the flocculation of suspended solids

Abstract

Aqueous dispersions of solids are readily flocculated with polymeric anionic flocculants containing comonomers of 2-acrylamido-2-methylpropanesulfonic acid and acrylamide. The polymeric flocculant should contain from about 1.0 to about 35.0 mole percent of repeating units derived from 2-acrylamido-2-methylpropanesulfonic acid and should have a Brookfield viscosity of at least 2.0 centipoises. In addition to their flocculating ability, employment of these copolymers achieves a high degree of compaction in the flocculated solids.

I claim: .[.1. A process for flocculating suspended solids which comprises adding to an aqueous suspension of solids selected from the group consisting of phosphate slime, uranium acid leach residue, copper acid leach residue, coal, coal refuse, and copper tailing from a flotation circuit an effective amount of a flocculant consisting essentially of a polymeric anionic flocculant wherein the polymeric anionic flocculant comprises from about 40 to about 99 mole percent of repeating units derived from acrylamide, from about 1 to about 35 mole percent of repeating units derived from 2-acrylamido-2-methylpropanesulfonic acid, and from 0 to about 25 mole percent of repeating units derived from acrylic acid, and wherein the polymeric anionic flocculant has a Brookfield viscosity of at least about 2.0 centipoises..]. .[.2. The process of claim 1 wherein the polymeric anionic flocculant employed comprises about 97 to 75 mole percent of repeating units derived from acrylamide, about 3 to 15 mole percent of repeating units derived from 2-acrylamido-2-methylpropanesulfonic acid and from 0 to 10 mole percent of repeating units derived from acrylic acid..]. .[.3. The process of claim 1 wherein the Brookfield viscosity is at least 3.30 centipoises..]. .[.4. The process of claim 1 wherein the polymeric anionic flocculant employed comprises about 97 to 85 mole percent of repeating units derived from acrylamide, about 3 to 15 mole percent of repeating units derived from 2-acrylamido-2-methylpropanesulfonic acid and from 0 to 10 mole percent of repeating units derived from acrylic acid and has a Brookfield viscosity of at least 3.30 centipoises..]. .[.5. A process for flocculating suspended solids which comprises adding to an aqueous suspension of phosphate slime solids an effective amount of a flocculant consisting essentially of a polymeric anionic flocculant wherein the polymeric anionic flocculant comprises from about 40 to about 99 mole percent of repeating units derived from acrylamide, from about 1 to about 35 mole percent of repeating units derived from 2-acrylamido-2-methylpropanesulfonic acid, and from 0 to about 25 mole percent of repeating units derived from acrylic acid, and wherein the polymeric anionic flocculant has a Brookfield viscosity of at least about 2.0 centipoises, flocculating solids causing them to settle and compacting the settled flocs to produce an underflow of flocculated material with a solids content greater than that of the suspension of solids..]. .[.6. The process of claim 5 wherein the polymeric anionic flocculant employed comprises about 97 to 85 mole percent of repeating units derived from acrylamide, about 3 to 15 mole percent of repeating units derived from 2-acrylamido-2-methylpropanesulfonic acid and from 0-10 mole percent of 
     
        repeating units derived from acrylic acid..]. .Iadd.7.  A process for flocculating suspending phosphate slime solids from an aqueous suspension thereof which comprises: (a) Adding to said suspension an effective amount of a polymeric anionic flocculant comprising: i. about 40 to about 99 mole percent of repeating units derived from acrylamide;   ii. about 10 to about 20 mole percent of repeating units derived from 2-acrylamido-2-methylpropanesulfonic acid; and   iii. 0 to about 25 mole percent of repeating units derived from acrylic acid; and wherein said polymeric anionic flocculant has a Brookfield viscosity of about 2.0 centipoises;       (b) Flocculating said solids causing them to settle; and   (c) Compacting the settled floc to produce an underflow of flocculated material with a solids content greater than that of the suspended solids; where the polymeric anionic flocculant has a Brookfield viscosity of at least about 2.0 centipoises. .Iaddend. .Iadd.8. The process according to claim 7 wherein said mole percent of said acrylic acid derived repeating units is 0 to about 10 mole percent. .Iaddend. .Iadd.9. The process according to claim 7 wherein said mole percent of said acrylamide derived units is about 80 to about 90 percent and the mole percent of said 2-acrylamide-2-methylpropanesulfonic acid derived units is about 10 to about 20 percent. .Iaddend. .Iadd.10. The process according to claim 7 wherein polymeric anionic flocculant is in the form of an emulsion comprising said polymer, water, oil and an emulsifier. .Iaddend. .Iadd.11. The process according to claim 10 wherein the mole percentage of said repeating units of said polymer derived from 2-acrylamido-2-methylpropanesulfonic acid is about 15 percent and the mole percentage of said repeating units of said polymer derived from acrylamide is about 85 percent. .Iaddend.