# US 5,346,628 A · Polymers for flocculating red mud from bayer process liquors

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- Number: US 5,346,628 A
- Document ID: US5346628A
- Status: Granted
- Kind: A
- Application number: 08/146,288
- Filed: 1993-10-29
- Granted: 1994-09-13
- Earliest claimed: 1993-10-29
- Assignees: Nalco Chemical Company
- Inventors: Anthony G. Sommese; Robert P. Mahoney
- Web page: https://patentgrep.com/patent/US5346628A

## CPC

- C02F 1/54: using organic material
- C01F 7/0653: characterised by the flocculant added to the slurry (final clarification of the aluminate solution C01F7/47)
- C02F: TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE (separation in general B01D; special arrangements on waterborne vessels of installations for treating water, waste water or sewage, e.g. for producing fresh water, B63J; adding materials to water to prevent corrosion C23F; treating radioactively-contaminated liquids G21F9/04; regeneration of reactants for recirculation into processes, see the relevant places for the processes)
- C01F: COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS (metal hydrides {monoborane, diborane or addition complexes thereof} C01B6/00; salts of oxyacids of halogens C01B11/00; peroxides, salts of peroxyacids C01B15/00; sulfides or polysulfides of magnesium, calcium, strontium, or barium C01B17/42; thiosulfates, dithionites, polythionates C01B17/64; compounds containing selenium or tellurium C01B19/00; binary compounds of nitrogen with metals C01B21/06; azides C01B21/08; {compounds other than ammonia or cyanogen containing nitrogen and non-metals and optionally metals C01B21/082; amides or imides of silicon C01B21/087}; metal {imides or} amides C01B21/092, {C01B21/0923}; nitrites C01B21/50; {compounds of noble gases C01B23/0005}; phosphides C01B25/08; salts of oxyacids of phosphorus C01B25/16; carbides C01B32/90; compounds containing silicon C01B33/00; compounds containing boron C01B35/00; compounds having molecular sieve properties but not having base-exchange properties C01B37/00; compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites, C01B39/00; cyanides C01C3/08; salts of cyanic acid C01C3/14; salts of cyanamide C01C3/16; thiocyanates C01C3/20; {double sulfates of magnesium with sodium or potassium C01D5/12; with other alkali metals C01D15/00, C01D17/00})

## Abstract

Red mud is flocculated from Bayer process liquors using a polymer which contains vinylamine and/or vinylformamide.

## Claims

### Claim 1

A method for settling red mud from a Bayer process liquor, the method comprises adding to a Bayer process liquor containing suspended red mud a flocculant polymer which contains acrylic acid and from about 1 to about 99 mole percent of at least one monomer selected from the group consisting of vinylamine and vinylformamide.

### Claim 2 (depends on 1)

The method of claim 1 where the polymer is a copolymer which contains between 2-50 mole percent of vinylamine.

### Claim 3 (depends on 1)

The method of claim 1 where the polymer is a terpolymer which contains vinylamine and vinylformamide in amounts ranging between from about 2 to about 50 and from about 2 to about 50 mole percent, respectively.

### Claim 4 (depends on 1)

The method of claim 1 where the polymer is a copolymer which contains between 10-40 mole percent of vinylamine.

### Claim 5 (depends on 1)

The method of claim 1 where the polymer is added to a settler feed of the Bayer process.

### Claim 6 (depends on 1)

The method of claim 1 where the polymer is added to a washer train of the Bayer process.

### Claim 7 (depends on 1)

The method of claim 1 where the copolymer is derived from a lower (meth)acrylate ester or amide and vinylformamide which is subjected to hydrolysis to produce (meth)acrylate-vinylamine copolymers.

### Claim 8 (depends on 1)

The method of claim 1, wherein the polymer is added to the Bayer liquor in conjunction with another flocculant selected from the group consisting of polyacrylates, hydroxamated polymer, acrylamide-acrylate copolymers, starch and dextran.