Nalco Chemical Company

Ralph W Kaesler

Dodd W Fong

Robert L Wetegrove

Lawrence J Connelly

Robert P Mahoney

Bhupati R Bhattacharyya

Daniel V Diep

Paul F Richardson

Gerard R Rose

Donald G Robinson

Brian K Failon

Wayne L Moss

A secondary polishing process for Bayer Process liquors suspension is described. The polishing process uses a combination of bio-polymers, particularly such bio-carbohydrates as dextran, with an inert insoluble solid, such as a filter aid, to treat the primary red mud settler overflow, then clarifying these treated overflow liquors in a secondary clarifier. Results provide for from 0-20 milligrams per liter suspended solids, often from 0-5 ppm suspended solids, and may make sand filter or Kelly filter operation an option in the Bayer Process.

Bayer liquor polishing

Improved methods are provided for the sulfomethylation of high molecular weight polyacrylamide polymers which reduce or minimize cross linking and result in polymers which have a reduced specific viscosity (RSV) greater than the polyacrylamide polymer used as the starting material polymer in the process.

Sulfomethylation of high molecular weight polyacrylamide

Acrylamide terpolymers which contain from 1-40 mole percent of acrylamido C.sub.1 -C.sub.3 alkyl of C.sub.1 -C.sub.3 hydroxy alkyl sulfonates may be prepared by using as the starting material aqueous acrylamide polymer gels.

Chemical modification of polyacrylamide and polyacrylic acids/acrylamide

Improved methods of sulfoethylation of high molecular weight polysoap acrylamide containing polymers to produce sulfoethylated acrylamide polymers in water-in-oil latex form having reduced specific viscosities (RSV's) above about 18.

Process for sulfoethylation of high molecular weight acrylamide

Separation of gypsum from phosphoric acid liquor produced during the production of phosphoric acid from finely ground phosphate rock. These aids are characterized as containing sulfonate and acrylamide.

Filtration aids for removal of calcium solids from aqueous phosphoric

A water-in-oil emulsion, the aqueous phase of which contains Amidase. An improved method of treating water-in-oil emulsions of acrylamide polymers with Amidase to reduce the acrylamide content thereof which comprises adding the Amidase in the form of a water-in-oil emulsion.

Water-in-oil emulsions of amidase

A high solids black liquor having the property of reduced turbulent flow/drag comprising a high solids black liquor which contains a few parts per million of a water soluble terpolymer containing the repeating units in the following mole percentages: ##STR1## wherein R is a lower alkyl group from 1-6 carbon atoms, M is H or alkali metal, said terpolymer having a Reduced Specific Viscosity of at least 25.

Viscosity/drag reducing additive for high solids black liquor

A process of flocculating suspended solids which comprises treating such suspension with an effective amount of a flocculant comprising a water-soluble terpolymer which contains sulfonate groups and has an RSV of at least 15.

Sulphonate-containing terpolymers as flocculants for suspended solids

An improved method for reducing the acrylamide present water-in-oil emulsions of acrylamide polymers with amidase which comprises adding the amidase to the water-in-oil emulsion of the acrylamide polymer upon completion of its polymerization and then subjecting the thus treated water-in-oil emulsion to one or more of the following steps:

Use of amidase for reducing the acrylamide content of water-in-oil

A method of dewatering BOF scrubbing liquid sludges which contain large amounts of finely divided iron oxides which comprises treating these sludges with a dewatering amount of an acrylamide acrylic acid, N-substituted lower alkyl acrylamide sulfonate terpolymer which contains from 35-80 mole percent of acrylamide, from 10-60 mole percent of acrylic acid and from 1-30 mole percent of the N-substituted lower alkyl acrylamide sulfonate which terpolymer has a reduced specific viscosity (RSV) of at least 25.

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Barrington, IL, United States of America

Ralph W Kaesler