Abstract: The addition of polymeric flocculant or other chemical dewatering modifier to a suspension flowing through a service line to a dewatering plant is controlled automatically in response to automatic determination of a filtration rate parameter. This may be determined using novel apparatus which includes a filtration assembly comprising a chamber with a filter element mounted across its open end and water sprays for washing the filter element. In one embodiment it is preferred to assist back-washing with an air purge while in another embodiment there are means for disassembling the filtration assembly to permit cleaning.

Abstract: A particulate composition comprises particles having a substantially anhydrous core comprising an active ingredient. Generally the core comprises a matrix polymer with the active ingredient distributed throughout this. Generally there is an outer protection shell of polymer, generally formed by coacervation. The invention is a value for the production of powders, dispersions in non-aqueous liquids (for instance when the active ingredient is a detergent enzyme) and dispersions in water (for instance when the active ingredient is an agrochemical.

Abstract: A water soluble, substantially linear, polymer is made by copolymerization of a water soluble blend of monoethylenically unsaturated monomers comprising carboxylic acid monomers such as acrylic acid and a hydroxylic monomer of the formula CHR.sup.1 .dbd.CR.sup.2 --Y--M.sub.a --H where R.sup.1 is hydrogen or carboxy, R.sup.2 is hydrogen, carboxy or methyl, Y is O, CH.sub.2 O or COO, M is alkyleneoxy and a is at least 5. This polymer can be cross linked, generally after being shaped by extrusion or other shaping of an aqueous solution of the polymer, to form cross linkages between the carboxyl and hydroxyl groups. The shaped elements can have water absorbency and can be in the form of, for instance, fibers or films.

Abstract: A graft copolymer is made by grafting, by a free radical reaction mechanism in aqueous solution, water soluble ethylenically unsaturated monomeric material on to a water soluble substrate having hydroxyl groups, and the free radicals are formed on the substrate using an oxidizing metal capable of being reduced by the substrate to a lower valency state (for instance cerium) and persulphate or other peroxy compound capable of oxidizing the metal back to a higher valency state. The process is preferably conducted as a reverse phase polymerization process and the invention includes also a novel reverse phase emulsion comprising a dispersion of reverse phase polymer particles of a graft copolymer of carboxymethyl cellulose, dextran or starch with acrylamide and acrylic acid and/or AMPS.

Abstract: In a Bayer process for production of aluminum, alumina trihydrate crystals are formed in the pregnant liquor and are flocculated using a combination of dextran and synthetic polymer, usually a homo- or copolymer of acrylic acid. The process is particularly advantageous where the liquor contains organic components such as humate and/or oxalate.

Abstract: Enzymes and other biologically produced materials are recovered from the fermentation broth or other liquor in which they are provided initially and simultaneously distributed throughout particles of a polymeric matrix by dissolving the polymer in the liquor, dispersing the resultant polymer solution in a non-aqueous liquor in the presence of a stabiliser, and azeotroping the dispersion to produce either dry beads or a dispersion of small particles in the non-aqueous liquid.

Abstract: Particulate metal ore is pellitized by use of a novel polymeric binder that comprises aggregates of polymer particles and that have a size mainly above 100 .mu.m and the aggregates are disintegrated during the process.

Abstract: The invention provides a substantially dry particulate composition comprising a polyacrylamide and an amidase. An aqueous composition made by dispersing this into water will then have a satisfactorily low content of residual acrylamide even if the initial polymer was contaminated with monomer. The composition is made by blending dry polyacrylamide particles with the amidase.

Abstract: Oil dispersions of water-soluble anionic polymer particles and water-soluble cationic polymer particles are mixed with water to form an aqueous solution containing one polymer in an amount in the range 10 to 40 mole % (moles of anionic groups) and the other polymer in an amount in the range 60 to 90 mole %. The solution is immediately applied to a surface to suppress release of dust from that surface.

Abstract: Dry market pulp is made by shearing a cellulosic suspension and draining it through a screen to form a pulp sheet which is then dried, and the productivity of the process is increased by adding a water soluble cationic polymer before the shearing and bentonite or other suitable inorganic material after the shearing.

Abstract: A water absorbent water insoluble polymeric element, such as fibre, film, coating, bonding layer or foam, is made by forming a substantially linear polymer by polymerization of water soluble ethylenically unsaturated monomer blends comprising carboxylic and hydroxylic monomers and then reacting the carboxylic and hydroxylic monomers in the linear polymer to form internal cross links within the polymer.

Abstract: An oil soluble polymeric surfactant that is particularly useful for stabilizing reverse phase polymer dispersions, especially when they are subjected to azeotroping, is a reaction product of an oil soluble polyester carboxylic acid (such as poly-hydroxy stearic acid) and a water soluble polyamine (such as polyethylene imine) of molecular weight above 500 and that contains at least 5 basic nitrogen atoms.

Abstract: When making an amide by hydrolysis of a nitrile in an aqueous medium containing a Raney copper or other black copper catalyst, the hydrolysis reaction can be improved if the catalyst has been contacted with an aqueous solution of a water soluble vanadium compound followed by thorough rinsing before introduction into the aqueous medium.

Abstract: When drying an aqueous polysaccharide solution, the viscosification properties are maintained, and often improved, by including a low molecular weight electrolyte in the solution before the drying is completed, and generally before the solution is heated above 50.degree. C.

Abstract: An intimate water soluble or water swellable blend of microbial polysaccharide and synthetic polymer derived from water soluble monomer or monomer blend is made by forming an emulsion in non-aqueous liquid of an aqueous fermentation solution of the microbial polysaccharide and the monomer or monomer blend and then polymerizing the monomer or monomer blend to form a dispersion in non-aqueous liquid of aqueous particles of the water soluble or water swellable blend. This dispersion may then be dehydrated.

Abstract: Sulfonated polymers and copolymers are used as thinners in aqueous drilling or packer fluids. The sulfonated polymer has polydispersity below 2 and has a low solution viscosity. It is generally a copolymer of beta-arylamidoalkane sulfonate or allyl sulfonate or other aliphatic sulfonate with an ethylenically unsaturated carboxylic acid, generally acrylic acid.

Abstract: When flocculating an aqueous suspension of suspended solids using a high molecular weight synthetic polymeric flocculant the shear stability of the flocs is increased if the polymeric material includes polymeric particles of below 10 .mu.m dry size. The flocculated solids can therefore be subjected to shear without increasing the amount of discrete suspended solids in the aqueous medium and generally they are suspended to shear by shearing the aqueous medium containing them, either before dewatering, generally on a centrifuge, piston press or belt press, or by continuously agitating them, for instance in a chemical reaction medium. The polymeric material is generally formed by mixing into water polymeric particles made by reverse phase or emulsion polymerization in the presence of added cross linking agent. Alternatively particles insolubilized by insoluble monomer may be used. A reverse phase dispersion of water soluble polymer may be used if the particles remain undissolved, e.g.

Abstract: Paper or paper board is made by passing an aqueous cellulosic suspension through a centriscreen or other shear device and then draining the purified suspension, and an improved combination of retention, drainage, drying and formation is achieved by adding to the suspension an excess of high molecular weight linear synthetic cationic polymer before shearing the suspension and adding bentonite after shearing.

Abstract: When making an a amide by hydrolysis of a nitrile in an aqueous medium containing a Raney copper catalyst, the yield of amide can be increased and the yield of impurities can be decreased by including vanadium metal in the catalyst. The vanadium may be present as Raney vanadium often as an alloy in the Raney copper.

Abstract: A particulate mass that can be dusty but is generally sticky, due to the presence of water, is coverted to an apparently dry, non-dusty granular material by polymerizing a polymerizable material within the mass and breaking the mass down to the desired granular form after the polymerization has gone sufficiently far that the mass is substantially non-sticky but before the polymerization is completed.