Allied Colloids Limited

Ciba Specialty Chemicals Water Treatments Limited

Ab Cdm

John R Field

Peter Flesher

David Farrar

Anthony P Allen

Malcolm Hawe

Michael Green

Gillian M Moody

Trevor K Hunter

Paul Stocks

Nicholas D Smith

Peter James Tovey

Tony Whittaker

Mark Stephen Glachan

Timothy Ian Cameron

Jens Sorensen

Geoffrey S Gagen

Kenneth Guthrie Andrew

The present invention is directed to a process of making fired mineral pellets by mixing particulate mineral material with moisture and binder comprising substantially water soluble organic polymer to form a moist pelletizable mix, pelletizing the moist mix by a tumbling process to form green pellets and firing the green pellets, characterized in that the binder comprises alkali metal silicate in a dry weight amount which is either (a) above 0.13% based on moist mix or (b) above 0.08% based on moist mix and at least three times the dry weight of substantially water soluble organic polymer.

Mineral pelletisation

Flocculating or viscosifying compositions and their production and use

Dewatering of suspensions

In an iron ore pelletization process in which particulate ore is mixed with particulate polymeric binder in the presence of moisture and the mixture is pelletised, the particulate binder is a blend of ionic synthetic water soluble polymer, such as a copolymer of acrylamide and sodium acrylate having intrinsic viscosity 2 to 16 dl/g, with a larger amount of a guar gum.

Ore pelletization

Process and apparatus for controlling the dewatering of suspensions

Process and apparatus for dewatering controlled by monitoring light

Pelletisation process

Water absorbent particulate polymers and their uses are described. Friable aggregates may be made by bonding substantially dry polymer particles with an aqueous liquid and drying the aggregates. These aggregates can be broken down to the individual polymer particles upon mixing with an aqueous medium and thus can have the flow properties of relatively coarse particles and the performance properties of relatively fine particles. They may be soluble nd used as flocculants or viscosifiers or binders for, for instance, iron ore pelletisation. Alternatively they may be swellable and insoluble, for instance for converting a sticky particulate mass (such as coal fines filter cake) to a crumbly solid. When pellets are formed by compression moulding from a crumbly solid made by mixing water absorbent polymer particles with a sticky mass of inorganic particles (such as a coal fines filter cake) improved properties are obtained when the absorbent polymer particles are introduced in the form of a dispersion in water-immiscible liquid.

Polymeric compositions

Particulate material such as iron ore is agglomerated into pellets or other agglomerates by being homogeneously mixed in the presence of moisture with a binder followed by agglomeration of the moist mixture, and the binder comprises a water soluble anionic polymer having intrinsic viscosity of from about 2 to about 7 dl/g and containing 5 to about 20% by weight carboxylic monomer groups (measured as sodium salt). The preferred polymer of is the copolymer of acrylamide and 5 to 20%, preferably 5 to 15%, sodium acrylate. The binder may also comprise bentonite.

Agglomeration of particulate material employing a polymer

Iron ore particles or other water insoluble non-swellable particulate material is converted into pellets or other agglomerates by mixing with substantially dry binder in the presence of moisture and is then bonded into agglomerates. The binder comprises substantially dry bentonite and particulate polymeric material, and the bentonite is blended with the insoluble particulate material and moisture before addition of the polymeric material.

Agglomeration of particulate material mixed prior to addition of polymer

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.

Process for pelletizing particulate materials

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.

Dust suppressant for minerals

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. if they are added in the absence of an oil in water emulsifying agent.

Flocculation processes

An aqueous organic or inorganic suspension can be coagulated and then flocculated by flowing it past a shaped body comprising a mixture of water soluble multivalent metal coagulant and a water soluble organic polymeric flocculant in the form of substantially discrete particles. The surface of the shaped body is eroded by the flowing stream to form a solution of the coagulant in which the polymeric flocculant particles are entrained, and these subsequently dissolve into the suspension.

Products and processes for the flocculation of aqueous suspensions

Measurement of the ionic value X of a solution of a polyelectrolyte after shearing, for instance by a rotating blade, and/or measurement of the ionic value Y of a solution of polyelectrolyte before shearing, and especially the difference between t he values X and Y, gives a useful indication of the degree of cross linking of the polyelectrolyte and so can be utilized to control the manufacture of the polyelectrolyte, for instance drying conditions, or the storage or use of the polyelectrolyte, for instance its suitability or dosage in a flocculation process.

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West Yorkshire, United Kingdom

John R Field