Allied Colloids Limited

Ciba Specialty Chemicals Water Treatments Limited

Anthony P Allen

John R Field

John G Langley

Philip McColl

George Thomas Staines

Sten Forsmo

Peter Albert Sedders

Belt pressing or other pressure dewatering of a high solids mineral suspension is facilitated by flocculating the suspension by mixing into the suspension anionic flocculant having IV at least 5 dl/g and a minor amount of a cationic flocculant which generally has IV at least 4 dl/g. The flocculants are normally such that counterionic precipitation occurs.

Dewatering of aqueous suspensions

Thickening of aqueous mineral suspensions

A process is provided for pelletising a metal ore comprising forming an intimate mixture of particulate ore and a binder in the presence of moisture, forming green pellets by agitation of the mixture and firing the green pellets to produce ore pellets. In the process the binder comprises a hydroxamate polymer made from water-soluble ethylenically unsaturated monomer or monomer blend and which has pendant groups of the formula ##STR1## This provides advantages in wet strength, dry strength and drop number of pellets, especially at low moisture content of the pellets.

Ore pelletization

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.

Pelletisation process

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

Finely divided mineral ore is pelletized using a soluble synthetic polymer. Preferably the polymer is in the form of beads made by reverse phase polymerization and all having a size of below 300 .mu.m. When the ore gives a pH in water of below 8 the soluble polymer is preferably cationic.

Finely particulate iron ore is pelletized using finely particulate, free flowing, anionic water soluble synthetic polymer having intrinsic viscosity of from 3 to 16 as binder.

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West Yorkshire, United Kingdom

Anthony P Allen