Phosphate recovery processes
AssigneeAllied Colloids Limited
InventorsDonald Allen Luke, Geoffrey Steven Gagen
Life of this patent
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Abstract
A phosphate feed is separated into an enriched phosphate fraction and a waste aqueous stream which includes recoverable phosphate feed particles in an aqueous clay slime and which is flowed along a flow passage through a settling zone (where recoverable phosphate feed is recovered) into a quiescent sedimentation area where the slime settles, and water soluble polymeric flocculant for the slime is added to the aqueous stream to promote settling of the phosphate feed particles substantially without settling of slime in the settling zone and to accelerate sedimentation of flocculated slime in the sedimentation zone.
Claims16
A process in which a phosphate feed is separated in one or more primary separation stages into one or more phosphate enriched fractions and a waste aqueous stream containing recoverable phosphate feed particles suspended in an aqueous clay slime,
- the waste aqueous stream is flowed turbulently from a flocculant dosing point along a flow passage which leads through a settling zone for recoverable phosphate feed particles and discharges into a quiescent slime sedimentation area in which the slime sediments, and
- recoverable phosphate feed particles are settled in the settling zone and are recovered from the settling zone and returned to the one or more primary separation stages, and
- settlement of the phosphate feed particles substantially in the absence of the slime is accelerated in the settling zone and sedimentation of the slime is accelerated in the quiescent sedimentation area by flocculating the slime while the phosphate feed particles remain substantially unflocculated by adding a slime-flocculating amount of a water soluble polymeric cationic flocculant for the slime at the flocculant dosing point.
A process in which a phosphate feed is separated in one or more primary separation stages into one or more phosphate enriched fractions and a waste aqueous stream containing recoverable phosphate feed particles suspended in an aqueous clay slime,
- the waste aqueous stream is flowed turbulently from a flocculant dosing point along a flow passage which leads through a settling zone for recoverable phosphate feed particles and discharges into a quiescent slime sedimentation area in which the slime sediments, and
- recoverable phosphate feed particles are settled in the settling zone and are recovered from the settling zone and returned to the one or more primary separation stages, and
- the slime is flocculated, while the phosphate feed particles remain substantially unflocculated, before or during flow through the settling zone by addition of a slime-flocculating amount of water soluble polymeric cationic flocculant for the slime at the flocculant dosing point, the flocculated slime is held in suspension by the flow of the waste stream through the flow passage, the phosphate feed particles settle in the settling zone while substantially unflocculated, and the flocculated slime sediments in the quiescent sedimentation area.
Dependencies are inferred from the claim text.