Claims
- 1. A process for recovering phosphorus from phosphorus sludge, produced in an electric furnace by reductive heating of agglomerated phosphate shale which comprises, passing said sludge into a centrifugal separator having a rotating bowl which is capable of exerting sufficient centrifugal pressure to break a stable phosphorus emulsion in the sludge and coalesce phosphorus globules present within said sludge and a subsequent recycle underflow stream from a hydrocyclone, coalescing phosphorus globules in said centrifugal separator removing a heavy fraction from one outlet of said separator containing the major portion of phosphorus in coalesced form along with heavy dirt, removing a light fraction containing fine dirt slimes and a minor amount of uncoalesced phosphorus from a second outlet of said separator, introducing said light fraction into a hydrocyclone having a diameter of not substantially larger than about 1-inch under sufficient pressure to effect a separation of phosphorus particles larger than about 8-15 micrometers from slime particles smaller than about 8-15 micrometers, recovering an underflow stream from the hydrocyclone containing a preponderance of the introduced phosphorus particles in a substantially uncoalesced form along with a reduced amount of dirt slimes, removing an overflow stream from the hydrocyclone containing a preponderance of the slimes and reduced amounts of phosphorus, recycling said underflow stream to said centrifugal separator, coalescing phosphorus contained in the recycled underflow stream having a particle size larger than about 8-15 micrometers within said centrifugal separator along with phosphorus globules contained in the sludge, and recovering said heavy fraction containing coalesced phosphorus from said centrifugal separator.
- 2. Process of claim 1 wherein the underflow stream from said hydrocyclone is passed into a clarifier, wherein the stream stratified into an upper phossy water stream and a lower phosphorus concentrate stream, and the lower phosphorus concentrate stream is recycled to the centrifugal separator for recovery of phosphorus.
- 3. Process of claim 1 wherein the said light fraction from said separator is introduced into said hydrocyclone at a differential pressure of about 20 to 40 lbs per square inch.
- 4. Process of claim 1 wherein said sludge is first passed into a preliminary hydrocyclone having a diameter not substantially larger than about 1-inch, removing a preliminary underflow from said preliminary hydrocyclone containing the major portion of phosphorus and introducing it into said centrifugal separator, removing a preliminary overflow from said preliminary hydrocyclone containing separated fine dirt slimes and a minor amount of phosphorus, and passing said preliminary overflow along with said light fraction from said centrifugal separator into said hydrocyclone where particles larger and smaller than about 8-15 micrometers are separated.
- 5. Process of claim 1 wherein a plurality of hydrocyclones are employed in parallel, and said light fraction from said centrifugal separator is introduced to said hydrocyclones through a common conduit.
- 6. Process of claim 1 wherein the centrifugal separator separates said sludge into said heavy fraction and said light fraction by rotating a bowl containing said sludge at a speed sufficient to exert a centrifugal force of about 400-1200 gravities on said sludge in the separation areas of the centrifugal separator.
Parent Case Info
This application is a continuation of application Ser. No. 379,228, filed May 17, 1982, now abandoned.
US Referenced Citations (10)
Foreign Referenced Citations (1)
Number |
Date |
Country |
931527 |
Aug 1973 |
CAX |
Continuations (1)
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Number |
Date |
Country |
Parent |
379228 |
May 1982 |
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