Recovery of elemental phosphorus from phosphorus sludge
AssigneeGlenn Springs Holdings, Inc.
InventorsMohan S. Saran, James R. Brooks, David C. Potts
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Abstract
Disclosed is a method of recovering elemental phosphorus from a sludge that contains water, dirt, and elemental phosphorus. In the first step, the sludge is melted. A mixture is formed of the melted sludge and about 0.5 to about 5 wt % of an oxidizing agent, based on the weight of elemental phosphorus in the sludge, and about 75 to about 580 wt % water, based on the weight of the sludge. The mixture is stirred until a continuous elemental phosphorus phase forms. The purified phosphorus phase is separated from the mixture.
Claims19
A method of recovering elemental phosphorus from a sludge that contains water, dirt, and elemental phosphorus as a discontinuous phase comprising, in a batch process,
- (A) melting said sludge;
- (B) forming a mixture of said sludge and about 75 to about 580 wt % water, based on the weight of said sludge, and about 0.5 to about 5 wt % of an oxidizing agent, based on the weight of said water;
- (C) stirring said mixture until a continuous elemental phosphorus phase forms then stopping said stirring before a phosphorus-in-water emulsion forms;
- and
- (D) separating said continuous elemental phosphorus phase from said mixture.
A method of recovering elemental phosphorus from a sludge that contains water, dirt, and about 5 to about 80 wt % elemental phosphorus as a discontinuous phase, comprising, in a batch process,
- (A) melting said sludge at a temperature of about 55 to about 75° C.;
- (B) forming a mixture of said sludge and, in an amount about 1 to about 5.8 times the amount of sludge, an aqueous solution containing about 0.5 to about 5 wt % chromic acid;
- (C) stirring said mixture until said elemental phosphorus forms a continuous phase then stopping said stirring before a phosphorus-in-water emulsion forms;
- and
- (D) separating said elemental phosphorus continuous phase from said mixture.
A method of recovering elemental phosphorus from a phosphorus sludge comprising, in a batch process,
- (A) melting a phosphorus sludge that contains about 5 to about 80 wt % elemental phosphorus in a discontinuous phase in a reactor at a temperature of about 55 to about 75° C.;
- (B) forming a mixture of said sludge and, in an amount about 1 to about 5.8 times the amount of sludge, an aqueous solution containing about 0.5 to about 5 wt % chromic acid;
- (C) stirring said mixture for about 15 minutes to about 30 minutes at about 150 to about 300 rpm whereby said elemental phosphorus forms a continuous phase but does not form a phosphorus-inter emulsion;
- (D) permitting said mixture to settle;
- (E) separating said elemental phosphorus continuous phase from said mixture;
- and
- (F) filtering or centrifuging said separated elemental phosphorus continuous phase.
Dependencies are inferred from the claim text.