US 4,787,970 AGranted

Process and system for dewatering metal oxide sludge

AssigneeSpecialized Process Equipment, Inc.

InventorRussell L. Sutphen

Life of this patent

Estimating the term…

Loading patent…

Abstract

A process of the type employing freezing and thawing of metal hydroxide sludge to effect phase separation by gravity settling of solids to permit removal of the purified water, and a preferred system for carrying out the process. Commercially available refrigeration equipment, suitably modified and adjusted to operate in the freezing of sludge in sheets and breaking the sheets into relatively small pieces, is utilized in order to minimize the costs of hardware end controls. The frozen sludge particles are deposited in a melt tank containing a quantity of sludge which has previously been frozen and thawed. The thawed sludge is circulated from the melt tank through a line passing through the condenser of the refrigeration system to absorb heat rejected by the condensing refrigerant, and directed by a valve back to the melt tank to assist in thawing the frozen particles until the level in the tank reaches a predetermined maximum, and then to a settling area until the level of thawed sludge in the melt tank is reduced to a predetermined minimum. The primarily liquid and solid phases are separated after a desired amount of gravity settling.

A system for receiving metal hydroxide sludge from a raw sludge supply and separating said sludge into primarily solid and liquid phases, said system comprising, in combination:

(a) a first tank in which said raw sludge from said supply is deposited;
(b) at least one pair of essentially flat, heat conducting plates arranged in spaced, parallel relation with inwardly and outwardly facing, vertically disposed, major surfaces;
(c) a first distribution header positioned above said plates to discharge liquid downwardly upon said outwardly facing plate surfaces;
(d) a first line connecting said first tank with said first header to conduct said raw sludge thereto for discharge onto said outwardly facing plate surfaces;
(e) means for chilling said plates to a temperature below the freezing point of said raw sludge, whereby some of said raw sludge is frozen on and adheres to said outwardly facing plate surfaces, and some drains by gravity off the lower portions of said plates;
(f) means for directing said raw sludge which drains off said plates back to said first tank for recirculation through said first header;
(g) means for releasing the frozen sludge from said outwardly facing plate surfaces, permitting said frozen sludge to fall from said plate surfaces by gravity;
(h) breaking means positioned below said plates to receive said frozen sludge released from said plate surfaces, and break the frozen sludge into pieces not larger than a predetermined size;
and to discharge said pieces;
(i) a second tank positioned to receive said pieces of frozen sludge discharged from said breaking means;
(j) means for increasing the temperature of said pieces of frozen sludge in said second tank to effect thawing thereof;
(k) a second line through which thawed sludge from said second tank is circulated out of and back to said second tank;
and
(l) a third line through which thawed sludge from said second tank is circulated to a processing area for separation into said primarily solid and liquid phases.

11 more elements

Facts

Application

07/170,364Filed 18 Mar 1988 · continuation in part

Priority

23 Apr 1987

Granted

29 Nov 1988

Term ends

Not estimatedThe source records don’t support an estimate.

Classification6 codes

B01D 9/04
From solutions: concentrating solutions by removing frozen solvent therefrom
C22B 3/22
Treatment or purification of solutions, e.g. obtained by leaching: by physical processes, e.g. by filtration, by magnetic means , or by thermal…
Y02P 10/20
Technologies related to metal processing: recycling
B01D
Separation

Abstract

Claims12