Patent US5131980A successfully refreshed from Google Patents.
US5131980A
Expired / Lapsed
US
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Hydrocyclone removal of sticky contaminants during paper recycling
Assignee: Andritz Inc
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Filing: 1990-09-17
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Granted: 1992-07-21
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Expires: 2010-09-17
Abstract
Abstract The removal of sticky contaminants during the production of recycled paper is accomplished utilizing a hydrocyclone froth flotation process. Paper having sticky contaminants from labels, tapes, hot melts, and other tacky substances, is reduced to a finely comminuted liquid solids suspension of about 1-4% consistency. The suspension is introduced into a first end of a vortex in a hydrocyclone, and the air is sparged radially inwardly into the suspension vortex by passing it through a porous inner wall of the hydrocyclone. Ligher weight sticky contaminants move to the center of the hydrocyclone, facilitated by the radially inward movement of the sparging air, and hydrophobic sticky contaminants attach to the air bubbles and form a foam. The foam and lightweight sticky contaminants are removed from the first end of the vortex, while the pulp which has had sticky contaminants removed therefrom is discharged from the second end of the vortex, opposite the first end. A plurality of vertical axis hydrocyclones may be connected together in series, with a plurality of the series connected in parallel, to provide the most effective treatment. Removal of sticky contaminants can be practiced prior to or simultaneously with deinking.
Inventors
- 👤 Wayne J. Chamblee
- 👤 Brian F. Greenwood
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 06:54
CPC Classifications
B; B03; B03D; B03D1/00; B03D1/14; B03D1/1418; B03D1/1425; D; D21; D21C; D21C5/00; B03D1/02; B03D1/1443; B03D1/1475; B03D1/24; B03D1/247; B04; B04C; B04C5/00; B04C5/08; B04C5/10; B04C7/00; D21B; D21B1/00; D21B1/04; D21B1/12; D21B1/30; D21B1/32; D21B1/325; D21D; D21D5/00; D21D5/18; D21D5/24; D21F; D21F1/00; D21F1/66; D21F1/68; D21F1/70; Y; Y02; Y02W; Y02W30/00; Y02W30/50; Y02W30/64
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
158 words
A method of removing sticky contaminants from recycled paper cellulosic pulp containing such contaminants, comprising the steps of continuously: (a) reducing paper having lightweight and hydrophobic sticky contaminants associated therein to a finely comminuted liquid-solids suspension flow having a solids consistency of about 1-4%; (b) introducing the suspension into a first end of a vortex; (c) sparging air radially inwardly into the suspension in the vortex, to cause the lightweight sticky contaminants to move radially, and to cause the hydrophobic sticky contaminants to attach to air bubbles and move toward the fist end of the vortex; a foam having a solids and liquid content being formed while cellulosic pulp moves to the second end, opposite the first end, of the vortex; and (d) removing foam and lightweight sticky contaminants from the first end of the vortex, while pulp with sticky contaminants removed is discharged from the second end of the vortex, using only the vortex and sparged air.
Claim 2
Independent Claim
158 words
A method of removing sticky contaminants from recycled paper cellulosic pulp containing such contaminants, comprising the steps of continuously: (a) reducing paper having lightweight and hydrophobic sticky contaminants associated therein to a finely comminuted liquid-solids suspension flow having a solids consistency of about 1-4%; (b) introducing the suspension into a first end of a vortex; (c) sparging air radially inwardly into the suspension in the vortex, to cause the lightweight sticky contaminants to move radially, and to cause the hydrophobic sticky contaminants to attach to air bubbles and move toward the fist end of the vortex; a foam having a solids and liquid content being formed while cellulosic pulp moves to the second end, opposite the first end, of the vortex; and (d) removing foam and lightweight sticky contaminants from the first end of the vortex, while pulp with sticky contaminants removed is discharged from the second end of the vortex, using only the vortex and sparged air.
Claim 3
Dependent Claim
20 words
A method as recited in claim 1 comprising the further step (e) of deaerating the pulp discharged in step (d).
Claim 4
Dependent Claim
33 words
A method as recited in claim 2 comprising the further step (f) of separating the gas component of the foam removed in step (d) from the solids and liquid component of the foam.
Claim 5
Dependent Claim
19 words
A method as recited in claim 3 wherein step (f) is practiced by feeding the foam to a cyclone.
Claim 6
Dependent Claim
85 words
A method as recited in claim 1 using a vertical axis hydrocyclone having an air permeable side wall, an overflow outlet from the top, and an underflow outlet from the bottom, and wherein steps (b)-(d) consist of by introducing the suspension into the hydrocyclone, directing air through the side wall of the hydrocyclone to create a foam of fine bubbles which thereby attach to trapped in suspension solids to be carried with foam to the overflow outlet, and withdrawing the pulp from the underflow outlet.
Claim 7
Dependent Claim
52 words
A method as recited in claim 1 comprising the further step (g), between steps (a) and (b), of breaking the suspension flow into a plurality of flow paths, and practicing steps (b)-(d) in each flow path, and recombining the pulp and foam flow streams from step (d) from all the flow paths.
Claim 8
Dependent Claim
26 words
A method as recited in claim 6 comprising the further step of practicing steps (b)-(d) a plurality of times in in-series stages within each flow path.
Claim 9
Dependent Claim
22 words
A method as recited in claim 7 comprising the further step of deaerating the pulp between each stage within each flow path.
Claim 10
Dependent Claim
23 words
A method as recited in claim 1 wherein step (a) is practiced to provide a suspension having a temperature of about 30°-60° C.
Claim 11
Dependent Claim
33 words
A method as recited in claim 1 wherein the paper in step (a) also has print thereon, and wherein steps (b)-(d) are practiced to effect deinking simultaneously with the removal of sticky contaminants.
Claim 12
Dependent Claim
36 words
A method as recited in claim 10 wherein step (a) is practiced to provide the liquid component of the suspension as primarily water, but also including other chemicals to facilitate separation of ink from comminuted paper.
Claim 13
Dependent Claim
35 words
A method as recited in claim 1 comprising the further step of deinking the pulp by practicing steps (b)-(d) in a second vortex, ink particles being removed from the first end of the second vortex.
Claim 14
Independent Claim
183 words
A method of manufacturing recycled paper, comprising the steps of continuously: reducing cellulosic paper having lightweight and hydrophobic sticky contaminants associated therewith to a finely comminuted liquid-solids suspension flow having a low solids consistency; screening the suspension to remove reject particles; subjecting the suspension to froth flotation to produce a pulp; washing and thickening the pulp; and making paper from the thickened pulp; wherein said froth flotation step is practiced with suspension having a solids consistency of over 1.5%, by: (i) introducing the suspension into a first end of a vortex; (ii) sparging air radially inwardly into the suspension in the vortex, to cause the lightweight sticky contaminants to move radially upwardly and the hydrophobic sticky contaminants to attach to air bubbles and move toward the first end of the vortex, a foam being formed while cellulosic pulp moves to the second end, opposite the first end, of the vortex; and (iii) removing foam and lightweight sticky contaminants from the first end of the vortex, while pulp with sticky contaminants partially or completely removed is discharged from the second end of the vortex.
Claim 15
Independent Claim
183 words
A method of manufacturing recycled paper, comprising the steps of continuously: reducing cellulosic paper having lightweight and hydrophobic sticky contaminants associated therewith to a finely comminuted liquid-solids suspension flow having a low solids consistency; screening the suspension to remove reject particles; subjecting the suspension to froth flotation to produce a pulp; washing and thickening the pulp; and making paper from the thickened pulp; wherein said froth flotation step is practiced with suspension having a solids consistency of over 1.5%, by: (i) introducing the suspension into a first end of a vortex; (ii) sparging air radially inwardly into the suspension in the vortex, to cause the lightweight sticky contaminants to move radially upwardly and the hydrophobic sticky contaminants to attach to air bubbles and move toward the first end of the vortex, a foam being formed while cellulosic pulp moves to the second end, opposite the first end, of the vortex; and (iii) removing foam and lightweight sticky contaminants from the first end of the vortex, while pulp with sticky contaminants partially or completely removed is discharged from the second end of the vortex.
Claim 16
Dependent Claim
101 words
A method as recited in claim 13 using a vertical axis hydrocyclone for the froth flotation step, the hydrocyclone having an air permeable side wall, an overflow outlet for the top, and an underflow outlet from the bottom; and wherein said introducing, sparging, and removing steps are practiced by introducing the suspension into the hydrocyclone adjacent the top thereof, directing air through the wall of the hydrocyclone to create a foam of fine bubbles which thereby attach to sticky contaminant solids trapped in suspension to be carried with foam to the overflow outlet, and withdrawing the pulp from the underflow outlet.
Claim 17
Dependent Claim
19 words
A method as recited in claim 13 wherein the froth flotation comprises the further step of deaerating the pulp.
Claim 18
Dependent Claim
30 words
A method as recited in claim 13 wherein the paper also has print thereon, and wherein steps (i)-(iii) are practiced to effect deinking simultaneously with the removal of sticky contaminants.
Claim 19
Dependent Claim
43 words
A method as recited in claim 13 wherein the paper has print thereon, and wherein steps (i) through (iii) are practiced in a second vortex, ink particles being removed from the first end of the second vortex, to effect deinking of the paper.
Claim 20
Independent Claim
182 words
A method of manufacturing recycled paper, comprising the steps of continuously: reducing cellulosic paper having lightweight and hydrophobic sticky contaminants associated therewith a finely comminuted liquid-solids suspension flow having a low solids consistency; screening the suspension to remove reject particles; subjecting the suspension to froth flotation to produce a pulp; washing and thickening the pulp; and making paper from the thickened pulp; wherein said froth flotation step is practiced with suspension having a solids consistency of about 1-4%, by: (i) introducing the suspension into a first end of a vortex; (ii) sparging air radially inwardly into the suspension in the vortex, to cause the lightweight sticky contaminants to move radially upwardly and the hydrophobic sticky contaminants to attach to air bubbles and move toward the first end of the vortex, a foam being formed while cellulosic pulp moves to the second end, opposite the first end, of the vortex; and (iii) removing foam and lightweight sticky contaminants from the first end of the vortex, while pulp with sticky contaminants partially or completely removed is discharged from the second end of the vortex.
Claim 21
Independent Claim
182 words
A method of manufacturing recycled paper, comprising the steps of continuously: reducing cellulosic paper having lightweight and hydrophobic sticky contaminants associated therewith a finely comminuted liquid-solids suspension flow having a low solids consistency; screening the suspension to remove reject particles; subjecting the suspension to froth flotation to produce a pulp; washing and thickening the pulp; and making paper from the thickened pulp; wherein said froth flotation step is practiced with suspension having a solids consistency of about 1-4%, by: (i) introducing the suspension into a first end of a vortex; (ii) sparging air radially inwardly into the suspension in the vortex, to cause the lightweight sticky contaminants to move radially upwardly and the hydrophobic sticky contaminants to attach to air bubbles and move toward the first end of the vortex, a foam being formed while cellulosic pulp moves to the second end, opposite the first end, of the vortex; and (iii) removing foam and lightweight sticky contaminants from the first end of the vortex, while pulp with sticky contaminants partially or completely removed is discharged from the second end of the vortex.
Claim 22
Dependent Claim
22 words
A method as recited in claim 18 wherein the froth flotation is practiced with suspension having a solids consistency of over 1.5%.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-07-21 | 1996-01-20 | 1996-07-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-07-21 | 2000-01-20 | 2000-07-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-07-21 | 2004-01-20 | 2004-07-21 | $7700.00 | Window Closed / Lapsed |