US3787283A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Treatment of waste liquor from pulp production
Assignee: Sonoco Products Co
•
Filing: 1972-03-28
•
Granted: 1974-01-22
•
Expires: 1992-03-28
Abstract
Abstract A process and apparatus for treating concentrated spent liquor from a soda-based pulping process to recover sodium for reuse in the pulping process and to prevent the usual pollution of streams and air caused by the usual effluent from the pulping process. The process and apparatus comprises the following steps and apparatus. Concentrated spent liquor containing sodium is mixed with recycled finely-divided reactive alumina hydrate and formed into solid pellets by spraying the concentrated liquor-aluminum hydrate mixture onto a bed of recycled sodium aluminate furnace ash in an enclosed rotating container and tumbling the mixture and ash. The solid pellets are combusted and reacted by feeding the pellets through a furnace operating at a temperature below the fusion temperature of sodium aluminate and at a sufficiently high temperature to combust the organic portion of the pellets and react the sodium content thereof with the alumina to form additional sodium aluminate as a particulate unfused ash. The resulting furnace ash is pulverized and a portion thereof is recycled for subsequent reuse in the treating process. The remaining portion of the ash is dissolved in water to form a solution of sodium aluminate. The sodium aluminate solution is reacted with either sulphur dioxide or carbon dioxide or both to form sodium sulfite and/or sodium carbonate pulping chemical and alumina and alumina is separated for reuse in the treating process.
Inventors
- 👤 D Sheeley
- 👤 W Biggs
- 👤 J Rion
- 👤 W Cook
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 21:47
CPC Classifications
D; D21; D21C; D21C11/00; D21C11/0085; D21C11/0092; Y; Y10; Y10S; Y10S423/00; Y10S423/03
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
26 words
A process for treating concentrated spent liquor, as set forth in claim 1, in which said combusting step is carried out at temperatures below 3000* F.
Claim 2
Dependent Claim
30 words
A process for treating concentrated spent liquor, as set forth in claim 2, in which said combusting step is carried out at temperatures between about 1500* F. to 2000* F.
Claim 3
Dependent Claim
31 words
A process for treating concentrated spent liquor, as set forth in claim 1, in which the sodium aluminate has a molar ratio of Na2O to A12O3 of about 1:1 to 2:1.
Claim 4
Dependent Claim
34 words
A process for treating concentrated spent liquor, as set forth in claim 1, in which the concentrated spent liquor has a solids content of from about 25% to 70% before mixing with alumina hydrate.
Claim 5
Dependent Claim
46 words
A process for treating concentrated spent liquor, as set forth in claim 1, wherein the step of reacting the sodium aluminate solution with sulphur dioxide includes withdrawing gases containing sulphur dioxide from said combusting step and feeding the gases into contact with the sodium aluminate solution.
Claim 6
Dependent Claim
281 words
A process for treating concentrated liquor from a soda-base sulfite pulping process to recover sodium for reuse in the pulping process and to prevent the usual pollution of streams and air caused by the usual effluent from the pulping process; said treating process comprising: mixing concentrated spent liquor containing sodium and sulfur with recycled reactive alumina hydrate in an amount necessary to react with the sodium content of the liquor for the ultimate formation of sodium aluminate as the reaction product; spraying the concentrated liquor-alumina hydrate mixture onto a bed of recycled sodium aluminate furnace ash and tumbling the mixture and ash to form solid pellets thereof; combusting and reacting the solid pellets by feeding the pellets through a furnace operating at a temperature below the fusion temperature of sodium aluminate and a sufficiently high temperature to combust the organic portion of the pellets and react the sodium content thereof with the alumina to form additional sodium aluminate as a particulate unfused ash; pulverizing the ash and recycling a portion thereof for subsequent reuse in the formation of pellets; dissolving the remaining portion of the pulverized ash in water to form a solution of sodium aluminate; withdrawing flue gases containing sulphur dioxide and carbon dioxide from the combusting and reacting step and feeding the gases into contact with the sodium aluminate solution; reacting the sodium aluminate solution with the flue gases containing sulphur dioxide and carbon dioxide to form a mixture of sodium sulfite and sodium carbonate in solution and aluminum hydrate as a slurry; filtering and separating the aluminum hydrate for reuse in the mixing step and separating the sodium sulfite and sodium carbonate for reuse in the pulping process.
Claim 7
Independent Claim
328 words
An apparatus for treating concentrated spent liquor from a soda-based pulping process to recover sodium for reuse in the pulping process and to prevent the usual pollution of streams and air caused by the usual effluent from the pulping process; said treating apparatus comprising: means for mixing concentrated spent liquor containing sodium from a soda-based pulping operation with recycled reactive alumina hydrate in an amount necessary to react with the sodium content of the liquor for ultimate formation of sodium aluminate as the reaction product; means for forming solid pellets from the concentrated liquor-aluminum hydrate mixture comprising a rotating enclosed tumbling means carrying a bed of recycled sodium aluminate furnace ash in the bottom thereof and spray means for spraying the concentrated liquor-aluMinum hydrate mixture onto the bed of recycled sodium aluminate furnace ash so that as the tumbling means rotates, solid pellets will be formed; furnace means for combusting and reacting the solid pellets and including means for feeding the pellets from the pellet forming means to the furnace means, said furnace means operating at a temperature below the fusion temperature of sodium aluminate and at a sufficiently high temperature to combust the organic portion of the pellets and react the sodium content thereof with alumina to form additional sodium aluminate as a particulate unfused ash; pulverizing means for receiving the ash from said furnace means and for pulverizing the same for subsequent use in the treating process; means for recycling a portion of the pulverized ash to said pellet forming means for use in the formation of solid pellets therefrom; means for receiving the remaining portion of the pulverized furnace ash and dissolving the same in water to form a solution of sodium aluminate; means for receiving the sodium aluminate solution and reacting the same with sulphur dioxide to form sodium sulfite and alumina; and means for separating the alumina for reuse in the mixing means and the sodium sulfite for reuse in the pulping process.
Claim 8
Dependent Claim
138 words
The apparatus for treating concentrated spent liquor, as set forth in claim 8, in which said means for receiving the sodium aluminate solution and reacting the same with sulphur dioxide comprises an elongate vertically extending hollow housing, a plurality of grids of spaced apart, parallel, generally cylindrical bars extending transversely across said housing wherein alternate grids of bars extend in opposite directions at 90* angles to each other so as to form venturi-like passages between the bars and a generally checkerboard arrangement of grids of bars so that the sodium aluminate solution may be introduced on top of said grids of bars and flow by gravity flow down through said venturi-like passages for intimate contact with the sulphur dioxide in the form of gases which enter said housing from the bottom thereof and flow counter-currently to the solution.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-01-21 | 1977-07-23 | 1978-01-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-21 | 1981-07-23 | 1982-01-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-21 | 1985-07-23 | 1986-01-22 | $7700.00 | Window Closed / Lapsed |