US2219781A - Process for demkmg imprinted - Google Patents
Process for demkmg imprinted Download PDFInfo
- Publication number
- US2219781A US2219781A US2219781DA US2219781A US 2219781 A US2219781 A US 2219781A US 2219781D A US2219781D A US 2219781DA US 2219781 A US2219781 A US 2219781A
- Authority
- US
- United States
- Prior art keywords
- pulp
- paper
- carbon particles
- flotation
- froth
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000000034 method Methods 0.000 title description 10
- 239000002245 particle Substances 0.000 description 40
- OKTJSMMVPCPJKN-UHFFFAOYSA-N carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 28
- 229910052799 carbon Inorganic materials 0.000 description 28
- 238000005188 flotation Methods 0.000 description 20
- HEMHJVSKTPXQMS-UHFFFAOYSA-M sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 18
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 16
- 235000015450 Tilia cordata Nutrition 0.000 description 16
- 235000011941 Tilia x europaea Nutrition 0.000 description 16
- 238000010411 cooking Methods 0.000 description 16
- 239000004571 lime Substances 0.000 description 16
- 239000000344 soap Substances 0.000 description 16
- 239000003350 kerosene Substances 0.000 description 14
- 239000000126 substance Substances 0.000 description 12
- 238000005189 flocculation Methods 0.000 description 10
- 230000016615 flocculation Effects 0.000 description 10
- 239000003153 chemical reaction reagent Substances 0.000 description 8
- CDBYLPFSWZWCQE-UHFFFAOYSA-L sodium carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 8
- 229920001131 Pulp (paper) Polymers 0.000 description 6
- 239000003513 alkali Substances 0.000 description 6
- 239000000976 ink Substances 0.000 description 6
- 235000011121 sodium hydroxide Nutrition 0.000 description 6
- 238000005406 washing Methods 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- KHPCPRHQVVSZAH-HUOMCSJISA-N Rosin Natural products O(C/C=C/c1ccccc1)[C@H]1[C@H](O)[C@@H](O)[C@@H](O)[C@@H](CO)O1 KHPCPRHQVVSZAH-HUOMCSJISA-N 0.000 description 4
- 239000003795 chemical substances by application Substances 0.000 description 4
- 239000000084 colloidal system Substances 0.000 description 4
- 239000002761 deinking Substances 0.000 description 4
- 230000002939 deleterious Effects 0.000 description 4
- 230000001419 dependent Effects 0.000 description 4
- 238000007127 saponification reaction Methods 0.000 description 4
- 238000004513 sizing Methods 0.000 description 4
- 235000017550 sodium carbonate Nutrition 0.000 description 4
- 229910000029 sodium carbonate Inorganic materials 0.000 description 4
- 239000011780 sodium chloride Substances 0.000 description 4
- 241000282320 Panthera leo Species 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000000470 constituent Substances 0.000 description 2
- 230000001276 controlling effect Effects 0.000 description 2
- 238000007865 diluting Methods 0.000 description 2
- 230000003467 diminishing Effects 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 239000000835 fiber Substances 0.000 description 2
- 239000000945 filler Substances 0.000 description 2
- 239000008394 flocculating agent Substances 0.000 description 2
- 239000008396 flotation agent Substances 0.000 description 2
- 238000005755 formation reaction Methods 0.000 description 2
- 238000009291 froth flotation Methods 0.000 description 2
- 125000001183 hydrocarbyl group Chemical group 0.000 description 2
- 229910052500 inorganic mineral Inorganic materials 0.000 description 2
- 230000014759 maintenance of location Effects 0.000 description 2
- 239000011707 mineral Substances 0.000 description 2
- 235000010755 mineral Nutrition 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000003921 oil Substances 0.000 description 2
- 239000010893 paper waste Substances 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 230000001105 regulatory Effects 0.000 description 2
- 230000000717 retained Effects 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 239000001187 sodium carbonate Substances 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
Definitions
- My invention relates to the recovery, forreuse, of imprinted papers made principally from chemical pulps and substantially free from ground wood or mechanical pulps, by removing the ink therefrom by a flotation process, and my invention resides in my discovery that by control of 'the temperature in the cooking preparation of the stock before entering the flotation step, more complete saponification is obtained and the soaps formed are readily precipitated or flocculated by simple means and do not retard the selective flocculation of the carbon particles in the pulp.
- the carbon particles constituent of printing inks are of such size that they exhibit colloidal properties. This does not infer that these particles are true colloid, and they may actually be suspensoids, but I mean that they exhibit true colloidal properties with respect to flotation treatment.
- asubstance To be successfully treated by the froth flotation method, asubstance must act as a finite particle and not as a colloid. To provide colloidal substances with finite particle characteristics they must be grouped together, or
- the paper In the deinking of waste papers the paper is usually given a cooking treatment with an alkali for the purpose of disintegrating or deflberizing the paper stock, and facilitating the separation of the carbon particles from the paper fibers and fillers.
- this treatment certain substances, contained in the paper, such as free rosin in the sizing of the paper, and certain .oils used in the imprinting inks react with the alkali of said treatment to form soaps, and these soaps, together with the soaps already present in the sizing, cause a dispersion of the pulp and of the carbon particles in the .pulp.
- the subsequent flocculation of the pulp and of the carbon particles in the pulp is dependent upon the proper control, or the removal of these soaps.
- This washing step is expensive in cost of time and equipment necessarily em-' ployed.
- Waste paper preferably shredded, is added to a water solution containing about 0.5% to 1.0% caustic soda (sodium hydroxide), soda ash (sodium carbonate) or any similar proportion of the two mixed as convenient.
- This solution is maintained preferably at about 140 F. and must not exceed 174 F. for 20 to minutes, or until disintegration of the paper manifests itself.
- the liquor or solution is then drained from the paper, and the paper is squeezed reasonably free of the liquor, but it is not to be washed, as retention of some of the soaps formed in the cooking liquor is desirable for later treatment of the pulp by flotation.
- the stock is then diluted with water to a suitable consistency, usually about 6%, and beaten or agitated until the stock is defiberized. Approximately 80 lb. of lime per ton dry weight of paper is then added, and the stock is agitated several minutes prior to flotation treatment.
- the lime may be added during the defiberizing step, but preferably it should not be in contact with the pulp over 45 minutes prior to flotation, as its effectiveness gradually diminishes after a period of 30 minutes.
- the pulp is then further diluted with water to a suitable consistency, usually between 1% and 2%.
- a suitable consistency usually between 1% and 2%.
- One of the lighter distillates of the hydrocarbon group, such as kerosene, is then introduced into the pulp to cause selective flocculation and collection of the carbon particles, and also to prevent excessive froth volume being produced.
- Air is then introduced into the pulp so as to cause froth to form and rise to the surface of the pulp. This froth, which contains the deleterious substances.
- the volume of froth can be regulated by the later addition of either lime or kerosene or similar reagent, lime producing a more voluminous froth,- and the kerosene diminishing it, and thus controlling its volume; and excess of kerosene will kill the froth completely. I have found by experimentation that about 80 lb. lime and about 5 lb.
- kerosene per ton of paper dry weight is satisfactory for most, types of papers.
- delnking printed paper which consists in cooking the stock inan alkaline solution of a strength equal to .5 to 1.0% of caustic soda at a temperature between 140 F. and 174 F. for a period of between twenty and thirty minutes, removing in part the cooking liquor by draining, and without washing, deflberizing the stock, diluting the stock to a consistency of approximately 1% to 2%, adding lime, adding a reagent having collective properties toward carbon particles and froth modifying characteristics, producing frothing in said stock by the aid of the soapy liquor retained in, the pulp, and removing the resulting froth from the surface of RICHARD H. LOWE.
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- Paper (AREA)
Description
Patented Oct. 29, 1940 PATENT oFrIcE PROCESS FOR DEINKING HWPRINTED PAPER Richard H. Lowe, Salt Lake City, Utah, assignor to The General Engineering Company, Salt Lake City, Utah, a corporation of Utah No Drawing. Application September 8, 1937,
-Serial No. 162,886
1 Claim.
My invention relates to the recovery, forreuse, of imprinted papers made principally from chemical pulps and substantially free from ground wood or mechanical pulps, by removing the ink therefrom by a flotation process, and my invention resides in my discovery that by control of 'the temperature in the cooking preparation of the stock before entering the flotation step, more complete saponification is obtained and the soaps formed are readily precipitated or flocculated by simple means and do not retard the selective flocculation of the carbon particles in the pulp.
The carbon particles constituent of printing inks are of such size that they exhibit colloidal properties. This does not infer that these particles are true colloid, and they may actually be suspensoids, but I mean that they exhibit true colloidal properties with respect to flotation treatment. To be successfully treated by the froth flotation method, asubstance must act as a finite particle and not as a colloid. To provide colloidal substances with finite particle characteristics they must be grouped together, or
flocculated in order that a large number of colloidal particles will have the physical characteristics of a single particle when grouped together. Therefore, the successful removal of carbon particles from a pulp is dependent on obtaining a proper state of flocculation of the carbon particles, so that their colloidal properties will be lost and they will acquire the properties of a finite particle.
In the deinking of waste papers the paper is usually given a cooking treatment with an alkali for the purpose of disintegrating or deflberizing the paper stock, and facilitating the separation of the carbon particles from the paper fibers and fillers. In this treatment certain substances, contained in the paper, such as free rosin in the sizing of the paper, and certain .oils used in the imprinting inks react with the alkali of said treatment to form soaps, and these soaps, together with the soaps already present in the sizing, cause a dispersion of the pulp and of the carbon particles in the .pulp. The subsequent flocculation of the pulp and of the carbon particles in the pulp is dependent upon the proper control, or the removal of these soaps. The present practice is to increase the speed of the saponification step by effecting the cooking at high temperatures. But, high temperatures cause the formation of substances which retard the action of the flocculation agents, later added to flocculate the carbon particles, and the pulp, thus making it necessary=to remove these substances by washing before proceeding to the flotation step in the process. This washing step is expensive in cost of time and equipment necessarily em-' ployed.
I have discovered that if-the temperature in the cooking treatment with alkali is controlled within certain limits, only such soaps and substances are formed which are readily flocculated by simple means, and further their presence is beneficial in the later flotation treatment or step.
I have, furthermore, discovered certain combinations of reagents that will successfully flocculate the pulp and selectively flocculate or collect the carbon particles in the presence of' such soaps,, and thus allow the carbon particles to become attached to the froth bubbles produced in the pulp, and thus rise to the surface of the pulp for removal. p
I carry out my invention in the following manner:
Waste paper, preferably shredded, is added to a water solution containing about 0.5% to 1.0% caustic soda (sodium hydroxide), soda ash (sodium carbonate) or any similar proportion of the two mixed as convenient. This solution is maintained preferably at about 140 F. and must not exceed 174 F. for 20 to minutes, or until disintegration of the paper manifests itself.
The liquor or solution is then drained from the paper, and the paper is squeezed reasonably free of the liquor, but it is not to be washed, as retention of some of the soaps formed in the cooking liquor is desirable for later treatment of the pulp by flotation. The stock is then diluted with water to a suitable consistency, usually about 6%, and beaten or agitated until the stock is defiberized. Approximately 80 lb. of lime per ton dry weight of paper is then added, and the stock is agitated several minutes prior to flotation treatment. The lime may be added during the defiberizing step, but preferably it should not be in contact with the pulp over 45 minutes prior to flotation, as its effectiveness gradually diminishes after a period of 30 minutes. The pulp is then further diluted with water to a suitable consistency, usually between 1% and 2%. One of the lighter distillates of the hydrocarbon group, such as kerosene, is then introduced into the pulp to cause selective flocculation and collection of the carbon particles, and also to prevent excessive froth volume being produced. Air is then introduced into the pulp so as to cause froth to form and rise to the surface of the pulp. This froth, which contains the deleterious substances.
is removed from the surface of the pulp in the same manner as is practiced in mineral flota tion. The pulp remaining in the flotation machine is then a clean pulp, devoid of deleterious" lection desired. A short time should elapse between the addition of lime and the addition'of kerosene or similar reagent to obtain the maximum results. The volume of froth can be regulated by the later addition of either lime or kerosene or similar reagent, lime producing a more voluminous froth,- and the kerosene diminishing it, and thus controlling its volume; and excess of kerosene will kill the froth completely. I have found by experimentation that about 80 lb. lime and about 5 lb. kerosene per ton of paper dry weight is satisfactory for most, types of papers. I have furthermore discovered that if the temperature used in cooking the paper is permitted to rise above -174 F. the efiectiveness of the flotation agents is-destroyed. In other words, at the inhibited higher temperatures the pulp remains in a semi-dispersed condition even in the presence of flocculating agents, and suiiicient collection and removal of the carbon particles is im- P ssible.
I have also discovered that complete removal of the carbon particles is not practicalif either a general pulp flocculent, such as lime, or a selecti-ve flocculent or collector such as kerosene is used alone; these two agents must be used together and approximately in the proportions stated.
I claim:
The process of delnking printed paper which consists in cooking the stock inan alkaline solution of a strength equal to .5 to 1.0% of caustic soda at a temperature between 140 F. and 174 F. for a period of between twenty and thirty minutes, removing in part the cooking liquor by draining, and without washing, deflberizing the stock, diluting the stock to a consistency of approximately 1% to 2%, adding lime, adding a reagent having collective properties toward carbon particles and froth modifying characteristics, producing frothing in said stock by the aid of the soapy liquor retained in, the pulp, and removing the resulting froth from the surface of RICHARD H. LOWE.
. the pulp.
Publications (1)
Publication Number | Publication Date |
---|---|
US2219781A true US2219781A (en) | 1940-10-29 |
Family
ID=3431529
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US2219781D Expired - Lifetime US2219781A (en) | Process for demkmg imprinted |
Country Status (1)
Country | Link |
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US (1) | US2219781A (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2676099A (en) * | 1948-09-25 | 1954-04-20 | Farnam Co F D | Process of coating fibers with gas agitation |
US2725985A (en) * | 1953-04-06 | 1955-12-06 | Monsanto Chemicals | Flotation of carbon black |
US2757797A (en) * | 1953-03-27 | 1956-08-07 | Monsanto Chemicals | Water treatment |
US3649250A (en) * | 1969-05-12 | 1972-03-14 | Minerals Technology Corp | Silver recovery process |
-
0
- US US2219781D patent/US2219781A/en not_active Expired - Lifetime
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2676099A (en) * | 1948-09-25 | 1954-04-20 | Farnam Co F D | Process of coating fibers with gas agitation |
US2757797A (en) * | 1953-03-27 | 1956-08-07 | Monsanto Chemicals | Water treatment |
US2725985A (en) * | 1953-04-06 | 1955-12-06 | Monsanto Chemicals | Flotation of carbon black |
US3649250A (en) * | 1969-05-12 | 1972-03-14 | Minerals Technology Corp | Silver recovery process |
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