CA1122730A - Flocculation of suspended solids of multivalent cations with anionic flocculants containing sulfonate ions - Google Patents
Flocculation of suspended solids of multivalent cations with anionic flocculants containing sulfonate ionsInfo
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- CA1122730A CA1122730A CA337,654A CA337654A CA1122730A CA 1122730 A CA1122730 A CA 1122730A CA 337654 A CA337654 A CA 337654A CA 1122730 A CA1122730 A CA 1122730A
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Abstract
27,591 Title: FLOCCULATION OF SUSPENDED SOLIDS OF MULTIVALENT
CATIONS WITH ANIONIC FLOCCULANTS CONTAINING
SULFONATE IONS
ABSTRACT OF THE DISCLOSURE
Aqueous dispersions of solids containing multivalent cations are more readily flocculated with polymeric anionic flocculants containing sulfonate ions than similar flocculants containing only carboxylate ions.
CATIONS WITH ANIONIC FLOCCULANTS CONTAINING
SULFONATE IONS
ABSTRACT OF THE DISCLOSURE
Aqueous dispersions of solids containing multivalent cations are more readily flocculated with polymeric anionic flocculants containing sulfonate ions than similar flocculants containing only carboxylate ions.
Description
;2t73~
27,591 This invention relates to an improved process for flocculating suspensions of sol ds containing multivalent cations. More particularly, this i~vention relates to such a process wherein the flocculant employed is a water-soluble anionic polymer containing as its source of anionicity the sulfonate ion.
Flocculants are reagents which are added to suspen-sions of solids to cause the solids to flocculate and-settle.
A highly effective type of flocculant is the polymeric type since this type can be prepared in numerous variations as des-ired. Typically, polymeric flocculants are of three types, nonionic, cationic, and anionic. The particular ty~e of floc-culant to be used in a given application will generally depend upon the nature of the surface of the suspended solids.
To provide nonionic polymers, nonionic monomers such as acrylamide are polymerized under conditions which lead to a nonionic polymer. Polymers containing amine groups, primary, secondary, tertiary, and quaternary types provide typical cat-ionic flocculants with increased charge increasing in the order given. For anionic polymers, carboxylic acid groups are intro-duced into the polymer. Polymers containing sulfonic acid group were also introduced as anionic flocculants. Compari-sons of polymers containing carboxylic acid groups with poly-mers containing sulfonic acid groups did not distinguish be-tween the two types of acid groups with respect to flocculant performance in certain applications. From these comparisons, there appears to be no advantage arising from the use of sul-fonic acid groups as the source of anionicity.
Accordingly, there concinues to exist the need for improved processes for flocculating suspensions of solids con-~l22~30 taining multivalent cations that provide better performance than can be obtained with processes employing anionic flocculants containing carboxylic acid grou2s as the sole source of anion-icity. The provision for such processes would fulfill a long-felt need and constitute a singificant advance in the art.
In accordance with the present invention, there is provided a process for flocculating suspensions of solids con-taining multivalent cations which comprises adding to an aqueous suspension of such suspended solids an effective amount of an anionic polymeric flocculant comprising from about 65 to about 99 mole percent of repeating units derived from acrylamide, from about 1 to about 25 mole percent of repeating units derived from a vinyl sulfonic acid, and from 0 to about 10 mole percent of repeating units derived from acrylic acid, the mole percent of units obtained from acrylic acid being less than the mole percent of units derived from said vinylsulfonic acid and the polymeric flocculant having a Brookfield viscosity of at least about 2.~0 centipoises.
The process of the present invention provides more rapid flocculation of suspensions containing multivalent cations at a given flocculant dosage than can be achieved with proces-ses employing anionic flocculants deriving their anionicity solely from carboxylic acid grol!~s. The process of the present invention also provides equal performance at lower flocculant dosages than can be obtained with processes employing anionic flocculants deriving their anionicity solely from carboxylic acid groups. These results are surprising in view of the fact that polymers containing either type of anionic ~roup are sub-stantially equivalent in performance when used in applications where multivalent cations are absent and suspension is not too acidic.
27,591 This invention relates to an improved process for flocculating suspensions of sol ds containing multivalent cations. More particularly, this i~vention relates to such a process wherein the flocculant employed is a water-soluble anionic polymer containing as its source of anionicity the sulfonate ion.
Flocculants are reagents which are added to suspen-sions of solids to cause the solids to flocculate and-settle.
A highly effective type of flocculant is the polymeric type since this type can be prepared in numerous variations as des-ired. Typically, polymeric flocculants are of three types, nonionic, cationic, and anionic. The particular ty~e of floc-culant to be used in a given application will generally depend upon the nature of the surface of the suspended solids.
To provide nonionic polymers, nonionic monomers such as acrylamide are polymerized under conditions which lead to a nonionic polymer. Polymers containing amine groups, primary, secondary, tertiary, and quaternary types provide typical cat-ionic flocculants with increased charge increasing in the order given. For anionic polymers, carboxylic acid groups are intro-duced into the polymer. Polymers containing sulfonic acid group were also introduced as anionic flocculants. Compari-sons of polymers containing carboxylic acid groups with poly-mers containing sulfonic acid groups did not distinguish be-tween the two types of acid groups with respect to flocculant performance in certain applications. From these comparisons, there appears to be no advantage arising from the use of sul-fonic acid groups as the source of anionicity.
Accordingly, there concinues to exist the need for improved processes for flocculating suspensions of solids con-~l22~30 taining multivalent cations that provide better performance than can be obtained with processes employing anionic flocculants containing carboxylic acid grou2s as the sole source of anion-icity. The provision for such processes would fulfill a long-felt need and constitute a singificant advance in the art.
In accordance with the present invention, there is provided a process for flocculating suspensions of solids con-taining multivalent cations which comprises adding to an aqueous suspension of such suspended solids an effective amount of an anionic polymeric flocculant comprising from about 65 to about 99 mole percent of repeating units derived from acrylamide, from about 1 to about 25 mole percent of repeating units derived from a vinyl sulfonic acid, and from 0 to about 10 mole percent of repeating units derived from acrylic acid, the mole percent of units obtained from acrylic acid being less than the mole percent of units derived from said vinylsulfonic acid and the polymeric flocculant having a Brookfield viscosity of at least about 2.~0 centipoises.
The process of the present invention provides more rapid flocculation of suspensions containing multivalent cations at a given flocculant dosage than can be achieved with proces-ses employing anionic flocculants deriving their anionicity solely from carboxylic acid grol!~s. The process of the present invention also provides equal performance at lower flocculant dosages than can be obtained with processes employing anionic flocculants deriving their anionicity solely from carboxylic acid groups. These results are surprising in view of the fact that polymers containing either type of anionic ~roup are sub-stantially equivalent in performance when used in applications where multivalent cations are absent and suspension is not too acidic.
- 2 -2t73~
27,591 As indicated, the process of the present invention involves the use of an anionic flocculant deriving its anioni-city from a content of sulfonic acid groups. Polymeric floc-culants useful in the process of the present invention are readily prepared using known processes.
A particular preferred type of anionic flocculant is one containing repeating units derived from acrylamide and a vinyl sulfonic acid, the latter constituting about 1 to 25 mole percent, preferably 3 to 15 mole percent, of the total polymer composition. A preferred vinyl sulfonic acid monomer is acryl-amidomethyIpropanesulfonic acid.
~ The polymeric flocculants used in the process of the present invention will have molecular weights useful in floccu-lating applications according to conventional teachings. Parti-cularly useful flocculants are those that have Brookfield viscos-ities of at least about 2.60 centipoises, preferably at least about 3.30 centipoises. Brookfield viscosity is the viscosity of a 0.08% solution of the polymer in 1 normal NaCl at 25C. with pH
adjusted to 8-.5 determined with a Brookfield viscometer using the UL adapter and the spindle rotating at 60 RPM.
In carrying out the process of the present invention, an aqueous solids suspension containing multivalent cations is selected for treatment. A particularly preferable multivalent cation suspension is that represented by Florida phosphate slimes.
Other suspensions containing Ca+2, Al+3, Fe+3, Fe+2, Mg+2, Be+2 or the like may also be effectively treated. Florida phosphate slimes contain Ca+2 cations as well as other multivalent cations in suspension. Many colored wastes are treated with alum or fer-ric chloride to precipitate the colorants from solution. These precipitates which remain suspended contain Al+3 or Fe+3 cations.
~22~3~) To flocculate the solids in these aqueous suspensions, an effective amount of the specified anionic flocculant is add-ed to the suspension. This addition is generally made in a man-ner which provides uniform distribution of the flocculant throughout the suspension so as to obtain maximum flocculation of solids. Mixing may be an added operation or may be inherent in processing, such as addition to a moving stream of suspen-sion en route to a settling tank. An effective amount of floc-culant is that amount which produces the desired level o~ floc-culation and will vary widely depending upon many factors such as the nature of the suspension, the specific flocculant em-ployed, the extent of flocculation or settIing rate desired, and the like. Generally, the amount of flocculant will follow conventional dosages except that the present invention allows for reductions in such dosages in appropriate instances. Usual-ly a dosage of about 0.01 to 1.0 milligram of flocculant per liter of suspension will be effective.
The invention is more fully illustrated in the exam-ples which follow wherein all parts and percentages are by weight unless otherwise specified. The following procedures were employed in evaluating performance of the process.
PHOSPHATE SLIMES SETTLING TEST
Florida phosphate slimes are adjusted to a solids level of 1.0~ with water and 1000 ml. of the resulting suspen-sion are placed in a one-liter graduated cylinder. The desired weight of polymer flocculant is prepared as a solution in 50 ml.
deionized water. This flocculant solution is admixed with the slimes in the cylinder with agitation to ensure thorough mix-ing of slimes with flocculant, the agitator is removed, and time during which the solids/liquid level settles from the ~L~ZZ73~
1000 ml. mark to the 800 ml~ mark is recorded. The distance between these two marks varies between cylinders, but in the set for these experiments it is 7.20+0.08 cm. Average rate of settling over this distance is given in units of cm./sec.
COLOR REMOVAL
~rest Procedure A Phipps-Bird six place gang stirrer, equipped with
27,591 As indicated, the process of the present invention involves the use of an anionic flocculant deriving its anioni-city from a content of sulfonic acid groups. Polymeric floc-culants useful in the process of the present invention are readily prepared using known processes.
A particular preferred type of anionic flocculant is one containing repeating units derived from acrylamide and a vinyl sulfonic acid, the latter constituting about 1 to 25 mole percent, preferably 3 to 15 mole percent, of the total polymer composition. A preferred vinyl sulfonic acid monomer is acryl-amidomethyIpropanesulfonic acid.
~ The polymeric flocculants used in the process of the present invention will have molecular weights useful in floccu-lating applications according to conventional teachings. Parti-cularly useful flocculants are those that have Brookfield viscos-ities of at least about 2.60 centipoises, preferably at least about 3.30 centipoises. Brookfield viscosity is the viscosity of a 0.08% solution of the polymer in 1 normal NaCl at 25C. with pH
adjusted to 8-.5 determined with a Brookfield viscometer using the UL adapter and the spindle rotating at 60 RPM.
In carrying out the process of the present invention, an aqueous solids suspension containing multivalent cations is selected for treatment. A particularly preferable multivalent cation suspension is that represented by Florida phosphate slimes.
Other suspensions containing Ca+2, Al+3, Fe+3, Fe+2, Mg+2, Be+2 or the like may also be effectively treated. Florida phosphate slimes contain Ca+2 cations as well as other multivalent cations in suspension. Many colored wastes are treated with alum or fer-ric chloride to precipitate the colorants from solution. These precipitates which remain suspended contain Al+3 or Fe+3 cations.
~22~3~) To flocculate the solids in these aqueous suspensions, an effective amount of the specified anionic flocculant is add-ed to the suspension. This addition is generally made in a man-ner which provides uniform distribution of the flocculant throughout the suspension so as to obtain maximum flocculation of solids. Mixing may be an added operation or may be inherent in processing, such as addition to a moving stream of suspen-sion en route to a settling tank. An effective amount of floc-culant is that amount which produces the desired level o~ floc-culation and will vary widely depending upon many factors such as the nature of the suspension, the specific flocculant em-ployed, the extent of flocculation or settIing rate desired, and the like. Generally, the amount of flocculant will follow conventional dosages except that the present invention allows for reductions in such dosages in appropriate instances. Usual-ly a dosage of about 0.01 to 1.0 milligram of flocculant per liter of suspension will be effective.
The invention is more fully illustrated in the exam-ples which follow wherein all parts and percentages are by weight unless otherwise specified. The following procedures were employed in evaluating performance of the process.
PHOSPHATE SLIMES SETTLING TEST
Florida phosphate slimes are adjusted to a solids level of 1.0~ with water and 1000 ml. of the resulting suspen-sion are placed in a one-liter graduated cylinder. The desired weight of polymer flocculant is prepared as a solution in 50 ml.
deionized water. This flocculant solution is admixed with the slimes in the cylinder with agitation to ensure thorough mix-ing of slimes with flocculant, the agitator is removed, and time during which the solids/liquid level settles from the ~L~ZZ73~
1000 ml. mark to the 800 ml~ mark is recorded. The distance between these two marks varies between cylinders, but in the set for these experiments it is 7.20+0.08 cm. Average rate of settling over this distance is given in units of cm./sec.
COLOR REMOVAL
~rest Procedure A Phipps-Bird six place gang stirrer, equipped with
3/4" x 1 3/4" paddles, was used for jar tests. Five hundred milliliters of the water to be treated were added to each of six 600 ml. beakers and placed on the stirrer. With the pad-dles rotating in the water at 150 rpm, a specified amount of alum (as a 1% solution) was added to each beaker, the additions being as near to simultaneous as possible. Stirring at 150 rpm was continued for 30 seconds after alum addition, then was reduced to 40 rpm. At the end of 3 minutes stirring was in-creased to 150 rpm, and the high molecular weight anionic poly-mer was added to each beaker as a solution in 30 ml. deionized water. Stirring at 150 rpm was continued for-30 seconds, then reduced to 40 rpm for 3 minutes, at which time stirring was stopped and paddles were raised out of the beakers.
Floc size was estimated during the latter part of the stirring period, on a scale of 1 to 10, with 1 representing flocs smaller than 0.5 mm, and 10 representing flocs lcm or larger. The contents of the six beakers in a set (those being ~5 treated simultaneously) were compared visually in terms of rate of settling of flocs, and ranked from 1 to 6, with 1 being the most rapid in the set. Residual soluble color was monitored by removing supernatant from each beaker at the end of five minutes, and measuring the optical density of a 4 cm path.
Solution color removal is determined primarily by the precipi-~lZ;~:~30 .
tation with aluminum, rather than by anionic flocculant addi-tion, and so does not vary much for a fixed alum addition.
HUMATE WASTES--SETTLING TE5T No .
-Seven hundred milliliters of humate wastes are placed in a 1 liter graduated cylinder. Fifty milliliters of 1~ FeSO4 7H20 solution are diluted to 150 milliliters total volume, and then added to the graduated cylinder with agi~ation to insure uniform mixing. The polymeric flocculant then is added to the cylinder as a solution in 150 ml of deionized water, with mix-ing to provide adequate dispersion of the polymer solution throughout the suspension for about 5-10 seconds. Following addition of the polymeric flocculant, very mild agitation is provided by three 1/8" diameter stainless steel fingers posit- -ioned equidistantly along the circumference of a circle with a radius about one half the internal radius of the cylinder, ex-tending from the top to bottom of the cylinder, and moved along the path of the circle at a rate of one revolution per minute. The height of the solidsjliquid interface is recorded as a function of time after addition of polymeric flocculant.
HUMATE WASTES-SETTLING TEST No. 2 Seven hundred milliliters of humate wastes are placed in a 1 liter graduated cylinder. The pH is adjusted to 7.0 with 0.5N NaOH. Fifty milliliters of 1~ FeSO4.7H2O solu- -tion are diluted with deionized water, in an amount necessary to provide a total volume of 850 ml in the graduated cylinder when added to the humate wastes~ This ferrous sulfate solution is added to the cylinder with agitation to insure thorough mixing.
A solution containing 5 mg polymeric flocculant in 150 ml deion-ized water then is added slowly to the cylinder (over about 10-15 seconds), with agitation to provide thorough mixing of Z;~730 flocculant with the suspension. Following addition of the polymeric flocculant, very mild agitation is provided by three 1/8" diameter stainless steel fingers extending from top to bottom of the cylinder, and traversing a cylindrical path in the cylinder with a radius about one half the radius of the cylinder. Each finger completes one traversal along the peri-phery of the circle per second. The height of the solids/
liquid interface is recorded as a function of time after ad-dition of flocculant. The rate of settling is computed from the number of minutes required for the interface to settle one centimeter below the 1000 ml mark on the graduated cylinder.
EXAMPLES 1 and 2 Following the Settling Test procedure, rates of set-tling at pH 7.5 as a function of flocculant dosage (mg polymer/
g dry slime solids) over a commercially viable range were determined and the results are given in Table I which follows which also indicates the polymer composition and Brookfield viscosity.
.
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TABLE I
SETTLING RATES OF FLORIDA PHOSPHATE SLIMES
Exam-Exam- Comp. Comp.
ple 1 ple 2 A B
Polymer Composition (Mole %) Acrylamidomethylpropane-sulfonic acid ~15 7 0 0 Acrylic Acid ~ 0 0 12 7 Acrylamide 85 93 88 93 Brookfield Viscosity(cps.)3.3 3.4 3.9 3.4 Settling Rates cm/sec.
Dosage mg/g 0.025 0.045 - - -0.050 0.140 0.062 0.075 0.200 0.105 0.100 0.270 0.160 0.072 0.125 - 0.205 0.100 0 150 - - 0.135 0.115 0 175 - - 0.195 0.135 0 200 - - - 0.165 0 225 - - - 0.195 Q As sodium salt.
The results given in Table I above indicate the super-ior settling rates achieved at lower polymer dosages using polymers containing ionicity derived from sulfonate groups.
Comparisons in performance can be made via dosages necessary to achieve a fixed settling rate from plots of the settling rate at various polymer dosages. Using this procedure, the polymer dosage required to provide a settling rate of 0.144 cm./sec. (17 ft./hr.) was determined using the same slimes as in Examples 1 and 2. The dosage value (D) is given below in Table II along with polymer compositions and Brookfield , viscosities.
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EXAMPT~E 7 Using phosphate slimes obtained from another source, settling tests to determine the dosage requirements for a set-tling rate of 0.144 cm./sec. were determined operating at pH=
7.85 . The polymers employed and the dosage requirements are given in Table III which follows.
TABLE III
DOSAGE REQUIREMENTS FOR SETTLING
OF FLORIDA PHOSPHATE SLIMES
_ Example Polymer Composition (Mole %) 7 Comp. G
Acrylamidomethylpropane-sulfonic acid 4 Acrylic Acid 2 7 Acrylamide 94 93 Brookfield Viscosity (c~s) 3.4 3.4 Dosage for 0.114 cm./sec.
settling rate (mg/g) 0.125 0.310 Using the procedure color removal described above, the effluent tested was a deep amber colored suspension with low solids from a paper mill in North Carolina. The suspension pH was adjusted from 7.8 to 6.5 with sulfuric acid. Alum add-ition was at a level of 350 ppm. A series of tests were run with aliquots of the suspension using flocculants at various dosages. The flocculant of Examples 8-10 contained 7 mole per-cent acrylamidomehtylpropanesulfonic acid and 93 mole percent acrylamide. The Comparative Flocculant G contained 7 mole per-cent acrylic acid and 93 mole percent acrylamide. Details and results are given in Table IV.
~L~l22730 TABLE IV
COLOR REMOVAL USING ALUM
FOLLOWED BY FLOCCULA~ION
_ Flocculant Brookfield Dosage Floc Perform-Example Viscosity (Mg/l) Sizeance Rank (cps) 8 3.4 0.1 3 3 9 3.4 0.2 5 2 3.4 0.3 6 G, run 1 3.4 0.1 2 6 G, run 2 3.4 - 0.2 2 5 G, run 3 3.~ 0.3 2 4 Thus, 0.1 mg/l of the flocculant of the invention pro-vides more rapid clarification than 0.3 mg./l. of the compara-tive flocculant.
The procedure of Examples 8-10 was repeated in every material detail except for the flocculants employed. The floc-culant of Examples 11-13 contained 5 mole percent acrylamido-methylpropanesulfonic acid and 95 mole percent acrylamide~ The Comparative Flocculant H contained 3.5 percent acrylic acid and 96.5 percent acrylamide. Details and Results are given in Table V, TABLE V
COLOR REMOVAL USING ALUM
FOLLOWED BY FLOCCUhATION
-Flocculant Brookfield Dosage Floc Perform-Example Viscosity ~ /1) Size an~ce_Rank - (cps) 11 3.6 0.1 5 3 12 3.6 0.2 6 2 13 3.6 0.3 7 H, run 1 3.5 0.1 3 6 H, run 2 3.5 0.2 4 5 H, run 3 3.5 0.3 4 4 Again, 0.1 mg/l of the flocculant of the invention pro-vides more rapid clarification than 0.3 mg/l of the comparative ~;Z730 flocculant.
Again repeating the procedure of Examples 8-10 in every material detail, two additional flocculants were evaluated.
The flocculant of the invention contained 15 mole percent acryl-amidomethylpropanesulfonic acid and 85 mole percent acrylamide.
- The Comparative Flocculant I contained 12 mole percent acrylic acid and 88 percent acrylamide. Details and results are given in Table VI.
TABLE VI
COLOR REMOVAL USING ALUM
FOLLOW~D BY FLOCCULATION
Flocculant Brookfield Dosage Floc Perform-ExamPleViscosity (Mq/l) Size ance Rank ( cps ) 14 3.3 0.1 2 3 3.3 0.2 3 2 16 3.3 0.3 4 I, run 1 3.9 0.1 1 5 I, run 2 3.9 0.2 1 6 I, run 3 3.9 0.3 1 4 Again repeating the procedure of Examples 8-10 in every material detail, two additional flocculants were evalu-ated. The flocculant of Examples 14-16 contained 15 mole per-cent acrylamidomethylpropanesulfonic acid and 85 mole percent acrylamide. The Comparative Flocculant J contained 15 mole per-cent acrylic acid and 85 mole percent acrylamide. Details and 25results are given in Table VII.
~122730 TABLE VII
COLOR REMOVAL USING ALUM
FOLLOWED BY FLOC~ULATION
Flocculant Brookfield Dosage Floc Perform-Example Viscosity (Mg/l) Size ance Rank (cps) 17. 4.0 0.1 4 3 18 4.0 0.2 5 2 19 4.0 0.3 7 J, run 1 4.6 . 0.1 1 6 J, run 2 4.6 0.2 1 5 J, run 3 4.6 : 0.3 1 4 _X~M-PL~S 20-22 Again following the procedure of Examples 8-10 in every material detail, two additional flocculants were evaluated~
The flocculant of Examples 0-22 contained 7 mole percent acrylamidomethylpropanesulfonic acid and 93 mole percent acryl-amide. The Comparative Flocculant K contained 7.7 mole percent acrylic acid and 92.3 mole percent acrylamide. Details and results are given in Table VIII.
TABLE VIII
COLOR REMOVAL USI~G ALUM
FOLLOWE~ ~Y FLOCCULATION
Flocculant BrookfieldDosage Floc Perform-Example Viscosity(Mg/l) Size ance Rank ( cps )
Floc size was estimated during the latter part of the stirring period, on a scale of 1 to 10, with 1 representing flocs smaller than 0.5 mm, and 10 representing flocs lcm or larger. The contents of the six beakers in a set (those being ~5 treated simultaneously) were compared visually in terms of rate of settling of flocs, and ranked from 1 to 6, with 1 being the most rapid in the set. Residual soluble color was monitored by removing supernatant from each beaker at the end of five minutes, and measuring the optical density of a 4 cm path.
Solution color removal is determined primarily by the precipi-~lZ;~:~30 .
tation with aluminum, rather than by anionic flocculant addi-tion, and so does not vary much for a fixed alum addition.
HUMATE WASTES--SETTLING TE5T No .
-Seven hundred milliliters of humate wastes are placed in a 1 liter graduated cylinder. Fifty milliliters of 1~ FeSO4 7H20 solution are diluted to 150 milliliters total volume, and then added to the graduated cylinder with agi~ation to insure uniform mixing. The polymeric flocculant then is added to the cylinder as a solution in 150 ml of deionized water, with mix-ing to provide adequate dispersion of the polymer solution throughout the suspension for about 5-10 seconds. Following addition of the polymeric flocculant, very mild agitation is provided by three 1/8" diameter stainless steel fingers posit- -ioned equidistantly along the circumference of a circle with a radius about one half the internal radius of the cylinder, ex-tending from the top to bottom of the cylinder, and moved along the path of the circle at a rate of one revolution per minute. The height of the solidsjliquid interface is recorded as a function of time after addition of polymeric flocculant.
HUMATE WASTES-SETTLING TEST No. 2 Seven hundred milliliters of humate wastes are placed in a 1 liter graduated cylinder. The pH is adjusted to 7.0 with 0.5N NaOH. Fifty milliliters of 1~ FeSO4.7H2O solu- -tion are diluted with deionized water, in an amount necessary to provide a total volume of 850 ml in the graduated cylinder when added to the humate wastes~ This ferrous sulfate solution is added to the cylinder with agitation to insure thorough mixing.
A solution containing 5 mg polymeric flocculant in 150 ml deion-ized water then is added slowly to the cylinder (over about 10-15 seconds), with agitation to provide thorough mixing of Z;~730 flocculant with the suspension. Following addition of the polymeric flocculant, very mild agitation is provided by three 1/8" diameter stainless steel fingers extending from top to bottom of the cylinder, and traversing a cylindrical path in the cylinder with a radius about one half the radius of the cylinder. Each finger completes one traversal along the peri-phery of the circle per second. The height of the solids/
liquid interface is recorded as a function of time after ad-dition of flocculant. The rate of settling is computed from the number of minutes required for the interface to settle one centimeter below the 1000 ml mark on the graduated cylinder.
EXAMPLES 1 and 2 Following the Settling Test procedure, rates of set-tling at pH 7.5 as a function of flocculant dosage (mg polymer/
g dry slime solids) over a commercially viable range were determined and the results are given in Table I which follows which also indicates the polymer composition and Brookfield viscosity.
.
1~2Z73(~
TABLE I
SETTLING RATES OF FLORIDA PHOSPHATE SLIMES
Exam-Exam- Comp. Comp.
ple 1 ple 2 A B
Polymer Composition (Mole %) Acrylamidomethylpropane-sulfonic acid ~15 7 0 0 Acrylic Acid ~ 0 0 12 7 Acrylamide 85 93 88 93 Brookfield Viscosity(cps.)3.3 3.4 3.9 3.4 Settling Rates cm/sec.
Dosage mg/g 0.025 0.045 - - -0.050 0.140 0.062 0.075 0.200 0.105 0.100 0.270 0.160 0.072 0.125 - 0.205 0.100 0 150 - - 0.135 0.115 0 175 - - 0.195 0.135 0 200 - - - 0.165 0 225 - - - 0.195 Q As sodium salt.
The results given in Table I above indicate the super-ior settling rates achieved at lower polymer dosages using polymers containing ionicity derived from sulfonate groups.
Comparisons in performance can be made via dosages necessary to achieve a fixed settling rate from plots of the settling rate at various polymer dosages. Using this procedure, the polymer dosage required to provide a settling rate of 0.144 cm./sec. (17 ft./hr.) was determined using the same slimes as in Examples 1 and 2. The dosage value (D) is given below in Table II along with polymer compositions and Brookfield , viscosities.
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EXAMPT~E 7 Using phosphate slimes obtained from another source, settling tests to determine the dosage requirements for a set-tling rate of 0.144 cm./sec. were determined operating at pH=
7.85 . The polymers employed and the dosage requirements are given in Table III which follows.
TABLE III
DOSAGE REQUIREMENTS FOR SETTLING
OF FLORIDA PHOSPHATE SLIMES
_ Example Polymer Composition (Mole %) 7 Comp. G
Acrylamidomethylpropane-sulfonic acid 4 Acrylic Acid 2 7 Acrylamide 94 93 Brookfield Viscosity (c~s) 3.4 3.4 Dosage for 0.114 cm./sec.
settling rate (mg/g) 0.125 0.310 Using the procedure color removal described above, the effluent tested was a deep amber colored suspension with low solids from a paper mill in North Carolina. The suspension pH was adjusted from 7.8 to 6.5 with sulfuric acid. Alum add-ition was at a level of 350 ppm. A series of tests were run with aliquots of the suspension using flocculants at various dosages. The flocculant of Examples 8-10 contained 7 mole per-cent acrylamidomehtylpropanesulfonic acid and 93 mole percent acrylamide. The Comparative Flocculant G contained 7 mole per-cent acrylic acid and 93 mole percent acrylamide. Details and results are given in Table IV.
~L~l22730 TABLE IV
COLOR REMOVAL USING ALUM
FOLLOWED BY FLOCCULA~ION
_ Flocculant Brookfield Dosage Floc Perform-Example Viscosity (Mg/l) Sizeance Rank (cps) 8 3.4 0.1 3 3 9 3.4 0.2 5 2 3.4 0.3 6 G, run 1 3.4 0.1 2 6 G, run 2 3.4 - 0.2 2 5 G, run 3 3.~ 0.3 2 4 Thus, 0.1 mg/l of the flocculant of the invention pro-vides more rapid clarification than 0.3 mg./l. of the compara-tive flocculant.
The procedure of Examples 8-10 was repeated in every material detail except for the flocculants employed. The floc-culant of Examples 11-13 contained 5 mole percent acrylamido-methylpropanesulfonic acid and 95 mole percent acrylamide~ The Comparative Flocculant H contained 3.5 percent acrylic acid and 96.5 percent acrylamide. Details and Results are given in Table V, TABLE V
COLOR REMOVAL USING ALUM
FOLLOWED BY FLOCCUhATION
-Flocculant Brookfield Dosage Floc Perform-Example Viscosity ~ /1) Size an~ce_Rank - (cps) 11 3.6 0.1 5 3 12 3.6 0.2 6 2 13 3.6 0.3 7 H, run 1 3.5 0.1 3 6 H, run 2 3.5 0.2 4 5 H, run 3 3.5 0.3 4 4 Again, 0.1 mg/l of the flocculant of the invention pro-vides more rapid clarification than 0.3 mg/l of the comparative ~;Z730 flocculant.
Again repeating the procedure of Examples 8-10 in every material detail, two additional flocculants were evaluated.
The flocculant of the invention contained 15 mole percent acryl-amidomethylpropanesulfonic acid and 85 mole percent acrylamide.
- The Comparative Flocculant I contained 12 mole percent acrylic acid and 88 percent acrylamide. Details and results are given in Table VI.
TABLE VI
COLOR REMOVAL USING ALUM
FOLLOW~D BY FLOCCULATION
Flocculant Brookfield Dosage Floc Perform-ExamPleViscosity (Mq/l) Size ance Rank ( cps ) 14 3.3 0.1 2 3 3.3 0.2 3 2 16 3.3 0.3 4 I, run 1 3.9 0.1 1 5 I, run 2 3.9 0.2 1 6 I, run 3 3.9 0.3 1 4 Again repeating the procedure of Examples 8-10 in every material detail, two additional flocculants were evalu-ated. The flocculant of Examples 14-16 contained 15 mole per-cent acrylamidomethylpropanesulfonic acid and 85 mole percent acrylamide. The Comparative Flocculant J contained 15 mole per-cent acrylic acid and 85 mole percent acrylamide. Details and 25results are given in Table VII.
~122730 TABLE VII
COLOR REMOVAL USING ALUM
FOLLOWED BY FLOC~ULATION
Flocculant Brookfield Dosage Floc Perform-Example Viscosity (Mg/l) Size ance Rank (cps) 17. 4.0 0.1 4 3 18 4.0 0.2 5 2 19 4.0 0.3 7 J, run 1 4.6 . 0.1 1 6 J, run 2 4.6 0.2 1 5 J, run 3 4.6 : 0.3 1 4 _X~M-PL~S 20-22 Again following the procedure of Examples 8-10 in every material detail, two additional flocculants were evaluated~
The flocculant of Examples 0-22 contained 7 mole percent acrylamidomethylpropanesulfonic acid and 93 mole percent acryl-amide. The Comparative Flocculant K contained 7.7 mole percent acrylic acid and 92.3 mole percent acrylamide. Details and results are given in Table VIII.
TABLE VIII
COLOR REMOVAL USI~G ALUM
FOLLOWE~ ~Y FLOCCULATION
Flocculant BrookfieldDosage Floc Perform-Example Viscosity(Mg/l) Size ance Rank ( cps )
4.7 0.1 4 3 21 4.7 0.2 5 2 22 4.7 0.3 6 K, run 1 4.4 0.1 2 6 K, run 2 4~4 0.2 2 5 K, run 3 4.4 0.3 2 4 Again following the procedure of Examples 8-10 in every material detail, two additional flocculant~ were evalu-ated. The flocculant of Examples 23-25 contained 5 mole percent acrylamidomethylpropanesulfonic acid and 95 mole percent acryl-- ~3 -1~22~730 amide. The Comparative Flocculant L contained 4 mole percent acrylic acid and 96 mole percent acrylamide. Details and res-ults are given in Table IX.
TABLE IX
TABLE IX
- 5 COLOR REMOVAL USING ALUM
FOLLOWED BY FLOCCULATION
Flocculant Brookfield Dosage Floc Perform-Example Viscosity (Mg/l) Size ance Rank (cps) 23 4.8 0.1 5 3 24 - 4.8 0~2 8 2 4.8 0.3 9 - L, run 1 4.2 0.1 1 6 L, run 2 4.2 0.2 2 5 L, run 3 4.2 0.3 2 4 Following the Humate Wastes-Settling Test No. 1, humate wastes from effluent stream to settling pond 20 grams solids per kilogram of substrate and pH 5.9 were treated with two flocculants in separate runs. Details and results are given below.
TABLE X
SETTkING RATES OF HUMATE WASTES
Example Comparative - Polymer Composition (Mole%) 26 Example M
Acrylamidomethylpropane-sulfonic acid~(AMPS)7 0 Acrylic Acid~ (AA) 0 7.7 Acrylamide (AM) 93 92.3 Brookfield Viscosity 4.7 4.4 Note 0As sodium ~alt The polymer of Example 26 provided an average settling rate of 0.24 centimeter per minute over 7.2 centimeters at a dosage of 0.36 milligrams polymer per gram of solids. For the same settling rate, the polymer of Comparative Example M re-quired a dosage of 5 milligrams of polymer per gram of solids.
E~AMPLE 27 Following the procedure of Example 26, two additional 5polymers were evaluated. Details and results are given below.
TABLE XI
SETTLING RATES OF HUMATE WASTES
Example Comparative Polymer Composition (Mole %) 27 Examp-e N
AMPS ~ 15 0 - .10 AA ~ 0 15 Brookfield Viscosity4.0 4~6 For a settling rate as in Example 26, 0.36 mg/gram solids of the polymer of Example 27 was required. For the same settling rate, 5 mg/gram solids of the polymer of Comparative Example N was required.
Again following the procedure of Example 26, two additional flocculants were evaluated. Details and results are given below.
TABLE XII
SETTLING RATES OF HUMATE WASTES
Example Comparative Polymer Composition tMole ~) 28 Example O
AMPS ~ 5 AA ~ o 3 5 AM 95 86.5 Broo~field Viscosity 3.6 3~5 ~;2Z730 For a settling rate as in Example 26, the dosage re-quired for the pol,vmer of Comparative Example 0 was four times that required for the polymer of Example 28.
EXAMPLES:29 - 32 The procedure of Humate Wastes-Settling Test No. 2 was followed using eight polymer flocculants in separate runs, four of the invention and four comparative. Details and Results are given below~
. , .. ~12Z730 .. ~n r~ ~ ~ o a) ~n I o ` ~ ~ o W P I O In u~ ~D O
,~ ao ~ O
~1 o ~ . . .
~-~ ~ D ~ O
~ o~
r~
. ~ ~i O 1` ~. ~
a~ ~ o ~ ~ o ~
Z . ~ r H
H ~ ~ U~
X tO ~ p O
~
l u~ o u~ ~
,~ X 11~
a~ I` o ~ ~ ,~
II: ~ a~, ~ O
,, _ ~ ~ ~ .
_ O
~3 , a~
O e ~ ~ e
FOLLOWED BY FLOCCULATION
Flocculant Brookfield Dosage Floc Perform-Example Viscosity (Mg/l) Size ance Rank (cps) 23 4.8 0.1 5 3 24 - 4.8 0~2 8 2 4.8 0.3 9 - L, run 1 4.2 0.1 1 6 L, run 2 4.2 0.2 2 5 L, run 3 4.2 0.3 2 4 Following the Humate Wastes-Settling Test No. 1, humate wastes from effluent stream to settling pond 20 grams solids per kilogram of substrate and pH 5.9 were treated with two flocculants in separate runs. Details and results are given below.
TABLE X
SETTkING RATES OF HUMATE WASTES
Example Comparative - Polymer Composition (Mole%) 26 Example M
Acrylamidomethylpropane-sulfonic acid~(AMPS)7 0 Acrylic Acid~ (AA) 0 7.7 Acrylamide (AM) 93 92.3 Brookfield Viscosity 4.7 4.4 Note 0As sodium ~alt The polymer of Example 26 provided an average settling rate of 0.24 centimeter per minute over 7.2 centimeters at a dosage of 0.36 milligrams polymer per gram of solids. For the same settling rate, the polymer of Comparative Example M re-quired a dosage of 5 milligrams of polymer per gram of solids.
E~AMPLE 27 Following the procedure of Example 26, two additional 5polymers were evaluated. Details and results are given below.
TABLE XI
SETTLING RATES OF HUMATE WASTES
Example Comparative Polymer Composition (Mole %) 27 Examp-e N
AMPS ~ 15 0 - .10 AA ~ 0 15 Brookfield Viscosity4.0 4~6 For a settling rate as in Example 26, 0.36 mg/gram solids of the polymer of Example 27 was required. For the same settling rate, 5 mg/gram solids of the polymer of Comparative Example N was required.
Again following the procedure of Example 26, two additional flocculants were evaluated. Details and results are given below.
TABLE XII
SETTLING RATES OF HUMATE WASTES
Example Comparative Polymer Composition tMole ~) 28 Example O
AMPS ~ 5 AA ~ o 3 5 AM 95 86.5 Broo~field Viscosity 3.6 3~5 ~;2Z730 For a settling rate as in Example 26, the dosage re-quired for the pol,vmer of Comparative Example 0 was four times that required for the polymer of Example 28.
EXAMPLES:29 - 32 The procedure of Humate Wastes-Settling Test No. 2 was followed using eight polymer flocculants in separate runs, four of the invention and four comparative. Details and Results are given below~
. , .. ~12Z730 .. ~n r~ ~ ~ o a) ~n I o ` ~ ~ o W P I O In u~ ~D O
,~ ao ~ O
~1 o ~ . . .
~-~ ~ D ~ O
~ o~
r~
. ~ ~i O 1` ~. ~
a~ ~ o ~ ~ o ~
Z . ~ r H
H ~ ~ U~
X tO ~ p O
~
l u~ o u~ ~
,~ X 11~
a~ I` o ~ ~ ,~
II: ~ a~, ~ O
,, _ ~ ~ ~ .
_ O
~3 , a~
O e ~ ~ e
Claims (10)
l. A process for flocculating suspensions of solids containing multivalent cations which comprises adding to an aque-ous suspension of such solids an effective amount of an anionic polymeric flocculant comprising from about 65 to about 99 mole percent of repeating units derived from acrylamide, from about
1 to about 25 mole percent of repeating units derived from a vinylsulfonic acid, and from 0 to about 10 mole percent of re-peating units derived from acrylic acid, the mole percent of units obtained from acrylic acid being less than the mole per-cent of units derived from said vinylsulfonic acid and the poly-meric flocculant having a Brookfield viscosity of at least about 2.60 centipoises.
2. The process of Claim 1 wherein said vinylsulfonic acid is acrylamidomethylpropanesulfonic acid.
3. The process of Claim 1 wherein said repeating units derived from acrylic acid is 0 mole percent.
4. The process of Claim 1 wherein said Brookfield vis-cosity is at least about 3.30 centipoises.
5. The process of Claim 3 wherein said anionic poly-meric flocculant comprises 3 to 15 mole percent of vinyl-sulfonic acid.
6. The process of Claim 1 wherein said suspended solids is Florida phosphate slimes.
7. The process of Claim 6 wherein said vinyl-sulfonic acid is acrylamidomethylpropanesulfonic acid.
8. The process of Claim 6 wherein aid repeating units derived from acrylic acid is 0 mole percent.
9. The process of Claim 6 wherein said Brookfield viscosity is at least about 3.30 centipoises.
10. The process of Claim 8 wherein said anionic flocculant comprises 3 to 15 mole percent vinylsulfonic acid.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US1227479A | 1979-02-15 | 1979-02-15 | |
| US12,274 | 1979-02-15 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1122730A true CA1122730A (en) | 1982-04-27 |
Family
ID=21754183
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA337,654A Expired CA1122730A (en) | 1979-02-15 | 1979-10-16 | Flocculation of suspended solids of multivalent cations with anionic flocculants containing sulfonate ions |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA1122730A (en) |
| ZA (1) | ZA795533B (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6041939A (en) * | 1998-03-20 | 2000-03-28 | Thiele Kaolin Company | Beneficiation with selective flocculation using hydroxamates |
| US9068776B2 (en) | 2009-10-30 | 2015-06-30 | Suncor Energy Inc. | Depositing and farming methods for drying oil sand mature fine tailings |
| US9404686B2 (en) | 2009-09-15 | 2016-08-02 | Suncor Energy Inc. | Process for dying oil sand mature fine tailings |
| US9909070B2 (en) | 2009-09-15 | 2018-03-06 | Suncor Energy Inc. | Process for flocculating and dewatering oil sand mature fine tailings |
-
1979
- 1979-10-16 CA CA337,654A patent/CA1122730A/en not_active Expired
- 1979-10-17 ZA ZA00795533A patent/ZA795533B/en unknown
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6041939A (en) * | 1998-03-20 | 2000-03-28 | Thiele Kaolin Company | Beneficiation with selective flocculation using hydroxamates |
| US9404686B2 (en) | 2009-09-15 | 2016-08-02 | Suncor Energy Inc. | Process for dying oil sand mature fine tailings |
| US9909070B2 (en) | 2009-09-15 | 2018-03-06 | Suncor Energy Inc. | Process for flocculating and dewatering oil sand mature fine tailings |
| US10590347B2 (en) | 2009-09-15 | 2020-03-17 | Suncor Energy Inc. | Process for flocculating and dewatering oil sand mature fine tailings |
| US9068776B2 (en) | 2009-10-30 | 2015-06-30 | Suncor Energy Inc. | Depositing and farming methods for drying oil sand mature fine tailings |
Also Published As
| Publication number | Publication date |
|---|---|
| ZA795533B (en) | 1980-11-26 |
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