AU2014201868B2 - Method of preventing or reducing aluminosilicate scale in industrial processes - Google Patents

Abstract

METHOD OF PREVENTING OR REDUCING ALUMINOSILICATE SCALE IN INDUSTRIAL PROCESSES Abstract Materials and a method are provided whereby polymers with least 0.5 mole % of the pendant group or end group containing - Si (OR")3 (where R" is H, an alkyl group, Na, K, or NH4) are used to control aluminosilicate scaling in an industrial process having an alkaline process stream such as a pulping mill process stream. When materials of the present 10 invention are added to the alkaline process stream, they reduce and even completely prevent formation of aluminosilicate scale on equipment surfaces such as evaporator walls and heating surfaces. The present materials are effective at treatment concentrations that make them economically practical.

Description

METHOD OF PREVENTING OR REDUCING ALUMINOSILICATE SCALE IN INDUSTRIAL PROCESSES Summary of the Invention 5 The invention describes materials and methods for preventing or inhibiting the formation of scale on or in equipment used in industrial processes having alkaline process streams 10 Background of the Invention The problem of scaling in and on process equipment used in industrial processes and particularly in those having an 15 alkaline process stream is very well known. The scales present a significant problem when they build up on the surface of process equipment and cause a loss in the heat transfer coefficient. Thus, additional heat may be required to be provided to the evaporator equipment in these processes 20 resulting in added cost. A an example of such an industrial process having an alkaline process stream is the Kraft recovery process for manufacturing paper which has been khown for over 100 years and is eloquently described in many texts on the subject (see 25 G.A. Smook "Handbook for Pulp and paper technologists, 3rd Edition) . More recently the development of closed loop cycles in kraft paper mills has resulted in an increase in scaling problems in process equipment due to the build up of aluminum and silicon in the system as is described by P.N. Wannamaker 30 and W.J. Frederick in "Application of solubility data to predicting the accumulation of aluminum and silicon in alkaline pulp mills", Minimum Effluent Mills Symposium, 1996, p303. It has, therefore, been a well recognized need to provide a method and compositions for inhibiting the formation 35 of aluminosilicate scales in kraft pulp mills. US 5409571 describes the use of terpolymers.of maleic acid, acrylic acid and hypophosphorous acid as scale inhibitor for kraft pulp mills. This type of polymer is shown to be effective against calcium carbonate scales but has not been shown to be effective for aluminosilicate scales. High Level Nuclear Waste (HLNW) facilities process radioactive-rich solid and liquid wastes in order to minimize 5 waste volume and immobilize the hazardous material for long term storage. HLNW treatment is currently performed via two processes; one process is performed under acidic conditions and one under alkaline conditions. Under alkaline processing conditions, sodium aluminosilicate scale growth is a 10 significant problem during the pretreatment stage, prior to waste vitrification. Within the pretreatment facility, the waste is evaporated, filtered, ion exchanged and further evaporated. 15 During evaporation, aluminosilicate scales can form on the surfaces of the evaporator walls and heating surfaces. Furthermore, transfer pipes can also become blocked due to the buildup of these scales and precipitates necessitating closure for maintenance. 20 The pretreated HLNW wastes go vitrification facilities. HLNW waste goes into a melter preparation vessel where silica and other glass-forming materials are added. The mixture is then heated and the molten mixture is then poured into large 25 stainless steel containers, cooled and moved into temporary storage until a permanent storage location is selected. From the vitrification unit operation, a portion of the Si-containing glass-forming materials are recycled back into 30 the evaporator unit (during pretreatment). The dissolved aluminum, in the form of sodium aluminate, and sodium silicate species react slowly in solution to form complex hydrated sodium aluminosilicate species. Among these species are families of amorphous aluminosilicates (aluminosilicate 35 hydrogel) , zeolites, sodalites, and cancrinites collectively known as "sodium aluminosilicate". These nuclear waste streams 2 also contain high concentrations (up to 2M for each ion) of nitrate and nitrite ions, and very high concentrations (up to 16M in some sections of the tank) of OH~ ions. These factors greatly enhance the rate of formation of aluminosilicate 5 scale. As a result, sodium aluminosilicate scale formed has a low solubility in the alkaline HLNW liquor. Also, sodium aluminosilicate scale is considered to be an undesirable HLNW product due to the incorporation of 10 radioactive lanthanides and actinides into the aluminosilicate scale cage structures and coprecipitation of sodium diuranate. (Peterson, R. A. and Pierce, R. A., (2000), Sodium diuranate and sodium aluminosilicate precipitation testing results, WSRC-TR-2000-00156,. Westinghouse Savannah River Company, 15 Aiken, SC.). It is therefore, desirable for HLNW facilities to minimize the volume of H-LNW's including those. resulting from aluminosilicate scales. Thus, it can be seen that, sodium aluminosilicate scale growth has a significant negative economic and operational impact on the treatment of nuclear 20 wastes. Therefore, it would be desirable to provide a solution to the sodium aluminosilicate scaling problem in the nuclear waste evaporators. Attempts to solve the aforementioned problems have lead 25 to limited success see Wilmarth and coworkers (Wilmarth, W. R., Mills, J. T. and Dukes, V. H., (2005), Removal of silicon from high-level waste streams via ferric flocculation, Separation Sci. Technol., 40, 1-11. These authors have examined the use of ferric nitrate to remove Si from solution 30 in the form of a ferric precipitate, in order to reduce or eliminate the formation of aluminosilicate scale. Although this approach has some merit, there is still the disposal of the high-level ferric precipitate to deal with and an additional filtration unit operation is required. Also, W. 35 R.Wilmarth and J. T. Mills "Results of Aluminosilicate Inhibitor Testing", WSRC-TR-2001-00230 have proposed using low 3 4 molecular weight compounds as scale inhibitors for HLNW s but have found none to be satisfactory. Thus there is a need for an economic and effective method for .reducing alumnosilicate scale buildup on equipment used in industrial processes where suc buildup~ is a problemL as fox examlfple, the Kraft tulp paper Process and in nuclear waste treatment streams. SUzMMA1RY OF TE TmIVENTION The present invention solves the arcmrntioned problems and others by providing material and a met-hod whereby plymer~ S ha-ving at least: 0,5 mole % of the roup -- Sl (OR") (where R" is H, an alkyl group Na, K, or )N) as an end group or pendant thereto are used to reduce or el te alutminloiicate scaling in a process having an al.kaline process stream such as a kraf r pulping mill or a high level nuclear waste evaporation process tr eatment stream. When materials of the present inv-ntion are ad to these industrial process streams, t-hy reduce and even completely prevent formation of alumnsilicate scale on the equipment surfaces. Moreover, the resent materials are Cffective at treatment concentratiots that make them economically practice. DETAILED DESCRIPTION OF THE INVENTION According to a first aspect of the present invention there is provided a composition for reducing aluminosilicate scale in an industrial process comprising a polymer which is the reaction product of polyethyleneimine with 3-glycidoxypropyltrimethoxvsilane. Described herein is a method and materials for the reduction of aluminosilicate containing scale in arn idusrial process having an alkal ine process stream such as in the kraft pulp mill process streams or a high level nuclear waste treatment stream. The process stream to be treated can be any proces stream having an alkaline in which scaling oc curs, e g. black, gree-'n and white liquors of the kraft process or a high level nuclear ws t e evaporation process stream. The method comprises the step olf adding to- the process stream an al-uminosilicate containing scale inhibiting amount 9309503 of a polymer having at least 5 mole % pendant thereto a group or end group containing -- Si(OR") 3 where R" = H, Cl-C3 alkyl, aryl, Na, K or NH 4 . The amount of fSi(OR")3 functionality present in the polymer will be an amount sufficient enough to 5 achieve the desired results and can range from a little as 0.5 mole % of the total monomer groups present in the polymer to as much as 100 mole%. However it will be most economical to use the least amount necessary to yield the desired results. The polymers are preferably prepared initially as the 10 silylether derivatives Polymer- iSi(OR)3 where R" iCl-C3 alkyl, aryl, eg Polymer

--

Si(OCH2 CH3)3 or Polymer-Si(OCH3)3 The silylether derivatives may be added directly to the industrial process stream or they may be hydrolyzed to the silanol derivatives to form polymers of the following generic 15 structures, Polymer--Si(OH) 3 , PolymerSi(ONa) 3 Polymer Si(OK)3 , and Polymer--Si(ONH4)3 before addition to the process stream. It is a convenient feature of this invention that any of these forms may be added to the process stream. The molecular weight of the polymer shol-d be - least about 500, 20 most preferably at least about 1000. In a preferred embodiment, the group containing Si(OR")3, where R" - H C1-C3 alkyl, aryl, Na, K or NH 4 comprises a group according to --G--R--X-O CSi(-R")3 where G 25 no group, NH-I, NR" or 0; R = no group, C=O, 0, Cl-ClO alkyl, or aryl; X no group, NR, 0, NH, amide, urethane, or urea; R' no group, 0, C1-C10 alkyl, or aryl; and R" = H, Cl-C3 alkyl, aryl, Na, K or NH 4 . In one embodiment, the group is --- NH- X- Si(R)3, 30 where R no group, 0, Cl-OC 1 alkyl, or aryl; X 0, NH, an amide, urethane, or urea; R'= no group, 0, Cl-dO alkyl, or aryl; and R" H, C1-C3 alkyl, aryl, Na, K or NH4. In another embodiment the polymer to which the group is pendant can comprise at least one nitrogen to which the 35 pend-ant group is attached. Exemplary polymers.acomprising at least one nitrogen to which the pendant group is attached 5 include, but are not limited to, a polymer according to the following formula: - ( (CH 2 ) 2 -- -N) x- ( (CH 2 ) 2 NH) ) y 5 R---Si (OR")3 where x = 0.1-100%, y = 99.9-0%; and R = no group, C1-C10 alkyl, aryl, or -COX-R'-, where X = 0 or NH and R' = no group, Cl-C10 alkyl or aryl; and R" = H, C1-C3 alkyl, aryl, Na, K or 10 NH 4 ; wherein polymers according to the formula: -- ((CH 2

)

2 -- N)x-- ( (CH 2

)

2 -- N)y- R-Si(ONa)3 15 where x = 0.5-20%, y = 99.5-80% and R = C2-C6 are preferred, and wherein polymers according to the formula: - ( (CH 2 ) 2 --N) -- ( (CH 2 ) 2 --N) y 20

(CH

2 ) 3 -Si (ONa) 3 where x = 0.5-20%, y = 99.5-80% are specific examples. In another embodiment the polymer having pendant thereto 25 a group or end group containing -- Si(OR") 3 is derived from an unsaturated polymerizable monomer containing the group -- Si(OR") 3 where R" H, Cl-C10 alkyl, aryl, Na, K or NH 4 and is optionally copolymerized with one or more additional polymerizable monomer(s) . Examples of such additional 30 polymerizable monomers include but are not limited to vinylpyrrolidone, (meth)acrylamide, N-substituted acrylamides such as N-alkylacrylamides or acrylamidomethylpropanesulfonic acid, (meth)acrylic acid and salts or esters thereof, maleimides, vinyl acetate, acrylonitrile, and styrene. 35 Particularly preferred unsaturated polymerizable monomers containing -- Si(OR") 3 groups are monomers of formula V and VI. Formula V: Formula VI: (CHP=CR') (CHP=CR') 40 COXRSi (OR") 3 Si (OR") 3 6 where P = H, C1-C3 alkyl, -CO2R", -CONHR R = C1- C1o alkyl, aryl, R'= H, C1-3 alkyl, or aryl 5 X 0, NH, or NR R" = H, Cl-C3 alkyl, aryl, Na, K or NH 4 . Examples of such polymers include homo- and copolymers of trialkoxy-viyl~silanes such as CH 2 =CHSi (OCH2CH3) 3 and monomers of the formula VII: 10 Formula VII: (CHP=CR') COXRSi(OR")3 15 where P = H, R = -CH 2

CH

2 CH2- , R1= H , X NH and R" H, Cl-C3 alkyl, aryl, Na, K or NH 4 . Monomers of this type may be copolymerized with any other polymerizable monomers such as those described above. Particularly preferred copolymerizable monomers include 20 -inylrroldne. (meth)acrVlamide, N-substituted (meth)acrylamides, (meth)acrylic acid and it's salts or esters and maleimides. Particularly preferred are N-substituted acrylamides containing 4- 2 0 carbon atoms such as N methylacrylamide, N,N-dimethylacrylami thylacrylamide

N

25 propylacrylamide, N-butylacrylamide, N-amylacrylamide,

N

hexylacrylamide, N-penylacrylamide, N-octylacrflamide. In a preferred embodiment a polymer according to the formula: (VPD),-

(CH

2 -- CP)x---

(CH

2 -CP)y---

(CH

2 -- CH)z 30///

CONL

2 COOM FSi(OR")3 where w=0-99% , x= 1-99%, y=1-9 9 % , z=0.5-20% and M = H, Na, K, NH 4 ; and R"= H, Cl-10 alkyl, aryl, Na, K or NH 4 -P H or 35 CH 3 , L=H, or 'C-CO alkyl, aryl or aralkyl, F -- G--R--X--R'--Si(OR")3 wherein G = no group, NH, NR" or 0; R no group, C=O, 0, C1-C1O alkyl, or aryl; X = no group, NR, 0, NH, amide, urethane, or urea; R' no group, 0, CClO alkyl, or aryl; and -1 H, Cl-C3 alkyl, aryl, Na, K or NH 4 and '7 VPD is a moeity derived from substituted or unsubstituted vinylpyrrolidone monomer. Exemplary polymers are homo- or copolymers of one or more comonomers of formulae VII: Formula VII: 5 (CHP=CR;) COXRSi(OR")3 where P = H, R = -CH 2

CH

2

CH

2 -, R'= H, X = NH and 10 R" = H, Cl-C3 alkyl, aryl, Na, K or NH 4 wherein polymers according to the following formula: (VPD) w-- (CH2--CH)X*--- (CH-2-CH)y--- (CH2--CH) z-- / / / 15 CONHC 8

H

17 COONa CONH (CH 2 ) 3 Si (OR") 3 wherein w = 0-90%, x=0-50%, Y=0-90%, Z=2-50 mole % are specific examples. 20 In another embodiment, a polymer according to the formula: - (CH 2 CHQ)w- C (CH) - (CH) )2------------ ((CH) - (CH) )y-- ((CH) --- (CH))z // /// I / ////I COOR COX-R' -Si (OR" ) 3 COOR COD CO 2 V" CO 2 V" 25 where w = 1-99.9 %, x = 0.1-50%, y = 0-50%, z = 0-50%; and Q = Cl-C10- alkyl, aryl, amide-, acrylate, ether, COXR -where X=O or NH and R = H, Na, K, NH 4 , Cl-C10 alkyl or aryl, or any other substituent; X = NH, NP where P= C1-C3 alkyl or aryl, or 0; R' = Cl-10 alkyl, or aryl; V"= H, C1-C3 alkyl, aryl, Na, K or 30 NH 4 or forms an anhydride ring; R" = H, C1-C3 alkyl, aryl, Na, K or NH 4 ; and D= NR1 2 or OR1 wherein RI = H, C1-C20 alkyl, Cl C20 alkenyl or aryl, with the proviso that all R, R", V" and R1 groups do not have to be the same, is used, and wherein polymers according to the formulae: 35 -- CH2CHQ) w-- ( (CH) (CH) ) -- ((CH) --- (CH) )y---( (CH) --- (CH)).z / / / / / / CO CO 2 Na CO 2 Na CO CO 2 Na CO 2 Na / ./ 40 NH (CH 2 ) 3 Si (ONa) 3 NH (C 4 H) where w =1-99.9%, x=0.1-50%, y=0-50%, z=0-50%; and 8 Q is phenyl, and: - (CH2CHQ) /- ( (CH) (CH) (CH) - (CH) /y-( (CH) (CH) ) y2 (CH) (CH) 5 CO CO 2 Na CO 2 Na CO CO 2 Na CO CO 2 Na CO 2 Na / / / NH (CH 2

)

3 Si (ONa) 3

N(CH

2

CH

3

)

2 NHtallow where w =1-99.9%, x=0.1-50%, yl+Y2 =0-50%, yl and y2 = 0-50% 10 z=0-50%; and Q is phenyl are specific examples. In another embodiment a polymer according to the formula: 15 A-O- (CH 2

CH

2 0) . (CH 2 CH (CH 3 ) O) y (CH 2

CH

2 0) -O-B where x = 5-100% (as mole %), y and z = 0-100% and at least one A and/or B unit is a group containing the group - Si(OR") 3 , where R" = H, Cl-C3 alkyl, aryl, Na, K or NH 4 , is 20 used. Exemplary such polymers include; A-O- (H2

C

H2O),x (CH 2 CH (CH 3 ) 0) y (CH 2 CHO) -O-B in which A and/or B = R-i(0")'/3, and x = 5 - 50 %, y = 5 - 95 % and z = 0 - 50 i.e. a copolymer of ethylene oxide and propylene oxide substituted with -Si(OR") 3 groups, and 25 A-O- (CH 2

CH

2 O) x (CH 2 CH (CH 3 ) O) y (CH 2

CH

2 6) -O-B in which A and/or B = R-Si(OR") 3 , x = 100%, y = 0% and z = 0% i.e., a homopolymer of polyethylene oxide substituted with R--Si(OR") 3 groups is used. In another embodiment a polymer prepared from a polysaccharide or polysaccharide derivative is used. Any 30 polysaccharide to which the pendant -- Si(OR") 3 groups can be attached may be employed. Preferably the polysaccharide should be soluble in the industrial process stream such as a kraft pulping mill process streams liquor or the high level nuclear -waste process stream. Polysaccharides useful in this invention 35 include but are not limited to cellulose and it's derivatives, such as hydroxyethylcellulose, hydroxypropylcellulose, methylcellulose, hydroxybutylcellulose, carboxymethylcellulose, starch and starch derivatives such as cationic starch, guar, dextran, dextrins, xanthan, agar, 9 10 carrageenan and the like, Pareicularly preferred are starch and cellulose derivatives wherein the reaction product of hydroxyethylcellulose with 3-glycidoxypropyltrimethoxys lane is a specific example. The polymers used herein can be made in a variety of ways. For example, they can b miade by poly merizing a monomer containing the group -- Si(OR"), where R" = N, CI-t3 alkyl, aryl, Na, K or N,, such as for example a silane monomer, or copolymierizing -uch monomer with one or mOre Co monomers. Suitable silane monomers include, but are not limited to vinyl triethoxysilaneri, vi ny&ltrimethoxysi1lane, allyltriethoxysilane, bitenyltri zkethoxysilane, gamma-N acrylamidopropyltriethoxy-ilane, p-triethoxysilyStyrene, 2 - (methyltrimethoxyailyl) avcylic acidic 2 (methyl trimethoxysilyl) -, butadiene , N triet hoxysilylpropy -male imide and other reaction products of, maleic anhydride and other unsaturated anhydride3 with amino compvuoundcs containingQ the -- Si (OR") g: roup. rTse monmErs Can be hydrolyzed by aqueous ase, either before or afte-r polymerization. Suitable co-monomers include, but are not limited to. vinyl acetate, acrylonitrile, styrene, tmeth) acrylic acid and its eaters or salts, (meth)acrylamide and substituted acrylamides such as acryl amidoxtiethylpranesulonic acid, N-methylacrylamide,

NN-

dimethylacrylamide, N ethylacrylamide N-propylacrylamide,

N

butylacylawide, N-amylacrylamide, N-hexylacrylamide, N phenylacrylamide, N-ctylacrylamide, The copolymers can also be graft copolymers such as pclyacryl ic acid-g poly (vinyltriethoxysilane) and poly (vinyl acetate -co-Crotonic aciOd) -g- poy (vinyl triethaxysi lan) . These polymers can be made in a' variety of solventsSlvn suitable 'or such use include-, ut are not Limited to, aetone, tetrahydrofuran, taluene, kylenie, etc In somc oases the polymer i soluble itn the reaction solvent and isr striping off the 11 solvent. Al ternati ely, if the polymer is not soluble in the reaction solvent, the product is recovered hy filtration. suitable initiators for use in the present iiventionilud, but are not limited to, 2,2'azobis(2,dimethylvaleronitrile) and 2,2-anobivisobutyronitrile, benzoyl peroxide, and cumen hydroperoxide. In another embodiment, polymers useKul in the invention can be made by reacting a compouzndt containing a -- Si (oR) group as well as a reactive group that reacts with either a pendant group or backbone atom of an exist ing polymer, Por example, polyamines and polysaccharides can he reacted with a variety of compounds containiu - Si (OR"); groups to give polymers which can be used for the invention, suitable reactive groups include, but are not limited to an alkyl haldWe group, such a for e Oxample, chloropropyl, bromoethyl, chloromethy1, and bromcundecyl. The compound containR can contain, an epoy functionality such as glycidoxypropyl, 1,2-epoxyamyl, 1,2 epoxydecyl or 3,4-epmryvyclonexylethy glycidoxypropyltrimethoxysilan is a particularly preferred compound The reactive grou an also be:' a combination of a hydroxyl group and a halide, such as 3-ohloro-2-hydrxypropyl The reactive moiety can also contain an isocyanate group, such as isocyanatopropyl, or isccyanatomethyl that react to form a urea linkage. In addition, silanes containing anhydride groups, such as triethoxysilylpropylsuccinic anhydride are suitable for use in making the polymers for the present invention.. The reactions can be carried out either neat or in a suitable solvent. In additio, other functional groups such as alkyl groups can be Odded by reaction oth-r ano qrolps or nitrogen atoms on the polymer with alkyl ha1ides, epoxides or isocyanate. The polyamines can be made by a variety of methods. They can be made by a ring opening polyerization of nziridine or similar: compounds. They also can be made by condensation reactions of aminessuch as ammloni; methylamine, dimethylamine, ethylenediamine etc. with reactive compounds such as 1,2-dichloroethane, epichlorohydrin, epibromohydrin and similar compounds. Polymers containing anhydride groups can be reacted with 5 a variety of compounds containing -Si (OR") 3 to make polymers suitable for use in the present invention. Suitable anhydride containing polymers include copolymers of maleic anhydride with ethylenically unsaturated monomers such as styrene, ethylene, alpha olefins such as octadecene, meth(acrylamide), 10 (meth)acrylic acid, acrylate esters such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl acrylate and methylvinylether. The polymer can also be a graft copolymer such as poly(1,4-butadiene)-g-maleic anhydride or polyethylene-g-maleic anhydride and the like. Other suitable 15 anhydride monomers include, but are not limited to, itaconic and citraconic anhydrides. Suitable reactive silane compounds include, but are not limited to T-aminopropyltriethoxysilane, his(gamma-triethoxysilylpropyl)aminA, N-phenyl-gamma aminopropyltriethoxysilane, p-aminophenyltriethoxysilane, 3 20 (m-aminophenoxypropyl)-trimethoxysilane, and gamma aminobutyltriethoxylsilane. Other functional groups can be added to the polymer by reacting it with amines, alcohols and other compounds. In a preferred polymer for use in the present invention, maleic anhydride is the anhydride and the 25 co-monomer is styrene. A preferred silane is gamma aminopropyltriethoxysilane. It is also advantageous to react some of the anhydride groups with another amine such as diethylamine. The same type of amino compound containing an --Si(OR") 3 30 group can be reacted with polymers containing a pendant isocyanate group, such as copolymers of for example, isopropenyldimethylbenzylisocyanate and vinyl isocyanate, with co-monomers including, but not limited to, vinyl acetate, styrene, acrylic acid, and acrylamide. These polymers can also 35 be reacted with other compounds such as amines to enhance performance. 12 Isocyanate functional compounds with an -- Si(OR") 3 group such as gamma-isocyanatopropyltrimethoxysilane can also be reacted with polymers containing hydroxyl groups such as hydrolyzed poly(vinyl acetate) and copolymers of vinyl acetate 5 with other monomers. Other hydroxyl containing polymers suitable for use include, but are not limited to, polysaccharides and polymers containing N-methylolacrylamide. In the present process, the amount of polymer added to the process stream can depend on the composition of the 10 industrial process stream (e.g. a Kraft pulping mill process or high level nuclear waste streams liquor involved and generally all that is required is an aluminosilicate containing scale inhibiting amount thereof. In general the polymer is preferably added to the process stream in 15 economically and practically favorable concentrations. A preferred concentration is one that is greater than about 0 ppm to about 300.ppm, more preferably in a concentration that is greater than about 0 ppm to about 50 ppm and most preferably the polymer is added to the process stream in a 20 concentration that is greater than about 0 ppm to about 10 ppm. The polymer can be added directly to any industrial process stream where scaling can occur, e.g. in the black liquor evaporators of the kraft pulp milling process, and in 25 green and white liquor process streams of that process. It is preferred, however to add the polymer to a charge stream or recycle stream or liquor leading to the black liquor evaporator. While the polymer can be added to the industrial process stream at any time during the process, it is 30 preferable to add it at any convenient point in the process before or during application of heat. Usually, the polymer is added immediately before the evaporator. Examples 35 High Level Nuclear Waste Comparative Example A 13 Preparation of the reaction product of styrene/maleic anhydride copolymer with butylamine (Comparative Polymer A) is as follows: 10.0 g of dry styrene/maleic anhydride copolymer 5 (SMA), with a mole ratio of styrene to maleic anhydride of about 1.I and M, about 16,000, is suspended in 100 ml of toluene. A solution of 1.72 g of butylamine in 10 ml of toluene is added at ambient temperature. The mixture is refluxed for 3 hr. The solid product is filtered off, washed, 10 and dried. This gives a polymer containing 53 mole% styrene, 24 mole% N-butyl half amide from maleic anhydride, and 23 mole% maleic anhydride. Comparative Example B 15 Preparation of the reaction product of SMA with tallow amine and diethylamine (Comparative Polymer B) is as follows: 100.0 g of dry SMA, with a mole ratio of styrene to maleic anhydride of about 1.1 and M, about 16,000, is suspended in. 20 941.7 g of toluene. A solution of 25.2 g tallow amine and 27.5 g diethylamine in 35.2 g toluene is added at ambient temperature and the mixture is then refluxed for 30 min. The resulting toluene slurry is cooled to room temperature and then added with mixing to about 700 ml of 2% aqueous caustic. 25 The toluene layer is separated and the residual toluene in the aqueous phase is removed by distillation. The aqueous solution is further purified by ultrafiltration using a 0.2 [pm hydrophilic polyethersulfone filter and then freeze dried to obtain the dry polymer. This gives a polymer containing 53 30 mole% styrene, 38 mole% N-diethyl half amide from maleic anhydride, and 9 mole% N- tallow half amide from maleic anhydride. Comparative Example C 35 14 Preparation of a copolymer of N-tert-octylacrylamide and acrylic acid (Comparative Polymer C) is as follows: 2.81 g Acrylic acid, 2.52 g N-tert-octylacrylamide, and 0.14 g 2 mercaptoethanol are dissolved in 12.~5 g DMF and 13.87 9 5 dioxane and purged with nitrogen. The mixture is heated to 750 C and 0.16 9 2,2'-azobis(2,4-dimethylvaleronitrile) in 3 9 dioxane is added. After 6 hr at 750 C, the mixture is cooled, giving the desired polymer in solution. This gives a polymer containing 73.7 mole% acrylic acid and 26.3 mole% N-tert 10 octylacrylamide. Example 1 - Polymer i Preparation of the reaction product of SMA with 15 butylamine and (3-aminopropyl)triethoxysilane to give a polymer with 1 mole% silane containing monomer units (Polymer i) is as follows: 10.0 g of dry SMA, with a mole ratio of styrene to maleic anhydride of about 1.0 and Mw about 16,000, is suspended in 100 ml of toluene. A solution of 1-72 - of 20 butylamine and 0.21 g of (3-aminopropyl)triethoxysilane in 10 ml of toluene is added at ambient temperature. The mixture is refluxed for 3 hr. The solid product is filtered off, washed, and dried. This gives a polymer containing 53 mole% styrene, 23.9 mole% N-butyl half amide from maleic anhydride, 1 mole% 25 N-(3-triethoxysilyl)propyl half amide from maleic anhydride, and 22.1 mole% maleic anhydride. Example 2 - Polymer ii 30 Preparation of the reaction product of SMA with butylamine and (3-aminopropyl)triethoxysilane to give a polymer with 3.8 mole% silane containing monomer units (Polymer ii) is as follows: 10.0 g of dry SMA, with a mole ratio of styrene to maleic anhydride of about 1.1 and M, about 35 16,000, is suspended in 100 ml of toluene. A solution of 1.72 g of butylamine and 0.83 g of (3-aminopropyl)triethoxysilane 15 in 10 ml of toluene is added at ambient temperature. The mixture is refluxed for 3 hr. The solid product is filtered off, washed, and dried. This gives a polymer containing 53 mole% styrene, 23.9 mole% N-butyl half amide from maleic 5 anhydride, 3.8 mole% N- (3-triethoxys iyl'propyl half amide from maleic anhydride, and 19.3 mole% maleic anhydride. Example 3 - Polymer iii 10 Preparation of the reaction product of SMA with butylamine and (3-aminopropyl)triethoxysilane to give a - polymer with 7.6 mole% silane containing monomer units (Polymer iii) is as follows: 10.0 g of dry SMA, with a mole ratio of styrene to maleic anhydride of about 1.1 and Mw about 15 16,000, is suspended in 100 ml of toluene. A solution of 1.72 g of butylamine and 1.66 g of (3-aminopropyl)triethoxysilane in 10 ml of toluene is added at ambient temperature. The mixture is refluxed for 3 hr. The solid product is filtered o-ff, w=ashed,anddrie This gives a polymer containing 53 20 mole% styrene, 23.9 mole% N-butyl half amide from maleic anhydride, 7.6 mole% N-(3-triethoxysilyl)propyl half amide from maleic anhydride, and 15.5 mole% maleic anhydride. Example 4 - Polymer iv 25 Preparation of the reaction product of SMA with tallow amine, diethylamine, and (3-aminopropyl)triethoxysilane to give a polymer with 3.8 mole% silane containing monomer units (Polymer iv) is as follows: 100.0 g of dry SMA, with a mole 30 ratio of styrene to maleic anhydride of about 1.1 and Mw about 16,000, is suspended in 941.7 g of toluene. A solution of 25.2 g tallow amine, 24.8 g diethylamine, and 8.3 g (3 aminopropyl)triethoxysilane in 38.9 g toluene is. added at ambient temperature and the mixture is then refluxed for 30 35 min. The resulting toluene slurry is cooled to room temperature and then added with mixing to about 700 ml of 2% 16 aqueous caustic. The toluene layer is separated and the residual toluene in the aqueous phase is removed by distillation. The aqueous solution is further purified by ultrafiltration using a 0.2 pm hydrophilic polyethersulfone 5 filter and then freeze dried to obtain the dry polymer. This gives a polymer containing 53 mole% styrene, 3..8 mole% N-(3 triethoxysilyl)propyl half amide from maleic anhydride, 9.4 mole% N-tallow half amide of maleic anhydride, and 33.8 mole% N,N-diethyl half amide of maleic anhydride. 10 Example 5 - Polymer v Preparation of the reaction product of SMA with tallow 15 amine, diethylamine, and (3-aminopropyl)triethoxysilane to give a polymer with 7.5 mole% silane containing monomer units (Polymer v) is as follows: 100.0 g of dry SMA, with a mole ratio of styrene to maleic anhydride of about 1.1 and M, about 16,000, is suspended in 941.7 g of toluene. A solution of 20 20.2 g tallow amine, 23.4 g diethylamine, and 16.7 g (3 aminopropyl)triethoxysilane in 40.2 g toluene is added at ambient temperature and the mixture is then refluxed for 30 min. The resulting toluene slurry is cooled to room temperature and then added with mixing to about 700 ml of 2% 25 aqueous caustic. The toluene layer is separated and the residual toluene in the aqueous phase is removed by distillation. The aqueous solution is further purified by ultrafiltration using a 0.2 stm hydrophilic polyethersulfone filter and then freeze dried to obtain the dry polymer. This 30 gives a polymer containing 53 mole% styrene, 7.5 mole% N-(3 triethoxysilyl)propyl half amide from maleic anhydride, 7.5 mole% N-tallow half amide of maleic anhydride, and 30 mole% N,N-diethyl half amide of maleic anhydride. 35 Example 6 - Polymer vi 17 Preparation of the reaction product of SMA with tallow amine, diethylamine, and (3-aminopropyl)triethoxysilane to give a polymer with 3.8 mole% silane containing monomer units (Polymer vi) is as follows: 100.0 g of dry SMA, with a mole 5 ratio of styrene to maleic anhydride of about 1.1 and M, about 16,000, is suspended in 941.7 g of toluene. A solution of 10.1 g tallow amine, 28.9 g diethylamine, and 8.3 g (3 aminopropyl)triethoxysilane in 31.3 g toluene is added at ambient temperature and the mixture is then refluxed for 30 10 min. The resulting toluene slurry is cooled to room temperature and then added with mixing to about 700 ml of 2% aqueous caustic. The toluene layer is separated and the residual toluene in the aqueous phase is removed by distillation. The aqueous solution is further purified by 15 ultrafiltration using a 0.2 pm hydrophilic polyethersulfone filter and then freeze dried to obtain the dry polymer. This gives a polymer containing 53 mole% styrene, 3.8 mole% N-(3 triethoxysilyl)propyl half amide from maleic anhydride, 3.8 mole- N-tallow half amide of maleic anhydride, and 39 mole'% 20 N,N-diethyl half amide of maleic anhydride. Example 7 Preparation of N-(3-triethoxysilyl)propylacrylamide 25 (TESPA) is as follows: 197.4 g of (3 aminopropyl)triethoxysilane and 89.9 g of triethylamine are dissolved in 330 g THF, purged with nitrogen, and cooled to 0' C. With mixing, 83.9 g of acryloyl chloride is added dropwise, and after the addition the mixture is heated to 400 30 C for 2 hr. The mixture is cooled to room temperature and the salt filtered out. The resulting solution of TESPA (42% in THF) is used as is without further purification. Example 8 - Polymer vii 35 18 - Preparation of the tetrapolymer of N-tert octylacrylamide, acrylic acid, 1-vinyl-2-pyrrolidinone, and TESPA to give a polymer containing 5 mole% silane containing monomer units (Polymer vii) is as follows: 1.89 g of 1-Vinyl 5 2-pyrrolidinone, 0.66 g acrylic acid, 2.21 g N-tert octylacrylamide, 1.30 g TESPA (42% in THF), and 0.14 g 2 mercaptoethanol are dissolved in 14 g DMF and 11.64 g dioxane and purged with nitrogen. The mixture is heated to 750 C and 0.16 g 2,2'-azobis(2,4-dimethylvaleronitrile) in 3 g dioxane 10 is added. After 6 hr at 750 C, the mixture is cooled,.giving the desired polymer in solution. The polymer is further purified by precipitation with isopropyl alcohol, washed, and dried. This gives a polymer containing 42.5 mole% 1-vinyl-2 pyrrolidinone, 22.5 mole% acrylic acid, 5 mole% TESPA, and 30 15 mole% N-tert-octylacrylamide. Example 9 - Polymer viii Preparation o f copolymer of 1-v.Linyl-2-pyrrolidinone* 20 and TESPA to give a polymer containing 5 mole% silane containing monomer units (Polymer viii) is as follows: 4.69 g of 1-Vinyl-2-pyrrolidinone, 1.44 g TESPA (42% in THF), and 0.14 g 2-mercaptoethanol are dissolved in 12.5 g DMF and 13.07 g dioxane and purged with nitrogen. The mixture is heated to 25 750 C and 0.16 g 2,2'-azobis(2,4-dimethylvaleronitrile) in 3 g dioxane is added. After 6 hr at 750 C, the mixture is cooled, giving the desired polymer in solution with 15% concentration. This gives a polymer containing 95 mole% I-vinyl-2 pyrrolidinone and 5 mole% TESPA. 30 Example 10 - Polymer ix Preparation of the terpolymer of N-tert-octylacrylamide, acrylic acid, and TESPA to give a polymer containing 5 mole% 35 silane containing monomer units (Polymer ix) is as follows: 2.46 g Acrylic acid, 2.21 g N-tert-octylacrylamide, 1.56 g 19 TESPA (42% in THF) , and 0.14 g 2 -mercaptoethanol are dissolved in 12.5 g DMF and 12.97 9 dioxane and purged with nitrogen. The mixture is heated to 750 C and 0.16 g 2,2dazobis(2, 4 dimethylvaleronitrile) in 3 g dioxane is added. After 6 hr at 5 750 C, the mixture is cooled, giving the desired polymer in solution with 15% concentration. This gives a polymer containing 70 mole% acrylic acid, 5 mole% TESPA, and 25 mole% N-tert-octylacrylamide. 10 Example 11 - Polymer x Preparation of the reaction product of polyethylene oxide with 3-glycidoxypropyltrimethoxysilane to give a polymer containing 2.2 mole% silane containing monomer units (Polymer 15 X) is as follows: 20.0 g of polyethyleneoxide (M, about 2000) is dissolved in 10.0 g DMSO and purged with nitrogen. To this mixture is added 2.63 g 3 -glycidoxypropyltrimethoxysilane, followed by 1.36 g of 45% KOH. The resulting mixture is heated to 800 C for 1 hr, giving th -dsred Dol-vmer in 20 solution with 65.8% concentration. This gives a polymer containing about 97.8 mole% ethylene oxide and 2.2 mole% 3 glycidoxypropyltrimethoxysilane. Example 12 - Polymer xi 25 Preparation of the reaction product of poly(ethylene glycol) -block-poly (propylene glycol) -block-poly (ethylene glycol) with 3-glycidoxypropyltrimethoxysilane to give a polymer containing 3.1 mole% silane containing monomer units 30 (Polymer xi) is as follows: 30.0 g of poly(ethylene glycol block-poly (propylene glycol)blockpoly(ethylene glycol) (with 50 wt% ethylene oxide and M, about 1900) is mixed with 4.52 g 3-glycidoxypropyltrimethoxysilane under nitrogen. 2.34 g 45% KOH is added and the resulting mixture heated to 80T C for1 35 hr, giving the desired polymer with 9m2.6% concentration. This gives a polymer containing about 55.1 mole% ethylene oxide, 20 41.8 mole% propylene oxide, and 3.1 mole% 3 glycidoxypropyltrimethoxysilane. Example 13 - Polymer xii 5 Preparation of the reaction product of poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) with 3-glycidoxypropyltrimethoxysilane to give a polymer containing 3.0 mole% silane containing monomer units 10 (Polymer xii) is as follows: 30.0 g of poly(ethylene glycol) block-poly(propylene glycol)-block-poly(ethylene glycol) (with 10 wt% ethylene oxide and M, about 2000) is mixed with 4.3 g 3 glycidoxypropyltrimethoxysilane under nitrogen. 2.2.2 g 45% KOH is added and the resulting mixture heated to 800 C for 1 15 hr, giving the desired polymer with 92.9% concentration. This gives a polymer containing about 12.3 mole% ethylene oxide, 84.7 mole% propylene oxide, and 3.0 mole% 3 glycidoxypropyltrimethnxysilane. 20 Example 14 - Polymer xiii Preparation of the reaction product of polyethylenimine with 3-glycidoxypropyltrimethoxysilane to give a polymer containing 0.5 mole% silane containing monomer units (Polymer 25 xiii) is as follows: 25.4 g Polyethylenimine (M, about 25,000) is mixed with 0.7 g 3-glycidoxypropyltrimethoxysilane, and the resulting mixture is heated at 70 0 C for 16 hr, giving the desired polymer as a soft friable gel. 30 Example 15 - Polymer xiv Preparation of the reaction product of polyethylenimine with 3-glycidoxypropyltrimethoxysilane to give a polymer containing 1.0 mole% silane containing monomer units (Polymer 35 xiv) is as follows: 25.72 g Polyethylenimine (M, about 25,000) is mixed with 1.43 g 3-glycidoxypropyltrimethoxysilane, and 21 the resulting mixture is heated at 700 C for 16 hr, giving the desired polymer as a soft friable gel. Example 16 - Polymer xv 5 Preparation of the reaction product of polyethylenimine with 3-glycidoxypropyltrimethoxysilane to give a polymer containing 2.0 mole% silane containing monomer units (Polymer xv) is as follows: 11.39 g Polyethylenimine (M, about 25,000) 10 is mixed with 1.28 g 3-glycidoxypropyltrimethoxysilane, and the resulting mixture is heated at 700 C for 16 hr, giving the desired polymer as a soft friable gel. Example 17 - Polymer xvi 15 Preparation of the reaction product of polyethylenimine with 3-glycidoxypropyltrimethoxysilane to give a polymer containing 4.0 mole% silane containing monomer units (Polymer xvi)is s fllow: 1.0 Poyethylenimine ( about 500 20 is mixed with 2.29 g 3-glycidoxypropyltrimethoxysilane, 'and the resulting mixture is heated at 700 C for 16 hr, giving the desired polymer as a soft friable gel. Example 18 - Polymer xvii 25 Preparation of the reaction product of hydroxyethyl cellulose with 3-glycidoxypropyltrimethoxysilane to give a polymer containing a high (-30 mole%) silane containing monomer units (Polymer xvii) is as follows: 8.0 g dry hydroxyethyl 30 cellulose (molecular weight 24,000-27,000) is mixed with 2.0 g 3-glycidoxypropyltrimethoxysilane in 5 g acetone. The acetone is removed by evaporation and the resulting mixture heated at 1001 C for 16 hr, giving the desired polymer. 35 Table 1 Summary of Polymers Used in Scale Inhibition Testing 22 Example Polymer Composition Mole% Silane* Comparative Comparative Reaction product of SMA with 0 A A butylamine Comparative Comparative Reaction product of SMA with 0 B B tallow amine and diethylamine lComparativel Comparative Copolymer of N-tert-octylamide O C ' C and acrylic acid Comparative Polyethylenimine (M,, ~25,000) 0 D obtained from Aldrich Comparative Polyvinylpyrrolidone (M, 0 E -10,000)from Aldrich 1 i Reaction product of SMA with 1 butylamine and (3 aminopropyl)triethoxysilane 2 ii reaction product of SMA with 3.8 butylamine and (3 aminopropyl)triethoxysilane 3 iii reaction product of SMA with 7.6 butylamine and (3 aminopropyl)triethoxysilane 4 iv Reaction product of SMA with 3.8 tallow amine, diethylamine, and (3-aminopropyl)triethoxysilane 5 v- reaction product of SMA with 7.5 tallow amine, diethylamine, and (3-aminopropyl)triethoxysilane 6 vi reaction product of SMA with 3.8 tallow amine, diethylamine, and (3-aminopropyl)triethoxysilane 7 vii tetrapolymer of N-tert- 5 octylacrylamide, acrylic acid, 1-vinyl-2-pyrrolidinone, and TESPA 8 viii copolymer of 1-vinyl-2- 5 pyrrolidinone and TESPA 9 ix terpolymer of N-tert- 5 octylacrylamide, acrylic acid, and TESPA 10 x reaction product of 2.2 polyethylene oxide with 3 glycidoxypropyltrimethoxysilane 11 xi reaction product of 3.1 poly(ethylene glycol)-block poly(propylene glycol)-block poly(ethylene glycol) with 3 glycidoxypropyltrimethoxysilane 12 xii reaction product of 3.0 poly(ethylene glycol)-block poly(propylene glycol)-block poly(ethylene glycol) with 3 glycidoxypropyltrimethoxysilane 13 xiii reaction product of 0.5 23 polyethylenimine with 3 glycidoxypropyltrimethoxysilane 1 14 xiv reaction product of polyethylenimine with 3 glycidoxypropyltrimethoxysilane 2 5 xv reaction product of 1xolyrethylenimine with 3 ci doxypropyltrimethoxysilane 4 6xvithe reaction product of polyethylenimine with 3 glycidoxypropyltrimethoxysilane 30 17 xvii the reaction product of ~ hydroxyethyl cellulose with 3 glycidoxypropyltrimethoxysilane *Mole% of monomer units in the polymer containing the.silane functional group. 5 Example 19 Test Procedure A synthetic high level nuclear waste liquor is made by 10 adding sodium carbonate, sodium sulfate, sodium hydroxide, sodium aluminate solution (made by digesting alumina trihydrate in caustic), sodium silicate, sodium nitrate, and sodium nitrite to demonized water. The final composition of the liquor is shown in Table 2 15 Table 2 Species Concentration (mole/1) 4.5 NaOH1.0 NaNO 3 1.0 NaNO 2 1.0 Na 2

CO

3 0.25 Na 2

SO

4 Alumina Trihydrate - 0.01 SiO 2 00 All of the polymer samples are dissolved in 2% aqueous 20 NaOH prior to addition to the nuclear waste liquor, hydrolyzing any anhydride and trialkoxylsilane groups that have not previously been reacted, transforming the trialkoxylsilane groups into silanol groups or the sodium 24 salts. Into a 125 ml polyethylene bottle, are placed the scale reducing additive (if used) as a 0.5% solution in 2% aqueous NaOH for the lower doses and for the higher doses a 3% solution is used. 120 ml of the above stock synthetic high 5 level nuclear waste solution is then added to the bottle mixing. The sealed bottle is heated with agitation at 1020 C for 18±2 hours. Up to 24 such tests (bottles) are done at one time. At the end of the 18 hours, the bottles are opened and the solution is filtered (0.45 pm filter). Considerable 10 aluminosilicate scale is observed to form as loose aluminosilicate in the liquor (which may have initially formed on the polyethylene surfaces) In the examples below, the weight of scale formed in the test is expressed as a percentage of the average weight of scale that formed on two 15 comparative blank tests (i.e. no additive used) that are part of the same set of tests Using Lhe test procedure outlined above, a series of SMA type polymers reacted with butylamine and containng varying 20 amounts of silane are examined for aluminosilicate scale inhibition activity and the results are reported in Table 3. Table 3 Polymer Mole% Silane Dosage, mg/l Total Scale Formed, .% vs. Blank Comparative 0 10 104.4 A Comparative 50 103.9 A 10 69.4 1 50 72.6 3.8 1063.3 ii3.8 50 37-1 iii 3.8 50 5.2 iii .650 .1.0 25 Example 20 Using the test procedure as outlined in Example 19, a series of SMA polymers reacted with tallow amine and 25 diethylamine and containing varying amounts of silane are examined for scale inhibition activity and the results are reported in Table 4. 5 Table 4 Polymer Mole% Silane Dosage, mg/i Total Scale Formed, % vs. Blank Comparative 0 10 87.4 B Comparative 0 50 95.8 B iv 3.8 10 59.2 iv 3.8 50 54.9 v 7..5 10 2.8 v 7.5 50 vi ~ 3.8 10 49.6 vi 3.8 50 66.8 Example 21 10 Using the test procedure as outlined in Example 19, a series of polymers made with the silane containing monomer TESPA are examined for scale inhibiLiou auLivity and the results are reported in Table 5. 15 Table 5 Polymer Mole% Silane Dosage, mg/l Total Scale Formed, % vs. Blank Comparative 0 10 102.8 C Comparative 0 50 104.2 C Comparative 0 10 93.5 E Comparative 0 50 101.2 E vii 5 10 3.1 vii 5 50 2.9 viii 5 10 1.6 viii 5 50 2.7 ix 5 10 2.7 ix 5 50 1.1 Example 22 26 Using the test procedure as outlined in Example 19, a series of polyether type polymers containing varying amounts of silane are examined for scale inhibition activity and the results are reported in Table 6. Table 6 Polymer Mole% Silane Dosage, ig/l Total Scale Formed, % vs . Bl ank x 2.2 10 68.0 x 2.2 50 6.2 x 2.2 300 2.2 xi 3.1 10 21.0 xi 3.1 50 1.0 xi 3.1 300 1.9 xii 3.0 10 23.3 xii 3.0 50 6-.2 xii 3.0 300 0.7 Example 23 10 Using the test procedure as outlined in Example 19, a series of polyethylenimine type polymers containing varying amounts of silane are examined for scale inhibition activity and the results are reported in Table 7. 15 Table 7 Polymer Mole% Silane Dosage, mg/l Total Scale Formed, % vs. Blank Comparative 0 10 102.0 D Comparative 0 50 105.5 D Comparative 0 300 112.8 D xiii 0.5 10 43.3 xiii 0.5 50 1.6 xiii 0.5 300 0 xiv 1 10 4.2 xiv 1 50 0 xiv 1 300 0.1 xv 2 10 0 xv 2 50 0 xv 2 300 0 xvi 4 10 0 xvi 4 50 0 27 xi4 3000 Example 24 Using the test procedure as outlined in Example 19, a 5 hydroxyethy. cellulose derivative containing silane is examined for scale inhibition act-ivity and he results are reported in Table 8. Table 8 10 Polymer Mole% S~ilane Dosage, mg/ Total Scale Formed, % vs. Blank xvii -30 10 17.5 xvii -30 s0 3.0 xvii 30 300 16.9 Kraft pulp mill scale inhibition testing 15 Example 25 In order to snulate the conditions found in a typical kraft pulp mill black liquor a synthetic process liquor simulating a typical black liquor is prepared in the following 20 way. A basic aluminate solution is prepared according to the recipe below by adding the aluminate and NatH solutionlto the water and stirring overnight. The solution is then filtered 25 through a 3-[tm filter membrane (Pall versapor-300 0 T w/wa, 47 mm): Na 2 0.A1203.3 H20 100.0 g 50% NaOH 146.6 g 30 Deionized water 753.4 g Total 1000.0 g This basic aluminate solution is used to prepare a 35 simulated kraft black liquor solution according to the recipe and procedure below. Sodium acetate is added to achieve the 28 desired sodium ion concentration. Amounts are in grams and percentages are w/w unless otherwise indicated. Sodium carbonate 121.9 5 Sodium sulfate 32.7 Sodium thiosulfate 36.4 Sodium hydrosulfide, 60% 70.9 Sodium acetate 445.3' 50% sodium hydroxide 290.7 10 29.55% Si0 2 14.0 Basic aluminate solution 25.1 Deionized water 1746 Total 2783 g = 2.30 liter 15 Calculated concentration: [C0 2 ] = 0.5 M [SO] = 0.1 M

[S

2 0 3 2 ] = 0.1 M 20 [SH ] = 0.33 M [Na*] = 5.7 M [CH] = 1.6 M [Si] = 0.03 M [Al] = 0.01 M 25 The solution is prepared by addiii the sodium carbonate, sodium.sulfate, sodium thiosulfate, sodium hydrosulfide, and sodium acetate to the water with rapid stirring. After 30 min stirring, the solution is filtered through a coarse glass frit 30 to remove minor amounts of insoluble material. The sodium hydroxide solution, silica solution, and finally basic aluminate solution is added, with stirring after each addition. The solution is used immediately as described below. For each of Examples 26 to 33, respective polymer, 35 solutions of polymers iii (Example 3), v (Example 5), vii (Example 8), viii (Example 9), x (Example 11), xi(Example 12), xvi (Example 17) and xvii (Example 18) are pre-diluted to 1% (w/w) active concentration in 2% NaOH solution prior to use. The amount of 1.45 g of a polymer solution, (or 1.45 g of 40 water for the control test), is added to a labeled 4-oz HDPE wide-mouth jar. Then 145 g (120 ml) of simulated kraft black liquor solution is added to each jar before capping and shaking. Each jar then contained a "test solution". The . polymer dose is 100 ppm. 29 The caps on the jars are then loosened so as to be able to relieve pressure, and the jars placed on the floor of a 102 oC oven to simulate heating in a kraft process liquor. After 1.5 hr the caps are tightened and the jars placed on a 5 rotisserie placed inside the oven. After turning on the rotisserie in the oven overnight (16.5 hr), each sample is filtered using a pre-weighed 3- im filter membrane (Pall Versapor- 3 0 0 0 T w/wa, 47 mm). Each membrane plus any collected solid is washed with about.5-ml water and placed on a . h 10 diameter watch glass. A steel tray containing all the watch glasses and membranes is placed in a 102 OC oven for 30 mi to dry the filtered solids. Each membrane plus solid is weighed and the weight of the solid calculated by difference. % Scale inhibition is then calculated in the following manner: 15 % Scale inhibition = 100 x Weight of scale formed with player present Weight of scale formed with polymer absent 20 The results of testing polymers in examples 26-33 at 100 ppm are shown in Table 9. Table 9. Example Polymer % Scale Reduction 26 iii 10.3 27 v 27.5 28 vii 29 viii 65.1 30 X 96.1 31 xi 96.5 32 v6.xv2 33 xvii 28.7 25 30

Claims (2)

1. A composition for reducing aluminosilicate scale in an industrial process comprising a polymer which is the reaction product of polyethyleneimine with

3-glycidoxypropyltrimethoxvsilane, Cytec Technology Corp. Patent Attorneys for the Applicant/Nominated Person SPRUSON & FERGUSON