CA2173168A1 - Methods for suppressing dust emissions - Google Patents
Methods for suppressing dust emissionsInfo
- Publication number
- CA2173168A1 CA2173168A1 CA 2173168 CA2173168A CA2173168A1 CA 2173168 A1 CA2173168 A1 CA 2173168A1 CA 2173168 CA2173168 CA 2173168 CA 2173168 A CA2173168 A CA 2173168A CA 2173168 A1 CA2173168 A1 CA 2173168A1
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- Prior art keywords
- dust
- copolymer
- producing materials
- group
- dust producing
- Prior art date
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Abstract
Methods for suppressing the dissemination of dust emissions from dust producing materials are disclosed. Fugitive dust emissions are sup-pressed by applying aqueous solutions of a graft copolymer obtained by graft copolymerizing cationic monomers onto polyvinyl alcohol to dust producing materials.
Description
., METHODS FOR SUPPRESSING DUST EMISSIONS
FIELD OF THE INVENTION
The present invention relates to methods for suppressing fugitive dust emissions from dust producing bulk solids by applying a polyvinyl 5 alcohol graft copolymer.
BACKGROUND OF THE INVENTION
Dust dissemination poses safety, health and enviro"",ental prob-10 lems in many commercial environments. For instance, in many indus-tries, such as mining, mineral processing, agricultural, power, steel and paper, the transportation, handling and storage of bulk solids is common.
One major problem associated with bulk solids is dust generation and the subsequent emission of the dust into the atmosphere.
Industrial sources of fugitive dust include open operations, leaks and spills, storage, disposal, transit or poor housekeeping of sundry fine-ly divided solid particulates. The iron and steel industries are replete with examples of the above enumerated categories. Wind erosion of exposed 20 masses of particulate matter such as coal or mine mill tailings, fertilizers, etc. c~ ~ses both air pollution and economic waste. Detrimental effects on health and cleanliness result where these fine particles are carried aloft by the winds.
A typical ",eti,od for controlling or suppressing dust is to apply a water spray. However water sprays only control dust for a short period of time depending upon enviror"nental conditions. The application of the spray has to be repeated frequently to provide ongoing dust control.
Various lrealments have been utilized to control dust emissions.
U.S. Pat. No. 3 954 662 diecloses aqueous foamable compositions and their use to suppress coal dust. The co",position contains water an interpolymer of a pol~",eri able vinyl ester and a partial ester compound interpolymerizable with the vinyl ester and a detergent wetting agent.
The interpolymer binds coal dust and keeps the dust particles encapsu-lated after the foam has collarsed U.S. Pat. No. 4 087 572 discloses a combination of an organic polymer latex such as a styrene-b~ ~t~diene interpolymer and a silicone applied to the surface of a coal pile or other mass of finely divided par-tiu ll~te materials. In addilion a wetting agent may be incor~oraled to prevent pre,nat.lre coag!J'~tion. The co"l~.nation is applied as an ~queo~ ~s mixture such as by spraying.
U.S. Pat. No. 4 551 261 discloses the suppression of dust with an ~ueous foam comprising a foaming agent and an elastomeric water in-soluble polymer. The foam provides immediate dust suppression and eases application. The polymer coats the material and continues to sup- .
5 press dust generation during handling of the material after the foam has collapsed.
U.S. Pat. No. 4 594 268 discloses the use of at least one meth-acrylate polymer for dust suppression. The methacrylate polymer pro-10 vides dust suppression when applied to a wide variety of materials. Afterapplication the polymer provides a tacky water resistai!t coating which effectively prevents dusting while additionally acting as an anti-freeze agent.
U.S. Pat. 4 801 635 discloses a combination of water soluble anionic acrylic polymers and nonionic glycol polymers and anionic and nonionic su, ractants useful for the control of dust emissions into the enviro"" ,enL
The p~sent invention relates to ,nethods for controlling fugitive dust emissions from bulk granular or powdered solids. Fugitive dust emissions are controlled by applying an ~ eous solution of a graft 25 copolymer of polyvinyl alcohol and a cationic monomer.
` 2173168 DESCRIPTION OF THE RELATED ART
U.S. Pat. No. 4 080 346 Bedell et al. teaches methods for grafting cationic and nonionic ",ono",ers onto polyvinyl alcohol using a transition 5 metal ion catalyst. The resulting polymers prove useful às dye mordents.
U.S. 4 308 189 I\~lorilani et al. teaches a method for preparing modified polyvinyl alcohol polymers via an emulsion process whereby a random copol~l"e,i~ation of vinyl acetale and calionic ",ono",ers is carried out.
The resulting copolymers are used as a binder in pulp and textiles.
U.S. 4 775 715 Beresniewicz et al. tea~;l,es a process for making cationic polyvinyl alcohol using ",echanical shear and a non-alkylene qualer"ary ammonium halide. This process achieved conversions up to 40%. The quaternized polyvinyl alcohol was used as a flocculating 15 agent a stabilizing colloid and in a~l ,esive formulations. U.S. 5 075 401 Zhang teaehes anionic graft copolymers useful in oil recovery. These copolymers are prepared using a reverse phase emulsion pol~",eri~ation teehnique. U.S. Pat. No. 5 345 803 Dragner et al. teaches grarling of predo"linantly non water soluble monoi"ers onto polyvinyl alcohol using 20 p~t~soiurn persulfate or ammonium hydroxide as the initiator. The graft-ed produet is a latex emulsion useful as t.nders for non-woven products.
French patent 2 214 687 tea~;l,es g(dfling of cationic monomers onto cellulose polyvinyl alcohol polyamides or polyethylene terephll ,al-25 ate using electron ir,adiation as the initiator however cerium is conjec-tured as a potential free radical initiator. The resulting polymers are used to improve dyeability of polymers. Japanese patent 131 003 teaches a polyvinyl alcohol grarled with acrylamido-type ",ono,ners using basic catalysts such as sodium hydroxide having efficaey as sizing agents.
Japanese Kokoku publication No. 21361 teaches a modified poly-vinyl alcohol which is prepared by polymerizing vinyl acetate with other mono,ners such as hydlophobic acrylamides. The vinyl acetale is hydro-lyzed after polymerization with the comonomers to form the polyvinyl 5 alcohol.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to me~hods for suppressing the dis-10 semination of fugitive dust pa, ~icl~s into the almosphere from dust pro-ducing materials comprising applying to the dust producing materials an aqueous solution of a graft copolymer obtained by graft copolymerizing cationic monomers onto polyvinyl alcohol.
The resulting polyvinyl alcohol graft copolymer has the general structure:
FORMULA I
(F)b I
-(~CH2~CH~)a~
OH
whereby F is H or a cationic monomer having the formula FORMULA ll R
l =O
.
wherein R in Formula ll is hydlogen or a C1 to C3 alkyl group and R1 is the salt of an a~""onium cation.
The ~",i"onium cation R1 has the structure OR2N+R3 4 5M-5 wherein R2 is a C1 to C4 linear Of branched chain alkylene group R3 R4and R5 are selected from the group consisting of hydrogen C1 to C4 linear or branched chain alkyl C5 to C8 cycloalkyl C5 to C8 aro",dlic or C5 to C8 alkylaror"dlic group and M is an anion selected from the group consisting of chloride bromide methyl sulfate and hydrogen sulfate.
The molar per~nlage of a:b in Formula I is from about 95:5 to about 5:95 with the proviso that the sum of a and b is 100%.
The cationic monomers can be selected from ethylenically unsatu-15 rated quaternary ~"""onium ions. Pleferably the cationic ",onG",er~ areselected from the group including but not limited to 2-acryloyloxyethyl-ll ime~l ,yls"""onium chloride (AETAC) 2-",etl ,ac~loyloxyethyltrimethyl-al"l"onium chloride (METAC) 3-"~ell,acrylamidopropyll,il"etllyl~"~monium chloride (MAPTAC) dimethyl sulfate salt of diethylaminoethyl acrylate 20 diallyldimethyl ammonium chloride and diallyldiethyl ammonium chloride.
Most preferably the cationic ~onol~er is 2-",etl)acryloyloxyethyl-trimethyla,r,l"onium chloride.
The number average molecular weight (Mn) of the resulting co-polymer is not critical as long as it is water soluble. The number average molecular weight is preferably in the range of 1 000 to 2 000 000 with a Mn range of 10 000 to 1 000 000 more preferable. Most preferably the 5 number average molecular weight will range from 50 000 to 500 000.
The preferred means of grafting the cationic ",ono",er onto the polyvinyl alcohol is by a solution polymer process using cerium IV as a redox initiator. The methodology for sy,ltl ,esi,ing polyvinyl alcohol graft 10 copolymers has been well documented in the literature and synthesis procedures similar to those described in U.S. Pat. No. 4 080 346 were utilized in this invention. The conte"ts of U.S. Pat. No. 4 080 346 are hereby incor~orated by reference herein.
Ceric a"""onium nitrate is used as the initiator although other cerium containing molecules which are oxidants such as ceric a" ,r"onium sulfate and ceric sulfate may also be used. The present inventors antici-pate that other lantl ,anides such as europium ytterbium and samarium and transition metals having more than one oxidation state such as vana-20 dium and manganese may also be employed as initiators.
Conventional initiators such as azo co",pounds persulfates per-oxides and redox col ~ples may also be employed. It is to be understood that the aforementioned polymerization methods do not limit the synthesis 25 of the copolymers useful in this invention.
FIELD OF THE INVENTION
The present invention relates to methods for suppressing fugitive dust emissions from dust producing bulk solids by applying a polyvinyl 5 alcohol graft copolymer.
BACKGROUND OF THE INVENTION
Dust dissemination poses safety, health and enviro"",ental prob-10 lems in many commercial environments. For instance, in many indus-tries, such as mining, mineral processing, agricultural, power, steel and paper, the transportation, handling and storage of bulk solids is common.
One major problem associated with bulk solids is dust generation and the subsequent emission of the dust into the atmosphere.
Industrial sources of fugitive dust include open operations, leaks and spills, storage, disposal, transit or poor housekeeping of sundry fine-ly divided solid particulates. The iron and steel industries are replete with examples of the above enumerated categories. Wind erosion of exposed 20 masses of particulate matter such as coal or mine mill tailings, fertilizers, etc. c~ ~ses both air pollution and economic waste. Detrimental effects on health and cleanliness result where these fine particles are carried aloft by the winds.
A typical ",eti,od for controlling or suppressing dust is to apply a water spray. However water sprays only control dust for a short period of time depending upon enviror"nental conditions. The application of the spray has to be repeated frequently to provide ongoing dust control.
Various lrealments have been utilized to control dust emissions.
U.S. Pat. No. 3 954 662 diecloses aqueous foamable compositions and their use to suppress coal dust. The co",position contains water an interpolymer of a pol~",eri able vinyl ester and a partial ester compound interpolymerizable with the vinyl ester and a detergent wetting agent.
The interpolymer binds coal dust and keeps the dust particles encapsu-lated after the foam has collarsed U.S. Pat. No. 4 087 572 discloses a combination of an organic polymer latex such as a styrene-b~ ~t~diene interpolymer and a silicone applied to the surface of a coal pile or other mass of finely divided par-tiu ll~te materials. In addilion a wetting agent may be incor~oraled to prevent pre,nat.lre coag!J'~tion. The co"l~.nation is applied as an ~queo~ ~s mixture such as by spraying.
U.S. Pat. No. 4 551 261 discloses the suppression of dust with an ~ueous foam comprising a foaming agent and an elastomeric water in-soluble polymer. The foam provides immediate dust suppression and eases application. The polymer coats the material and continues to sup- .
5 press dust generation during handling of the material after the foam has collapsed.
U.S. Pat. No. 4 594 268 discloses the use of at least one meth-acrylate polymer for dust suppression. The methacrylate polymer pro-10 vides dust suppression when applied to a wide variety of materials. Afterapplication the polymer provides a tacky water resistai!t coating which effectively prevents dusting while additionally acting as an anti-freeze agent.
U.S. Pat. 4 801 635 discloses a combination of water soluble anionic acrylic polymers and nonionic glycol polymers and anionic and nonionic su, ractants useful for the control of dust emissions into the enviro"" ,enL
The p~sent invention relates to ,nethods for controlling fugitive dust emissions from bulk granular or powdered solids. Fugitive dust emissions are controlled by applying an ~ eous solution of a graft 25 copolymer of polyvinyl alcohol and a cationic monomer.
` 2173168 DESCRIPTION OF THE RELATED ART
U.S. Pat. No. 4 080 346 Bedell et al. teaches methods for grafting cationic and nonionic ",ono",ers onto polyvinyl alcohol using a transition 5 metal ion catalyst. The resulting polymers prove useful às dye mordents.
U.S. 4 308 189 I\~lorilani et al. teaches a method for preparing modified polyvinyl alcohol polymers via an emulsion process whereby a random copol~l"e,i~ation of vinyl acetale and calionic ",ono",ers is carried out.
The resulting copolymers are used as a binder in pulp and textiles.
U.S. 4 775 715 Beresniewicz et al. tea~;l,es a process for making cationic polyvinyl alcohol using ",echanical shear and a non-alkylene qualer"ary ammonium halide. This process achieved conversions up to 40%. The quaternized polyvinyl alcohol was used as a flocculating 15 agent a stabilizing colloid and in a~l ,esive formulations. U.S. 5 075 401 Zhang teaehes anionic graft copolymers useful in oil recovery. These copolymers are prepared using a reverse phase emulsion pol~",eri~ation teehnique. U.S. Pat. No. 5 345 803 Dragner et al. teaches grarling of predo"linantly non water soluble monoi"ers onto polyvinyl alcohol using 20 p~t~soiurn persulfate or ammonium hydroxide as the initiator. The graft-ed produet is a latex emulsion useful as t.nders for non-woven products.
French patent 2 214 687 tea~;l,es g(dfling of cationic monomers onto cellulose polyvinyl alcohol polyamides or polyethylene terephll ,al-25 ate using electron ir,adiation as the initiator however cerium is conjec-tured as a potential free radical initiator. The resulting polymers are used to improve dyeability of polymers. Japanese patent 131 003 teaches a polyvinyl alcohol grarled with acrylamido-type ",ono,ners using basic catalysts such as sodium hydroxide having efficaey as sizing agents.
Japanese Kokoku publication No. 21361 teaches a modified poly-vinyl alcohol which is prepared by polymerizing vinyl acetate with other mono,ners such as hydlophobic acrylamides. The vinyl acetale is hydro-lyzed after polymerization with the comonomers to form the polyvinyl 5 alcohol.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to me~hods for suppressing the dis-10 semination of fugitive dust pa, ~icl~s into the almosphere from dust pro-ducing materials comprising applying to the dust producing materials an aqueous solution of a graft copolymer obtained by graft copolymerizing cationic monomers onto polyvinyl alcohol.
The resulting polyvinyl alcohol graft copolymer has the general structure:
FORMULA I
(F)b I
-(~CH2~CH~)a~
OH
whereby F is H or a cationic monomer having the formula FORMULA ll R
l =O
.
wherein R in Formula ll is hydlogen or a C1 to C3 alkyl group and R1 is the salt of an a~""onium cation.
The ~",i"onium cation R1 has the structure OR2N+R3 4 5M-5 wherein R2 is a C1 to C4 linear Of branched chain alkylene group R3 R4and R5 are selected from the group consisting of hydrogen C1 to C4 linear or branched chain alkyl C5 to C8 cycloalkyl C5 to C8 aro",dlic or C5 to C8 alkylaror"dlic group and M is an anion selected from the group consisting of chloride bromide methyl sulfate and hydrogen sulfate.
The molar per~nlage of a:b in Formula I is from about 95:5 to about 5:95 with the proviso that the sum of a and b is 100%.
The cationic monomers can be selected from ethylenically unsatu-15 rated quaternary ~"""onium ions. Pleferably the cationic ",onG",er~ areselected from the group including but not limited to 2-acryloyloxyethyl-ll ime~l ,yls"""onium chloride (AETAC) 2-",etl ,ac~loyloxyethyltrimethyl-al"l"onium chloride (METAC) 3-"~ell,acrylamidopropyll,il"etllyl~"~monium chloride (MAPTAC) dimethyl sulfate salt of diethylaminoethyl acrylate 20 diallyldimethyl ammonium chloride and diallyldiethyl ammonium chloride.
Most preferably the cationic ~onol~er is 2-",etl)acryloyloxyethyl-trimethyla,r,l"onium chloride.
The number average molecular weight (Mn) of the resulting co-polymer is not critical as long as it is water soluble. The number average molecular weight is preferably in the range of 1 000 to 2 000 000 with a Mn range of 10 000 to 1 000 000 more preferable. Most preferably the 5 number average molecular weight will range from 50 000 to 500 000.
The preferred means of grafting the cationic ",ono",er onto the polyvinyl alcohol is by a solution polymer process using cerium IV as a redox initiator. The methodology for sy,ltl ,esi,ing polyvinyl alcohol graft 10 copolymers has been well documented in the literature and synthesis procedures similar to those described in U.S. Pat. No. 4 080 346 were utilized in this invention. The conte"ts of U.S. Pat. No. 4 080 346 are hereby incor~orated by reference herein.
Ceric a"""onium nitrate is used as the initiator although other cerium containing molecules which are oxidants such as ceric a" ,r"onium sulfate and ceric sulfate may also be used. The present inventors antici-pate that other lantl ,anides such as europium ytterbium and samarium and transition metals having more than one oxidation state such as vana-20 dium and manganese may also be employed as initiators.
Conventional initiators such as azo co",pounds persulfates per-oxides and redox col ~ples may also be employed. It is to be understood that the aforementioned polymerization methods do not limit the synthesis 25 of the copolymers useful in this invention.
The reaction temperature is not critical and generally occurs be-tween 20 and 99C, preferably 35 to 65C. The pH of the reaction mix-ture is not critical and is generally in the range of 4 to 6. The resulting copolymer structure has been verified by 13C NMR, IR spectroscopy, 5 and viscosity studies.
The present inventors anticipate that in another embodiment of the invention that anionic and nonionic ",Gno",er~ can be grarled onto the polyvinyl alcohol with or without cationic mGno",er present.
The anionic monomer can be selected from the group containing ethylenically unsaturated c rboxylic acid or sulfonic acid functional groups.
These monomers include but are not limited to acrylic acid, methacrylic acid, vinyl acetic acid, itaconic acid, maleic acid, allylacetic acid, styrene 15 sulfonic acid, 2-acrylamido-2-methyl propane sulfonic acid (AMPS~) and 3-allyloxy-2-hydroxypropane sulfonic acids and salts thereof.
The nonionic monomer can be selected from the group of ethyleni-cally unsaturated nonionic monomers which comprise but are not limited 20 to acrylamide, methacrylamide, N-methyloylacrylamide, N,N-dimethyl-- acrylamide; lower alkyl (C1-C6) esters including vinyl ~cet~te, methyl acrylate, ethyl acrylate, and methyl ",ethac~late; hydroxylated lower alkyl (C1-C6) esters including hydroxyethyl acrylate, hydroxypropyl acrylate and hydroxyethyl metl ,ac~late; allyl glycidyl ether; and ethoxylated allyl 25 ethers of polyethylene glycol, polypropylene glycol and propoxylated acrylates.
The copolymers of the present invention may be applied to the dust producing material (subslrale) by either spraying as a liquid onto the substrate or by applying as a foam which inco~,uorales an effective sur-factant-based foaming agent. The liquid spray incorporates a suitable 5 solvent for the copolymers which is preferably aqueous.
For purposes of the present invention, the term "effective amount for the purpose" is defined as that amount of copolymer which will sup-press the dissemination of dust. For ex~mple, aqueous solutions of from 10 about 0.1 to about 10.0% polymer can be sprayed or foamed onto the substrate. The feed rate of sprayed ~queo~ ~s solution ranges from about 0.1 to about 10.0 gallons of solution per ton of subsl~ate. P,eferably, 0.5 to about 5.0 gallons per ton of subslrate are applied by spraying. When applied as a foam, the copolymers are fed in a range from about 0.1 to 15 about 5.0 gallons of foamed solution per ton of subsl,ate. Pleferred foam feed rates range from about 0.5 to about 2.5 gallons of foamed solution per ton of dust producing material. The foam for the dust control treat-ment may be foamed and applied via conventional techniques such as those disclosed in U.S. Pat. No. 4,400,220 (Cole), the contents of which 20 are hereby incor~ Graled by reference.
The copolymers of the present invention are suitable for use on any material prone to create dust, which include but are not limited to rock, green and calcined petroleum coke, ores (for example, iron ore), 25 grains, li",estone, gypsum, fly ash, ce,nent clinker, steel mill sinter, coal, bauxite, fertilizers (such as potash and phosphates), metallurgical coke dust, basic oxygen furnace dust and road dust.
The copolymers of the present invention may also be used with other additives for improved dust control. In addition to acting as foaming agents, anionic, nonionic and/or cationic s~" ra-;tants may also be em-ployed to improve the wetting properties of the copolymer solutions.
E~tAMPLES
Preparation of polyvinyl alcohol (PVA)/2-methacryloyloxyethyl-lrin,etl,yl aml''G,'ium chloride (METAC) graft copolymer (1/1 molar ratio).
A suitable flask was equipped with a mechanical stirrer, thermo-couple and nitrogen line. 57.3 9 of a PVA solution (0.2 moles, 15.3%), 55.3 9 of METAC (0.2 moles, 75%), 70.0 9 of H2O and six drops of 1 M
HNO3 were charged to the flask. 3.29 9 of ceric a"""onium nitrate dis-15 solved in 9 9 of water was then shot fed to the flask. The nitrogen purgewas continued for the duration of the reaction. After allowing the tem-perature to equilibrate, the solution was heated to 35C and held for 3 hours.
The copolymer solution had a Brookfield viscosity of 108 cps at 28.0% solids and 25C. The structure of the copolymer was verified by 13C NMR. There was no sign of residu~l monomer in the spectrum.
Similar procedures were used to prepare copolymers of PVA/METAC
with clirrerent mole ratios. Table I s~""",ari es the physical and chemical prope, lies of these PVA/METAC copolymers.
2l73l68 TABLE I
ExamPle Polvmer ComDosition Ratio % Solids Viscositv (ccs) 1 PVA/METAC 1/1 28.0 108 2 PVA/METAC 1/2.5 17.5 40 3 PVA/METAC 1/5 21.9 99 In order to more clearly illustrate this invention the data set forth below were dcveloped. The following exa"~pl~s are included as being illustrations of the invention and should not be construed as limiting the scope thereof.
15 Perforrnance Testing The substrate tested was minus 1/4 inch sub-bituminous coal. The copolymer treal",ents were applied as 0.25% active ~ueous solutions at a feed rate of 2.5 gal/ton.
The ll edted coal samples were allowed to dry for 48 hours to dete"nine residual (long-term) dust control effects compared to control samples (coal treated with water). Relative dustiness measurements were made using a laboratory dust chamber (modified ASTM dust box).
25 Percent dust suppression (%DS) was cAIculAted based on the relative dustiness number (RDN) of the control versus treated samples as follows:
%DS = Control RDN - Treated RDN x 100 Control RDN
2l73~68 All RDN values were measured in triplicate; the average RDN
value was used for the %DS calculation. The results of this testing are presented in Table Il.
TABLE ll Treat",ent% Dust SuPPresSiOn Control o Example 1 45 Example 2 58 Example 3 50 These results de",onsl(ate that the graft copolymers of the instant invention in a range of PVA/METAC ratios are effective at suppressing dust emissions.
While this invention has been desc, ibed with respect to particular embodiments thereof it is apparent that numerous other forms and modi-fications of this invention will be obvious to those skilled in the art. The app~"ded claims and this invention generally should be construed to cover all such obvious forms and ",odif,calions which are within the true 20 spirit and scope of the present invention.
The present inventors anticipate that in another embodiment of the invention that anionic and nonionic ",Gno",er~ can be grarled onto the polyvinyl alcohol with or without cationic mGno",er present.
The anionic monomer can be selected from the group containing ethylenically unsaturated c rboxylic acid or sulfonic acid functional groups.
These monomers include but are not limited to acrylic acid, methacrylic acid, vinyl acetic acid, itaconic acid, maleic acid, allylacetic acid, styrene 15 sulfonic acid, 2-acrylamido-2-methyl propane sulfonic acid (AMPS~) and 3-allyloxy-2-hydroxypropane sulfonic acids and salts thereof.
The nonionic monomer can be selected from the group of ethyleni-cally unsaturated nonionic monomers which comprise but are not limited 20 to acrylamide, methacrylamide, N-methyloylacrylamide, N,N-dimethyl-- acrylamide; lower alkyl (C1-C6) esters including vinyl ~cet~te, methyl acrylate, ethyl acrylate, and methyl ",ethac~late; hydroxylated lower alkyl (C1-C6) esters including hydroxyethyl acrylate, hydroxypropyl acrylate and hydroxyethyl metl ,ac~late; allyl glycidyl ether; and ethoxylated allyl 25 ethers of polyethylene glycol, polypropylene glycol and propoxylated acrylates.
The copolymers of the present invention may be applied to the dust producing material (subslrale) by either spraying as a liquid onto the substrate or by applying as a foam which inco~,uorales an effective sur-factant-based foaming agent. The liquid spray incorporates a suitable 5 solvent for the copolymers which is preferably aqueous.
For purposes of the present invention, the term "effective amount for the purpose" is defined as that amount of copolymer which will sup-press the dissemination of dust. For ex~mple, aqueous solutions of from 10 about 0.1 to about 10.0% polymer can be sprayed or foamed onto the substrate. The feed rate of sprayed ~queo~ ~s solution ranges from about 0.1 to about 10.0 gallons of solution per ton of subsl~ate. P,eferably, 0.5 to about 5.0 gallons per ton of subslrate are applied by spraying. When applied as a foam, the copolymers are fed in a range from about 0.1 to 15 about 5.0 gallons of foamed solution per ton of subsl,ate. Pleferred foam feed rates range from about 0.5 to about 2.5 gallons of foamed solution per ton of dust producing material. The foam for the dust control treat-ment may be foamed and applied via conventional techniques such as those disclosed in U.S. Pat. No. 4,400,220 (Cole), the contents of which 20 are hereby incor~ Graled by reference.
The copolymers of the present invention are suitable for use on any material prone to create dust, which include but are not limited to rock, green and calcined petroleum coke, ores (for example, iron ore), 25 grains, li",estone, gypsum, fly ash, ce,nent clinker, steel mill sinter, coal, bauxite, fertilizers (such as potash and phosphates), metallurgical coke dust, basic oxygen furnace dust and road dust.
The copolymers of the present invention may also be used with other additives for improved dust control. In addition to acting as foaming agents, anionic, nonionic and/or cationic s~" ra-;tants may also be em-ployed to improve the wetting properties of the copolymer solutions.
E~tAMPLES
Preparation of polyvinyl alcohol (PVA)/2-methacryloyloxyethyl-lrin,etl,yl aml''G,'ium chloride (METAC) graft copolymer (1/1 molar ratio).
A suitable flask was equipped with a mechanical stirrer, thermo-couple and nitrogen line. 57.3 9 of a PVA solution (0.2 moles, 15.3%), 55.3 9 of METAC (0.2 moles, 75%), 70.0 9 of H2O and six drops of 1 M
HNO3 were charged to the flask. 3.29 9 of ceric a"""onium nitrate dis-15 solved in 9 9 of water was then shot fed to the flask. The nitrogen purgewas continued for the duration of the reaction. After allowing the tem-perature to equilibrate, the solution was heated to 35C and held for 3 hours.
The copolymer solution had a Brookfield viscosity of 108 cps at 28.0% solids and 25C. The structure of the copolymer was verified by 13C NMR. There was no sign of residu~l monomer in the spectrum.
Similar procedures were used to prepare copolymers of PVA/METAC
with clirrerent mole ratios. Table I s~""",ari es the physical and chemical prope, lies of these PVA/METAC copolymers.
2l73l68 TABLE I
ExamPle Polvmer ComDosition Ratio % Solids Viscositv (ccs) 1 PVA/METAC 1/1 28.0 108 2 PVA/METAC 1/2.5 17.5 40 3 PVA/METAC 1/5 21.9 99 In order to more clearly illustrate this invention the data set forth below were dcveloped. The following exa"~pl~s are included as being illustrations of the invention and should not be construed as limiting the scope thereof.
15 Perforrnance Testing The substrate tested was minus 1/4 inch sub-bituminous coal. The copolymer treal",ents were applied as 0.25% active ~ueous solutions at a feed rate of 2.5 gal/ton.
The ll edted coal samples were allowed to dry for 48 hours to dete"nine residual (long-term) dust control effects compared to control samples (coal treated with water). Relative dustiness measurements were made using a laboratory dust chamber (modified ASTM dust box).
25 Percent dust suppression (%DS) was cAIculAted based on the relative dustiness number (RDN) of the control versus treated samples as follows:
%DS = Control RDN - Treated RDN x 100 Control RDN
2l73~68 All RDN values were measured in triplicate; the average RDN
value was used for the %DS calculation. The results of this testing are presented in Table Il.
TABLE ll Treat",ent% Dust SuPPresSiOn Control o Example 1 45 Example 2 58 Example 3 50 These results de",onsl(ate that the graft copolymers of the instant invention in a range of PVA/METAC ratios are effective at suppressing dust emissions.
While this invention has been desc, ibed with respect to particular embodiments thereof it is apparent that numerous other forms and modi-fications of this invention will be obvious to those skilled in the art. The app~"ded claims and this invention generally should be construed to cover all such obvious forms and ",odif,calions which are within the true 20 spirit and scope of the present invention.
Claims (12)
1. A method for suppressing the dissemination of fugitive dust particles into the atmosphere from dust producing materials comprising applying to said dust producing materials an effective amount for the purpose of an aqueous solution of a graft copolymer having the formula:
whereby F is H or a cationic monomer having the formula:
wherein R is hydrogen or a C1 to C3 alkyl group, R1 is the salt of an ammonium cation and the molar percentage of a:b is from about 95:5 to about 5:95 with the proviso that the sum of a and b is 100%.
whereby F is H or a cationic monomer having the formula:
wherein R is hydrogen or a C1 to C3 alkyl group, R1 is the salt of an ammonium cation and the molar percentage of a:b is from about 95:5 to about 5:95 with the proviso that the sum of a and b is 100%.
2. The method as claimed in claim 1 wherein R1 has the struc-ture OR2N+R3,4,5M-, wherein R2 is a C1 to C4 linear or branched chain alkylene group,R3,R4 and R5 are selected from the group consisting of hydrogen C1 to C4 linear or branched chain alkyl C5 to C8 cycloalkyl, C5 to C8 aromatic or C5 to C8 alkylaromatic group; and M is an anion selected from the group consisting of chloride bromide methyl sulfate and hydrogen sulfate.
3. The method as claimed in claim 1 wherein F is a cationic mono-mer selected from the group consisting of 2-acryloyloxyethyltrimethylammo-nium chloride, 3-methacrylamidopropyltrimethylammonium chloride, 2-meth-acryloyloxyethyltrimethylammonium chloride, and dimethylammonium chloride.
4. The method as claimed in claim 1 wherein said copolymer has a number average molecular weight from about 1,000 to 2,000,000.
5. The method as claimed in claim 1 wherein said copolymer has a number average molecular weight from about 10,000 to 1,000,000.
6. The method as claimed in claim 1 wherein said copolymer has a number average molecular weight from about 50,000 to 500,000.
7. The method as claimed in claim 1 wherein said aqueous solution contains from about 0.1 to about 10.0% copolymer.
8. The method as claimed in claim 1 wherein said copolymer is added to said dust producing materials by spraying as an aqueous solution.
9. The method as claimed in claim 1 wherein said copolymer is added to said dust producing materials as a foamed liquid.
10. The method as claimed in claim 8 wherein said copolymer is sprayed onto said dust producing materials in an amount of about 0.1 gallons to about 10.0 gallons per ton of dust producing materials.
11. The method as claimed in claim 9 wherein said foamed liquid is applied to said dust producing materials in an amount of about 0.1 gallons to about 5.0 gallons per ton of dust producing materials.
12. The method as claimed in claim 1 wherein said dust produc-ing material is selected from the group consisting of rock, green and cal-cined petroleum coke, ores, grains, limestone, gypsum, fly ash, cement clinker, steel mill sinter, coal, bauxite, and fertilizer.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US48990695A | 1995-06-12 | 1995-06-12 | |
| US08/489,906 | 1995-06-12 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2173168A1 true CA2173168A1 (en) | 1996-12-13 |
Family
ID=23945770
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2173168 Abandoned CA2173168A1 (en) | 1995-06-12 | 1996-04-01 | Methods for suppressing dust emissions |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2173168A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104830277A (en) * | 2015-03-30 | 2015-08-12 | 内蒙古博冉科技有限责任公司 | Wall hanging anti-freezing tackifier |
-
1996
- 1996-04-01 CA CA 2173168 patent/CA2173168A1/en not_active Abandoned
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104830277A (en) * | 2015-03-30 | 2015-08-12 | 内蒙古博冉科技有限责任公司 | Wall hanging anti-freezing tackifier |
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