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Description  |
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Many industrial processes employ solid chemicals which must be continually
added thereto. These chemicals are difficult to handle in a way that they
can be reliably metered into the process stream because of various
problems. Often when these chemicals are added to systems containing
solvents they tend to be slowly soluble and therefore clump or agglomerate
so as to make addition slow or difficult. In certain instances where they
are dissolved in a solvent, they produce solutions even at low
temperatures which are so viscous they are difficult to meter into the
process.
By way of illustration, various synthetic and naturally-occurring
water-soluble polymers have been developed which exhibit, in aqueous
solution, superior thickening and flocculating properties. These polymers
are being used increasingly in a number of commercial applications such
as, for example, in the clarification of aqueous solutions, in papermaking
operations, in the treatment of sewage and industrial wastes, as
stabilizers for drilling muds, and in the secondary recovery of petroleum
by waterflooding.
Although these polymers are most often available commercially as powders or
as a finely-divided solid, they are most frequently utilized as aqueous
solutions. This necessitates that the solid polymer material be dissolved
in water. Although the various polymers are more or less soluble in water,
difficulty is often experienced in preparing aqueous polymer solutions
because of their slow dissolution and because the solid polymer is not
readily dispersible in water. Furthermore, dispersion of solid polymers in
water is hindered by their tendency to clump or remain as agglomerates on
contact with water. Lumps of solid polymer immediately form by the
encapsulation of undissolved solids in an outer coating of water-wet
polymer which retards the penetration of additional water into the
agglomerate. Although many of these lumps are eventually dissolved by
continued agitation, it is frequently impractical to agitate the solution
for a sufficiently long period to obtain complete dissolution.
These polymers are well-know to the art and have been described in numerous
publications and patents. The polymers most commonly used in many
industrial applications are acrylamide and its water-soluble copolymeric
derivatives such as, for instance, acrylamide-acrylic acid, and
acrylamide-acrylic acid salt copolymers which contain from about 95-5% by
weight of acrylamide. Also useful are copolymers of acrylamide with other
vinyl monomers such as maleic anhydride, acrylonitrile, styrene and the
like.
Other water-soluble vinyl polymers are described in detail in the following
U.S. Pat. Nos. 3,418,237, 3,259,570 and 3,171,805.
In examining the disclosures of these patents it will be seen that the
water-soluble polymers may be either cationic or anionic and, in some
instances, the ionic charges are sufficiently slight so that the polymers
may be considered as nonionic.
For example, water-soluble polymers and copolymers of allyl, diallyl
amines, or dimethylaminoethylmethacrylate are cationic. Polymers such as
polyvinyl alcohol are non-ionic, and polymers such as polyacrylic acid or
polystyrene sulfonates are anionic. All of these polymers may be used in
the practice of the invention.
The molecular weight of the polymers described above may vary over a wide
range, e.g. 10,000-25,000,000. The invention, however, finds its greatest
usefulness in preparing aqueous solutions or dispersions of these polymers
and, in particular, acrylamide polymers whose molecular weights are in
excess of 1,000,000. Polymers having higher molecular weights are more
difficulty dissolved in water and tend to form extremely viscous solutions
at relatively low concentrations. Also, the polymers may be produced by
any known methods of conducting polymerization reactions. Thus, solution
suspension or emulsion polymerization techniques may be used. The gums are
well-known water-soluble polymers and are described in vol. 10 of the
Encyclopedia of Chemical Technology, 2nd edition, Interscience Publishers,
1966.
The invention is capable of producing rapidly aqueous solutions of the
water-soluble vinyl addition polymers or gums having concentrations within
the range of 0.1-20% by weight. The invention most often finds usefulness
when it is desired to form aqueous solutions of polymers having a solution
concentration of 0.2-2.0% by weight.
I have now discovered a method of avoiding many of these problems which
comprises suspending the solid that one wishes to add to the process in a
high internal phase ratio emulsion, neither phase of the emulsion being
capable of dissolving or swelling the solid. These suspensions of solid
materials in an emulsion, being non-Newtonian fluids are stable to
settling or deterioration, can be metered with conventional equipment into
the reaction. The solid can be added to the emulsion after it has been
prepared or can be added to one phase and this phase emulsified with
another phase.
In the practice of this invention an emulsion is made of the principal
liquid in a small amount of a second immiscible liquid. These emulsions
are characterized by having a very low volume percent of external phase,
and are highly thixotropic. Although they appear to be elastic solids,
having much the consistency of a gelatin gel when at rest, they can
however be easily pumped under low pump pressures.
The present invention suspends solid particles by an entirely different
mechanism. In the composition of this invention the solid particles may be
said to be encapsulated in the individual globules of internal liquid
phase. Thus, in order to settle they would have to pass through a
multiplicity of interfaces which they cannot do without breaking the
emulsion. Therefore, as long as the emulsion is stable the solids remain
suspended.
The emulsions of this invention are high internal phase-low external phase
emulsions. They may be either oil-in-non-oil and non-oil-in-oil type
emulsions, but preferably oil-in-non-oil. The internal phase of the
emulsion may be at least 80% by volume, for example at least 85%,
preferably at least 90%, but can be at least 95% by volume or greater, the
residue of the emulsion comprising the external phase and the emulsifier.
A minor but sufficient amount of emulsifier is added to form the emulsion,
for example from 0.05-10% by volume such as from 0.1-5%, but preferably
from 0.2-3% of emulsifier, based on the volume of total emulsion.
The emulsion has two phases, one of which is the non-aqueous or oily phase
and the other the non-oily phase.
The term "oily phase," as herein employed, is intended to include a vast
number of substances, both natural and artificial, possessing widely
different physical properties and chemical structures. All of the
substances included within this term are practically insoluble in water,
possess a characteristic greasy touch and have a low surface tension.
These include the animal oils of both land and sea animals; vegetable
oils, both drying and non-drying; petroleum or mineral oils of various
classes, includng those of open chain hydrocarbons, cyclic hydrocarbons or
cycloparaffins, with or without the presence of solid paraffins and
asphalts and various complex compounds, and which may or may not contain
sulphur or nitrogenous bodies; resin oils and wood distillates including
the distillates of turpentine, rosin spirits, pine oil, and acetone oil;
various oils, obtained from petroleum products, such as gasolenes,
naphthas, gas fuel, lubricating and heavier oils; coal distillate,
including benzene, toluene, xylene, solvent naphtha, creosote oil and
anthracene oil and ethereal oils.
The choice of oily phase materials is not limited to hydrocarbons since
esters such as dibutyl phthalate, diethylmaleate, tricresylphosphate,
acrylate or methacrylate esters, natural esters, and the like have been
employed by us successfully in the preparation of useful emulsions. Tung
oil, oiticica oil, castor oil, linseed oil, poppyseed oil, soyabean oil,
animal and vegetable oils such as cottonseed oil, corn oil, fish oils,
walnut oils, pineseed oils, olive oil, coconut oil, degras, and the like,
may also be used.
The primary consideration is that the "oily" phase must not dissolve, swell
or react with the solid suspended polymer particles and it must be
immiscible with the other liquid phase.
The non-oily phase may be any relatively polar liquid composition which is
immiscible with the oily phase and does not dissolve, swell, or react with
the suspended materials.
Particularly preferred are aqueous systems, particularly those whose
solubility is adjusted with auxiliary agents such as solutes, inorganic or
organic materials, salts, sugars, etc., employed alone or in conjunction
with water containing other solvents such as alcohols, glycols, polyols,
ketones, etc. Particularly preferred are salts employed with water, or
aqueous solvent systems such as aqueous alcohol, aqueous glycol, etc.,
most preferably those salts which are hydroscopic such as CaCl.sub.2,
particularly where acrylic-type polymers and copolymers are to be
suspended.
The following description of the non-oily, non-aqueous phase which can be
employed in preparing emulsions is presented in U.S. Pat. No. 3,539,406.
This description may be useful in selecting non-oily phases, with the
further provisions that the phase selected does not dissolve, swell or
react with the suspended particles.
The non-oily phase employed herein is one which possesses a cohesive energy
density number in excess of about 10, whereas hydrocarbons typically
possess values of less than about 10.
Cohesive energy density is the quotient of the molar heat of vaporization
and the molar volume. The cohesive energy density (C.E.D.) is the amount
of energy necessary to separate one ml. of liquid into its molecules.
Conversely, the C.E.D. is the energy which holds 1 ml. of liquid together.
The following compounds have a C.E.D. number of about 10 or greater.
The C.E.D. number is defined as .sqroot.C.E.D. and is usually employed in
comparisons and calculations.
The following is a list of compounds having a C.E.D. number of about 10 or
greater. In general, there should be sufficient difference in the C.E.D.
numbers of each phase to make a suitable emulsion.
______________________________________
Description C.E.D. No.
______________________________________
N,N-diethyl acetamide 9.92
1,4-dioxane 9.95
Acetone 10.00
Carbon disulfide 10.00
Dioxane 10.00
Ethylamine 10.00
Nitrobenzene 10.00
Propionic anhydride 10.00
Acetic Acid 10.10
t-Butyl alcohol 10.10
Methyl formate 10.10
Polymethyl chloroacrylate
10.10
m-Cresol 10.20
Cyclohexanol 10.20
Methyl formate 10.20
Methyl iodide 10.20
Propionitrile 10.20
Pyridine 10.20
Acetaldehyde 10.30
Aniline 10.30
Carbon disulfide 10.30
Isobutyric acid 10.30
Methylene chloride 10.30
n-Octyl alcohol 10.30
sec-Butyl alcohol 10.40
Cyclopentanone 10.40
1,2-dibromomethane 10.40
Methyl formate 10.40
Acrylonitrile 10.50
Bromoform 10.50
n-Butyric acid 10.50
Tris (dimethylamido)phosphate
10.50
Isobutyl alcohol 10.50
Cellulose dinitrate 10.56
Acetic anhydride 10.60
tert-Butyl alcohol 10.60
N,N-diethylformamide 10.60
n-Heptyl alcohol 10.60
Propionitrile 10.60
n-Butyl alcohol 10.70
n-Hexyl alcohol 10.70
Polyglycol terephthalate
10.70
Polymethacrylonitrile 10.70
Pyridine 10.70
Benzyl alcohol 10.80
N,N-dimethylacetamide 10.80
Amyl alcohol 10.90
Cellulose diacetate 10.90
N-acetylpiperidine 11.00
Dichloroacetic acid 11.00
Ethyl cyanoacetate 11.00
Di-methyl malonate 11.00
Cyclobutanedione 11.10
Dimethyl oxalate 11.10
Ethyl oxide 11.10
Furfural 11.20
Methyl amine 11.20
Dipropyl sulphone 11.30
N-acetylpyrrolidine 11.40
n-Butanol 11.40
NNN'N'-tetramethyloxamide
11.40
Bromine 11.50
N-formylpiperidine 11.50
Isopropanol 11.50
N-acetylmorpholine 11.60
Acetonitrile 11.70
Allyl alcohol 11.80
Methylene iodide 11.80
Acetonitrile 11.90
N-propyl alcohol 11.90
2:3-butylene carbonate
12.00
Acetonitrile 12.10
Dimethyl formamide 12.10
Dimethyltetramethylene sulphone
12.10
Formic acid 12.10
Hydrogen cyanide 12.10
Ethylene chlorhydrin 12.20
Methylene glycollate 12.40
Nitromethane 12.40
Diethyl sulphone 12.50
Dimetyl phosphite 12.50
Methyl propyl sulphone
12.50
Chloroacetonitrile 12.60
Osmium tetroxide 12.60
.alpha.-Caprolactam 12.70
Ethyl alcohol 12.70
Nitro methane 12.70
.beta.-Methyltetramethylene sulphone
12.90
N-formylmorpholine 13.00
N,N-dimethylnitroamine
13.10
Butyrolactone 13.30
Propiolactone 13.30
1:2-propylene carbonate
13.30
Methyl ethyl sulphone 13.40
.gamma.-Pyrone 13.40
Maleic anhydride 13.60
.gamma.-Piperidone 13.60
Dimethyl sulfoxide 13.90
Methyl alcohol 14.30
Tetramethylene sulphone
14.30
EtOH 14.40
Methanol 14.40
Dimethyl sulphone 14.60
Ethylene glycol 14.60
Ethylene carbonate 14.70
.gamma.-Pyrrolidone 14.70
Polyacrylonitrile 14.80 - 15.20
Malonylnitrile 15.10
Succinic anhydride 15.40
Ammmonia 16.30
Water 24.20
______________________________________
In general, in addition, the non-oily phase possesses the following
characteristics:
1. Is liquid over the range of use.
2. Is essentially immiscible with the other liquid phase and/or is capable
of forming a distinct separate phase.
3. If used as the external phase is capable of dissolving the emulsifier so
as to concentrate it at the liquid interfaces to prevent coalescence of
the internal phase.
4. Is itself a solvating agent, or contains a solvating agent or mixture of
solvating agents, for the emulsifier.
Thus, the non-oily phase contains one or more non-oily materials and an
emulsifier dissolved therein, said non-oily phase being essentially
insoluble in the oily phase and said emulsifier being capable of preparing
and maintaining a stable, viscous, thixotropic or pseudoplastic emulsion.
Stated another way, the non-oily phase may be looked upon as having two
functions:
1. Is essentially immiscible in the oily phase and/or is capable of forming
a distinct separate phase.
2. When used as the external phase is itself a solvent for the emulsifier,
or containing a solvent capable of dissolving the emulsifier so as to
concentrate the emulsifier at the interface to prevent coalescence of the
internal phase.
The non-oily phase if not aqueous may be of (1) the polar protic type as
illustrated by: Alcohols, e.g., methanol, ethanol, propanol, etc. Glycols,
e.g., ethylene glycol, propylene glycol, etc. Polyglycols, e.g.,
H(OA).sub.n H where A is alkylene and n is an integer, for example 1-10 or
greater, for example diethyleneglycol, triethyleneglycol,
dipropyleneglycol, tripropyleneglycol, etc., polyalcohols, aldehydes,
polyaldehydes, etc.; and (2) of the polar aprotic type as illustrated by
N-alkylcarboxylamides such as N,N-dialkylcarboxylamides such as
N,N-dimethylformamide, N,N-dimethyl acetamide, N,N-diethylformamide,
N,N-diethylacetamide, etc., and closely related compounds such as
formamide, N-methyl formamide, N,N-dimethyl methoxy acetamide, etc.
Other illustrative solvents are dimethyl sulfoxide, dimethyl sulfone,
N-methyl-2-pyrrolidone, tetramethylurea, pyridine, hexamethyl
phosphoramide, tetramethylene sulfone, butyrolactone, nitroalkanes such as
nitromethanes, nitroethanes, etc.
Mixtures of a variety of polar aprotic solvents can also be employed, as
well as polar aprotic solvents in combination with polar protic solvents.
The emulsions of the present invention possess the following advantages:
1. Nonadhesive. -- They tend not to stick to the sides of the container.
Thus "hold up" in tanks is minimized.
2. Viscosity. -- The apparent rest viscosity is greater than 1000 cps.,
generally in the range of 10,000-100,000 or greater. However, under low
shear, they will flow with a viscosity approaching that of the liquid
phases. On removal of shear, the recovery to original apparent rest
viscosity is nearly instantaneous. The hysteresis loop is very small.
3. Temperature Stability. -- Increased temperature has little effect on
viscosity until the critical stability temperature is reached at which
point emulsions break into their liquid components. This permits a wide
temperature range of operation.
4. Pumpable. -- Although behaving like a semi-solid at rest, the
compositions may be pumped easily by any equipment capable of dealing with
liquids containing particulate matter.
5. Quality Control. -- With these emulsions it is easy to reproduce batches
with identical properties due to the absence of any "gel" structure.
6. Solid loading. -- Emulsions will flow well even with high solids loading
since they have a broad range between rest viscosity and viscosity under
modest shear.
In contrast to very high volume percent solid loading in gels or slurries
which result in a "putty," these emulsions can suspend such solids in the
internal phase while allowing the external phase to govern "flowability."
Any suitable emulsifier can be employed. The emulsifiers most usually
employed in the practice of this invention are generally known as
oxyalkylated surfactants or more specifically polyalkylene ether or
polyoxyalkylene surfactants. Oxyalkylated surfactants as a class are well
known. The possible sub-classes and specific species are legion. The
methods employed for the preparation of such oxyalkylated surfactants are
also too well known to require much elaboration. Most of these surfactants
contain, in at least one place in the molecule and often in several
places, an alkanol or a polyglycolether chain. These are most commonly
derived by reacting a starting molecule, possessing one or more
oxyalkylatable reactive groups, with an alkylene oxide such as ethylene
oxide, propylene oxide, butylene oxide, or higher oxides, epichlorohydrin,
etc. However, they may be obtained by other methods such as shown in U.S.
Pat. Nos. 2,588,771 and 2,596,091-3, or by esterification or amidification
with an oxyalkylated material, etc. Mixtures of oxides may be used as well
as successive additions of the same or different oxides may be employed.
Any oxyalkylatable material may be employed. As typical starting materials
may be mentioned alkyl phenols, phenolic resins, alcohols, glycols,
amines, organic acids, carbohydrates, mercaptans, and partial esters of
polybasic acids. In general, the art teaches that, if the starting
material is water-soluble, it may be converted into an oil-soluble
surfactant by the addition of polypropoxy or polybutoxy chains. If the
starting material is oil-soluble, it may be converted into a water-soluble
surfactant by the addition of polyethoxy chains. Subsequent additions of
ethoxy units to the chains tend to increase the water solubility, while,
subsequent additions of high alkoxy chains tend to increase the oil
solubility. In general, the final solubility and surfactant properties are
a result of a balance between the oil-soluble and water-soluble portions
of the molecule.
In the practice of this invention it has been found that emulsifiers
suitable for the preparation of high internal phase ratio emulsions may be
prepared from a wide variety of starting materials. For instance, if one
begins with an oil-soluble material such as a phenol or a long chain fatty
alcohol and prepare a series of products by reaction with successive
portions of ethylene oxide, one finds that the members of the series are
successively more water-soluble. One finds also that somewhere in the
series there will be a limited range where the products are useful for the
practice of this invention. Similarly it is possible to start with water
or a water-soluble material such as polyethylene glycol and add,
successively, portions of propylene oxide. The members of this series will
be progressively less water-soluble and more oil-soluble. Again there will
be a limited range where the materials are useful for the practice of this
invention.
In general, the compounds which would be selected for testing as to their
suitability are oxyalkylated surfactants of the general formula
Z [(OR).sub.n OH] .sub.m
wherein Z is the oxyalkylatable material, R is the radical derived from the
alkylene oxide which can be, for example, ethylene, propylene, butylene,
epichlorohydrin and the like, n is a number determined by the moles of
alkylene oxide reacted, for example 1 to 2000 or more and m is a whole
number determined by the number of reactive oxyalkylatable groups. Where
only one group is oxyalkylatable as in the case of a monofunctional phenol
or alcohol R'OH, then m = 1. Where Z is water, or a glycol, m = 2. Where Z
is glycerol, m = 3, etc.
In certain cases, it is advantageous to react alkylene oxides with the
oxyalkylatable material in a random fashion so as to form a random
copolymer on the oxyalkylene chain, i.e. the [(OR).sub.n OH] .sub.m chain
such as
--AABAAABBABABBABBA--
in addition, the alkylene oxides can be reacted in an alternate fashion to
form block copolymers on the chain, for example
--BBBAAABBBAAAABBBB-- or --BBBBAAACCCAAAABBBB--
where A is the unit derived from one alkylene oxide, for example ethylene
oxide, and B is the unit derived from a second alkylene oxide, for example
propylene oxide, and C is the unit derived from a third alkylene oxide,
for example, butylene oxide, etc. Thus, these compounds include
terpolymers or higher copolymers polymerized randomly or in a block-wise
fashion or many variations of sequential additions.
Thus, (OR).sub.n in the above formula can be written --A.sub.a B.sub.b
C.sub.c -- or any variation thereof, wherein a, b, and c are 0 or a number
provided that at least one of them is greater than 0.
It cannot be overemphasized that the nature of the oxyalkylatable starting
material used in the preparation of the emulsifier is not critical. Any
species of such material can be employed. By proper additions of alkylene
oxides, this starting material can be rendered suitable as an emulsifier
and its suitablility can be evaluated by plotting the oxyalkyl content of
said surfactant versus its performance, based on the ratio of the oil to
water which can be satisfactorily incorporated into water as a stable
emulsion. By means of such a testing system any oxyalkylated material can
be evaluated and its proper oxyalkylation content determined.
As is quite evident, new oxyalkylated materials will be constantly
developed which could be useful in our compositions. It is therefore not
only impossible to attempt a comprehensive catalogue of such compositions,
but to attempt to describe the invention in its broader aspects in terms
of specific chemical names of its components used would be too voluminous
and unnecessary since one skilled in the art could be following the
testing procedures described herein select the proper agent. This
invention lies in the use of suitable oxyalkylated emulsifiers in
preparing the compositions of this invention and their individual
composition is important only in the sense that their properties can
effect these emulsions. To precisely define each specific oxyalkylated
surfactant useful as an emulsifier in light of the present disclosure
would merely call for chemical knowledge within the skill of the art in a
manner analogous to a mechanical engineer who prescribes in the
construction of a machine the proper materials and the proper dimensions
thereof. From the description in this specification and with the knowledge
of a chemist, one will know or deduct with confidence the applicability of
oxyalkylated emulsifiers suitable for this invention by means of the
evaluation tests set forth herein. In analogy to the case of a machine
wherein the use of certain materials of construction or dimensions of
parts would lead to no practical useful result, various materials will be
rejected as inapplicable where others would be operative. One can
obviously assume that no one will wish to make a useless composition or
will be misled because it is possible to misapply the teachings of the
present disclosure in order to do so. Thus, any oxyalkylated surfactant
that can perform the function stated herein can be employed.
______________________________________
REPRESENTATIVE EXAMPLES OF Z
No. Z
______________________________________
##STR1##
2
##STR2##
3 RO
4 RS
5
##STR3##
6
##STR4##
7
##STR5##
8
##STR6##
9 Phenol-aldehyde resins.
10 O (Ex.: Alkylene oxide block polymers.)
11
##STR7##
##STR8##
12
##STR9##
13 RPO.sub.4 H
14
##STR10##
15 PO.sub.4 .quadbond.
16
##STR11##
17
##STR12##
18
##STR13##
19 Polyol-derived. (Ex.: Glycerol, glucose,
pentacrythritol.)
20 Anhydrohexitan or anhydrohexide derived. (Spans
and Tweens.)
21 Polycarboxylic derived.
22
##STR14##
The amount of solid chemical present as a suspension in the emulsion in
either phase or the total emulsion can vary widely, from about 1 to 60%
or more by weight of chemical to volume of emulsion, such as from about 5
o 50%, for example from about 10 to 40%, but preferably from about 15 to
35%. Of course the particular percent will depend on the particular
chemical and the particular system.
The following examples are presented for purposes of illustration and not
of limitation.
EXAMPLE 1
100 grams of calcium chloride dihydrate, 60 grams of water and 40 grams of
denatured ethanol were mixed until all the solids were dissolved. This was
designated solution A.
16 milliliters of kerosene and 4 milliliters of emulsifier made by reacting
one part of dinonylphenol with 0.7 parts of ethylene oxide were mixed in a
tall form beaker using a split-disc stirrer. 50 milliliters of solution A
were added while stirring. A translucent water-in-oil emulsion resulted.
41 grams of a solid granular acrylic acid polymer were added slowly while
stirring. The result was a thick suspension.
EXAMPLE 2
A solution was made by mixing 210 grams of calcium chloride dihydrate, 120
grams of water and 100 grams of denatured ethanol. This was called
solution B.
8 milliliters of kerosene and 2 milliliters of emulsifier made according to
the process of examples 1 through 8 of U.S. Pat. No. 3,352,109 except that
a commercial grade 8 to 10 carbon alcohol was used and 2.50 wts. of
propylene oxide and 1.49 wts. of ethylene oxide added, were mixed as in
Example 1 above, and a mixture of 60 milliliters of solution B and 30
grams of a solid granular polymer acrylic acid added. The result was a
stable suspension of the polymer in a water-in-oil emulsion.
EXAMPLE 3
13 parts of calcium chloride dihydrate, 7.5 parts of water and 6.2 parts of
denatured ethanol were mixed in a tank and 2.5 parts of a material
equivalent to example 12 of U.S. Pat. No. 3,352,109 except that nonyl
phenol was used, i.e., nonyl phenol + 1.2 pt. wgt. EtO, were added and
mixed thoroughly. In a separate tank, 35.2 parts of kerosene and 32.6
parts of a solid powdered high molecular weight acrylic polymer were
mixed.
The kerosene-polymer slurry was added slowly with continuous agitation to
the aqueous emulsifier solution. The product was a stable, pumpable
oil-in-water high internal phase ratio emulsion in which the polymer was
suspended.
EXAMPLE 4
Essentially the same procedure was followed as Example 3 above except that
the solid powdered polymer was a copolymer of acrylic acid and acrylamide.
EXAMPLE 5
14.31 parts of calcium chloride dihydrate, 13.69 parts of water and 6 parts
of the material of Example 12 of U.S. Pat. No. 3,352,109, except that
nonyl phenol was used, i.e., nonyl phenol + 1.2 pt. wgt. EtO, were added
and mixed thoroughly. In a separate tank 35.2 parts of kerosene and 32.6
parts of solid powdered high molecular weight acrylic polymer (Cyfloc 326)
were mixed. The kerosene-polymer slurry was added slowly with continuous
agitation to the aqueous emulsifier solution. The product was a stable,
pumpable, oil-in-water high internal phase ratio emulsion in which the
polymer was suspended.
These improved polymer suspensions in a high internal phase ratio emulsion
can be added to systems to which the polymer is usually added as a solid
such as in the treatment of sewage and industrial wastes, in stabilizing
drilling muds, in the secondary recovery of petroleum by water flooding.
Not only may this invention be used as a means of adding water-soluble
polymers to aqueous systems but it may also be used to add oil-soluble
polymers to non-aqueous systems. For instance, oil-soluble polymers such
as (poly) butadiene, (poly) vinyl butryal, (poly) vinyl chloride, etc. can
be suspended in an emulsion of either the oil-in-water or water-in-oil
type and dispersed into oily media such as paint vehicles.
WATER CLARIFICATION
The present invention also relates to a method for the clarification of
water containing suspended matter.
Accordingly clarification of water containing suspended particles of matter
is effected by adding polymer emulsions of this invention.
Water containing suspended particles which may be treated by the present
invention may have its origin either in natural or artificial sources,
including industrial and sanitary sources. Waters containing suspended
particles of natural origin are usually surface waters, wherein the
particles are suspended soil particles (silt), although sub-surface waters
may also be treated according to the present invention. Water having its
origin in industrial process (including sanitary water) operations may
contain many different varieties of suspended particles. These particles
are generally the result of the particular industrial or sanitary
operation concerned. Prior to discharging such industrial waste waters
into natural water courses it generally is desired that the suspended
matter be removed.
The present process may likewise be applied to water contained in stock or
fish ponds, lakes or other natural or artificial bodies of water
containing suspended solids. It may be applied to industrial water
supplied either in preparation therefor, during or after use and prior to
disposal. It may be applied to sanitary water supplies either for the
elimination of suspended solids prior to use for such purposes, or it may
be applied to such waters which have become contaminated with impurities
from any source.
Most naturally occurring waters contain an amount of simple electrolytes
(sodium, potassium, ammonium, calcium, aluminum salts, etc.) in excess of
that necessary for the initial aggregation of the ultimate silt particles.
This is likewise true of particles of suspended material in industrial or
sanitary waters. The ultimate particles of silt or other materials are
therefore naturally somewhat aggregated by reason of the presence of such
electrolytes. However, the forces binding such ultimate particles together
are not great and moreover are not such as to generally effect either
rapid settling rates of the flocculated material or strong enough to
prevent deflocculation.
The polymer emulsions of this invention cause rapid flocculation and also
reinforce the formed aggregates of particles causing a general tightening
or bonding together of the initial particles and an increased rate of
coagulation and settling, thus forming a less turbid supernatant liquid.
The addition of the polymer emulsions of this invention to the water
suspension should be made in such a fashion that the resulting
flocculation and aggregation of the particles takes place uniformly
throughout the body of water. In order to obtain a uniform addition of the
compositions of the invention to the water-borne suspension it is
generally desirable to prepare a relatively dilute stock solution of the
polymer compositions and then to add such solutions to the body of water
in the proportions indicated above. Clarification may take place either in
the natural body of water or it may be caused to take place in hydraulic
thickeners of known design.
The amount of polymer emulsions to be employed will vary depending upon the
amount and the degree of subdivision of the solids to be agglomerated or
flocculated, the chemical nature of such solid and the particular polymer
emulsion employed. In general, one employs at least a sufficient amount of
the polymer emulsion to promote flocculation. In general, one employes
0.005-10,000 p.p.m. of active polymer or more, such as about 0.5-1,000
p.p.m., for example about 1-500 p.p.m., but preferably about 2-5 p.p.m.
Since the economics of these processes are important, no more than the
minimum amount required for efficient removal is generally employed. It is
desired, of course, to employ sufficient polymer so flocculation will take
place without causing the formation of stable dispersions. The above
p.p.m. relates to the polymer itself in the emulsion.
The precipitating action of the polymer can be employed in the application
of loading or filling materials to textiles or paper.
In the processing of fine mineral particles in aqueous suspension the
polymer emulsion flocculating agents will be especially useful. In the
processing of ores to separate valuable mineral constituents from
undesirable matrix constituents, it is frequent practice to grind the ore
into a finely-divided state to facilitate separation steps such as
selective flotation and the like. In many ore dressing procedures, the
finely-divided ore is suspended in water to form a pulp or slime. After
processing, it is usually desirable to dewater the pulps or slimes either
by sedimentation or filtering. In such operations, certain ores are
particularly troublesome in that the finely-divided ore, when suspended in
water, forms stable slime which settles very slowly, if at all. Such
slimes are unsuitable for concentration or dewatering by sedimentation and
are difficult to dewater by filtration because of the tendency to clog the
pores of the filter, thus leading to excessively time-consuming and
inefficient operation of the filters. In some cases, for example, in
certain phosphate mining operations, the formation of very stable
suspensions of finely-divided mineral results not only in the loss of
considerable valuable minerals as waste but also requires large
expenditures for the maintenance of holding ponds for the waste. Similar
problems are involved in processing gold, copper, nickel, lead, zinc,
iron, such as taconite ores, uranium and other ores, and the inventive
flocculating agents will be useful in these operations.
Some specific additional applications for the polymer emulsions of this
invention, not intended to be limiting but merely illustrative are listed
below. The polymer emulsions can be used for the clarification of beers or
wines during manufacture. Another use is in processing effluents in
pharamaceutical operations for the recovery of valuable products or
removal of undesirable by-products. A particularly important use for these
polymer emulsion flocculating agents is in the clarification of both beet
sugar and cane sugar juices in their processing. Still another use is for
flocculation and recovery of pigments from aqueous suspensions thereof.
The polymer emulsions will be particularly useful in sewage treatment
operations as a flocculating agent. A further use is to promote by
flocculation the removal of coal from aqueous suspensions thereof. In
other words, the polymer emulsion flocculating agents of the invention are
generally useful for processing aqueous effluents of all types to
facilitate the removal of suspended solids.
A water soluble or water dispersible polymer, to the extent of effective
concentrations, is employed.
These compositions can also be employed in the process of flocculating
white water/or recycling of the precipitate solids in the paper making
process of U.S. Pat. No. 3,393,157, and other processes described therein.
Naturally occurring water from many sources, and in some instances, brine
and brackish waters are used in the recovery of petroleum by secondary
water-flooding operations. Clarification of the water is necessary in many
instances prior to water flooding because the suspended impurities tend to
plug the underground formations into which waters are pumped.
These polymer emulsions are also effective in flocculating the other
systems described herein.
The following is a partial list of industry systems in which the polymer
emulsions of the present invention can be employed as flocculating agents.
1. Petroleum industry.
2. Food industry such as in the dairy industry, the canning, freezing and
dehydration industries
3. Metal plating industry
4. Chemical and pharmaceutical industries
5. Mining industry, for example, in the phosphate mining industry such as
in phosphate slimes
6. Fermen | | |
