ACUMER 5000-2

ACUMER™ 5000 is a proprietary multifunctional polymer with a molecular weight of 5000 that provides exceptional silica and magnesium silicate scale inhibition.ACUMER 5000 is Silica and Magnesium Silicate Scale Inhibitor.
Acumer 5000 is an excellent scale inhibitor and dispersant for silica and magnesium silicate.

Uses: Industrial water treatment

Benefits: Excellent scale inhibition for a variety of applications including cooling circuits, boilers and RO units.

Scale Control / Inhibition: Calcium Carbonate, Calcium Phosphate / Phosphonate, Iron Oxide Dispersion, Silica / Silicate

Application: Boilers, Cooling Water, Membranes

ACUMER™ 5000 Silica and Magnesium Silicate Scale Inhibitor

Typical Properties These properties are typical but do not constitute specifications
Property Typical Values
Appearance: Dark yellow to brown clear solution*
Average molecular weight: 5000 (Mw)
Total solids (%): 45
Active solids (%): 42
pH as is (at 25°C): 2.5
Bulk density (at 25°C): 1.20
Viscosity Brookfield (mPa.s/cps at 25°C): 400
Neutralization: 0.13 g of NaOH (100%) per g of ACUMER™ 5000
*A slight haze may appear; this does not affect the intrinsic properties of the product or its performance.
Chemistry and Mode of Action
ACUMER™ 5000 is a proprietary multifunctional polymer with a molecular weight of 5000
that provides exceptional silica and magnesium silicate scale inhibition.
ACUMER 5000 helps prevent silica-based scale formation by dispersing colloidal silica and
by minimizing magnesium silicate scale formation at heat transfer surfaces.
Performance Control of silica-based scale is a complex problem due to the many forms of silica species
that exist:
• Molybdate-reactive silica: frequently referred to as dissolved silica.
• Colloidal silica: polymerized silica particles of 0.1 microns or less.
• Silica scale: primarily magnesium silicate, but may also be iron or calcium silicate.
Colloidal silica can dissolve to form silicate in the high temperature/high pH environment
near a corroding cathodic surface where dissolved oxygen is reduced to hydroxide ions.
These freshly formed silicate anions, added to the dissolved silica already present, can then
form magnesium silicate scale (MgSiO3). In addition, colloidal silica alone can co-precipitate
with magnesium hydroxide to form a scale of magnesium silicate having non-stoichiometric
ratios of magnesium to silica.
Normally, if silica levels exceed about 180 ppm SiO2 in the recirculation water of a cooling
circuit, severe scaling can occur on heat transfer surfaces. Moreover, the scale that forms is
frequently difficult or impossible to remove by conventional means.
ACUMER™ 5000 has been evaluated under field conditions, allowing up to 300 ppm silica
in the recirculating water without scale. Case histories are available upon request from your
local technical representative.
ACUMER™ 5000 Silica and Magnesium Silicate Scale Inhibitor / Dow Coating Materials 09/2011, Rev. 0
Applications • Recirculating cooling circuits
ACUMER™ 5000 offers distinct features for the treatment of silica-limited cooling waters,
allowing up to at least 300 ppm silica in the recirculating water without scale or corrosion
problems.
• Boilers
The excellent hydrothermal stability of ACUMER 5000 makes it an ideal choice for use in
controlling magnesium silicate scale in boilers operating up to about 900 psig, although
silica may carry over in steam at >600 psig.
Benefits of
ACUMER™ 5000
• Helps keep surfaces clean for maximum heat transfer and enhances the performance of
organic corrosion inhibitors.
• Has excellent thermal and chemical stability.
• Can be formulated at any pH without degradation.
• Exhibits a very good stability in the presence of hypochlorite.
• Contains no phosphorus, making its use acceptable where legislation requires that
discharge waters contain low or no phosphorus

Cooling water reuse is frequently limited by a ceiling
on the amount of tolerable silica in the recirculation
water. Normally, if silica levels exceed about 180 ppm
SiO2, severe scaling can occur on heat transfer surfaces. Moreover, the scale that forms is frequently difficult or impossible to remove by conventional
means. ACUMER 5000 silica control polymer has
now raised that ceiling to at least 300 ppm SiO2,
proven by exacting pilot studies and field trials,
allowing for greater water reuse than ever before.
ACUMER 5000 polymer prevents silica-based scale formation by dispersing colloidal silica and by preventing
magnesium silicate scale formation at the heat transfer surfaces.

The typical physical properties of ACUMER 5000 polymer are listed in Table 1.
TABLE 1
TYPICAL PHYSICAL PROPERTIES
(these do not constitute specifications)
Molecular Weight 5000
Total Solids, % 44.5 to 45.5
Active Solids, % 42
pH 2.1 to 2.6
Brookfield Viscosity, cp 700 max.
Specific Gravity 1.2
Bulk Density, lb/gal (g/cc) 10 (1.19)
Lb (Kg) of 100% NaOH to
neutralize 1 lb (kg) of polymer 0.131
FORMATION OF SILICA-BASED SCALE
Silica forms particles with different structures depending upon the pH, presence of other ions and process
by which the particles are formed. The three main
forms of silica encountered in cooling water are:
• Molybdate-reactive silica: frequently referred to as
dissolved silica.
• Colloidal silica: polymerized silica particles of 0.1
micron or less.
• Silicate scale: primarily magnesium silicate, but
may also be iron or calcium silicate.

Colloidal silica, which forms when the solubility level
of silica is exceeded, is difficult to measure under field
conditions, and a total silica mass balance cannot be
achieved with a simple field test. The most effective
method of determining total silica is described in
“Standard Methods for the Examination of Water and
Wastewater”, 17th edition (Method 4500-SiC). A simpler method that converts other forms of silica to
molybdate-reactive silica is described in Rohm and
Haas Technical Bulletin FC-267, “ACUMER TST sm,
Total Silica Test for High-Silica Waters”.
As the colloidal silica passes into the Nernst diffusion
layer at the heat transfer surface, it dissolves and
acquires a negative (anionic) charge. Polyvalent
cations, especially magnesium, tend to react with these
anionic colloidal particles effectively “gluing” them
together and ultimately forming a hard, glassy magnesium silicate scale.
Figure 1 shows how colloidal silica can dissolve to
form silicate in the high temperature/high pH environment near a corroding cathodic surface where dissolved oxygen is reduced to hydroxide ions. These
freshly formed silicate anions, added to the dissolved
silica already present, can then form magnesium silicate scale (MgSiO3). In addition, colloidal silica
alone can coprecipitate with magnesium hydroxide to
form a scale of magnesium silicate having non-stoichiometric ratios of magnesium to silicate.

Mechanism for Controlling Silica
The remarkable properties of ACUMER 5000 polymer
derive in large part from its three distinctive functionalities. The weak acid (carboxylate) group provides a
means of attaching the polymer to metal ions in solution and to the surfaces of particles or crystals. This
enables the polymer to act as a dispersant to prevent
agglomeration and deposit formation as well as stabilizing contaminants. The strong acid (sulfonate) contributes to this process by increasing the solubility and
charge density of the polymer which enhances electrostatic repulsion of particles.
What sets ACUMER 5000 polymer apart, however, is a
unique third set of functionalities, based on balanced
hydrophilicity and lipophilicity (hydrophobicity)1
.
Where the other functionalities operate primarily
through charge-transfer, this so-called HLB functionality promotes physical adsorption on the surfaces of
contaminant particles especially at higher temperatures. By promoting adsorption, this third type of
functionality also contributes to the strength of the
energy barrier (or the net repulsive force) created by
the polymer around the silica particle.
ACUMER 5000 polymer adsorbed on the colloid surfaces provides an energy barrier that prevents precipitation and agglomeration. Moreover, even if the silica
particles precipitate, they are spaced too far apart for
magnesium or redissolved silicate anions to bind them
together. As a result, the scale formed by these particles will be powdery and, thus, easier to remove.

ACUMER™ 5000 Silica and Magnesium Silicate Scale Inhibitor
Chemistry and Mode of Action
ACUMER 5000 is a proprietary multifunctional polymer with a molecular weight of 5000 that provides outstanding
silica and magnesium silicate scale inhibition.
ACUMER 5000 prevents silica-based scale formation by dispersing colloidal silica and by preventing magnesium
silicate scale formation at heat transfer surfaces.
Performance
Control of silica-based scale is a complex problem due to the many forms of silica species that exist:

Molybdate-reactive silica: frequently referred to as dissolved silica.

Colloidal silica: polymerized silica particles of 0.1 microns or less.

Silica scale: primarily magnesium silicate, but may also be iron or calcium silicate.
Colloidal silica can dissolve to form silicate in the high temperature/high pH environment near a corroding cathodic surface where dissolved oxygen is reduced to hydroxide ions. These freshly formed silicate anions, added to the dissolved silica already present, can then form magnesium silicate scale (MgSiO3). In addition, colloidal silica alone can co-precipitate with magnesium hydroxide to form a scale of magnesium silicate having non-stoichiometric ratios of magnesium to silica. Normally, if silica levels exceed about 180 ppm SiO2 in the recirculation water of a cooling circuit, severe scaling can occur on heat transfer surfaces. Moreover, the scale that forms is frequently difficult or impossible to remove by conventional means.
ACUMER 5000 has been evaluated under field conditions, allowing up to 300 ppm silica in the recirculating water without scale. Case histories are available upon request from your local technical representative. Applications

Recirculating cooling circuits
ACUMER 5000 offers unique features for the treatment of silica-limited cooling waters, allowing up to at least 300 ppm silica in the recirculating water without scale or corrosion problems.

Typical Properties
These properties are typical but do not constitute specifications.
Appearance Dark yellow to brown clear solution*
Average molecular weight 5000 (Mw)
Total solids (%): 45
Active solids (%): 42
pH as is (at 25°C): 2.5
Bulk density (at 25°C): 1.20
Viscosity Brookfield (mPa.s/cps at 25°C): 400
Neutralization 0.13g of NaOH (100%) per g of ACUMER 5000
*A slight haze may appear; this does not affect the intrinsic properties of the product or its performance. 
These suggestions and data are based on information we believe to be reliable. They are offered in good faith, but without guarantee, as conditions and methods of use of our products are beyond our control. We recommend that the prospective user determine the suitability of
our materials and suggestions before adopting them on a commercial scale.

Boilers
The superior hydrothermal stability of ACUMER 5000 enables its use for controlling magnesium silicate scale in boilers operating up to about 900 psig, although silica may carry over in steam at > 600 psig.
Benefits of ACUMER 5000:

Keeps surfaces clean for maximum heat transfer and enhances the performance of organic corrosion
inhibitors.

Has excellent thermal and chemical stability.

Can be formulated at any pH without degradation.

Exhibits a very good stability in the presence of hypochlorite.

Contains no phosphorus, making its use acceptable where legislation requires that discharge waters contain
low or no phosphorus.