ASTM C1545-02
(Practice)Practice for Dispersing Pigments and Other Materials into Water-Based Suspensions with a High Intensity Mixer
Practice for Dispersing Pigments and Other Materials into Water-Based Suspensions with a High Intensity Mixer
SCOPE
1.1 In preparing ceramic glazes and slurries for use, it is often necessary to add pigments to develop a desired fired color, to incorporate viscosity control agents for developing, or providing to develop the desired thickness of the glaze on the ware, to add materials which stabilize the suspension, control bacterial growth, and develop the desired hardness of the glaze on the ware to allow moving and handling before firing. While it is convenient to add these materials to the glaze or slurry in the dry form, it is often possible to use slurries where these materials are dispersed in a slurry and the slurry then added to the liquid glaze. Regardless of the state of the additions (dry or slurry), the dispersion can be done efficiently and effectively by the use of a high intensity mixer (sometimes referred to as a dissolver) and the procedure used is described here.
1.2 The values stated in SI units are to be regarded as the standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact ASTM
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Designation:C1545–02
Practice for
Dispersing Pigments and Other Materials into Water-Based
Suspensions with a High Intensity Mixer
This standard is issued under the fixed designation C 1545; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope along with normal batch materials such as clay, frit, quartz,
feldspar, whiting (calcium carbonate), zinc oxide, opacifier,
1.1 In preparing ceramic glazes and slurries for use, it is
and so forth. This method had the disadvantage of over
often necessary to add pigments to develop a desired fired
grinding some of the materials of the batch and under grinding
color, to incorporate viscosity control agents for developing, or
other materials. While part of the disadvantage could be
providing to develop the desired thickness of the glaze on the
alleviated by double or triple batching (where the pebble mill
ware, to add materials which stabilize the suspension, control
was stopped at one or two points in the cycle and one or more
bacterial growth, and develop the desired hardness of the glaze
materials added), the practice was labor intensive and not
on the ware to allow moving and handling before firing. While
always well controlled.Another disadvantage of the traditional
it is convenient to add these materials to the glaze or slurry in
method was that it was necessary to thoroughly wash out the
the dry form, it is often possible to use slurries where these
mill between batches of different colors. An obvious advan-
materials are dispersed in a slurry and the slurry then added to
tage, however, was that small components of the batch (such as
the liquid glaze. Regardless of the state of the additions (dry or
pigments) were thoroughly dispersed in the batch and even
slurry),thedispersioncanbedoneefficientlyandeffectivelyby
today it is necessary to use this procedure when small
the use of a high intensity mixer (sometimes referred to as a
quantities of strongly colored pigments are to be used.
dissolver) and the procedure used is described here.
4.2 With the advent of high speed intensive mixers using a
1.2 The values stated in SI units are to be regarded as the
rotating shaft-mounted impeller, it is now the usual practice to
standard.
add pigments, conditioners, and so forth, to the batch from the
1.3 This standard does not purport to address all of the
pebble mill and accomplish the same uniform dispersion as
safety concerns, if any, associated with its use. It is the
would be the case if the pigments were milled in rather than
responsibility of the user of this standard to establish appro-
“stirred” in. In addition, the pigments tend to yield a stronger
priate safety and health practices and determine the applica-
color in the glaze because they have not been over ground in
bility of regulatory limitations prior to use.
the pebble mill. It is not uncommon to make a reduction in the
2. Referenced Documents
amount of pigment needed to develop the desired color when
the pigment is stirred in rather than milled in. An even greater
2.1 ASTM Standards:
benefit is using the “stirred in” technique is that a single large
C 242 Terminology of Ceramic Whitewares and Related
batch of a base glaze (for example, clear) can be made by
Products
milling,andindividualcolorsdevelopedbystirringappropriate
3. Terminology
pigments and conditioners into small amounts of the base
glaze. In this way, a large pebble mill can be dedicated to clear
3.1 Standard terminology for ceramic whitewares and re-
baseglazeandcleaningthemillbetweenbatchesisnotneeded.
lated products is given in Terminology C 242.
Glaze stains frequently are treated with proprietary materials
4. Significance and Use
which assist in dispersing the stain into the glaze.
4.1 The traditional method of preparing glazes and slurries
5. Apparatus
has been to add stains (pigments), stabilizers, viscosity control
5.1 There are two types of high intensity mixers (dissolv-
agents, bactericides, and so forth, to the pebble mill batch
ers), those designed for laboratory use, where capacity is
approximately 10 to 15 litres of liquid, and those designed for
This practice is under the jurisdiction of Committee C21 on Ceramic Whitew-
production use, where capacity can be 1200 litres or more.
ares and Related Products and is the direct responsibility of Subcommittee C21.03
Typical characteristics of both types of mixer are shown in
on Methods for Whitewares and Environmental Concerns.
Table 1.
Current edition approved Oct. 10, 2002. Published December 2002.
Annual Book of ASTM Standards, Vol 15.02.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact ASTM
International (www.astm.org) for the latest information.
C1545–02
A
TABLE 1 Characteristics of Intensive Mixers
5.2.7 The speed of rotation, the viscosity of the liquid, the
Laboratory Production
size of the impeller, and the height of the impeller (from the
Capacity (litres) 10 to 15 1000 to 1500
bottom of the tub) determine the effectiveness of mixing the
Motor power (KW) 0.75 7.5 to 25.0
pigments into the glaze. The correct setting results in the depth
Motor speed (RPM) 0 to 16000 1800
Shaft speed (RPM) 0 to 16000 850 to 1500
of the vortex being one third of the depth of the glaze batch
Typical tank diameter (mm) 200 1200
when at rest.
Typical tank height (mm) N/A 1200
Mounting Bench Floor
5.2.8 When there is no vortex, mixing will not be thorough;
Tachometer on shaft Yes Yes
when the vortex is too deep there will be considerable air
Hydraulic lift for drive and shaft N/A Yes
entrainment and splashing if the impeller is exposed. See Fig.
A
From a Morehouse-Cowles information sheet
1 for a view of the recommended tub, and Fig. 2 for the tub,
impeller, and pattern of liquid flow.
5.2 Essential installation and operating “tips” for the mixers
are:
6. Procedure
5.2.1 The motor power must be sufficient to maintain
desired speed with specified load.
6.1 It is convenient to standardize on one size of container
5.2.2 The floor mounted model must be rigidly secured to
(for example, 1200 mm diameter 3 1200 mm height).
the floor.
6.2 Add the desired amount of base glaze to the container.
5.2.3 A cylindrical container can be used for the glaze
Thefillheightshouldbenomorethan80 %oftheheightofthe
w
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