ASTM C1545-02(2012)
(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
SIGNIFICANCE AND USE
The traditional method of preparing glazes and slurries has been to add stains (pigments), stabilizers, viscosity control agents, bactericides, and so forth, to the pebble mill batch along with normal batch materials such as clay, frit, quartz, feldspar, whiting (calcium carbonate), zinc oxide, opacifier, and so forth. This method had the disadvantage of over grinding some of the materials of the batch and under grinding other materials. While part of the disadvantage could be alleviated by double or triple batching (where the pebble mill was stopped at one or two points in the cycle and one or more materials added), the practice was labor intensive and not always well controlled. Another disadvantage of the traditional method was that it was necessary to thoroughly wash out the mill between batches of different colors. An obvious advantage, however, was that small components of the batch (such as pigments) were thoroughly dispersed in the batch and even today it is necessary to use this procedure when small quantities of strongly colored pigments are to be used.
With the advent of high speed intensive mixers using a rotating shaft-mounted impeller, it is now the usual practice to add pigments, conditioners, and so forth, to the batch from the pebble mill and accomplish the same uniform dispersion as would be the case if the pigments were milled in rather than “stirred” in. In addition, the pigments tend to yield a stronger color in the glaze because they have not been over ground in the pebble mill. It is not uncommon to make a reduction in the amount of pigment needed to develop the desired color when the pigment is stirred in rather than milled in. An even greater benefit is using the “stirred in” technique is that a single large batch of a base glaze (for example, clear) can be made by milling, and individual colors developed by stirring appropriate pigments and conditioners into small amounts of the base glaze. In this way, a large pebble mill can be dedicate...
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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Standards Content (Sample)
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Designation: C1545 − 02(Reapproved 2012)
Practice for
Dispersing Pigments and Other Materials into Water-Based
Suspensions with a High Intensity Mixer
This standard is issued under the fixed designation C1545; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 4. Significance and Use
1.1 In preparing ceramic glazes and slurries for use, it is 4.1 The traditional method of preparing glazes and slurries
often necessary to add pigments to develop a desired fired has been to add stains (pigments), stabilizers, viscosity control
color,toincorporateviscositycontrolagentsfordeveloping,or agents, bactericides, and so forth, to the pebble mill batch
providing to develop the desired thickness of the glaze on the along with normal batch materials such as clay, frit, quartz,
ware, to add materials which stabilize the suspension, control feldspar, whiting (calcium carbonate), zinc oxide, opacifier,
bacterialgrowth,anddevelopthedesiredhardnessoftheglaze and so forth. This method had the disadvantage of over
on the ware to allow moving and handling before firing.While grinding some of the materials of the batch and under grinding
it is convenient to add these materials to the glaze or slurry in other materials. While part of the disadvantage could be
the dry form, it is often possible to use slurries where these alleviated by double or triple batching (where the pebble mill
materials are dispersed in a slurry and the slurry then added to was stopped at one or two points in the cycle and one or more
theliquidglaze.Regardlessofthestateoftheadditions(dryor materials added), the practice was labor intensive and not
slurry),thedispersioncanbedoneefficientlyandeffectivelyby alwayswellcontrolled.Anotherdisadvantageofthetraditional
the use of a high intensity mixer (sometimes referred to as a method was that it was necessary to thoroughly wash out the
dissolver) and the procedure used is described here. mill between batches of different colors. An obvious
advantage, however, was that small components of the batch
1.2 The values stated in SI units are to be regarded as the
(such as pigments) were thoroughly dispersed in the batch and
standard.
even today it is necessary to use this procedure when small
1.3 This standard does not purport to address all of the
quantities of strongly colored pigments are to be used.
safety concerns, if any, associated with its use. It is the
4.2 With the advent of high speed intensive mixers using a
responsibility of the user of this standard to establish appro-
rotating shaft-mounted impeller, it is now the usual practice to
priate safety and health practices and determine the applica-
add pigments, conditioners, and so forth, to the batch from the
bility of regulatory limitations prior to use.
pebble mill and accomplish the same uniform dispersion as
would be the case if the pigments were milled in rather than
2. Referenced Documents
“stirred” in. In addition, the pigments tend to yield a stronger
2.1 ASTM Standards:
color in the glaze because they have not been over ground in
C242Terminology of Ceramic Whitewares and Related
the pebble mill. It is not uncommon to make a reduction in the
Products
amount of pigment needed to develop the desired color when
the pigment is stirred in rather than milled in.An even greater
3. Terminology
benefit is using the “stirred in” technique is that a single large
3.1 Standard terminology for ceramic whitewares and re-
batch of a base glaze (for example, clear) can be made by
lated products is given in Terminology C242.
milling,andindividualcolorsdevelopedbystirringappropriate
pigments and conditioners into small amounts of the base
glaze. In this way, a large pebble mill can be dedicated to clear
1 baseglazeandcleaningthemillbetweenbatchesisnotneeded.
This practice is under the jurisdiction of Committee C21 on Ceramic White-
waresandRelatedProductsandisthedirectresponsibilityofSubcommitteeC21.03
Glaze stains frequently are treated with proprietary materials
on Methods for Whitewares and Environmental Concerns.
which assist in dispersing the stain into the glaze.
Current edition approved April 1, 2012. Published April 2012. Originally
approvedin2002.Lastpreviouseditionapprovedin2007asC1545–02(2007).DOI:
5. Apparatus
10.1520/C1545-02R12.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
5.1 There are two types of high intensity mixers
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
(dissolvers), those designed for laboratory use, where capacity
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. is approximately 10 to 15 litres of liquid, and those designed
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C1545 − 02 (2012)
for production use, where capacity can be 1200 litres or more.
Typical characteristics of both types of mixer are shown in
Table 1.
5.2 Essentialinstallationandoperating“tips”forthemixers
are:
5.2.1 The motor power must be sufficient to maintain
desired speed with specified load.
5.2.2 The floor mounted model must be rigidly secured to
the floor.
5.2.3 A cylindrical container can be used for the glaze
whether it is laboratory or production equipment. Production
equipment must be fitted with a guide which centers and holds
in place the container on the same center as the impeller. A
rectangular container can be used, provided that the side and
bottom corners are well-rounded to avoid “dead” areas in the
mixture, just as is necessary with the bottom corner of the
round tub. A rectangular container has an advantage over the
round one in that there is less “spinning” of the glaze during
mixing. See Fig. 1 for details of a round tub.
5.2.4 There must be a guard for the impeller (production
machine) when the machine is not being used. This can be a
FIG. 1
split disk of plywood slightly larger in diameter than the
impeller.
5.2.5 The drive unit must have sufficient vertical travel to
6.2 Add the desired amount of base glaze to the container.
clear the tub when the tub is on a pallet.
Thefillheightshouldbenomorethan80%oftheheightofthe
5.2.6 The impeller size is determined by the size of the
containerwiththeimpellerinplace.Thedryweightofthebase
container and the viscosity of the glaze. For a 1200 mm
g
...
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