1、Designation: C1545 02 (Reapproved 2016)Practice forDispersing Pigments and Other Materials into Water-BasedSuspensions with a High Intensity Mixer1This standard is issued under the fixed designation C1545; the number immediately following the designation indicates the year oforiginal adoption or, in
2、 the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 In preparing ceramic glazes and slurries for use, it isoften necessary to add pigme
3、nts to develop a desired firedcolor, to incorporate viscosity control agents for developing, orproviding to develop the desired thickness of the glaze on theware, to add materials which stabilize the suspension, controlbacterial growth, and develop the desired hardness of the glazeon the ware to all
4、ow moving and handling before firing. Whileit is convenient to add these materials to the glaze or slurry inthe dry form, it is often possible to use slurries where thesematerials are dispersed in a slurry and the slurry then added tothe liquid glaze. Regardless of the state of the additions (dry or
5、slurry), the dispersion can be done efficiently and effectively bythe use of a high intensity mixer (sometimes referred to as adissolver) and the procedure used is described here.1.2 The values stated in SI units are to be regarded as thestandard.1.3 This standard does not purport to address all of
6、thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C242 Terminology of Ceram
7、ic Whitewares and RelatedProducts3. Terminology3.1 Standard terminology for ceramic whitewares and re-lated products is given in Terminology C242.4. Significance and Use4.1 The traditional method of preparing glazes and slurrieshas been to add stains (pigments), stabilizers, viscosity controlagents,
8、 bactericides, and so forth, to the pebble mill batchalong 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 overgrinding some of the materials of the batch and under grindingother mat
9、erials. While part of the disadvantage could bealleviated by double or triple batching (where the pebble millwas stopped at one or two points in the cycle and one or morematerials added), the practice was labor intensive and notalways well controlled.Another disadvantage of the traditionalmethod was
10、 that it was necessary to thoroughly wash out themill between batches of different colors. An obviousadvantage, however, was that small components of the batch(such as pigments) were thoroughly dispersed in the batch andeven today it is necessary to use this procedure when smallquantities of strongl
11、y colored pigments are to be used.4.2 With the advent of high speed intensive mixers using arotating shaft-mounted impeller, it is now the usual practice toadd pigments, conditioners, and so forth, to the batch from thepebble mill and accomplish the same uniform dispersion aswould be the case if the
12、 pigments were milled in rather than“stirred” in. In addition, the pigments tend to yield a strongercolor in the glaze because they have not been over ground inthe pebble mill. It is not uncommon to make a reduction in theamount of pigment needed to develop the desired color whenthe pigment is stirr
13、ed in rather than milled in. An even greaterbenefit is using the “stirred in” technique is that a single largebatch of a base glaze (for example, clear) can be made bymilling, and individual colors developed by stirring appropriatepigments and conditioners into small amounts of the baseglaze. In thi
14、s way, a large pebble mill can be dedicated to clearbase glaze and cleaning the mill between batches is not needed.Glaze stains frequently are treated with proprietary materialswhich assist in dispersing the stain into the glaze.5. Apparatus5.1 There are two types of high intensity mixers(dissolvers
15、), those designed for laboratory use, where capacityis approximately 10 to 15 litres of liquid, and those designed1This practice is under the jurisdiction of Committee C21 on Ceramic White-wares and Related Products and is the direct responsibility of Subcommittee C21.03on Methods for Whitewares and
16、 Environmental Concerns.Current edition approved Nov. 1, 2016. Published November 2016. Originallyapproved in 2002. Last previous edition approved in 2012 as C1545 02 (2012).DOI: 10.1520/C1545-02R16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service
17、 at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1for production use, where capacity can be 1200 l
18、itres or more.Typical characteristics of both types of mixer are shown inTable 1.5.2 Essential installation and operating “tips” for the mixersare:5.2.1 The motor power must be sufficient to maintaindesired speed with specified load.5.2.2 The floor mounted model must be rigidly secured tothe floor.5
19、.2.3 A cylindrical container can be used for the glazewhether it is laboratory or production equipment. Productionequipment must be fitted with a guide which centers and holdsin place the container on the same center as the impeller. Arectangular container can be used, provided that the side andbott
20、om corners are well-rounded to avoid “dead” areas in themixture, just as is necessary with the bottom corner of theround tub. A rectangular container has an advantage over theround one in that there is less “spinning” of the glaze duringmixing. See Fig. 1 for details of a round tub.5.2.4 There must
21、be a guard for the impeller (productionmachine) when the machine is not being used. This can be asplit disk of plywood slightly larger in diameter than theimpeller.5.2.5 The drive unit must have sufficient vertical travel toclear the tub when the tub is on a pallet.5.2.6 The impeller size is determi
22、ned by the size of thecontainer and the viscosity of the glaze. For a 1200 mmdiameter tank, the impeller should have diameter of 250 to 350mm.5.2.7 The speed of rotation, the viscosity of the liquid, thesize of the impeller, and the height of the impeller (from thebottom of the tub) determine the ef
23、fectiveness of mixing thepigments into the glaze. The correct setting results in the depthof the vortex being one third of the depth of the glaze batchwhen at rest.5.2.8 When there is no vortex, mixing will not be thorough;when the vortex is too deep there will be considerable airentrainment and spl
24、ashing if the impeller is exposed. See Fig.1 for a view of the recommended tub, and Fig. 2 for the tub,impeller, and pattern of liquid flow.6. Procedure6.1 It is convenient to standardize on one size of container(for example, 1200 mm diameter 1200 mm height).6.2 Add the desired amount of base glaze
25、to the container.The fill height should be no more than 80 % of the height of thecontainer with the impeller in place. The dry weight of the baseglaze in the container can be obtained by the use of a percentsolids vs. specific gravity curve, the weight of base glaze in thecontainer, and (from the cu
26、rve) the percent solids in the glaze.An example of the percent solids vs. specific gravity curve isshown in Fig. 3. See 4.4 for the procedure for developing thiscurve.6.3 Start the dissolver at a low speed and if necessary, adjustthe height of the impeller to avoid splashing and to develop thedesire
27、d vortex. Extremely fluid base glazes may require asmaller diameter impeller or a lower level of the base glaze inthe container. Continue stirring for a few minutes.6.4 Knowing the dry weight of the base glaze in thecontainer, calculate the weight of the pigments and condition-ers to be added, weigh
28、 these materials and add slowly (in thecenter of the vortex) to the container, increasing the speed ofthe dissolver if necessary to develop a good vortex. It may benecessary for better dispersion to make a slurry of the pigmentsand conditioners with a small amount of the base glaze and addthe slurry
29、 to the container rather than the dry materials.6.5 Mix the glaze, pigments, conditioners, and so forth, for15 to 20 min (time depends on the types and amounts ofmaterials being added), stop the dissolver and take the requiredsample for testing (viscosity, fired color, and so forth). Exces-sive mixi
30、ng time, especially with a high viscosity glaze, willincrease the temperature of the glaze in the tub, as well asshortening the life of the impeller.6.5.1 Rules for glaze storage:6.5.1.1 Always keep tight-fitting covers on glaze tubs.6.5.1.2 Tubs must be washed and cleaned thoroughly afterone batch
31、is finished and before another batch (even if the samecolor) is added.TABLE 1 Characteristics of Intensive MixersALaboratory ProductionCapacity (litres) 10 to 15 1000 to 1500Motor power (KW) 0.75 7.5 to 25.0Motor speed (RPM) 0 to 16000 1800Shaft speed (RPM) 0 to 16000 850 to 1500Typical tank diamete
32、r (mm) 200 1200Typical tank height (mm) N/A 1200Mounting Bench FloorTachometer on shaft Yes YesHydraulic lift for drive and shaft N/A YesAFrom a Morehouse-Cowles information sheetFIG. 1C1545 02 (2016)26.5.1.3 Leaking tubs must be repaired (epoxy/fiberglass isuseful for repairing small holes or crack
33、s) or discarded.6.6 Developing the Percent Solids vs. Specific GravityCurve6.6.1 The dry weight of solids per millilitre of slip iscalculated by Brongniants equation:Wd5 WS2 WW! (1)where:WS= slip weight/millilitre (in grams),WW= Weight of water/millilitre (in grams),Wd= Dry weight/millilitre (in gra
34、ms), andSG = Specific gravity of the dry material.6.6.2 Substitute several values forWS, calculate the percent-age of solids corresponding to these values, and finally plot theseveral points on a percent solids vs. specific gravity curve asshown in Fig. 3.NOTE 1Fig. 3 does not represent actual data
35、and is shown here forillustration only.7. Safety and Health Precautions7.1 The dissolver must be fitted with a guard that will ensurethat a hand or paddle cannot be placed in the machine while itis in operation.7.2 The machine must be in direct line of sight with the“start/stop” button.7.3 The emplo
36、yer shall have a program to ensure that themachine cannot be energized accidentally during cleaning orrepair of the machine.7.4 The walls of the container can easily be damaged if therevolving dissolver blade contacts them.7.5 Inspect the blade once a week to determine the amountof wear on the teeth
37、. The more the teeth wear, the less effectivewill be the mixing. It is false economy to keep a blade inservice with badly worn teeth.7.6 An appropriate ventilation system should be installed toprotect employees from dust exposure during dry operations. Ifsuch a system is not feasible, the employer s
38、hould develop anOSHA respiratory protection program.7.7 Electrical connections and equipment must be properlygrounded, water-tight, and in compliance with all local elec-trical codes.7.8 Surface dust and spills should be washed up as fre-quently as needed to keep the area clean.As the very minimum,t
39、he floor of the glaze preparation area must be washed daily.7.9 Bagged materials must be stored on pallets or racks,never on the floor, and protected from water and dust.FIG. 2C1545 02 (2016)37.10 Drums of materials, liquid or dry, are to be kept onpallets or racks and kept tightly covered and prote
40、cted fromwater and dust.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringe
41、ment of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard o
42、r for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views k
43、nown to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting A
44、STM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 3C1545 02 (2016)4
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