1、Designation: C 1545 02 (Reapproved 2007)Practice forDispersing Pigments and Other Materials into Water-BasedSuspensions with a High Intensity Mixer1This standard is issued under the fixed designation C 1545; the number immediately following the designation indicates the year oforiginal adoption or,
2、in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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 pi
3、gments 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
4、allow 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
5、 orslurry), 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
6、of 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:2C 242 Terminology of C
7、eramic Whitewares and RelatedProducts3. Terminology3.1 Standard terminology for ceramic whitewares and re-lated products is given in Terminology C 242.4. Significance and Use4.1 The traditional method of preparing glazes and slurrieshas been to add stains (pigments), stabilizers, viscosity controlag
8、ents, 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 grindingothe
9、r materials. 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 traditionalmeth
10、od was that it was necessary to thoroughly wash out themill between batches of different colors. An obvious advan-tage, however, was that small components of the batch (such aspigments) were thoroughly dispersed in the batch and eventoday it is necessary to use this procedure when smallquantities of
11、 strongly 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 cas
12、e if the 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
13、is stirred 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
14、. In this 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.1This practice is under the jurisdiction of Committee C21 on Ce
15、ramic Whitew-ares and Related Products and is the direct responsibility of Subcommittee C21.03on Methods for Whitewares and Environmental Concerns.Current edition approved May 1, 2007. Published May 2007. Originallyapproved in 2002. Last previous edition approved in 2002 as C 154502.2For referenced
16、ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Consh
17、ohocken, PA 19428-2959, United States.5. Apparatus5.1 There are two types of high intensity mixers (dissolv-ers), those designed for laboratory use, where capacity isapproximately 10 to 15 litres of liquid, and those designed forproduction use, where capacity can be 1200 litres or more.Typical chara
18、cteristics 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.5.2.3 A cylindrical containe
19、r 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 andbottom corners are well-rounded
20、 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 be a guard for the impeller
21、 (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 determined by the size of theconta
22、iner 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 effectiveness of mixing thepi
23、gments 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 splashing if the impeller is e
24、xposed. 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 3 1200 mm height).6.2 Add the desired amount of base glaze to the container.The fill
25、 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 curve) the percent solids i
26、n 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 thedesired vortex. Extremely fluid
27、 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 these materials and add
28、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 to the container rather
29、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 mixing time, especially with
30、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 is finished and before an
31、other batch (even if the samecolor) is added.6.5.1.3 Leaking tubs must be repaired (epoxy/fiberglass isuseful for repairing small holes or cracks) or discarded.TABLE 1 Characteristics of Intensive MixersALaboratory ProductionCapacity (litres) 10 to 15 1000 to 1500Motor power (KW) 0.75 7.5 to 25.0Mot
32、or speed (RPM) 0 to 16000 1800Shaft speed (RPM) 0 to 16000 850 to 1500Typical tank diameter (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. 1C 1545 02 (2007)26.6 Deve
33、loping 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 grams), andSG = Specific gr
34、avity of the dry material.6.6.2 Substitute several values for WS, 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 and is shown here foril
35、lustration 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 employer shall have a progra
36、m 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. The more the teeth we
37、ar, 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 should develop anOSHA re
38、spiratory 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,the floor of the glaze p
39、reparation 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.7.10 Drums of materials, liquid or dry, are to be kept onpallets or racks and kept tightly covered and protected fromwater and dust.FIG. 2C 1545 02 (2007
40、)3ASTM 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 infringement of such rights, a
41、re 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 or for additional stand
42、ardsand 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 known to the ASTM Commi
43、ttee 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 ASTM 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).FIG. 3C 1545 02 (2007)4
