1、Designation: C 866 77 (Reapproved 2006)Standard Test Method forFiltration Rate of Ceramic Whiteware Clays1This standard is issued under the fixed designation C 866; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last r
2、evision. 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 This test method covers the determination of the rate atwhich a layer of clay-water paste is formed from a clay-waterslip u
3、nder pressure filtration. The filtration rate is directlyrelated to such whiteware operations as filter pressing, slipcasting, and drying of ware in which water permeabilitythrough a clay-water paste is the controlling mechanism.1.2 A straight-line relationship exists between the time offilter press
4、ing and the square of the thickness of the paste layer.The filtration rate is directly related to the filter press pressureand the void fraction of the paste layer, and is inversely relatedto the square of the clay surface area, the ratio of solids toliquid in the slip, and the viscosity of water at
5、 the testingtemperature.1.3 This standard does not purport to address all 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 prio
6、r to use.2. Referenced Documents2.1 ASTM Standards:2C 324 Test Method for Free Moisture in Ceramic Whitew-are Clays3. Apparatus3.1 Balance, 0.001-g sensitivity.3.2 Blender.3.3 Filter Press, capable of operation at 345 kPa (50 psi).3.4 Stop Watch.3.5 Vernier Calipers, capable of measuring thickness t
7、o thenearest 0.1 mm.4. Procedure4.1 Weigh 100 g of clay, dried in accordance with TestMethod C 324, to the nearest 0.1 g and mix with 300 mL ofwater measured to the nearest 1.0 mL for 10 min in a blender.4.2 Store the slip in a closed container for at least 24 h toallow the clay and water to reach e
8、quilibrium conditions.4.3 Remix the clay-water slurry for 5 min in the blender.4.4 Pour the clay-water slurry into the filter press and apply345 kPa (50 psi) air pressure for 30 min.4.5 Relieve the pressure from the filter press and then pourthe clay-water slurry from the top of the filter cake that
9、 hasformed. A sharp movement of the wrist is required to removeall of the remaining slip from the filter press.4.6 Record the temperature of the filtrate.4.7 Reapply air pressure to the filter press for 10 min toforce some of the water from the cake that has formed.NOTE 1Some clays have a fast filtr
10、ation rate and the air may passthrough the cake in less than 10 min. In this case, the air pressure shouldbe relieved as soon as the sound of air emitting from the press is detected.4.8 Remove the filter cake from the press and measure thethickness to the nearest 0.1 mm with the vernier calipers.4.9
11、 Place the cake in a drying oven at 100 to 110C for aperiod of 24 h. Weigh the dried filter cake to the nearest 0.01g.5. Calculations5.1 Calculate the filtration rate as follows:FR 5 L2/T (1)where:FR = filtration rate, cm2/s,L = thickness of the wet filter cake, cm, andT = filtration time, s.NOTE 2T
12、he filtration time is based upon the 30-min period duringwhich the clay-water slip is being filter pressed and does not include theadditional 10-min period for removal of water from the cake after it hasbeen formed.5.2 The void fraction in the filter cake varies considerablydepending upon ions in th
13、e water that modify the packingstructure of the clay particles in the filter cake. Water that isnormally used for mixing with the clays should be used for the1This test method is under the jurisdiction ofASTM Committee C21 on CeramicWhitewares and Related Products and is the direct responsibility of
14、 SubcommitteeC21.04 on Raw Materials.Current edition approved Feb. 15, 2006. Published February 2006.Originally approved in 1977. Last previous edition approved in 1997 asC 866 77 (1997)e1.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at servic
15、eastm.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 Conshohocken, PA 19428-2959, United States.test so that interactions between ions in the water with
16、the clayare considered. However, in some cases distilled water may beused for mixing with the clay so that only those ions introducedwith the clay are considered in the test. The void fraction iscalculated as follows based upon the density of the clay being2.60 Mg/m3:VF 5 1 2W2.60 3 A 3 L(2)where:VF
17、 = void fraction in the filter cake,W = dry weight of the filter cake, g,A = cross-sectional area of the filter press, cm2, andL = thickness of the wet filter cake, cm.6. Precision and Bias6.1 The experience of several laboratories indicates that thistest method is capable of a precision of 62 % (95
18、 % confi-dence level).7. Keywords7.1 clay; filtrationASTM 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 ri
19、ghts, and the riskof infringement 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 fo
20、r revision of this standard or 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 hearin
21、g you shouldmake your views known 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 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).C 866 77 (2006)2
