1、Designation: D 6408 99 (Reapproved 2004)Standard Test Method forAnalysis of Tannery Liquors1This standard is issued under the fixed designation D 6408; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A nu
2、mber 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 analysis of tannery liquorsmade up from vegetable tanning materials.1.2 The values stated in SI units are to
3、 be regarded as thestandard.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
4、prior to use.2. Referenced Documents2.1 ASTM Standards:2D 4903 Test Method for Total Solids and Water in VegetableTanning Material ExtractsD 4904 Practice for Cooling of Analytical SolutionsD 6401 Test Method for Determining Non-Tannins andTannin in Extracts of Vegetable Tanning MaterialsD 6402 Test
5、 Method for Determining Soluble Solids andInsolubles in Extracts of Vegetable Tanning MaterialsD 6404 Practice for Sampling of Vegetable Materials Con-taining TanninD 6410 Test Method for Determining Acidity of VegetableTanning Liquors2.2 ALCA Methods:A25 Analysis of Tannery Liquors33. Terminology3.
6、1 Definitions:3.1.1 tannery liquorwater solutions containing vegetabletannin that are made up and used in a vegetable tannery.3.1.2 tanninan astringent substance found in the variousparts of plants such as bark, wood, leaves, nuts, fruits, roots,etc. Also, quantitatively, tannins are operationally d
7、efined asthe non-volatile materials present in tannin extracts and raw orspent materials that are dissolved or suspended in water, arepart of the soluble solids determined by Test Method D 6402,and do react with or bind to hide powder when mixed as in thistest method.3.1.3 vegetable tanninsmixtures
8、of substances (naturalproducts) obtained from plant tissues by water extractionwhich have the chemical and physical properties necessary toconvert animal hides and skins into leather.4. Summary of Test Method4.1 An analytical solution is prepared from the sample oftannery liquor (Practice D 6404). S
9、pecimen aliquots from thisanalytical solution are then analyzed for total solids (TestMethod D 4903), soluble solids and insolubles (Test MethodD 6402), non-tannins and tannin (Test Method D 6401), andtotal acidity (Test Method D 6410).5. Significance and Use5.1 This test method is used to determine
10、 the chemicalproperties of tannery liquors which are relevant for thevegetable tanning process and influence the astringency ofvegetable tanning liquors. The astringency of liquors is depen-dent upon the solids and tannin content and the acidity. Thismethod provides a standard procedure for determin
11、ing theseproperties for any sample of vegetable tanning liquor.5.2 The specimens are aliquots from the analytical solutionprepared from the sample of tannery liquor collected for thispurpose.5.3 The total solids, soluble solids, and non-tannins contentare determined and then the tannin content of th
12、e liquor sampleis calculated. Because the amount of tannin per liter ofanalytical solution is less than that required for Test MethodD 6401, a table specifying the quantity of prepared hidepowder to be used for solutions with lower tannin concentra-tions is included in this test method.5.4 The total
13、 acidity of the liquor sample is determined byone of two titrametric procedures described in Test MethodD 6410.5.5 The results of this test method are dependent on a greatmany variables but particularly upon: the temperature condi-tions under which the solutions were prepared and stored andthe tempe
14、rature at which the current analysis is performed; theuniformity and consistency of the Kaolin paste layer deposited1This test method is under the jurisdiction of ASTM Committee D31 on Leatherand is the direct responsibility of Subcommittee D31.01 on Vegetable Leather . Thistest method has been adap
15、ted from and is a replacement for Method A25 of theOfficial Methods of the American Leather Chemists Association.Current edition approved April 1, 2004. Published May 2004. Originallyapproved in 1999. Last previous edition approved in 1999 as D 6408 99.2For referenced ASTM standards, visit the ASTM
16、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.3Official Methods of the American Leather Chemists Association. Availablefrom the American Leather Chemists
17、Association, University of Cincinnati, P.O.Box 210014, Cincinnati, OH 45221-0014.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.onto the filter paper; the rate of solution run-out from thepipette; conditions related to the propertie
18、s of the hide powderused to react with the tannin content of the solution; etc. It is,therefore, essential that the method be followed exactly inorder to obtain reproducible results both among specimenswithin a laboratory and for analyses between laboratories.6. Apparatus and Reagents6.1 Analytical
19、Solution:6.1.1 Flask, 1 L volumetric. ClassAflasks with a bulb in theneck (M.C.A. type) are especially suitable for this work.6.1.2 Hydrometer, preferably with a Barkometer scale (i.e. ascale calibrated in Bk). The three digits to the right of thedecimal point on a standard specific gravity reading
20、are equalto the Barkometer scale reading. That is, a sp.gr. of 1.200equals 200Bk and a sp.gr. of 1.020 equals 20Bk.6.2 Acidity DeterminationMethod 1:6.2.1 Graduated Cylinder, glass-stoppered, graduated tocontain 250 mL.6.2.2 Gelatin Solution, 1 %, neutral to bromocresol purple.The addition of 25 mL
21、of 95 % ethyl alcohol per litre isrecommended to prevent frothing. The solution shall be ad-justed to neutrality to bromocresol purple with 0.1 N aceticacid or 0.1 N sodium hydroxide.6.2.3 Kaolin4, acid-washed kaolin clay which conforms tothe following specifications:6.2.3.1 Suspend 1.0 g kaolin in
22、100 mL distilled water. ThepH value should be between 4.5 and 6.0 after 5 min.6.2.3.2 Amixture of 2.0 g kaolin and 200 mL distilled waterare shaken for 10 min and the mixture filtered through thestandard filter paper (see 6.5). A 100 mL aliquot of the clearfiltrate should have less than 0.001 g of r
23、esidue after evapora-tion and oven-drying in a platinum dish.6.2.4 Alkaline Titrant, 0.1 N sodium hydroxide solution.6.3 Acidity DeterminationMethod 2:6.3.1 Pipet, transfer pipette with 6 mL capacity.6.3.2 pH Meter, with glass/calomel electrodes.6.3.3 Alkaline Titrant, 0.1 N sodium hydroxide solutio
24、n.7. Test Specimen7.1 The specimens for the tannin determination shall consistof 100 mL aliquots of the analytical solution prepared from thetannery liquor sample or the filtrates collected for particularmethods.7.2 The specimen for determination of acidity shall be eithera 25 mL aliquot (for titrat
25、ion - Method 1) or a 6.0 mL aliquot(for titration - Method 2) from the analytical solution preparedfrom the tannery liquor sample.8. Procedure8.1 Preparation of the Analytical Solution:8.1.1 Collect the tannery liquor sample as described inPractice D 6404 (11.10).8.1.2 Prepare the analytical solutio
26、n for this analysis bydiluting a specimen aliquot from the tannery liquor sample tothe mark ina1Lvolumetric flask with distilled water. Thealiquot specimen shall be of such size that, after dilution theanalytical solution shall contain as nearly as possible 7.0 g totalsolids per litre. Follow the ab
27、ove procedure except where suchdilution would give more than 3.5 g tannin per litre. In this caseselect the aliquot specimen size such that after dilution theanalytical solution shall contain as nearly as possible, but notexceed, 3.5 g tannin per litre, irrespective of the solids content.8.1.3 Dilut
28、ion Procedure:8.1.3.1 When the liquor sample has a specific gravity of65Bk (that is, sp.gr. $ 1.065) or more, dilute the aliquotspecimen with water at 40C, and cool as in Practice D 4904.8.1.3.2 When the liquor sample has a specific gravity of lessthan 65Bk (that is, sp.gr. 1.065), dilute the aliquo
29、t specimenwith water at 23C.8.2 Analytical Procedures:8.2.1 Determine total solids as in Test Method D 4903.8.2.2 Determine soluble solids and insolubles as in TestMethod D 6402.8.2.3 Determine non-tannins and tannin as in Test MethodD 6401, except adjust the quantity of prepared hide powderused (pe
30、r Test Method D 6401) according to Table 1.8.2.4 In the calculation for the (%) non-tannins (TestMethod D 6401), calculate the factor F in the formula accord-ing to the weight of water contained in the actual amount ofhide powder used for each specimen.8.2.5 Determine the total acidity as in Test Me
31、thod D 6410.9. Calculation9.1 Calculate the results of the analyses as directed in eachof the referenced test methods.10. Report10.1 Record the following information:10.1.1 Tannin analysis results to the nearest 0.01 %, and10.1.2 Total acidity to the nearest 0.1 % acetic acid.11. Precision and Bias1
32、1.1 This test method is adopted from Method A25 of TheOfficial Methods of the ALCA. This test method has long beenin use and was approved for publication before the inclusion ofprecision and bias statements were mandated. The originalinter-laboratory test data is no longer available. The user iscaut
33、ioned to verify by the use of reference materials, ifavailable, that the precision and bias (or reproducibility) of thisstandard practice is adequate for the contemplated use.4The sole source of supply of Kaolin known to the committee at this time is L.H. Lincoln tannery liquor; tanning liquor; tann
34、ins; tanninanalysis; vegetable tannin analysisASTM 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, a
35、nd 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 for revis
36、ion 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 hearing you s
37、houldmake 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).D 6408 99 (2004)3
