1、Designation: D6408 99 (Reapproved 2014)Standard Test Method forAnalysis of Tannery Liquors1This standard is issued under the fixed designation D6408; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A numb
2、er in parentheses indicates the year of last reapproval. Asuperscript epsilon () 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 be
3、 regarded asstandard. No other units of measurement are included in thisstandard.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 de
4、termine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D4903 Test Method for Total Solids and Water in VegetableTanning Material ExtractsD4904 Practice for Cooling of Analytical SolutionsD6401 Test Method for Determining Non-Tannins and Tan-nin i
5、n Extracts of Vegetable Tanning MaterialsD6402 Test Method for Determining Soluble Solids andInsolubles in Extracts of Vegetable Tanning MaterialsD6404 Practice for Sampling Vegetable Materials Contain-ing TanninD6410 Test Method for Determining Acidity of VegetableTanning Liquors2.2 ALCA Methods:A2
6、5 Analysis of Tannery Liquors33. Terminology3.1 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. Als
7、o, quantitatively, tannins are operationally defined 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 D6402,and do react with or bind to hide powder when mixed as in thi
8、stest method.3.1.3 vegetable tanninsmixtures 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
9、 sample oftannery liquor (Practice D6404). Specimen aliquots from thisanalytical solution are then analyzed for total solids (TestMethod D4903), soluble solids and insolubles (Test MethodD6402), non-tannins and tannin (Test Method D6401), andtotal acidity (Test Method D6410).5. Significance and Use5
10、.1 This test method is used to determine 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 pr
11、ovides a standard procedure for determining 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 dete
12、rmined and then the tannin content of the liquor sampleis calculated. Because the amount of tannin per liter ofanalytical solution is less than that required for Test MethodD6401, a table specifying the quantity of prepared hide powderto be used for solutions with lower tannin concentrations isinclu
13、ded in this test method.1This test method is under the jurisdiction of ASTM Committee D31 on Leatherand is the direct responsibility of Subcommittee D31.01 . This test method has beenadapted from and is a replacement for Method A25 of the Official Methods of theAmerican Leather Chemists Association.
14、Current edition approved Nov. 1, 2014. Published December 2014. Originallyapproved in 1999. Last previous edition approved in 2009 as D6408 99 (2009).DOI: 10.1520/D6408-99R14.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For
15、 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 Association, University of Cincinnati, P.O.Box 210014, Cincinnati, OH 45221-00
16、14.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15.4 The total acidity of the liquor sample is determined byone of two titrametric procedures described in Test MethodD6410.5.5 The results of this test method are dependent on a great
17、many variables but particularly upon: the temperature condi-tions under which the solutions were prepared and stored andthe temperature at which the current analysis is performed; theuniformity and consistency of the Kaolin paste layer depositedonto the filter paper; the rate of solution run-out fro
18、m thepipette; conditions related to the properties 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 labo
19、ratories.6. Apparatus and Reagents6.1 Analytical 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 thedeci
20、mal point on a standard specific gravity reading 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 %, neu
21、tral to bromocresol purple.The addition of 25 mL 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 followin
22、g specifications:6.2.3.1 Suspend 1.0 g kaolin in 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). A100 mL aliquot of the
23、clearfiltrate should have less than 0.001 g of residue 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
24、Alkaline Titrant, 0.1 N sodium hydroxide solution.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 ac
25、idity shall be eithera 25 mL aliquot (for titration - 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 D64
26、04 (11.10).8.1.2 Prepare the analytical solution 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 poss
27、ible 7.0 g totalsolids per litre. Follow the above 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,
28、 irrespective of the solids content.8.1.3 Dilution 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 D4904.8.1.3.2 When the liquor sample has a specific gravity of lessthan 65B
29、k (that is, sp.gr. 1.065), dilute the aliquot specimenwith water at 23C.8.2 Analytical Procedures:8.2.1 Determine total solids as in Test Method D4903.8.2.2 Determine soluble solids and insolubles as in TestMethod D6402.8.2.3 Determine non-tannins and tannin as in Test MethodD6401, except adjust the
30、 quantity of prepared hide powderused (per Test Method D6401) according to Table 1.8.2.4 In the calculation for the (%) non-tannins (TestMethod D6401), calculate the factor F in the formula accordingto the weight of water contained in the actual amount of hidepowder used for each specimen.8.2.5 Dete
31、rmine the total acidity as in Test Method D6410.9. 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 %
32、 acetic acid.4The sole source of supply of Kaolin known to the committee at this time is L.H. Lincoln tannery liquor; tanning liquor; tannins; tanninanalysis; vegetable tannin analysisASTM International takes no position respecting the validity of any patent rights asserted in connection with any it
33、em 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, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical com
34、mittee 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 standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a
35、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 Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Driv
36、e, 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). 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:/ 99 (2014)3
