ImageVerifierCode 换一换
格式:PDF , 页数:2 ,大小:58.28KB ,
资源ID:515758      下载积分:10000 积分
快捷下载
登录下载
邮箱/手机:
温馨提示:
如需开发票,请勿充值!快捷下载时,用户名和密码都是您填写的邮箱或者手机号,方便查询和重复下载(系统自动生成)。
如填写123,账号就是123,密码也是123。
特别说明:
请自助下载,系统不会自动发送文件的哦; 如果您已付费,想二次下载,请登录后访问:我的下载记录
支付方式: 支付宝扫码支付 微信扫码支付   
注意:如需开发票,请勿充值!
验证码:   换一换

加入VIP,免费下载
 

温馨提示:由于个人手机设置不同,如果发现不能下载,请复制以下地址【http://www.mydoc123.com/d-515758.html】到电脑端继续下载(重复下载不扣费)。

已注册用户请登录:
账号:
密码:
验证码:   换一换
  忘记密码?
三方登录: 微信登录  

下载须知

1: 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。
2: 试题试卷类文档,如果标题没有明确说明有答案则都视为没有答案,请知晓。
3: 文件的所有权益归上传用户所有。
4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
5. 本站仅提供交流平台,并不能对任何下载内容负责。
6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。

版权提示 | 免责声明

本文(ASTM D3898-1993(2015) Standard Test Method for Chromic Oxide in Basic Chromium Tanning Liquors《鞣皮液体碱性铬中氧化铬的标准试验方法》.pdf)为本站会员(medalangle361)主动上传,麦多课文库仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对上载内容本身不做任何修改或编辑。 若此文所含内容侵犯了您的版权或隐私,请立即通知麦多课文库(发送邮件至master@mydoc123.com或直接QQ联系客服),我们立即给予删除!

ASTM D3898-1993(2015) Standard Test Method for Chromic Oxide in Basic Chromium Tanning Liquors《鞣皮液体碱性铬中氧化铬的标准试验方法》.pdf

1、Designation: D3898 93 (Reapproved 2015)Standard Test Method forChromic Oxide in Basic Chromium Tanning Liquors1This standard is issued under the fixed designation D3898; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of l

2、ast 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 This test method covers the determination of chromicoxide in chrome tanning liquors, either simple, with addedaluminum

3、or zirconium, or with the usual masking complexingagents.1.2 The values stated in SI units are to be 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 theresp

4、onsibility 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:2D2807 Test Method for Chromic Oxide in Leather (Perchlo-ric Acid Oxidation)3. Summary of Te

5、st Method3.1 The solution is oxidized with sodium peroxide until thechromium is completely converted to the chromate ion. Thesolution is boiled to complete oxidation of organic materialsand to destroy excess peroxide; it is then cooled and acidified.Potassium iodide is added and the liberated iodine

6、 is titratedwith standardized sodium thiosulfate.4. Significance and Use4.1 The procedure described is for the quality control formanufacturing liquors and specifications for the purchase ofsuch liquors.4.2 The chromium content of the liquors determines theamount to be used to obtain the desired deg

7、ree of tannage, andhence may be a matter for specification in the purchase ofleather.5. Interferences5.1 The test method is generally the most accurate andconvenient for the purpose. However, if the liquor containsiron or copper, which interfere with the sodium thiosulfatetitration, or complex organ

8、ic or inorganic reducing agents(sodium thiosulfate, for example) which are not oxidized byalkaline peroxide but reduce hexavalent chromium onacidification, an alternate procedure must be used. The per-chloric acid method described in Test Method D2807, using theferrous sulfate titration, is suitable

9、, although the results ob-tained may be one to two percent low.6. Reagents and Materials6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of

10、 The American Chemical Society,where such specifications are available.3Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.6.2 Purity of WaterUnless otherwise indicated, referen

11、ceto water shall be understood to mean distilled water or water ofequal purity.6.3 Sodium Peroxide, (Na2O2). Store in original metal can.6.4 Starch Indicator,1%Make a paste of1gofsolublestarch in about 10 mL of water, add 90 mL water and boil for1 min with stirring. Cool and add 1 drop of chloroform

12、. Thesolution is subject to decomposition and should be renewed ifa deep blue color is not obtained on addition of 1 drop ofindicator to a solution of 1 drop tincture of iodine in 100 mLof water.1This test method is under the jurisdiction of ASTM Committee D31 on Leatherand is the direct responsibil

13、ity of Subcommittee D31.06 on Chemical Analysis Thistest method was developed in cooperation with the American Leather ChemistsAssoc.Current edition approved Sept. 1, 2015. Published October 2015. Originallyapproved in 1991. Last previous edition approved in 2009 as D3898 93 (2009).DOI: 10.1520/D389

14、8-93R15.2For referenced 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.3Reagent Chemicals, American Chemical Society Specifi

15、cations , AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmaceutical Conven

16、tion, Inc. (USPC), Rockville,MD.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States16.5 Sodium Thiosulfate Solution , 0.1 NDissolve 24.85 gof Na2S2O35 H2O in water, add1gNa2CO3, and dilute to 1 L.6.5.1 StandardizationDry potassium dichrom

17、ate(K2Cr2O7) in an oven at 130C for 2 h and cool in a desiccator.Weigh into a glass stoppered Erlenmeyer flask (500 mL) about0.2 g of potassium dichromate to an accuracy of 0.1 mg.Dissolve in 250 mL water, add 15 mL 1:4 hydrochloric acid, 20mL of 10 % potassium iodide solution, stopper the flask and

18、allow to stand 5 min in the dark. Titrate with the sodiumthiosulfate to be standardized. When the color of the solutionhas faded to a brownish-green, add 2 mL of 1 % starch solutionand continue titrating until the deep blue color changes to aclear green. Record the titration.normality of sodium thio

19、sulfate 5weight potassium dichromate0.04903 3mL titration(1)The thiosulfate solution is quite stable but should be restan-dardized at least once a month.6.6 Potassium Dichromate, K2Cr2O7, Primary StandardGrade.6.7 Potassium Iodide, 10 %. Dissolve 10 g KI in 100 mLwater.6.8 Hydrochloric Acid, 1:4. Di

20、lute 250 mL concentratedhydrochloric acid (sp gr 1.19) to 1 L with water.7. Procedure7.1 Weigh the liquor to the nearest milligram before dilu-tion. The specimen shall consist of a weighed quantity of theliquor diluted to a definite volume containing from 0.003 to0.004 g of Cr2O3per millilitre. Tran

21、sfer a 25 mL aliquot to a500 mL Erlenmeyer flask and dilute to approximately 250 mL.Add sodium peroxide, about1gatatime, with swirling, untilall green color or green precipitate has disappeared, and thesolution becomes a clear yellow. (The presence of a whitepercipitate is of no consequence.) Add a

22、few boiling granulesor glass beads and boil gently for at least 30 min to destroyperoxide. Cool, dilute to 250 mL, and add 1:4 hydrochloricacid until the yellow color changes to orange. Add an addi-tional 25 mL of 1:4 hydrochloric acid, 20 mL of potassiumiodide solution and stopper the flask.Allow t

23、o stand in the darkfor 5 min. Titrate with 0.1 N sodium thiosulfate standardized asdescribed in 6.4.1. When the color of the solution has faded toa brownish-green, add 2 mL of 1 % starch solution andcontinue the titration until the deep blue color changes to aclear green. Record the titration. Calcu

24、late results as describedin Section 8.8. Calculation8.1 Calculate the chromic oxide in the liquor as follows:Cr2O3,%5A 3 N 30.02533W3V253100 (2)where:A = the number of millilitres of standard thiosulfate (orferrous sulfate) required to titrate the 25 mL aliquot ofthe specimen,N = the normality of th

25、e thiosulfate (or ferrous sulfate)solution,W = the weight of the specimen before dilution, g, andV = the volume to which W was diluted, mL.8.2 Unless otherwise specified, test two 25 mL aliquotsfrom the diluted specimen.8.3 The chromic oxide in the sample for the test shall be theaverage of the test

26、 results obtained from the two aliquotstested.8.4 Record the chromic oxide in the sample to the nearest0.1 %.9. Precision and Bias9.1 Precision:9.1.1 Repeatability on triplicate runs by four laboratories onfour samples shows an estimated deviation of 0.17 % of thechromium present.9.1.2 Reproducibili

27、ty between laboratories on the samefactorial experiment shows an estimated standard deviationamounting to 0.9 % of the chromium present.9.2 Bias:9.2.1 The average result of the factorial experiment aboveshows a bias of +0.07 % of the chromium present and, henceon the average, the test method does no

28、t yield biased results.9.2.2 On the four samples studied, the standard deviationdue to variation in composition was 0.35 % of the chromiumpresent.10. Keywords10.1 basic chromium tanning liquors; chrome oxideASTM International takes no position respecting the validity of any patent rights asserted in

29、 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, are entirely their own responsibility.This standard is subject to revision at any time by the re

30、sponsible 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 standardsand should be addressed to ASTM International Headquarters. Your comments will receive care

31、ful 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 Committee on Standards, at the address shown below.This standard is copyrighted by ASTM Internationa

32、l, 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). 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:/ 93 (2015)2

copyright@ 2008-2019 麦多课文库(www.mydoc123.com)网站版权所有
备案/许可证编号:苏ICP备17064731号-1