1、Designation: E291 09E291 18Standard Test Methods forChemical Analysis of Caustic Soda and Caustic Potash(Sodium Hydroxide and Potassium Hydroxide)1This standard is issued under the fixed designation E291; the number immediately following the designation indicates the year oforiginal adoption or, in
2、the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope*1
3、.1 These test methods cover only the analyses usually required on the following commercial products:1.1.1 Caustic soda (sodium hydroxide), 50 and 73 % liquors; anhydrous (solid, flake, ground, or powdered), and1.1.2 Caustic potash (potassium hydroxide), 45 % liquor; anhydrous (solid, flake, ground,
4、or powdered).1.2 The analytical procedures appear in the following order:Alkalinity (Total), Titrimetric (for 50 to 100 %NaOH and 45 to 100 % KOH)8 to 14Carbonate, Gas-Volumetric (0.001 g CO2, min) 15 to 24Carbonate, Gravimetric (0.001 g CO2, min) 25 to 33Chloride, Titrimetric, (0.001 g Cl, min) 34
5、to 40Chloride, Potentiometric Titration (0.3 to 1.2 %) 41 to 47Chloride, Ion Selective Electrode (0.6 to 120 g/g) 48 to 55Iron, Photometric (0.005 mg Fe, min) 56 to 64Sulfate, Gravimetric, (0.002 g SO3, min) 65 to 71Keywords 74Alkalinity (Total), Titrimetric (for 50 to 100 %NaOH and 45 to 100 % KOH)
6、3 to 4Carbonate, Gas-Volumetric (0.001 g CO2, min) 4 to 7Carbonate, Gravimetric (0.001 g CO2, min) 7 to 10Chloride, Titrimetric, (0.001 g Cl, min) 10 to 11Chloride, Potentiometric Titration (0.3 to 1.2 %) 11 to 12Chloride, Ion Selective Electrode (0.6 to 120 g/g) 12 to 13Iron, Photometric (0.005 mg
7、Fe, min) 13 to 15Sulfate, Gravimetric, (0.002 g SO3, min) 15 to 16Keywords 161.3 UnitsThe values stated in SI units are to be regarded as standard. No other units of measurement are included in thisstandard with the exception of inch-pound units for apparatus descriptions.1.4 In determining the conf
8、ormance of the test results using this method to applicable specifications, results shall be roundedoff in accordance with the rounding-off method of Practice E29.1.5 Review the current Material Safety Data Sheet (MSDS)(SDS) for detailed information concerning toxicity, first-aidprocedures, handling
9、, and safety precautions.1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine theapplicability of
10、 regulatory limitations prior to use. Specific hazard statements are given in Section 6.1.7 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, G
11、uides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.1 These test methods are under the jurisdiction of ASTM Committee D16 on Aromatic Hydrocarbons Aromatic, Industrial, Specialty and Related Chemicals and are thedirect responsibility of Subcomm
12、ittee D16.15 on Industrial and Specialty General Standards.Current edition approved April 1, 2009Jan. 1, 2018. Published April 2009May 2018. Originally approved in 1965. Last previous edition approved in 20042009 asE291 04.E291 09. DOI: 10.1520/E0291-09.10.1520/E0291-18.This document is not an ASTM
13、standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all
14、cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States12. Reference
15、d Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD6809 Guide for Quality Control and Quality Assurance Procedures for Aromatic Hydrocarbons and Related MaterialsE29 Practice for Using Significant Digits in Test Data to Determine Conformance with SpecificationsE60 Practice for Anal
16、ysis of Metals, Ores, and Related Materials by SpectrophotometryE180 Practice for Determining the Precision of ASTM Methods for Analysis and Testing of Industrial and Specialty Chemicals(Withdrawn 2009)3E200 Practice for Preparation, Standardization, and Storage of Standard and Reagent Solutions for
17、 Chemical AnalysisE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method2.2 Other Document:OSHA Regulations, 29 CFR paragraphs 1910.1000 and 1910.120043. Significance and Use3.1 Caustic soda and caustic potash are used in a large number of manufacturing pro
18、cesses. The chemicals are available inseveral grades depending on their intended use. The test methods listed in 1.2 provide procedures for analyzing caustic soda andcaustic potash to determine if they are suitable for their intended use.4. Apparatus4.1 Photometers and Photometric PracticePhotometer
19、s and photometric practice used in these test methods shall conform toPractice E60.5. Reagents5.1 Purity of ReagentsReagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that allreagents shall conform to the specifications of the Committee on Analytical Reage
20、nts of the American Chemical Society, wheresuch specifications are available.5 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently highpurity to permit its use without lessening the accuracy of the determination.5.2 Purity of WaterUnless otherwise indicated
21、, references to water shall be understood to mean Type II or Type III reagentwater conforming to Specification D1193.6. Hazards6.1 Sodium and potassium hydroxides are caustic alkalies which, in their anhydrous or strong solution form, are hazardousmaterials. In contact with the skin they produce bur
22、ns which may be quite serious unless promptly treated. Their action is insidioussince they produce no immediate stinging or burning sensation and damage may result before their presence is realized.6.2 Eyes are particularly vulnerable to severe damage from these alkalies.6.3 Laboratory workers handl
23、ing these alkalies should use safety goggles or face shields and rubber gloves and avoid spillageon clothing. These materials rapidly attack wool and leather.6.4 Spilled caustic should be flushed away with water where possible, or covered with absorbent material (such as sawdust,vermiculite, or baki
24、ng soda) and swept up and discarded in accordance with all applicable federal, state, and local health andenvironmental regulations. Last traces may be neutralized with dilute acetic acid and the area washed with water.6.5 Perchloric acid is toxic, corrosive, and a strong oxidizer. Laboratory worker
25、s handling this acid should use safety gogglesor face shields and rubber gloves.7. Sampling7.1 GeneralThe nature of the caustic alkalies is such as to require special care at all points of sampling and preparation foranalysis. The following information is included in order that representative sample
26、s may be ensured. Additional precautions maybe necessary if trace constituents, not covered in these test methods, are to be determined. Instructions for such procedures maybe obtained from the publications of most major producers. Sampling techniques must be such as to limit or prevent atmospherice
27、xposure since sodium and potassium hydroxides, both as aqueous solutions and as anhydrous products, rapidly absorb moisture2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, ref
28、er to the standards Document Summary page on the ASTM website.3 The last approved version of this historical standard is referenced on www.astm.org.4 Available from U.S. Government Printing Office, Superintendent of Documents, 732 N. Capitol St., NW, Washington, DC 20401-0001, http:/www.access.gpo.g
29、ov.5 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed bythe American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Phar
30、macopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.E291 182and carbon dioxide (and other acid gases) from the atmosphere. The aqueous solutions are corrosive and sampling devices andsample containers must be selected to avoid contamination with any constituent
31、later to be determined. Strong aqueous solutionsof these alkalies are available commercially under the names liquid caustic soda and liquid caustic potash. Liquid caustic potashat a concentration of 45 % remains liquid at temperatures down to 29C, and freezing or crystallization will only be encount
32、eredunder severe cold weather. Caustic soda liquors are usually shipped in insulated tank cars at elevated temperatures, and minimumtemperatures must be maintained if unloading and sampling problems are to be avoided. Viscosity increases near the freezing pointand creates pumping problems. Even part
33、ial freezing changes the composition of the remaining liquor and causes sampling andanalysis problems. Be sure contents are completely liquid and well mixed before sampling. The following minimum temperaturesshould be maintained for proper sampling of bulk shipments:50 % NaOH liquor 20C53 % NaOH liq
34、uor 30C70 to 73 % NaOH liquor 71C7.2 Sample ContainersThe choice of container construction material is important for caustic liquor samples, especially forthose to be taken or held at elevated temperatures. Glass can be used except where silica is to be determined. Polyethylene orpolypropylene conta
35、iners which have high-temperature properties may also be used. Nickel is the best practical metal for a metallicsample container for caustic liquors. For the analysis of 73 % caustic soda, the entire sample should be in the liquid state beforeremoving any portion, and such portions must then be used
36、 in their entirety to avoid the factor of segregation on freezing. Causticsoda of 73 % concentration may also be “cast” into glass or plastic bottles or tubes, or nickel or silver metallic molds. The moldsare later removed and the samples chipped or crushed for analysis. If this is done, the factors
37、 of segregation on freezing andatmospheric exposure while crushing must be borne in mind.7.3 Sampling Devices and Techniques:7.3.1 Liquid CausticSimple “dipper” or “tap” samples from large quantity shipments or tanks of caustic liquor are inadequatefor purchaser and vendor purposes. Numerous special
38、ly designed devices are available to procure samples from various levels intanks. A useful type of such samplers for small tanks has three or five containers mounted on a single rod so that when the deviceis lowered into a tank and the stoppers are pulled, samples are simultaneously taken at the dif
39、ferent levels. These are then combinedto provide a representative average sample. Shipments should be sampled at least at the upper, middle, and lower thirds. Samplesshould never be taken at the surface of the liquid. If it is not necessary to analyze the liquor before unloading, sampling may beacco
40、mplished by a “continuous drip” from a small tap-off with the regulating valve in a vertical section of the unloading line. The“drip” is so timed as to collect the desired amount of sample uniformly during the time of unloading.7.3.2 Anhydrous Products:7.3.2.1 Commercial anhydrous caustic soda or ca
41、ustic potash is packaged in drums in solid, flake, ground, or powdered forms.Sampling and handling of these materials must be done with minimum atmospheric exposure.7.3.2.2 In the case of flake, ground, or powdered sodium or potassium hydroxides, the top 75 or 100 mm of material in a drumshould firs
42、t be removed and a sample then taken from the center part of the drum. The sample should be placed immediately ina suitable wide-mouth container then closed and sealed with taps or wax.7.3.2.3 Solid caustic shall be packaged by filling metal drums with molten anhydrous product and allowing drums and
43、 contentsto cool before sealing air tight. On cooling and solidifying, impurities present in the caustic tend to segregate and concentrate inthe bottom section. To sample such material properly, the metal drum must be opened at the vertical seam and removed. The solidcake may then be sampled either
44、by drilling at representative levels with a 19-mm auger bit (may cause metal contamination) orby splitting the cake in half vertically with hammer and chisel and chiseling off representative small fragments so that the totalsample represents a vertical cross section through the cake. In either case,
45、 the sample shall be promptly bottled and sealed in awide-mouth container. In the laboratory, the lumps shall be reduced to convenient size by enclosing in several thicknesses of cleancloth or kraft paper and pounding with a hammer. The crushed material shall be bottled and thoroughly mixed before a
46、nalysis.TOTAL ALKALINITY8. Scope8.1 This test method covers the determination of the total alkalinity of 50 and 73 % liquid caustic soda, 45 % liquid causticpotash, and anhydrous caustic soda and caustic potash.8. Scope8.1 This test method covers the determination of the total alkalinity of 50 and 7
47、3 % liquid caustic soda, 45 % liquid causticpotash, and anhydrous caustic soda and caustic potash.9. Summary of Test Method9.1 Total alkalinity is determined by titration with standard hydrochloric acid solution using methyl orange indicator solutionor modified methyl orange indicator solution.E291
48、18310. Reagents10.1 Hydrochloric (or Sulfuric Acid), Special(1.0 meq/mL)Prepare in accordance with Practice E200.10.2 Methyl Orange Indicator SolutionSee Practice E200.10.3 Modified Methyl Orange Indicator SolutionSee Practice E200.10.4 Water, Distilled, carbon dioxide-free (freshly boiled and coole
49、d).11. Procedure11.1 Transfer to a tared, covered weighing bottle a sample of such size as determined from Table 1.11.2 Weigh the sample to the nearest 1 mg and transfer it to a 1-L volumetric flask using several rinses of water to remove alltraces of caustic from the weighing bottle. Dilute the solution to about 400 mL with water and cool to room temperature. Aftercooling, dilute to 1 L and mix thoroughly.11.3 With a volumetric pipet, transfer 50 mL (see Note 1) of the prepared solution to a 500-mL Erlenmeyer flask and add 2 to4 drops of modified methyl or
