ASTM E291 - 09

    Standard Test Methods for Chemical Analysis of Caustic Soda and Caustic Potash (Sodium Hydroxide and Potassium Hydroxide)

    Active Standard ASTM E291 | Developed by Subcommittee: E15.01

    Book of Standards Volume: 15.05


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    Significance and Use

    Caustic soda and caustic potash are used in a large number of manufacturing processes. The chemicals are available in several grades depending on their intended use. The test methods listed in 1.2 provide procedures for analyzing caustic soda and caustic potash to determine if they are suitable for their intended use.

    1. Scope

    1.1 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), and

    1.1.2 Caustic potash (potassium hydroxide), 45 % liquor; anhydrous (solid, flake, ground, 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 14
    Carbonate, Gas-Volumetric (0.001 g CO2, min)15 to 24
    Carbonate, Gravimetric (0.001 g CO2, min)25 to 33
    Chloride, Titrimetric, (0.001 g Cl, min)34 to 40
    Chloride, Potentiometric Titration (0.3 to 1.2 %)41 to 47
    Chloride, Ion Selective Electrode (0.6 to 120 μg/g)48 to 55
    Iron, Photometric (0.005 mg Fe, min)56 to 64
    Sulfate, Gravimetric, (0.002 g SO3, min)65 to 71
    Keywords72

    1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard with the exception of inch-pound units for apparatus descriptions.

    1.4 Review the current Material Safety Data Sheet (MSDS) for detailed information concerning toxicity, first-aid procedures, handling, and safety precautions.

    1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific hazard statements are given in Section 6.

    8.1 This test method covers the determination of the total alkalinity of 50 and 73 % liquid caustic soda, 45 % liquid caustic potash, and anhydrous caustic soda and caustic potash.

    15.1 This test method describes the gas-volumetric determination of sodium carbonate or potassium carbonate in caustic soda or caustic potash respectively. The lower limit of determination is 0.001 g as carbon dioxide.

    25.1 This test method covers the gravimetric determination of carbonate in caustic soda or caustic potash. The lower limit of determination is 0.001 g as carbon dioxide.

    34.1 This test method covers the volumetric determination of chloride in caustic soda or caustic potash by the Volhard test method. The lower limit of determination is 0.001 g as chloride.

    41.1 This test method was developed for the analysis of chloride in caustic soda and caustic potash. It covers the potentiometric titration of 0.3 to 1.2 % of chloride in caustic soda and caustic potash. This test method may be applied to other concentrations by using equivalent sample weights.

    49.1 This test method was developed for the analysis of chloride in caustic soda and caustic potash. It covers the ion selective electrode determination of 1 to 120 μg/g chloride in caustic soda and caustic potash. This test method may be applied to other concentrations by using equivalent sample weights.

    58.1 This test method covers the photometric determination of iron in caustic soda or caustic potash. The lower limit of determination is 0.1 μg/g as iron.

    67.1 This test method covers the gravimetric determination of sulfate present in caustic soda or caustic potash. The lower limit of determination is 0.002 g.


    2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

    ASTM Standards

    D1193 Specification for Reagent Water

    E60 Practice for Analysis of Metals, Ores, and Related Materials by Spectrophotometry

    E180 Practice for Determining the Precision of ASTM Methods for Analysis and Testing of Industrial and Specialty Chemicals

    E200 Practice for Preparation, Standardization, and Storage of Standard and Reagent Solutions for Chemical Analysis


    ICS Code

    ICS Number Code 71.060.40 (Bases)

    UNSPSC Code

    UNSPSC Code 12352305(Inorganic hydroxides)


    Referencing This Standard

    DOI: 10.1520/E0291-09

    ASTM International is a member of CrossRef.

    Citation Format

    ASTM E291-09, Standard Test Methods for Chemical Analysis of Caustic Soda and Caustic Potash (Sodium Hydroxide and Potassium Hydroxide), ASTM International, West Conshohocken, PA, 2009, www.astm.org

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