ASTM E291-2018 苛性钠和苛性钾（氢氧化钠和氢氧化钾）化学分析试验方法 Standard Test Methods for Chemical Analysis of Caustic Soda and Caustic Potash (Sodium Hydroxide and Potassium Hydroxide)

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) 3 to 4 Carbonate, Gas-Volumetric (0.001 g CO2, min) 4 to 7 Carbonate, Gravimetric (0.001 g CO2, min) 7 to 10 Chloride, Titrimetric, (0.001 g Cl−, min) 10 to 11 Chloride, Potentiometric Titration (0.3 to 1.2 %) 11 to 12 Chloride, Ion Selective Electrode (0.6 to 120 μg/g) 12 to 13 Iron, Photometric (0.005 mg Fe, min) 13 to 15 Sulfate, Gravimetric, (0.002 g SO3, min) 15 to 16 Keywords 16 1.3 Units—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 In determining the conformance of the test results using this method to applicable specifications, results shall be rounded off in accordance with the rounding-off method of Practice E29. 1.5 Review the current Safety Data Sheet (SDS) for detailed information concerning toxicity, first-aid procedures, handling, 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 responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of 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 sta