Meaning and use

4.1 Mercury is a toxic substance and is also harmful if present in caustic soda and caustic potassium used in some manufacturing processes. It therefore needs to be controlled as a possible pollutant. These test methods provide a way to measure mercury content of caustic soda and caustic potassium in liquids and solids.

ASTM E538-2017 Standard Test Method for Mercury in Caustic Soda (Sodium Hydroxide) and Caustic Potassium (Potassium hydroxide)

Step 1: Scope

1.1 These test methods include routine determination of mercury and anhydrous caustic soda in solid, flake, ground and bead forms in caustic soda and caustic potassium solutions by flameless atomic absorption method.

1.2 The two test methods are described as follows: Test method A uses an alkaline reducing agent to analyze the sample directly, and the detection limit is 0.1ppb (ng/g). Test method A was developed using caustic soda and caustic potassium salts. Test method B, which requires pre-neutralization of the sample followed by permanganate oxidation followed by analysis with an acid reducing agent, has a lower detection limit of 0.01ppm (μg/ g). Test method B was developed using caustic soda.

1.3 Review the current Safety Data Sheet (SDS) for details on toxicity, first aid procedures and safety precautions.

1.4 Values expressed in SI units shall be regarded as standard values. No other units of measurement are included in this standard.

1.5 This standard is not intended to address all safety concerns (if any) associated with its use. It is the responsibility of users of this standard to establish appropriate safety and health practices and to determine the applicability of regulatory restrictions prior to use. Specific hazards are described in sections 7 and 18.

1.6 This international standard is based on internationally recognized standardization principles established in the “Decision on Principles for the Development of International Standards, Guidelines and Recommendations” issued by the WTO Committee on Technical Barriers to Trade (TBT).