ASTM E359 Standard Test Methods for Analysis of Soda Ash (Sodium Carbonate)

Get Certified ASTM E359 Testing for Reliable Soda Ash Composition Verification 

Certification confirms that commercial soda ash meets the requirements of the ASTM E359 test, in terms of total alkalinity, bicarbonate content, and impurity levels within specification limits. ASTM E359 certified testing evaluates the chemical composition of a soda ash batch before manufacturers use it in glass, chemical, or detergent manufacturing applications. Testing and certification assure compliance with ASTM E359 requirements and minimize the potential for composition-related manufacturing defects. 

ASTM E359 is primarily used to determine the chemical composition and purity of commercial soda ash to establish specification acceptance and manufacturing control. These test methods are applied in industry for quality control, supplier verification, and monitoring of the manufacturing process.

The scope of ASTM E359 includes 

• Material type: Commercial soda ash (sodium carbonate) (dense and light grade). 
• Purpose: Assessment of soda ash composition and purity. 
• Properties measured: Total alkalinity, sodium bicarbonate, loss on heating, moisture, sodium chloride, sodium sulfate, iron, and particle size distribution. 
• Testing Method: Technicians use titrimetric methods for alkalinity and chloride, gravimetric methods for loss on heating and sulfate, and sieve analysis for particle size. 
• Result: Total alkalinity is expressed in percent sodium oxide (Na₂O); the detection limits for chloride and sulfate are 0.005%. 
• Test Limitations: All materials used must be reagent-grade chemicals, and each analytical section has its own distinct hazards. 
• Environmental conditions: Reagent purity, titration endpoint accuracy, and sample handling affect the measured composition results. 
• Applications: Quality Control in Glass Manufacturing, Chemical Production Verification, Detergent Manufacturing, and Soda Ash Specification Acceptance Testing. 

What are the Uses of ASTM E359 Testing?

ASTM E359 testing helps manufacturers characterize commercial soda ash based on a number of analytical parameters. Quality control teams use these results to ensure compliance with the specifications and to check the consistency of production. This standard-

• Determines the total alkalinity of soda ash by titration.
• Makes artificial conversion of bicarbonates to carbonates by adding excess standard sodium hydroxide (NaOH) for quantification.
• Determines loss on heating and moisture content gravimetrically and by calculation.
• Detects trace chloride and sulfate impurities as low as 0.005%.
• Helps to measure the iron content by doing a photometric analysis.
• Helps with size verification of particles by sieving
• Helps with specification acceptance and manufacturing control decisions. 

What Materials Can Be Tested Under ASTM E359? 

ASTM E359 is applicable to commercial soda ash (sodium carbonate) dense grade and light grade. Sodium carbonate (soda ash) is commonly used to make glass, chemicals, and detergents. Analysts choose the reagent-grade chemicals to use for each test contained in the standard, and they prepare the samples following the procedure used by each analytical section.

Why is ASTM E359 Important? 

ASTM E359 is important as it provides a set of analytical procedures, standardized for commercial soda ash, which manufacturers utilize in specification acceptance and during manufacturing control. Laboratories use these test methods in quality control to verify the purity and composition of soda ash for its use downstream. 

ASTM E359 Testing Process and Data Collection

Testing starts when the technician dissolves the soda ash sample in water and chooses reagent-grade chemicals to use for the evaluated analytical portion. For Total alkalinity, the technician titrates the sample with standard Hydrochloric or sulphuric acid and records the volume of acid used and the temperature to the nearest degree with a methyl orange indicator. In the case of sodium bicarbonate, the technician is titrating a separate sample that is treated with excess standard sodium hydroxide to ensure that all the bicarbonates are converted to carbonates. The technician then follows gravimetric procedures for loss on heating and sulfate content, and sieve analysis to check the particle size distribution. Lastly, the analyst determines each result with this formula, as it is given in the corresponding section, and adjusts the quantity of acid used to compensate for any deviation from the standard. 

Common Challenges and Troubleshooting

The endpoint of a titration is often inaccurate because of reagent impurities; reagent-grade chemicals are required in each section of the analytical scope of the standard. Inconsistent titration endpoint detection also results in error, especially if technicians use visual color change indicators, such as methyl orange. If technicians don’t sample carefully across the surface area, sample segregation during handling of boxcar shipments yields unrepresentative results. Laboratories solve these problems by using reagent-grade chemicals, training the technicians to detect the endpoint, and ensuring that the proper technique is used to sample the product without segregation. 

• The laboratory reports total alkalinity as a percentage of sodium oxide (Na₂O) based on the titration volume and the normality of the acid.
• The technician determines the grade of soda ash tested (dense or light)
• The analyst notes the sodium bicarbonate, chloride, sulfate, and iron levels obtained under the conditions outlined in each section of the procedure and compares the results to the tested batch.
• The chemist considers reagent purity, endpoint accuracy, and sampling technique when interpreting composition results.
• The manufacturer uses the measured composition values for the acceptance and control of the specification. 

Link to ASTM E359