ASTM E359-17

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

SIGNIFICANCE AND USE
3.1 Soda ash is used in a number of manufacturing processes. The procedures listed in 1.2 are suitable for specification acceptance and manufacturing control of commercial soda ash.
SCOPE
1.1 These test methods cover the analyses usually required on commercial soda ash (sodium carbonate).  
1.2 The analytical procedures appear in the following sections:    
Sections  
Total Alkalinity, Titrimetric  
8 – 15  
Sodium Bicarbonate, Titrimetric  
17 – 24  
Loss on Heating, Gravimetric  
26 – 32  
Moisture, Calculation  
34 – 38  
Sodium Chloride, Titrimetric  
40 – 46  
Sodium Sulfate, Gravimetric  
48 – 54  
Iron, Photometric  
56 – 64  
Sieve Analysis  
66 – 72  
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
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 Sheets (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 and health practices and determine the applicability of regulatory limitations prior to use. Specific hazards statements are given in Section 6.  
1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 14-Jun-2017
• ICS: 71.060.50 - Salts
• Technical Committee: D16 - Aromatic, Industrial, Specialty and Related Chemicals
• Drafting Committee: D16.12 - Caustics and Peroxides

Relations

• Replaces: ASTM E359-10 - Standard Test Methods for Analysis of Soda Ash (Sodium Carbonate)
• Effective Date: 15-Jun-2017
• Refers: ASTM E70-24 - Standard Test Method for pH of Aqueous Solutions With the Glass Electrode
• Effective Date: 01-Jan-2024
• Refers: ASTM E145-19 - Standard Specification for Gravity-Convection and Forced-Ventilation Ovens
• Effective Date: 01-Mar-2019
• Refers: ASTM D6809-02(2016) - Standard Guide for Quality Control and Quality Assurance Procedures for Aromatic Hydrocarbons and Related Materials
• Effective Date: 01-Nov-2016
• Refers: ASTM E70-07(2015) - Standard Test Method for pH of Aqueous Solutions With the Glass Electrode
• Effective Date: 01-Jun-2015
• Refers: ASTM E11-13 - Standard Specification for Woven Wire Test Sieve Cloth and Test Sieves
• Effective Date: 01-Oct-2013
• Refers: ASTM E145-94(2011) - Standard Specification for Gravity-Convection and Forced-Ventilation Ovens
• Effective Date: 01-Dec-2011
• Refers: ASTM C429-01(2011) - Standard Test Method for Sieve Analysis of Raw Materials for Glass Manufacture
• Effective Date: 01-Oct-2011
• Refers: ASTM E11-09e1 - Standard Specification for Woven Wire Test Sieve Cloth and Test Sieves
• Effective Date: 01-May-2009
• Refers: ASTM E29-08 - Standard Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
• Effective Date: 01-Oct-2008
• Refers: ASTM D6809-02(2007) - Standard Guide for Quality Control and Quality Assurance Procedures for Aromatic Hydrocarbons and Related Materials
• Effective Date: 01-Jun-2007
• Refers: ASTM E29-06b - Standard Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
• Effective Date: 15-Nov-2006
• Refers: ASTM E145-94(2006) - Standard Specification for Gravity-Convection And Forced-Ventilation Ovens
• Effective Date: 01-Nov-2006
• Refers: ASTM C429-01(2006) - Standard Test Method for Sieve Analysis of Raw Materials for Glass Manufacture
• Effective Date: 01-Oct-2006
• Refers: ASTM E29-06a - Standard Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
• Effective Date: 15-Sep-2006

Overview

ASTM E359-17, Standard Test Methods for Analysis of Soda Ash (Sodium Carbonate), is an internationally recognized standard developed by ASTM International. It specifies reliable analytical procedures for the quality control and specification acceptance of commercial soda ash (sodium carbonate). Soda ash is a critical industrial chemical used in glass manufacturing, chemicals production, detergents, water treatment, and other industrial processes. The methods outlined in this standard enable laboratories to routinely analyze key compositional and impurity parameters of soda ash, ensuring product consistency and regulatory compliance.

Key Topics

ASTM E359-17 covers the following essential test methods and parameters for soda ash analysis:

• Total Alkalinity (Titrimetric Analysis): Determines the overall alkali content, expressed as sodium oxide.
• Sodium Bicarbonate (Titrimetric Analysis): Measures the presence of sodium bicarbonate in the sample.
• Loss on Heating (Gravimetric Analysis): Quantifies the weight lost upon heating, indicating moisture and volatile content.
• Moisture Content (Calculation): Determines the moisture in soda ash by calculation based on loss on heating and sodium bicarbonate decomposition.
• Sodium Chloride (Titrimetric Analysis): Identifies chloride impurities through titration.
• Sodium Sulfate (Gravimetric Analysis): Measures sulfate impurities via gravimetric precipitation.
• Iron Content (Photometric Analysis): Determines trace iron levels using photometric methods.
• Sieve Analysis: Assesses particle size distribution to ensure product uniformity.

The standard strictly utilizes SI units and prescribes rounding practices according to ASTM E29. Laboratories are advised to implement rigorous quality control procedures and refer to Safety Data Sheets (SDS) for safe handling practices.

Applications

ASTM E359-17 plays a pivotal role in several industrial and regulatory applications involving soda ash:

• Manufacturing Quality Control: Ensures that commercial soda ash meets industry specifications for purity and composition, vital in glass production, detergent manufacturing, and other chemical processes.
• Specification Acceptance: Provides standardized methods for supplier and purchaser agreement on testing and acceptance criteria.
• Process Monitoring: Enables manufacturers to monitor and adjust processes, minimizing impurities such as sodium chloride, sodium sulfate, moisture, and iron, which can affect product quality.
• Regulatory Compliance: Assists organizations in meeting environmental and safety regulations by monitoring impurities in raw and finished products.
• R&D Laboratories: Facilitates accurate research and development by providing validated analytical methods for soda ash evaluation.

Adherence to ASTM E359-17 benefits quality assurance, cost control, and continuous improvement in industries reliant on soda ash.

Related Standards

ASTM E359-17 references and is supported by several related ASTM standards, including:

• ASTM E11: Specification for Woven Wire Test Sieve Cloth and Test Sieves (for sieve analysis)
• ASTM E29: Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
• ASTM E70: Test Method for pH of Aqueous Solutions With the Glass Electrode
• ASTM E145: Specification for Gravity-Convection and Forced-Ventilation Ovens
• ASTM E200: Practice for Preparation, Standardization, and Storage of Standard and Reagent Solutions for Chemical Analysis
• ASTM D1193: Specification for Reagent Water
• ASTM D6809: Guide for QA/QC Procedures for Aromatic Hydrocarbons and Related Materials

Compliance with ASTM E359-17 ensures confidence in soda ash analysis, supporting both producers and end-users with standardized, reproducible chemical testing protocols.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E359 − 17
Standard Test Methods for
Analysis of Soda Ash (Sodium Carbonate)
This standard is issued under the fixed designation E359; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript 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* 2. Referenced Documents
1.1 These test methods cover the analyses usually required 2.1 ASTM Standards:
on commercial soda ash (sodium carbonate). C429 Test Method for Sieve Analysis of Raw Materials for
Glass Manufacture
1.2 The analytical procedures appear in the following sec-
D1193 Specification for Reagent Water
tions:
D6809 Guide for Quality Control and Quality Assurance
Sections
Procedures for Aromatic Hydrocarbons and Related Ma-
Total Alkalinity, Titrimetric 8–15 terials
Sodium Bicarbonate, Titrimetric 17–24
E11 Specification for Woven Wire Test Sieve Cloth and Test
Loss on Heating, Gravimetric 26–32
Sieves
Moisture, Calculation 34–38
Sodium Chloride, Titrimetric 40–46 E29 Practice for Using Significant Digits in Test Data to
Sodium Sulfate, Gravimetric 48–54
Determine Conformance with Specifications
Iron, Photometric 56–64
E60 Practice for Analysis of Metals, Ores, and Related
Sieve Analysis 66–72
Materials by Spectrophotometry
1.3 The values stated in SI units are to be regarded as
E70 Test Method for pH of Aqueous Solutions With the
standard. No other units of measurement are included in this
Glass Electrode
standard.
E145 Specification for Gravity-Convection and Forced-
1.4 In determining the conformance of the test results using
Ventilation Ovens
this method to applicable specifications, results shall be
E180 Practice for Determining the Precision of ASTM
rounded off in accordance with the rounding-off method of
Methods for Analysis and Testing of Industrial and Spe-
Practice E29.
cialty Chemicals (Withdrawn 2009)
E200 Practice for Preparation, Standardization, and Storage
1.5 Review the current Safety Data Sheets (SDS) for de-
of Standard and Reagent Solutions for ChemicalAnalysis
tailed information concerning toxicity, first aid procedures,
E300 Practice for Sampling Industrial Chemicals
handling and safety precautions.
2.2 Other Documents:
1.6 This standard does not purport to address all of the
OSHA Regulations, 29 CFR paragraphs 19100.1000 and
safety concerns, if any, associated with its use. It is the
1910.1200
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
3. Significance and Use
mine the applicability of regulatory limitations prior to use.
Specific hazards statements are given in Section 6.
3.1 Soda ash is used in a number of manufacturing pro-
1.7 This international standard was developed in accor- cesses. The procedures listed in 1.2 are suitable for specifica-
dance with internationally recognized principles on standard-
tion acceptance and manufacturing control of commercial soda
ization established in the Decision on Principles for the ash.
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
These test methods are under the jurisdiction of ASTM Committee D16 on the ASTM website.
Aromatic, Industrial, Specialty and Related Chemicals and are the direct responsi- The last approved version of this historical standard is referenced on
bility of Subcommittee D16.12 on Caustics and Peroxides. www.astm.org.
Current edition approved June 15, 2017. Published August 2017. Originally Available from U.S. Government Printing Office, Superintendent of
approved in 1968. Last previous edition approved in 2010 as E359 – 10. DOI: Documents, 732 N. Capitol St., NW, Washington, DC 20401-0001, http://
10.1520/E0359-17. www.access.gpo.gov.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E359 − 17
4. Apparatus ity of dense ash in bulk to segregate in relation to particle size
as the result of normal transit vibrations.
4.1 Photometers and Photometric Practice—Photometers
7.2.3 Details of good sampling depend on: (1) the type of
and photometric practice used in these test methods shall
shipment, whether in containers or in bulk; (2) the type of
conform to Practice E60.
product, whether light or dense soda ash; and (3) the type of
4.2 pH Meters—pH meters and their use shall conform to
analysis desired, whether chemical or physical.
Test Method E70.
7.3 Bulk Shipments:
4.3 Buret—A calibrated 50-mL buret, or any standard
7.3.1 Although bulk shipments are normally in transit a
50-mL buret calibrated by either the National Institute of
Standards and Technology or by the user. Alternatively, a relatively short time, there is likely to be some absorption of
moisture and carbon dioxide in exposed surface areas. If
100-mL calibrated buret with a 50-mL bulb at the top and a
50-mL stem below may be used. physical tests such as screen analysis are to be included, it is
particularly important to avoid segregation that occurs on
5. Purity of Reagents and Water
surface areas.
7.3.2 To sample boxcar shipments, brush aside the surface
5.1 Purity of Reagents—Reagent grade chemicals shall be
used in all tests. Unless otherwise indicated, it is intended that layer to a depth of 12 in. (305 mm) and take portions
systematically from the newly exposed area to the bottom of
all reagents shall conform to the specifications of the Commit-
tee onAnalytical Reagents of theAmerican Chemical Society, the car by means of a sample thief.
where such specifications are available. Other grades may be
7.3.3 Hopper cars and trucks are more difficult to sample
used, provided it is first ascertained that the reagent is of
adequately. Samples can be taken through the hatches with a
sufficiently high purity to permit its use without lessening the
sample thief, as for boxcar sampling. Preferably, samples
accuracy of the determination.
should be taken during the unloading operation at the point of
discharge to the bin, or from any open section of the conveyor.
5.2 Unless otherwise indicated, references to water shall be
understood to meanType II orType III reagent water conform-
7.4 Bag Shipments:
ing to Specification D1193.
7.4.1 Packaged soda ash that has been in storage for some
time can be sampled satisfactorily only by emptying the whole
6. Hazards
packageandmixingthoroughlybeforetakingthesample.Even
6.1 Soda ash is a primary skin irritant. Dusts or mists are
such a portion is likely to represent only the package sampled
moderately irritating to the mucous membrane of the nose and
rather than the stock of packages as a whole.The reason is that
eyes. The irritation is temporary and symptoms usually disap-
abagorothercontainertakenfromanouterlayerofthestorage
pear shortly after contact is ended.
pile is subject to more air contact and consequently more
6.2 Consult current OSHA regulations, suppliers’ Safety
moisture and carbon dioxide absorption than are packages
Data Sheets, and local regulations for all materials used in this
buried farther back in the stock.
test method.
7.4.2 To get an idea of the quality of the soda ash as packed,
it is the usual practice to take the sample from somewhere near
7. Sampling
the center of the package. This may be done by removing the
7.1 The general principles for sampling solids are covered top 6 or 8 in. (150 or 200 mm) of soda ash from the package,
in Practice E300. The following aspects of soda ash sampling then removing the sample from the center of the remaining
must be considered:
portion. Such a sample carefully taken will generally be found
representative except in cases of long storage or unusually
7.2 General:
damp storage conditions.
7.2.1 The selection of a representative sample is a necessary
prerequisite for any accurate analysis, and this is particularly
7.5 Sample Preparation:
important with the alkalies, since they are susceptible to rapid
7.5.1 Thoroughly mix the total sample taken. Then quarter
contamination by moisture and carbon dioxide upon exposure
or riffle the entire sample to obtain the required size sample for
to air. Also, some of them are not uniform in particle size and
analysis. Minimize exposure to moisture and carbon dioxide.
tend to segregate on handling.
7.5.2 Store the sample for analysis in a glass or other
7.2.2 The characteristics of soda ash that make proper
suitablecontainerthatwillnotcontaminatethesampleandthat
sampling difficult at times are its tendency to absorb moisture
can be sealed to prevent exposure of the sample to moisture or
and carbon dioxide from the air through any commercial
carbon dioxide.
container in which it is generally shipped, and the susceptibil-
TOTAL ALKALINITY
Reagent Chemicals, American Chemical Society Specifications, American
8. Scope
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
listed by the American Chemical Society, see Analar Standards for Laboratory
8.1 This test method covers the titrimetric determination of
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
the total alkalinity of soda ash. This alkalinity is normally
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
MD. expressed as percent sodium oxide (Na O).
E359 − 17
9. Summary of Test Method where:
A =Na CO , % (see 13.2), and
9.1 Total alkalinity is determined by titration with standard 2 3
B = NaHCO , % (see 22.1).
hydrochloric(orsulfuric)acidusingmethylorangeormodified 3
methyl orange indicator solution.
14. Report
10. Interferences
14.1 Report the percentage of sodium oxide to the nearest
10.1 Alkalies other than soda ash (sodium carbonate) and
0.01 %.
compounds that consume acid will affect the accuracy of this
test method.
15. Precision and Bias
15.1 Precision—The following criteria should be used for
11. Reagents
judging the acceptability of results (Note 4):
11.1 Hydrochloric (or Sulfuric) Acid (1.0 meq/mL)—
15.1.1 Repeatability (Single Analyst)—The standard devia-
Prepare in accordance with Practice E200 (record temperature
tion for a single determination has been estimated to be
of solution when standardized).
0.032 % absolute at 52 DF. The 95 % limit for the difference
11.2 Modified Methyl Orange Indicator Solution or Methyl
between two such runs is 0.09 % absolute.
Orange Indicator Solution—See Practice E200.
15.1.2 Laboratory Precision (Within-Laboratory, Between-
11.3 Water, carbon dioxide-free (freshly boiled and cooled).
Days Variability)—The standard deviation of results (each the
average of duplicates), obtained by the same analyst on
12. Procedure
different days, has been estimated to be 0.038 % absolute at 26
12.1 Weigh, to the nearest 0.1 mg, 4.4 60.1g(Note 1)of
DF. The 95 % limit for the difference between two such
the sample and transfer to a 500-mLconical flask.Add 100 mL
averages is 0.11 % absolute.
of water and swirl to dissolve the sample.
15.1.3 Reproducibility (Multilaboratory)—The standard de-
viation of results (each the average of duplicates), obtained by
NOTE1—Useofthespecifiedweightofsamplerequiresa100-mLburet
for titration and is recommended. If a 50-mL buret is used, the sample analysts in different laboratories, has been estimated to be
weight should be halved.
0.154 % absolute at 8 DF. The 95 % limit for the difference
between two such averages is 0.43 % absolute.
12.2 Add 3 drops of modified methyl orange indicator
solution (Note 2). Titrate this solution with standard 1.0
NOTE 4—These precision estimates are based on an interlaboratory
meq/mL acid to a gray end point (Note 3). Record the volume
study of analyses performed in 1967 on three samples of soda ash
to the nearest 0.02 mL and temperature of the acid used.
covering the range from 58.190 to 58.385 % sodium oxide. Ten labora-
Correct the acid normality for any difference from the stan- tories analyzed the three samples, with one analyst in each laboratory
performing duplicate determinations and repeating 1 day later. Practice
dardization temperature by use of the factor ∆N/°C = 0.00035
E180 was used for developing these precision estimates.
between20and30°C.Addthecorrectionwhenthetemperature
of use is below and subtract when above the temperature of
15.2 Bias—The bias of this test method has not been
standardization (see Practice E200). determined because of the lack of acceptable reference mate-
rial.
NOTE 2—If desired, 0.1 % methyl orange indicator solution may be
used.
NOTE 3—The analyst should end the titration at the same shade of color 16. Quality Guidelines
as was used for the end point in the standardization of the acid.
16.1 Laboratories shall have a quality control system in
13. Calculation place.
16.1.1 Confirm the performance of the test instrument or
13.1 Calculate the total alkalinity as percent sodium oxide
test method by analyzing a quality control sample following
(Na O) as follows:
the guidelines of standard statistical quality control practices.
A 3 B 30.030990 3100
~ !
sodium oxide, weight % 5 (1) 16.1.2 Aquality control sample is a stable material isolated
W
from the production process and representative of the sample
where:
being analyzed.
A = acid required for titration of the sample, mL,
16.1.3 When QA/QC protocols are already established in
B = corrected meq/mL of the acid, and
the testing facility, these protocols are acceptable when they
W = sample used, g.
confirm the validity of test results.
13.2 Alternatively, calculate the alkalinity as sodium car- 16.1.4 When there are no QA/QC protocols established in
bonate as follows: the testing facility, use the guidelines described in Guide
D6809 or similar statistical quality control practices.
sodium carbonate, weight % 5 1.7101 3Na O, wt % (2)
13.3 If actual sodium carbonate content is desired, the
sodium bicarbonate content must be determined separately as
Supporting data have been filed ASTM Headquarters and may be obtained by
described in Sections 17 and 24. Then:
requesting Request Research Report RR:E15-0046. Contact ASTM Customer
sodium carbonate actual ,% 5 A 2 B 30.6308 (3) Service at service @astm.org.
~ ! ~ !
E359 − 17
SODIUM BICARBONATE 21.4 Weigh, to the nearest 1 mg, 4.0 g of the sample (or of
the primary standard) and transfer to the solution in the
17. Scope
600-mLbeaker. Place the beaker on a magnetic stirrer, insert a
stirring bar, and stir to dissolve.
17.1 Thistestmethoddescribesthetitrimetricdetermination
of sodium bicarbonate in soda ash. The lower limit of deter-
NOTE 7—The subsequent operations should be completed within 5 min
mination is 0.02 % sodium bicarbonate.
to minimize absorption of atmospheric CO .
21.5 While continuing to stir, add the 200 mLof neutralized
18. Summary of Test Method
BaCl solutionbymeansofa100-mL(or200-mL,ifavailable)
18.1 Bicarbonate is determined titrimetrically by adding a
pipet, allowing the reagent to run freely into the stirring
sample to an excess of standard sodium hydroxide solution
solution.
(thus converting bicarbonate to carbonate), precipitating the
21.6 Insert the electrodes into the solution and titrate slowly
carbonate with barium chloride solutions and back-titrating the
with 0.1 meq/mL HCl using a 10-mL buret, stirring continu-
excess sodium hydroxide with standard acid solution using a
ously. When pH 8.8 is reached, allow the solution to stir for 1
pH meter to determine the end point.
min. If the pH remains at 8.8, the end point has been reached.
18.2 Aprimary standard is run simultaneously to correct the
Ifnot,continuethetitrationuntilthispHisreached.Recordthe
titration for adsorption or occlusion of sodium hydroxide on volume of titrant to the nearest 0.05 mL.
the barium carbonate.
22. Calculation
19. Apparatus
22.1 Calculate the percentage of sodium bicarbonate as
19.1 pH Meter,withglassandcalomelelectrodes.Standard-
follows:
ize the pH meter with commercially available pH 10 buffer
sodium bicarbonate, weight %
solution.
~B 2 A! 3 N 30.084 3100
5 (4)
19.2 Magnetic Stirrer, with TFE-fluorocarbon-covered stir-
W
ring bar.
where:
20. Reagents
A = acid for sample, mL,
B = acid for primary standard, mL,
20.1 Barium Chloride Solution (120 g/L)—See Practice
N = meq/mL of acid, and
E200.
W = sample used, g.
20.2 Hydrochloric Acid, Standard (0.1 meq/mL)—See Prac-
tice E200.
23. Report
20.3 Sodium Carbonate, Primary Standard Na CO —Dry
2 3
23.1 Report the percentage of sodium bicarbonate to the
about 10 g of anhydrous primary standard sodium carbonate
nearest 0.01 %.
(Na CO ) in a platinum dish or low-form weighing bottle
2 3
(70-mm diameter) for4hat 250°C (minimum) but do not
24. Precision and Bias
exceed 300°C. Cool in a desiccator. Prepare fresh for use.
24.1 Precision—The following criteria should be used for
20.4 Sodium Hydroxide, Standard Solution (0.1 meq/mL)—
judging the acceptability of results (Note 8):
See Practice E200.
24.1.1 Repeatability (Single Analyst)—The standard devia-
20.5 Water, carbon dioxide-free (freshly boiled and cooled).
tion for a single determination has been estimated to be
0.030 % absolute at 60 DF. The 95 % limit for the difference
21. Procedure
between two such runs is 0.08 % absolute.
24.1.2 Laboratory Precision (Within-Laboratory, Between-
21.1 Perform the following steps of the procedure on equal
Days Variability)—The standard deviation of results (each the
mass of both the sample and the primary standard sodium
average of duplicates), obtained by the same analyst on
carbonate (Na CO)(Note 5). Make duplicate determinations.
2 3
different days, has been estimated to be 0.078 % absolute at 30
NOTE 5—To compensate for the adsorption or occlusion of NaOH by
DF. The 95 % limit for the difference between two such
the precipitated BaCO (21.5), the use of primary standard Na CO as a
3 2 3
averages is 0.22 % absolute.
blank is required.
24.1.3 Reproducibility (Multilaboratory)—The standard de-
21.2 Place 200 mL of BaCl solution in a 400-mL beaker.
viation of results (each the average of duplicates), obtained by
Using a pH meter, adjust the solution to pH 8.8 by addition of
analysts in different laboratories, has been estimated to be
0.1 meq/mL NaOH solution (or HCl) as required.
0.084 % absolute at 9 DF. The 95 % limit for the difference
21.3 Into a 600-mLbeaker place 150 mLof CO -free water.
2 between two such averages is 0.24 % absolute.
Add by pipet 5.0 mL of 0.1 meq/mL NaOH solution.
NOTE 8—These precision estimates are based on an interlaboratory
NOTE 6—If, in 21.6, the pH of the sample solution is below 8.8 before study of analyses performed in 1967 on three samples covering the range
titrating with 0.1 meq/mLHCl, repeat the test adding by pipet 10.0 mLof from 0.23 to 0.98 % sodium bicarbonate. One analyst in ten laboratories
0.1 meq/mL NaOH solution to the beakers being prepared for both the performed duplicate determinations and repeated 1 day later. Practice
sample and the primary standard Na CO . E180 was used in developing these precision estimates.
2 3
E359 − 17
24.2 Bias—The bias of this test method has not been
W = sample used, g.
determined because of the lack of acceptable reference mate-
rial.
31. Report
31.1 Report the percentage loss in mass to the nearest
25. Quality Guidelines
0.01 %.
25.1 Laboratories shall have a quality control system in
place.
32. Precision and Bias
25.1.1 Confirm the performance of the test instrument or
32.1 Precision—The following criteria should be used for
test method by analyzing a quality control sample following
judging the acceptability of results (Note 9):
the guidelines of standard statistical quality control practices.
32.1.1 Repeatability (Single Analyst)—The standard devia-
25.1.2 Aquality control sample is a stable material isolated
tion for a single determination has been estimated to be
from the production process and representative of the sample
0.016 % absolute at 54 DF. The 95 % limit for the difference
being analyzed.
between two such runs is 0.04 % absolute.
25.1.3 When QA/QC protocols are already established in
32.1.2 Laboratory Precision (Within-Laboratory, Between-
the testing facility, these protocols are acceptable when they
Days Variability)—The standard deviation of results (each the
confirm the validity of test results.
average of duplicates), obtained by the same analyst on
25.1.4 When there are no QA/QC protocols established in
different days, has been estimated to be 0.015 % absolute at 27
the testing facility, use the guidelines described in Guide
DF. The 95 % limit for the difference between two such
D6809 or similar statistical quality control practices.
averages is 0.04 % absolute.
32.1.3 Reproducibility (Multilaboratory)—The standard de-
LOSS ON HEATING
viation of results (each the average of duplicates), obtained by
26. Scope analysts in different laboratories, has been estimated to be
0.030 % absolute at 8 DF. The 95 % limit for the difference
26.1 This test method covers the gravimetric determination
between two such averages is 0.08 % absolute.
of loss on heating of soda ash.
NOTE 9—These precision estimates are based on an interlaboratory
27. Summary of Test Method
study of analyses performed in 1967 on three samples covering the range
from 0.35 to 0.55 % loss on heating. One analyst in each of ten
27.1 Loss on heating is determined gravimetrically by
laboratories performed duplicate determinations and repeated 1 day later.
heating a weighed sample under controlled conditions to expel
Practice E180 was used in developing these precision estimates.
moisture and thermally convert sodium bicarbonate to sodium
32.2 Bias—The bias of this test method has not been
carbonate by elimination of water and carbon dioxide.
determined because of the lack of acceptable reference mate-
rial.
28. Apparatus
28.1 Drying Oven, gravity-convection, Type IB. See Speci-
33. Quality Guidelines
fication E145.
33.1 Laboratories shall have a quality control system in
28.2 Weighing Bottle, 70-mm diameter, low-form, glass,
place.
with cover.
33.1.1 1 Confirm the performance of the test instrument or
test method by analyzing a quality control sample following
29. Procedure
the guidelines of standard statistical quality control practices.
29.1 Dry the weighing bottle at 250°C minimum (270°C
33.1.2 Aquality control sample is a stable material isolated
max) for 30 min. Cool in a desiccator and weigh to the nearest
from the production process and representative of the sample
0.1 mg.
being analyzed.
33.1.3 When QA/QC protocols are already established in
29.2 Place 5 6 0.1 g of the sample in the weighing bottle,
the testing facility, these protocols are acceptable when they
cover and weigh to the nearest 0.1 mg. Determine the sample
confirm the validity of test results.
weight by difference.
33.1.4 When there are no QA/QC protocols established in
29.3 Dry with the cover ajar for4hat 250°C minimum
the testing facility, use the guidelines described in Guide
(270°C maximum). Cool in a desiccator with the cover ajar.
D6809 or similar statistical quality control practices.
Weigh to the nearest 0.1 mg with the cover closed.
MOISTURE
30. Calculation
34. Scope
30.1 Calculate the percentage loss in weight as follows:
34.1 This test method covers the calculation of moisture in
A 2 B 3100
~ !
loss in weight, weight % 5 (5)
soda ash.
W
where:
35. Summary of Test Method
A = mass of bottle and sample before heating, g,
35.1 Moisture is determined by calculation. The percent of
B = mass of bottle and sample after heating, g, and
volatile products resulting from decomposition of sodium
E359 − 17
bicarbonate, 22.1, is subtracted from the percent loss on 39.1.4 When there are no QA/QC protocols established in
heating, 30.1, and the difference is reported as moisture. the testing facility, use the guidelines described in Guide
D6809 or similar statistical quality control practices.
NOTE 10—The test method makes the assumption that in commercial
soda ash, nonvolatile matter other than moisture and products of sodium
SODIUM CHLORIDE
bicarbonate decomposition will not be evolved at 250 to 270°C.
40. Scope
36. Calculation
40.1 Thistestmethodcoversthetitrimetricdeterminationof
36.1 Calculate the percentage of moisture as follows:
sodium chloride in soda ash. The lower limit of detection is
...

This document is not an ASTM 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. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E359 − 10 E359 − 17
Standard Test Methods for
Analysis of Soda Ash (Sodium Carbonate)
This standard is issued under the fixed designation E359; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript 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*
1.1 These test methods cover the analyses usually required on commercial soda ash (sodium carbonate).
1.2 The analytical procedures appear in the following sections:
Sections
Total Alkalinity, Titrimetric 8 – 15
Sodium Bicarbonate, Titrimetric 16 – 23
Sodium Bicarbonate, Titrimetric 17 – 24
Loss on Heating, Gravimetric 24 – 30
Loss on Heating, Gravimetric 26 – 32
Moisture, Calculation 31 – 35
Moisture, Calculation 34 – 38
Sodium Chloride, Titrimetric 36 – 42
Sodium Chloride, Titrimetric 40 – 46
Sodium Sulfate, Gravimetric 43 – 49
Sodium Sulfate, Gravimetric 48 – 54
Iron, Photometric 50 – 58
Iron, Photometric 56 – 64
Sieve Analysis 59 – 65
Sieve Analysis 66 – 72
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
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 Materials Safety Data Sheets (MSDS)(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 safety, health and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use. Specific hazards statements are given in Section 6.
1.7 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
C429 Test Method for Sieve Analysis of Raw Materials for Glass Manufacture
D1193 Specification for Reagent Water
D6809 Guide for Quality Control and Quality Assurance Procedures for Aromatic Hydrocarbons and Related Materials
E11 Specification for Woven Wire Test Sieve Cloth and Test Sieves
E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
These test methods are under the jurisdiction of ASTM Committee D16 on Aromatic Hydrocarbons Aromatic, Industrial, Specialty and Related Chemicals and are the
direct responsibility of Subcommittee D16.16 on Industrial and Specialty Product Standards.
Current edition approved March 1, 2010June 15, 2017. Published April 2010August 2017. Originally approved in 1968. Last previous edition approved in 20052010 as
ε1
E359 – 00 (2005)E359 – 10. . DOI: 10.1520/E0359-10.10.1520/E0359-17.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E359 − 17
E60 Practice for Analysis of Metals, Ores, and Related Materials by Spectrophotometry
E70 Test Method for pH of Aqueous Solutions With the Glass Electrode
E145 Specification for Gravity-Convection and Forced-Ventilation Ovens
E180 Practice for Determining the Precision of ASTM Methods for Analysis and Testing of Industrial and Specialty Chemicals
(Withdrawn 2009)
E200 Practice for Preparation, Standardization, and Storage of Standard and Reagent Solutions for Chemical Analysis
E300 Practice for Sampling Industrial Chemicals
2.2 Other Documents:
OSHA Regulations, 29 CFR paragraphs 19100.1000 and 1910.1200
3. Significance and Use
3.1 Soda ash is used in a number of manufacturing processes. The procedures listed in 1.2 are suitable for specification
acceptance and manufacturing control of commercial soda ash.
4. Apparatus
4.1 Photometers and Photometric Practice—Photometers and photometric practice used in these test methods shall conform to
Practice E60.
4.2 pH Meters—pH meters and their use shall conform to Test Method E70.
4.3 Buret—A calibrated 50-mL buret, or any standard 50-mL buret calibrated by either the National Institute of Standards and
Technology or by the user. Alternatively, a 100-mL calibrated buret with a 50-mL bulb at the top and a 50-mL stem below may
be used.
5. Purity of Reagents and Water
5.1 Purity of Reagents—Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all
reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where
such specifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high
purity to permit its use without lessening the accuracy of the determination.
5.2 Unless otherwise indicated, references to water shall be understood to mean Type II or Type III reagent water conforming
to Specification D1193.
6. Hazards
6.1 Soda ash is a primary skin irritant. Dusts or mists are moderately irritating to the mucous membrane of the nose and eyes.
The irritation is temporary and symptoms usually disappear shortly after contact is ended.
6.2 Consult current OSHA regulations, suppliers’ Safety Data Sheets, and local regulations for all materials used in this test
method.
7. Sampling
7.1 The general principles for sampling solids are covered in Practice E300. The following aspects of soda ash sampling must
be considered:
7.2 General:
7.2.1 The selection of a representative sample is a necessary prerequisite for any accurate analysis, and this is particularly
important with the alkalies, since they are susceptible to rapid contamination by moisture and carbon dioxide upon exposure to
air. Also, some of them are not uniform in particle size and tend to segregate on handling.
7.2.2 The characteristics of soda ash that make proper sampling difficult at times are its tendency to absorb moisture and carbon
dioxide from the air through any commercial container in which it is generally shipped, and the susceptibility of dense ash in bulk
to segregate in relation to particle size as the result of normal transit vibrations.
7.2.3 Details of good sampling depend on: (1) the type of shipment, whether in containers or in bulk; (2) the type of product,
whether light or dense soda ash; and (3) the type of analysis desired, whether chemical or physical.
7.3 Bulk Shipments:
The last approved version of this historical standard is referenced on www.astm.org.
Available from U.S. Government Printing Office, Superintendent of Documents, 732 N. Capitol St., NW, Washington, DC 20401-0001, http://www.access.gpo.gov.
Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by
the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National
Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.
E359 − 17
7.3.1 Although bulk shipments are normally in transit a relatively short time, there is likely to be some absorption of moisture
and carbon dioxide in exposed surface areas. If physical tests such as screen analysis are to be included, it is particularly important
to avoid segregation that occurs on surface areas.
7.3.2 To sample boxcar shipments, brush aside the surface layer to a depth of 12 in. (305 mm) and take portions systematically
from the newly exposed area to the bottom of the car by means of a sample thief.
7.3.3 Hopper cars and trucks are more difficult to sample adequately. Samples can be taken through the hatches with a sample
thief, as for boxcar sampling. Preferably, samples should be taken during the unloading operation at the point of discharge to the
bin, or from any open section of the conveyor.
7.4 Bag Shipments:
7.4.1 Packaged soda ash that has been in storage for some time can be sampled satisfactorily only by emptying the whole
package and mixing thoroughly before taking the sample. Even such a portion is likely to represent only the package sampled
rather than the stock of packages as a whole. The reason is that a bag or other container taken from an outer layer of the storage
pile is subject to more air contact and consequently more moisture and carbon dioxide absorption than are packages buried farther
back in the stock.
7.4.2 To get an idea of the quality of the soda ash as packed, it is the usual practice to take the sample from somewhere near
the center of the package. This may be done by removing the top 6 or 8 in. (150 or 200 mm) of soda ash from the package, then
removing the sample from the center of the remaining portion. Such a sample carefully taken will generally be found representative
except in cases of long storage or unusually damp storage conditions.
7.5 Sample Preparation:
7.5.1 Thoroughly mix the total sample taken. Then quarter or riffle the entire sample to obtain the required size sample for
analysis. Minimize exposure to moisture and carbon dioxide.
7.5.2 Store the sample for analysis in a glass or other suitable container that will not contaminate the sample and that can be
sealed to prevent exposure of the sample to moisture or carbon dioxide.
TOTAL ALKALINITY
8. Scope
8.1 This test method covers the titrimetric determination of the total alkalinity of soda ash. This alkalinity is normally expressed
as percent sodium oxide (Na O).
8. Scope
8.1 This test method covers the titrimetric determination of the total alkalinity of soda ash. This alkalinity is normally expressed
as percent sodium oxide (Na O).
9. Summary of Test Method
9.1 Total alkalinity is determined by titration with standard hydrochloric (or sulfuric) acid using methyl orange or modified
methyl orange indicator solution.
10. Interferences
10.1 Alkalies other than soda ash (sodium carbonate) and compounds that consume acid will affect the accuracy of this test
method.
11. Reagents
11.1 Hydrochloric (or Sulfuric) Acid (1.0 meq/mL)—Prepare in accordance with Practice E200 (record temperature of solution
when standardized).
11.2 Modified Methyl Orange Indicator Solution or Methyl Orange Indicator Solution—See Practice E200.
11.3 Water, carbon dioxide-free (freshly boiled and cooled).
12. Procedure
12.1 Weigh, to the nearest 0.1 mg, 4.4 6 0.1 g (Note 1) of the sample and transfer to a 500-mL conical flask. Add 100 mL of
water and swirl to dissolve the sample.
NOTE 1—Use of the specfiedspecified weight of sample requires a 100-mL buret for titration and is recommended. If a 50-mL buret is used, the sample
weight should be halved.
12.2 Add 3 drops of modified methyl orange indicator solution (Note 2). Titrate this solution with standard 1.0 meq/mL acid
to a gray end point (Note 3). Record the volume to the nearest 0.02 mL and temperature of the acid used. Correct the acid normality
E359 − 17
for any difference from the standardization temperature by use of the factor ΔN/°C = 0.00035 between 20 and 30°C. Add the
correction when the temperature of use is below and subtract when above the temperature of standardization (see Practice E200).
NOTE 2—If desired, 0.1 % methyl orange indicator solution may be used.
NOTE 3—The analyst should end the titration at the same shade of color as was used for the end point in the standardization of the acid.
13. Calculation
13.1 Calculate the total alkalinity as percent sodium oxide (Na O) as follows:
~A 3B 30.030990!3100
sodium oxide, %mass m/m 5 (1)
~ !
W
A 3B 30.030990 3100
~ !
sodium oxide, weight % 5 (1)
W
where:
A = acid required for titration of the sample, mL,
B = corrected meq/mL of the acid, and
W = sample used, g.
13.2 Alternatively, calculate the alkalinity as sodium carbonate as follows:
sodium carbonate, % mass ~m/m!5 1.7101 3Na O, wt % (2)
sodium carbonate, weight % 5 1.7101 3Na O, wt % (2)
13.3 If actual sodium carbonate content is desired, the sodium bicarbonate content must be determined separately as described
in Sections 1617 and 2324. Then:
sodium carbonate actual ,%5 A 2 B 30.6308 (3)
~ ! ~ !
where:
A = Na CO , % (see 13.2), and
2 3
B = NaHCO , % (see 21.1).
B = NaHCO , % (see 22.1).
14. Report
14.1 Report the percentage of sodium oxide to the nearest 0.01 %.
15. Precision and Bias
15.1 Precision—The following criteria should be used for judging the acceptability of results (Note 4):
15.1.1 Repeatability (Single Analyst)—The standard deviation for a single determination has been estimated to be 0.032 %
absolute at 52 DF. The 95 % limit for the difference between two such runs is 0.09 % absolute.
15.1.2 Laboratory Precision (Within-Laboratory, Between-Days Variability)—The standard deviation of results (each the
average of duplicates), obtained by the same analyst on different days, has been estimated to be 0.038 % absolute at 26 DF. The
95 % limit for the difference between two such averages is 0.11 % absolute.
15.1.3 Reproducibility (Multilaboratory)—The standard deviation of results (each the average of duplicates), obtained by
analysts in different laboratories, has been estimated to be 0.154 % absolute at 8 DF. The 95 % limit for the difference between
two such averages is 0.43 % absolute.
NOTE 4—These precision estimates are based on an interlaboratory study of analyses performed in 1967 on three samples of soda ash covering the range
from 58.190 to 58.385 % sodium oxide. Ten laboratories analyzed the three samples, with one analyst in each laboratory performing duplicate
determinations and repeating 1 day later. Practice E180 was used for developing these precision estimates.
15.2 Bias—The bias of this test method has not been determined because of the lack of acceptable reference material.
16. Quality Guidelines
16.1 Laboratories shall have a quality control system in place.
16.1.1 Confirm the performance of the test instrument or test method by analyzing a quality control sample following the
guidelines of standard statistical quality control practices.
16.1.2 A quality control sample is a stable material isolated from the production process and representative of the sample being
analyzed.
Supporting data are available from ASTM Headquarters. have been filed ASTM Headquarters and may be obtained by requesting Request Research Report RR:E15-0046.
Contact ASTM Customer Service at service @astm.org.
E359 − 17
16.1.3 When QA/QC protocols are already established in the testing facility, these protocols are acceptable when they confirm
the validity of test results.
16.1.4 When there are no QA/QC protocols established in the testing facility, use the guidelines described in Guide D6809 or
similar statistical quality control practices.
SODIUM BICARBONATE
16. Scope
16.1 This test method describes the titrimetric determination of sodium bicarbonate in soda ash. The lower limit of
determination is 0.02 % sodium bicarbonate.
17. Scope
17.1 This test method describes the titrimetric determination of sodium bicarbonate in soda ash. The lower limit of
determination is 0.02 % sodium bicarbonate.
18. Summary of Test Method
18.1 Bicarbonate is determined titrimetrically by adding a sample to an excess of standard sodium hydroxide solution (thus
converting bicarbonate to carbonate), precipitating the carbonate with barium chloride solutions and back-titrating the excess
sodium hydroxide with standard acid solution using a pH meter to determine the end point.
18.2 A primary standard is run simultaneously to correct the titration for adsorption or occlusion of sodium hydroxide on the
barium carbonate.
19. Apparatus
19.1 pH Meter, with glass and calomel electrodes. Standardize the pH meter with commercially available pH 10 buffer solution.
19.2 Magnetic Stirrer, with TFE-fluorocarbon-covered stirring bar.
20. Reagents
20.1 Barium Chloride Solution (120 g/L)—See Practice E200.
20.2 Hydrochloric Acid, Standard (0.1 meq/mL)—See Practice E200.
20.3 Sodium Carbonate, Primary Standard Na CO —Dry about 10 g of anhydrous primary standard sodium carbonate
2 3
(Na CO ) in a platinum dish or low-form weighing bottle (70-mm diameter) for 4 h at 250°C (minimum) but do not exceed 300°C.
2 3
Cool in a desiccator. Prepare fresh for use.
20.4 Sodium Hydroxide, Standard Solution (0.1 meq/mL)—See Practice E200.
20.5 Water, carbon dioxide-free (freshly boiled and cooled).
21. Procedure
21.1 Perform the following steps of the procedure on equal mass of both the sample and the primary standard sodium carbonate
(Na CO ) (Note 5). Make duplicate determinations.
2 3
NOTE 5—To compensate for the adsorption or occlusion of NaOH by the precipitated BaCO (20.521.5), the use of primary standard Na CO as a blank
3 2 3
is required.
21.2 Place 200 mL of BaCl solution in a 400-mL beaker. Using a pH meter, adjust the solution to pH 8.8 by addition of 0.1
meq/mL NaOH solution (or HCl) as required.
21.3 Into a 600-mL beaker place 150 mL of CO -free water. Add by pipet 5.0 mL of 0.1 meq/mL NaOH solution.
NOTE 6—If, in 20.621.6, the pH of the sample solution is below 8.8 before titrating with 0.1 meq/mL HCl, repeat the test adding by pipet 10.0 mL
of 0.1 meq/mL NaOH solution to the beakers being prepared for both the sample and the primary standard Na CO .
2 3
21.4 Weigh, to the nearest 1 mg, 4.0 g of the sample (or of the primary standard) and transfer to the solution in the 600-mL
beaker. Place the beaker on a magnetic stirrer, insert a stirring bar, and stir to dissolve.
NOTE 7—The subsequent operations should be completed within 5 min to minimize absorption of atmospheric CO .
21.5 While continuing to stir, add the 200 mL of neutralized BaCl solution by means of a 100-mL (or 200-mL, if available)
pipet, allowing the reagent to run freely into the stirring solution.
21.6 Insert the electrodes into the solution and titrate slowly with 0.1 meq/mL HCl using a 10-mL buret, stirring continuously.
When pH 8.8 is reached, allow the solution to stir for 1 min. If the pH remains at 8.8, the end point has been reached. If not,
continue the titration until this pH is reached. Record the volume of titrant to the nearest 0.05 mL.
E359 − 17
22. Calculation
22.1 Calculate the percentage of sodium bicarbonate as follows:
B 2 A N 30.084 3100
~ !
sodium bicarbonate, % mass ~m/m!5 (4)
W
B 2 A 3N 30.084 3100
~ !
sodium bicarbonate, weight % 5 (4)
W
where:
A = acid for sample, mL,
B = acid for primary standard, mL,
N = meq/mL of acid, and
W = sample used, g.
23. Report
23.1 Report the percentage of sodium bicarbonate to the nearest 0.01 %.
24. Precision and Bias
24.1 Precision—The following criteria should be used for judging the acceptability of results (Note 8):
24.1.1 Repeatability (Single Analyst)—The standard deviation for a single determination has been estimated to be 0.030 %
absolute at 60 DF. The 95 % limit for the difference between two such runs is 0.08 % absolute.
24.1.2 Laboratory Precision (Within-Laboratory, Between-Days Variability)—The standard deviation of results (each the
average of duplicates), obtained by the same analyst on different days, has been estimated to be 0.078 % absolute at 30 DF. The
95 % limit for the difference between two such averages is 0.22 % absolute.
24.1.3 Reproducibility (Multilaboratory)—The standard deviation of results (each the average of duplicates), obtained by
analysts in different laboratories, has been estimated to be 0.084 % absolute at 9 DF. The 95 % limit for the difference between
two such averages is 0.24 % absolute.
NOTE 8—These precision estimates are based on an interlaboratory study of analyses performed in 1967 on three samples covering the range from 0.23
to 0.98 % sodium bicarbonate. One analyst in ten laboratories performed duplicate determinations and repeated 1 day later. Practice E180 was used in
developing these precision estimates.
24.2 Bias—The bias of this test method has not been determined because of the lack of acceptable reference material.
25. Quality Guidelines
25.1 Laboratories shall have a quality control system in place.
25.1.1 Confirm the performance of the test instrument or test method by analyzing a quality control sample following the
guidelines of standard statistical quality control practices.
25.1.2 A quality control sample is a stable material isolated from the production process and representative of the sample being
analyzed.
25.1.3 When QA/QC protocols are already established in the testing facility, these protocols are acceptable when they confirm
the validity of test results.
25.1.4 When there are no QA/QC protocols established in the testing facility, use the guidelines described in Guide D6809 or
similar statistical quality control practices.
LOSS ON HEATING
26. Scope
26.1 This test method covers the gravimetric determination of loss on heating of soda ash.
26.2 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
27. Summary of Test Method
27.1 Loss on heating is determined gravimetrically by heating a weighed sample under controlled conditions to expel moisture
and thermally convert sodium bicarbonate to sodium carbonate by elimination of water and carbon dioxide.
28. Apparatus
28.1 Drying Oven, gravity-convection, Type IB. See Specification E145.
28.2 Weighing Bottle, 70-mm diameter, low-form, glass, with cover.
E359 − 17
29. Procedure
29.1 Dry the weighing bottle at 250°C minimum (270°C max) for 30 min. Cool in a desiccator and weigh to the nearest 0.1
mg.
29.2 Place 5 6 0.1 g of the sample in the weighing bottle, cover and weigh to the nearest 0.1 mg. Determine the sample weight
by difference.
29.3 Dry with the cover ajar for 4 h at 250°C minimum (270°C maximum). Cool in a desiccator with the cover ajar. Weigh to
the nearest 0.1 mg with the cover closed.
30. Calculation
30.1 Calculate the percentage loss in weight as follows:
~A 2 B! 3100
loss in weight, % mass ~m/m!5 (5)
W
A 2 B 3100
~ !
loss in weight, weight %5 (5)
W
where:
A = mass of bottle and sample before heating, g,
B = mass of bottle and sample after heating, g, and
W = sample used, g.
31. Report
31.1 Report the percentage loss in mass to the nearest 0.01 %.
32. Precision and Bias
32.1 Precision—The following criteria should be used for judging the acceptability of results (Note 9):
32.1.1 Repeatability (Single Analyst)—The standard deviation for a single determination has been estimated to be 0.016 %
absolute at 54 DF. The 95 % limit for the difference between two such runs is 0.04 % absolute.
32.1.2 Laboratory Precision (Within-Laboratory, Between-Days Variability)—The standard deviation of results (each the
average of duplicates), obtained by the same analyst on different days, has been estimated to be 0.015 % absolute at 27 DF. The
95 % limit for the difference between two such averages is 0.04 % absolute.
32.1.3 Reproducibility (Multilaboratory)—The standard deviation of results (each the average of duplicates), obtained by
analysts in different laboratories, has been estimated to be 0.030 % absolute at 8 DF. The 95 % limit for the difference between
two such averages is 0.08 % absolute.
NOTE 9—These precision estimates are based on an interlaboratory study of analyses performed in 1967 on three samples covering the range from 0.35
to 0.55 % loss on heating. One analyst in each of ten laboratories performed duplicate determinations and repeated 1 day later. Practice E180 was used
in developing these precision estimates.
32.2 Bias—The bias of this test method has not been determined because of the lack of acceptable reference material.
33. Quality Guidelines
33.1 Laboratories shall have a quality control system in place.
33.1.1 1 Confirm the performance of the test instrument or test method by analyzing a quality control sample following the
guidelines of standard statistical quality control practices.
33.1.2 A quality control sample is a stable material isolated from the production process and representative of the sample being
analyzed.
33.1.3 When QA/QC protocols are already established in the testing facility, these protocols are acceptable when they confirm
the validity of test results.
33.1.4 When there are no QA/QC protocols established in the testing facility, use the guidelines described in Guide D6809 or
similar statistical quality control practices.
MOISTURE
31. Scope
31.1 This test method covers the calculation of moisture in soda ash.
34. Scope
34.1 This test method covers the calculation of moisture in soda ash.
E359 − 17
35. Summary of Test Method
35.1 Moisture is determined by calculation. The percent of volatile products resulting from decomposition of sodium
bicarbonate, 21.122.1, is subtracted from the percent loss on heating, 28.130.1, and the difference is reported as moisture.
NOTE 10—The test method makes the assumption that in commercial soda ash, nonvolatile matter other than moisture and products of sodium
bicarbonate decomposition will not be evolved at 250 to 270°C.
36. Calculation
36.1 Calculate the percentage of moisture as follows:
moisture, % mass m/m 5 A 2 B 30.369 (6)
~ ! ~ !
moisture, weight % 5 A 2 B 30.369 (6)
~ !
where:
A = loss on heating, % (see
...