ASTM C25-11e1
(Test Method)Standard Test Methods for Chemical Analysis of Limestone, Quicklime, and Hydrated Lime
Standard Test Methods for Chemical Analysis of Limestone, Quicklime, and Hydrated Lime
SIGNIFICANCE AND USE
4.1 These test methods provide accurate and reliable analytical procedures to determine the chemical constituents of limestone, quicklime, and hydrated lime (See Note 1). The percentages of specific constituents which determine a material's quality or fitness for use are of significance depending upon the purpose or end use of the material. Results obtained may be used in relation to specification requirements.
4.2 Because quicklime and hydrated lime quickly absorb water and carbon dioxide from the air, precision and bias are extremely dependent upon precautions taken during sample preparation and analysis to minimize excessive exposure to ambient conditions.
Note 1: These test methods can be applied to other calcareous materials if provisions are made to compensate for known interferences.
SCOPE
1.1 These test methods cover the chemical analysis of high-calcium and dolomitic limestone, quicklime, and hydrated lime. These test methods are classified as either standard (preferred) or alternative (optional).
1.2 The standard test methods are those that employ classical gravimetric or volumetric analytical procedures and are typically those required for referee analyses where chemical specification requirements are an essential part of contractual agreement between buyer and seller.
1.3 Alternative or optional test methods are provided for those who wish to use procedures shorter or more convenient than the standard methods for the routine determinations of certain constituents. Optional test methods may sometimes be preferred to the standard test methods, but frequently the use of modern and expensive instrumentation is indicated which may not be accessible to everyone. Therefore, the use of these test methods must be left to the discretion of each laboratory.
1.4 The analytical procedures appear in the following order:
Section
Aluminum Oxide
15
Available Lime Index
28
Calcium and Magnesium Oxide:
Alternative EDTA Titration Method
31
Calcium Carbonate Equivalent
33
Calcium Oxide:
Gravimetric Method
16
Volumetric Method
17
Carbon Dioxide by Standard Method
22
Combined Oxides of Iron and Aluminum
12
Ferrous Iron
Appendix X5
Free Calcium Oxide
Appendix X6
Free Moisture in Hydrated Lime
21
Free Moisture in Limestone
20
Free Silica
29
Insoluble Matter Including Silicon Dioxide:
Standard Method
8
Optional Perchloric Acid Method
9
Insoluble Matter Other Than Silicon Dioxide
11
Loss on Ignition
19
Magnesium Oxide
18
Manganese:
Bismuthate Method
Appendix X4
Periodate (Photometric) Method
27
pH Determination of Alkaline Earth Solutions
34
Phosphorus:
Titrimetric Method
Appendix X3
Molybdovanadate Method
26
Silicon Dioxide
10
Strontium Oxide
Appendix X2
Sulfur Trioxide
23
Total Carbon:
Direct Combustion-Thermal Conductivity Cell Method
32
Total Carbon and Sulfur:
Combustion/Infrared Detection Method
35
Total Iron:
Standard Method, Potassium Dichromate Titration
13
Potassium Permanganate Titration Method
Appendix X1
Ortho-Phenanthroline, Photometric Method
14
Total Sulfur:
Sodium Carbonate Fusion
24
Combustion-Iodate Titration Method
25
Unhydrated Oxides
30
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. For specific precautionary statements, see 9.3, 10.2.1, 18.4.3, 31.6.4.2, X2.3.1, and X5.4.1.1.
General Information
Relations
Buy Standard
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
´1
Designation: C25 − 11
StandardTest Methods for
Chemical Analysis of Limestone, Quicklime, and Hydrated
Lime
ThisstandardisissuedunderthefixeddesignationC25;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscript
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.
ε NOTE—Designation was corrected editorially in December 2014.
1. Scope
Carbon Dioxide by Standard 22
Method
1.1 These test methods cover the chemical analysis of
Combined Oxides of Iron and 12
Aluminum
high-calcium and dolomitic limestone, quicklime, and hy-
Ferrous Iron Appendix X5
dratedlime.Thesetestmethodsareclassifiedaseitherstandard
Free Calcium Oxide Appendix X6
(preferred) or alternative (optional).
Free Moisture in Hydrated Lime 21
Free Moisture in Limestone 20
1.2 The standard test methods are those that employ classi-
Free Silica 29
cal gravimetric or volumetric analytical procedures and are
Insoluble Matter Including Silicon Dioxide:
Standard Method 8
typically those required for referee analyses where chemical
Optional Perchloric Acid Method 9
specification requirements are an essential part of contractual
Insoluble Matter Other Than Silicon 11
agreement between buyer and seller.
Dioxide
Loss on Ignition 19
1.3 Alternative or optional test methods are provided for
Magnesium Oxide 18
those who wish to use procedures shorter or more convenient Manganese:
Bismuthate Method Appendix X4
than the standard methods for the routine determinations of
Periodate (Photometric) Method 27
certain constituents. Optional test methods may sometimes be
pH Determination of Alkaline Earth 34
Solutions
preferredtothestandardtestmethods,butfrequentlytheuseof
Phosphorus:
modern and expensive instrumentation is indicated which may
Titrimetric Method Appendix X3
not be accessible to everyone. Therefore, the use of these test
Molybdovanadate Method 26
Silicon Dioxide 10
methods must be left to the discretion of each laboratory.
Strontium Oxide Appendix X2
1.4 Theanalyticalproceduresappearinthefollowingorder:
Sulfur Trioxide 23
Total Carbon:
Section
Direct Combustion-Thermal 32
Aluminum Oxide 15
Conductivity Cell Method
Available Lime Index 28
Total Carbon and Sulfur:
Calcium and Magnesium Oxide:
Combustion/Infrared Detection 35
Alternative EDTATitration 31
Method
Method
Total Iron:
Calcium Carbonate Equivalent 33
Standard Method, Potassium 13
Calcium Oxide:
Dichromate Titration
Gravimetric Method 16
Potassium Permanganate Appendix X1
Volumetric Method 17
Titration Method
Ortho-Phenanthroline, 14
Photometric Method
These test methods are under the jurisdiction of ASTM Committee C07 on Total Sulfur:
Sodium Carbonate Fusion 24
Lime and Limestone and are the direct responsibility of Subcommittee C07.05 on
Combustion-Iodate Titration 25
Chemical Tests.
Method
CurrenteditionapprovedJune1,2011.PublishedJuly2011.Originallyapproved
Unhydrated Oxides 30
in1919.Lastpreviouseditionapprovedin2006asC25–06.DOI:10.1520/C0025-
11E01.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
´1
C25−11
1.5 This standard does not purport to address all of the extremely dependent upon precautions taken during sample
safety concerns, if any, associated with its use. It is the preparation and analysis to minimize excessive exposure to
responsibility of the user of this standard to establish appro- ambient conditions.
priate safety and health practices and determine the applica-
NOTE 1—These test methods can be applied to other calcareous
bility of regulatory limitations prior to use. For specific
materials if provisions are made to compensate for known interferences.
precautionary statements, see 9.3, 10.2.1, 18.4.3, 31.6.4.2,
5. General Apparatus and Materials and Reagents
X2.3.1, and X5.4.1.1.
5.1 General Apparatus and Materials:
2. Referenced Documents
5.1.1 Balance—The balance shall be of an analytical type
with a capacity not to exceed 200 g. It may be of conventional
2.1 ASTM Standards:
designoritmaybeaconstant-load,direct-readingtype.Itshall
C50Practice for Sampling, Sample Preparation, Packaging,
be capable of reproducing weighings within 0.0002 g with an
and Marking of Lime and Limestone Products
accuracy of 60.0002 g. Rapid weighing devices that may be
C51Terminology Relating to Lime and Limestone (as used
provided such as a chain, damper, or heavy riders shall not
by the Industry)
increase the basic inaccuracy by more than 0.0001 g at any
C911Specification for Quicklime, Hydrated Lime, and
reading and with any load within the rated capacity of the
Limestone for Selected Chemical and Industrial Uses
balance.
D1193Specification for Reagent Water
5.1.2 Weights—Weights used for analysis shall conform to
E29Practice for Using Significant Digits in Test Data to
Class S-1 requirements of the National Institute of Standards
Determine Conformance with Specifications
andTechnologyasdescribedinNISTCircular547. Theyshall
E50Practices for Apparatus, Reagents, and Safety Consid-
be checked at least once a year or when questioned, and
erations for Chemical Analysis of Metals, Ores, and
adjusted to within allowable tolerances for Class S-1 weights.
Related Materials
All new sets of weights purchased shall have the weights of 1
E70Test Method for pH of Aqueous Solutions With the
g and larger made of stainless steel or other corrosion-resistant
Glass Electrode
alloy not requiring protective coating and shall meet the
E173Practice for Conducting Interlaboratory Studies of
density requirements for Class S.
Methods for Chemical Analysis of Metals (Withdrawn
5.1.3 Glassware and Laboratory Containers—Standard
1998)
volumetric flasks, burets, pipets, dispensers, etc., shall be
E177Practice for Use of the Terms Precision and Bias in
carefully selected precision grade or better and shall be
ASTM Test Methods
calibrated, if necessary, to meet the requirements of each
E200Practice for Preparation, Standardization, and Storage
operation.Standard-typeinterchangeablegroundglassorTFE-
of Standard and Reagent Solutions for ChemicalAnalysis
fluorocarbon joints are recommended for all volumetric glass-
E691Practice for Conducting an Interlaboratory Study to
ware. Polyethylene containers are recommended for all aque-
Determine the Precision of a Test Method
ous solutions of alkalies and for standard solutions where the
E832Specification for Laboratory Filter Papers
presence of dissolved silica or alkali from the glass would be
objectionable.
3. Terminology
5.1.4 Desiccators—Desiccators shall be provided with a
3.1 Definitions:Definitions—Unlessotherwisespecified,for
good desiccant such as anhydrous magnesium perchlorate,
definitions of terms used in these test methods refer to
activated alumina, sulfuric acid, or phosphoric anhydride.
Terminology C51.
Anhydrous calcium sulfate may also be used provided it has
been treated with a color-changing indicator to show when the
4. Significance and Use
desiccant has lost its effectiveness. Calcium chloride and silica
4.1 These test methods provide accurate and reliable ana-
gel are not satisfactory desiccants for this type of analysis.
lytical procedures to determine the chemical constituents of
5.1.5 Filter Paper—Filter paper shall conform to the re-
limestone, quicklime, and hydrated lime (See Note 1). The
quirements of Specification E832,Type II (quantitative). Class
percentages of specific constituents which determine a materi-
E shall be used for coarse and gelatinous precipitates. When
al’s quality or fitness for use are of significance depending
medium-texturedpaperisrequired,ClassFfilterpapershallbe
upon the purpose or end use of the material. Results obtained
used. When a retentive paper is needed, Class G shall be used.
may be used in relation to specification requirements.
Recommendations: Filter Pore Size Filter Speed
Class (microns)
4.2 Because quicklime and hydrated lime quickly absorb
E 20 to 25 fast speed
water and carbon dioxide from the air, precision and bias are
F 8 medium speed
G 2.5 slow speed
5.1.6 Crucibles—Platinum crucibles and tight fitting lids
should preferably be made of pure unalloyed platinum and be
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
of 25 to 35-mL capacity. Where alloyed platinum is used for
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
3 4
The last approved version of this historical standard is referenced on Available from National Institute of Standards and Technology (NIST), 100
www.astm.org. Bureau Dr., Stop 3460, Gaithersburg, MD 20899-3460.
´1
C25−11
greater stiffness or to obviate sticking of fused material to 6. General Procedures
crucible or lid, the alloyed platinum should not decrease in
6.1 Sampling—Samples of lime and limestone for chemical
weight by more than 0.2 mg when heated at 1200 °C for 1 h.
analysis shall be taken and prepared in accordance with the
5.1.7 MuffleFurnace—Theelectricmufflefurnaceshouldbe
requirements of Practice C50 applicable to the material to be
capable of continuous operation up to 1000 °C and be capable
tested.
of intermittent operation at higher temperatures if required. It
6.2 Tared or Weighed Crucibles—The tare weight of cru-
should have an indicating pyrometer accurate to 625 °C.
cibles shall be determined by preheating the empty crucible to
5.2 Reagents:
constant weight at the same temperature and under the same
5.2.1 Purity of Reagents—Reagent grade chemicals shall be
conditionsasshallbeusedforthefinalignitionofaresidueand
used in all tests. Unless otherwise indicated, it is intended that
cooling in a desiccator for the same period of time used for the
all reagents shall conform to the specifications of the Commit-
crucible containing the residue.
tee onAnalytical Reagents of theAmerican Chemical Society
where such specifications are available. Other grades may be 6.3 Constancy of Weight of Ignited Residue—To definitely
establish the constancy of weight of the ignited residue, the
used provided it is first ascertained that the reagent is of
residue and container shall be ignited at the specified tempera-
sufficiently high purity to permit its use without lessening the
accuracyofthedetermination.Inadditiontothis,itisdesirable ture and time, cooled to room temperature in a desiccator, and
weighed. The residue and container shall then be reheated for
in many cases for the analyst to ensure the accuracy of his
results by running blanks or checking against a comparable at least 30 min at the same temperature, cooled in a desiccator
forthesameperiodoftime,andreweighed.Additionalignition
sample of known composition.
5.2.2 Purity of Water—Unless otherwise indicated, refer- periods may be required until two consecutive weights do not
differbymorethan0.2mg,atwhichtimeitshallbeconsidered
ences to water are understood to mean distilled water or other
water of equivalent purity. Water conforming to Specification that constant weight has been attained. For ignition loss, each
reheating period shall be 5 min.
D1193 meets these requirements.
5.2.3 Concentration of Reagents:
6.4 Calculation:
5.2.3.1 Concentrated Acids and Ammonium Hydroxide—
6.4.1 Thecalculationsincludedintheindividualprocedures
When acids and ammonium hydroxide are specified by name
sometimes assume that the exact weight specified has been
or chemical formula only, it shall be understood that concen-
used. Accurately weighed samples which are approximately
trated reagents approximating the following specific gravities
but not exactly equal to the weight specified may be used
or concentrations are intended:
provided appropriate corrections are made in the calculation.
Acetic acid (HC H O ) 99.5 %
2 3 2
Unless otherwise stated, weights of all samples and residues
Hydrochloric acid (HCl) sp gr 1.19
should be recorded to the nearest 0.0001 g.
Hydrofluoric acid (HF) 48 %
Nitric acid (HNO ) sp gr 1.42
6.4.2 In all mathematical operations on a set of observed
Perchloric acid (HClO)70%
values, the equivalent of two more places of figures than in the
Phosphoric acid (H PO)85%
3 4
Sulfuric acid (H SO ) sp gr 1.84 single observed values shall be retained. For example, if
2 4
Ammonium hydroxide (NH OH) sp gr 0.90
4 observed values are read or determined to the nearest 0.1 mg,
carry numbers to the nearest 0.001 mg in calculation.
5.2.3.2 Dilute Reagents—The concentration of dilute acids
and NH OH except when standardized, are specified as a ratio
6.5 Rounding Figures—Rounding figures to the nearest
stating the number of measured volumes of the concentrated
significant place required in the report should be done after the
reagenttobedilutedwithagivennumberofmeasuredvolumes
calculations are completed, in order to keep the final results
of water. In conformance with international practice, new and
free from calculation errors. The rounding procedure should
revised methods will use the “plus” designation instead of the
follow the principle outlined in Practice E29.
ratio (:) symbol as the specified designation of dilution; for
example, H SO (5+95) means 5 volumes of concentrated
2 4
7. Performance Requirements for Test Methods
H SO (sp gr 1.84) diluted with 95 volumes of water.
2 4
7.1 Referee Analyses—The reference test methods that ap-
5.2.3.3 Standard Solutions—Concentrations of standard so-
pear in Sections 8 through 32, or any other test methods
lutions shall be expressed as normalities (N) or as equivalents
qualified in accordance with 7.3, are required for referee
in grams per millilitre of the component to be determined, for
analysis in those cases where conformance to the requirements
example:0.1 NK Cr O solution(1mL=0.004gFe O ).The
2 2 7 2 3
of a chemical specification are questioned. In these cases a
average of at least three determinations shall be used for all
limestone,quicklime,orhydratedlimeshallnotberejectedfor
standardizations. The standardization used to determine the
failure to conform to chemical requirements unless all sample
strength of the standard solutions is described in the text under
preparationandanalysisofanyoneconstituentismadeentirely
each of the appropriate procedures.
byreferencetestmethodsprescribedintheappropriatesections
of this test method or by other qualified test methods. Excep-
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
tion can be made when specific test methods are prescribed in
listed b
...
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.
´1
Designation: C25 − 11 C25 − 11
Standard Test Methods for
Chemical Analysis of Limestone, Quicklime, and Hydrated
Lime
This standard is issued under the fixed designation C25; 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.
ε NOTE—Designation was corrected editorially in December 2014.
1. Scope
1.1 These test methods cover the chemical analysis of high-calcium and dolomitic limestone, quicklime, and hydrated lime.
These test methods are classified as either standard (preferred) or alternative (optional).
1.2 The standard test methods are those that employ classical gravimetric or volumetric analytical procedures and are typically
those required for referee analyses where chemical specification requirements are an essential part of contractual agreement
between buyer and seller.
1.3 Alternative or optional test methods are provided for those who wish to use procedures shorter or more convenient than the
standard methods for the routine determinations of certain constituents. Optional test methods may sometimes be preferred to the
standard test methods, but frequently the use of modern and expensive instrumentation is indicated which may not be accessible
to everyone. Therefore, the use of these test methods must be left to the discretion of each laboratory.
1.4 The analytical procedures appear in the following order:
Section
Aluminum Oxide 15
Available Lime Index 28
Calcium and Magnesium Oxide:
Alternative EDTA Titration 31
Method
Calcium Carbonate Equivalent 33
Calcium Oxide:
Gravimetric Method 16
Volumetric Method 17
Carbon Dioxide by Standard 22
Method
Combined Oxides of Iron and 12
Aluminum
Ferrous Iron Appendix X5
Free Calcium Oxide Appendix X6
Free Moisture in Hydrated Lime 21
Free Moisture in Limestone 20
Free Silica 29
Insoluble Matter Including Silicon Dioxide:
Standard Method 8
Optional Perchloric Acid Method 9
Insoluble Matter Other Than Silicon 11
Dioxide
Loss on Ignition 19
Magnesium Oxide 18
Manganese:
Bismuthate Method Appendix X4
Periodate (Photometric) Method 27
pH Determination of Alkaline Earth 34
Solutions
These test methods are under the jurisdiction of ASTM Committee C07 on Lime and Limestone and are the direct responsibility of Subcommittee C07.05 on Chemical
Tests.
Current edition approved June 1, 2011. Published July 2011. Originally approved in 1919. Last previous edition approved in 2006 as C25C25 – 06.–06. DOI:
10.1520/C0025-11.10.1520/C0025-11E01.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
´1
C25 − 11
Phosphorus:
Titrimetric Method Appendix X3
Molybdovanadate Method 26
Silicon Dioxide 10
Strontium Oxide Appendix X2
Sulfur Trioxide 23
Total Carbon:
Direct Combustion-Thermal 32
Conductivity Cell Method
Total Carbon and Sulfur:
Combustion/Infrared Detection 35
Method
Total Iron:
Standard Method, Potassium 13
Dichromate Titration
Potassium Permanganate Appendix X1
Titration Method
Ortho-Phenanthroline, 14
Photometric Method
Total Sulfur:
Sodium Carbonate Fusion 24
Combustion-Iodate Titration 25
Method
Unhydrated Oxides 30
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. For specific precautionary statements, see 9.3, 10.2.1, 18.4.3, 31.6.4.2, X2.3.1, and X5.4.1.1.
2. Referenced Documents
2.1 ASTM Standards:
C50 Practice for Sampling, Sample Preparation, Packaging, and Marking of Lime and Limestone Products
C51 Terminology Relating to Lime and Limestone (as used by the Industry)
C911 Specification for Quicklime, Hydrated Lime, and Limestone for Selected Chemical and Industrial Uses
D1193 Specification for Reagent Water
E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
E50 Practices for Apparatus, Reagents, and Safety Considerations for Chemical Analysis of Metals, Ores, and Related Materials
E70 Test Method for pH of Aqueous Solutions With the Glass Electrode
E173 Practice for Conducting Interlaboratory Studies of Methods for Chemical Analysis of Metals (Withdrawn 1998)
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E200 Practice for Preparation, Standardization, and Storage of Standard and Reagent Solutions for Chemical Analysis
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
E832 Specification for Laboratory Filter Papers
3. Terminology
3.1 Definitions:Definitions—Unless otherwise specified, for definitions of terms used in these test methods refer to Terminology
C51.
4. Significance and Use
4.1 These test methods provide accurate and reliable analytical procedures to determine the chemical constituents of limestone,
quicklime, and hydrated lime (See Note 1). The percentages of specific constituents which determine a material’s quality or fitness
for use are of significance depending upon the purpose or end use of the material. Results obtained may be used in relation to
specification requirements.
4.2 Because quicklime and hydrated lime quickly absorb water and carbon dioxide from the air, precision and bias are extremely
dependent upon precautions taken during sample preparation and analysis to minimize excessive exposure to ambient conditions.
NOTE 1—These test methods can be applied to other calcareous materials if provisions are made to compensate for known interferences.
5. General Apparatus and Materials and Reagents
5.1 General Apparatus and Materials:
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
The last approved version of this historical standard is referenced on www.astm.org.
´1
C25 − 11
5.1.1 Balance—The balance shall be of an analytical type with a capacity not to exceed 200 g. It may be of conventional design
or it may be a constant-load, direct-reading type. It shall be capable of reproducing weighings within 0.0002 g with an accuracy
of 6 0.0002 g. Rapid weighing devices that may be provided such as a chain, damper, or heavy riders shall not increase the basic
inaccuracy by more than 0.0001 g at any reading and with any load within the rated capacity of the balance.
5.1.2 Weights—Weights used for analysis shall conform to Class S-1 requirements of the National Institute of Standards and
Technology as described in NIST Circular 547. They shall be checked at least once a year or when questioned, and adjusted to
within allowable tolerances for Class S-1 weights. All new sets of weights purchased shall have the weights of 1 g and larger made
of stainless steel or other corrosion-resistant alloy not requiring protective coating and shall meet the density requirements for Class
S.
5.1.3 Glassware and Laboratory Containers—Standard volumetric flasks, burets, pipets, dispensers, etc., shall be carefully
selected precision grade or better and shall be calibrated, if necessary, to meet the requirements of each operation. Standard-type
interchangeable ground glass or TFE-fluorocarbon joints are recommended for all volumetric glassware. Polyethylene containers
are recommended for all aqueous solutions of alkalies and for standard solutions where the presence of dissolved silica or alkali
from the glass would be objectionable.
5.1.4 Desiccators—Desiccators shall be provided with a good desiccant such as anhydrous magnesium perchlorate, activated
alumina, sulfuric acid, or phosphoric anhydride. Anhydrous calcium sulfate may also be used provided it has been treated with a
color-changing indicator to show when the desiccant has lost its effectiveness. Calcium chloride and silica gel are not satisfactory
desiccants for this type of analysis.
5.1.5 Filter Paper—Filter paper shall conform to the requirements of Specification E832, Type II (quantitative). Class E shall
be used for coarse and gelatinous precipitates. When medium-textured paper is required, Class F filter paper shall be used. When
a retentive paper is needed, Class G shall be used.
Recommendations: Filter Pore Size Filter Speed
Class (microns)
E 20 to 25 fast speed
F 8 medium speed
G 2.5 slow speed
5.1.6 Crucibles—Platinum crucibles and tight fitting lids should preferably be made of pure unalloyed platinum and be of 25
to 35-mL capacity. Where alloyed platinum is used for greater stiffness or to obviate sticking of fused material to crucible or lid,
the alloyed platinum should not decrease in weight by more than 0.2 mg when heated at 1200 °C for 1 h.
5.1.7 Muffle Furnace—The electric muffle furnace should be capable of continuous operation up to 1000 °C and be capable of
intermittent operation at higher temperatures if required. It should have an indicating pyrometer accurate to 6 25 °C.
5.2 Reagents:
5.2.1 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. In addition to this, it is desirable in many cases for
the analyst to ensure the accuracy of his results by running blanks or checking against a comparable sample of known composition.
5.2.2 Purity of Water—Unless otherwise indicated, references to water are understood to mean distilled water or other water of
equivalent purity. Water conforming to Specification D1193 meets these requirements.
5.2.3 Concentration of Reagents:
5.2.3.1 Concentrated Acids and Ammonium Hydroxide—When acids and ammonium hydroxide are specified by name or
chemical formula only, it shall be understood that concentrated reagents approximating the following specific gravities or
concentrations are intended:
Acetic acid (HC H O ) 99.5 %
2 3 2
Hydrochloric acid (HCl) sp gr 1.19
Hydrofluoric acid (HF) 48 %
Nitric acid (HNO ) sp gr 1.42
Perchloric acid (HClO ) 70 %
Phosphoric acid (H PO ) 85 %
3 4
Sulfuric acid (H SO ) sp gr 1.84
2 4
Ammonium hydroxide (NH OH) sp gr 0.90
5.2.3.2 Dilute Reagents—The concentration of dilute acids and NH OH except when standardized, are specified as a ratio
stating the number of measured volumes of the concentrated reagent to be diluted with a given number of measured volumes of
water. In conformance with international practice, new and revised methods will use the “plus” designation instead of the ratio (:)
symbol as the specified designation of dilution; for example, H SO (5 + 95) means 5 volumes of concentrated H SO (sp gr 1.84)
2 4 2 4
diluted with 95 volumes of water.
Available from National Institute of Standards and Technology (NIST), 100 Bureau Dr., Stop 3460, Gaithersburg, MD 20899-3460.
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. Pharmacopeia Convention, Inc. (USPC), Rockville, MD.
´1
C25 − 11
5.2.3.3 Standard Solutions—Concentrations of standard solutions shall be expressed as normalities (N) or as equivalents in
grams per millilitre of the component to be determined, for example: 0.1 N K Cr O solution (1 mL = 0.004 g Fe O ). The average
2 2 7 2 3
of at least three determinations shall be used for all standardizations. The standardization used to determine the strength of the
standard solutions is described in the text under each of the appropriate procedures.
6. General Procedures
6.1 Sampling—Samples of lime and limestone for chemical analysis shall be taken and prepared in accordance with the
requirements of Practice C50 applicable to the material to be tested.
6.2 Tared or Weighed Crucibles—The tare weight of crucibles shall be determined by preheating the empty crucible to constant
weight at the same temperature and under the same conditions as shall be used for the final ignition of a residue and cooling in
a desiccator for the same period of time used for the crucible containing the residue.
6.3 Constancy of Weight of Ignited Residue—To definitely establish the constancy of weight of the ignited residue, the residue
and container shall be ignited at the specified temperature and time, cooled to room temperature in a desiccator, and weighed. The
residue and container shall then be reheated for at least 30 min at the same temperature, cooled in a desiccator for the same period
of time, and reweighed. Additional ignition periods may be required until two consecutive weights do not differ by more than 0.2
mg, at which time it shall be considered that constant weight has been attained. For ignition loss, each reheating period shall be
5 min.
6.4 Calculation:
6.4.1 The calculations included in the individual procedures sometimes assume that the exact weight specified has been used.
Accurately weighed samples which are approximately but not exactly equal to the weight specified may be used provided
appropriate corrections are made in the calculation. Unless otherwise stated, weights of all samples and residues should be recorded
to the nearest 0.0001 g.
6.4.2 In all mathematical operations on a set of observed values, the equivalent of two more places of figures than in the single
observed values shall be retained. For example, if observed values are read or determined to the nearest 0.1 mg, carry numbers
to the nearest 0.001 mg in calculation.
6.5 Rounding Figures—Rounding figures to the nearest significant place required in the report should be done after the
calculations are completed, in order to keep the fina
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