ASTM D4517-15(2023)
(Test Method)Standard Test Method for Low-Level Total Silica in High-Purity Water by Flameless Atomic Absorption Spectroscopy
Standard Test Method for Low-Level Total Silica in High-Purity Water by Flameless Atomic Absorption Spectroscopy
SIGNIFICANCE AND USE
5.1 Control of silica in boiler feedwater and boiler water is necessary to minimize the formation of scale-forming silicates that decrease heat transfer in the boiler. Volatilization and carryover of silica with the steam may cause hard, glassy siliceous deposits to form on turbine blades that reduce turbine efficiency.
5.2 Colloidal silica that is not removed by boiler water pretreatment processes may be solubilized in the boiler and thus contribute to the dissolved silica concentration in the boiler. Both dissolved and total silica are of interest.
SCOPE
1.1 This test method covers the determination of total silica in water.
1.2 This test method is applicable in the range from 25 μg/L to 250 μg/L of silica as SiO2. Higher concentrations may be determined by decreasing the aliquot volume (see Note 6). Concentration range should not be extended by dilution.
1.3 This test method determines total silica, and does not distinguish between soluble and insoluble forms.
1.4 This test method was tested on reagent water only. It is the user's responsibility to assure the validity of the test method for waters of other matrices.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
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
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: D4517 − 15 (Reapproved 2023)
Standard Test Method for
Low-Level Total Silica in High-Purity Water by Flameless
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Atomic Absorption Spectroscopy
This standard is issued under the fixed designation D4517; 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.
1. Scope D1066 Practice for Sampling Steam
D1129 Terminology Relating to Water
1.1 This test method covers the determination of total silica
D1192 Guide for Equipment for Sampling Water and Steam
in water.
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in Closed Conduits (Withdrawn 2003)
1.2 This test method is applicable in the range from 25 μg ⁄L
D1193 Specification for Reagent Water
to 250 μg ⁄L of silica as SiO . Higher concentrations may be
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D2777 Practice for Determination of Precision and Bias of
determined by decreasing the aliquot volume (see Note 6).
Applicable Test Methods of Committee D19 on Water
Concentration range should not be extended by dilution.
D3370 Practices for Sampling Water from Flowing Process
1.3 This test method determines total silica, and does not Streams
D3919 Practice for Measuring Trace Elements in Water by
distinguish between soluble and insoluble forms.
Graphite Furnace Atomic Absorption Spectrophotometry
1.4 This test method was tested on reagent water only. It is
D4453 Practice for Handling of High Purity Water Samples
the user’s responsibility to assure the validity of the test
D5810 Guide for Spiking into Aqueous Samples
method for waters of other matrices.
D5847 Practice for Writing Quality Control Specifications
1.5 The values stated in SI units are to be regarded as
for Standard Test Methods for Water Analysis
standard. No other units of measurement are included in this
standard.
3. Terminology
1.6 This standard does not purport to address all of the
3.1 Definitions:
safety concerns, if any, associated with its use. It is the
3.1.1 For definitions of terms used in this standard, refer to
responsibility of the user of this standard to establish appro-
Terminology D1129.
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
4. Summary of Test Method
1.7 This international standard was developed in accor-
dance with internationally recognized principles on standard- 4.1 Total silica is determined using an atomic absorption
ization established in the Decision on Principles for the spectrophotometer in conjunction with a graphite furnace. A
Development of International Standards, Guides and Recom- sample is placed in a graphite tube, evaporated to dryness,
mendations issued by the World Trade Organization Technical charred, and atomized. Since the graphite furnace uses the
Barriers to Trade (TBT) Committee. sample much more efficiently than flame atomization, the
detection of low concentrations of elements in small sample
2. Referenced Documents
volumes is possible. Finally, the absorption signal during
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atomization is recorded and compared to standards. A general
2.1 ASTM Standards:
guide for the application of the graphite furnace is given in
D859 Test Method for Silica in Water
Practice D3919. Pretreatment of the graphite tube may be used
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to enhance the sensitivity and repeatability, or both, of the test.
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This test method is under the jurisdiction of ASTM Committee D19 on Water
4.2 Total silica is determined using a freshly ultrasonically
and is the direct responsibility of Subcommittee D19.03 on Sampling Water and
treated and shaken aliquot of sample.
Water-Formed Deposits, Analysis of Water for Power Generation and Process Use,
On-Line Water Analysis, and Surveillance of Water.
Current edition approved April 1, 2023. Published April 2023. Originally
approved in 1985. Last previous edition approved in 2015 as D4517 – 15. DOI:
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10.1520/D4517-15R23. The last approved version of this historical standard is referenced on
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For referenced ASTM standards, visit the ASTM website, www.astm.org, or www.astm.org.
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contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Rawa, J. A., and Henn, E. L., “Determination of Trace Silica in Industrial
Standards volume information, refer to the standard’s Document Summary page on Process Waters by Flameless Atomic Absorption Spectrometry,” Analytical
the ASTM website. Chemistry, Vol 51, March 1979.
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