ASTM D4517-15

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 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 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.

General Information

• Status: Historical
• Publication Date: 31-Jul-2015
• ICS: 71.060.20 - Oxides
• Technical Committee: D19 - Water
• Drafting Committee: D19.03 - Sampling Water and Water-Formed Deposits, Analysis of Water for Power Generation and Process Use, On-Line Water Analysis, and Surveillance of Water

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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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
Designation: D4517 − 15
Standard Test Method for
Low-Level Total Silica in High-Purity Water by Flameless
1
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 D2777 Practice for Determination of Precision and Bias of
Applicable Test Methods of Committee D19 on Water
1.1 This test method covers the determination of total silica
D3370 Practices for Sampling Water from Closed Conduits
in water.
D3919 Practice for Measuring Trace Elements in Water by
1.2 This test method is applicable in the range from 25 to
Graphite Furnace Atomic Absorption Spectrophotometry
250 µg/L of silica as SiO . Higher concentrations may be
2
D4453 Practice for Handling of High Purity Water Samples
determined by decreasing the aliquot volume (see Note 6).
D5810 Guide for Spiking into Aqueous Samples
Concentration range should not be extended by dilution.
D5847 Practice for Writing Quality Control Specifications
for Standard Test Methods for Water Analysis
1.3 This test method determines total silica, and does not
distinguish between soluble and insoluble forms.
3. Terminology
1.4 This test method was tested on reagent water only. It is
3.1 Definitions:
the user’s responsibility to assure the validity of the test
3.1.1 For definitions of terms used in this standard, refer to
method for waters of other matrices.
Terminology D1129.
1.5 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this
4. Summary of Test Method
standard.
4.1 Total silica is determined using an atomic absorption
1.6 This standard does not purport to address the safety
spectrophotometer in conjunction with a graphite furnace. A
concerns, if any, associated with its use. It is the responsibility
sample is placed in a graphite tube, evaporated to dryness,
of the user of this standard to establish appropriate safety and
charred, and atomized. Since the graphite furnace uses the
health practices and determine the applicability of regulatory
sample much more efficiently than flame atomization, the
limitations prior to use.
detection of low concentrations of elements in small sample
volumes is possible. Finally, the absorption signal during
2. Referenced Documents
atomization is recorded and compared to standards. A general
2
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
D1066 Practice for Sampling Steam 4
to enhance the sensitivity and repeatability, or both, of the test.
D1129 Terminology Relating to Water
4.2 Total silica is determined using a freshly ultrasonically
D1192 Guide for Equipment for Sampling Water and Steam
3
treated and shaken aliquot of sample.
in Closed Conduits (Withdrawn 2003)
D1193 Specification for Reagent Water
4.3 This test method determines low-level total silica in
high purity water. Refer to Test Method D859, Test Method B,
for determination of molybdate-reactive silica.
1
This test method is under the jurisdiction of ASTM Committee D19 on Water
and is the direct responsibility of Subcommittee D19.03 on Sampling Water and
Water-Formed Deposits, Analysis of Water for Power Generation and Process Use, 5. Significance and Use
On-Line Water Analysis, and Surveillance of Water.
5.1 Control of silica in boiler feedwater and boiler water is
Current edition approved Aug. 1, 2015. Published September 2015. Originally
necessary to minimize the formation of scale-forming silicates
approved in 1985. Last previous edition approved in 2009 as D4517 – 04 (2009).
DOI: 10.1520/D4517-15.
that decrease heat transfer in the boiler. Volatilization and
2
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
4
the ASTM website. Rawa, J. A., and Henn, E. L., “Determination of Trace Silica in Industrial
3
The last approved version of this historical standard is referenced on Process Waters by Flameless Atomic Absorption Spectrometry,” Analytical
www.astm.org. Chemistry, Vol 51, March 1979.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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D4517 − 15
carryover of silica with the steam may cause hard, glassy 7.4 Graphite Tubes, compatible with furnace device. Stan-
siliceous deposits to fo
...

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: D4517 − 04 (Reapproved 2009) D4517 − 15
Standard Test Method for
Low-Level Total Silica in High-Purity Water by Flameless
1
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
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 to 250 μg/L of silica as SiO . Higher concentrations may be determined
2
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 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.
2. Referenced Documents
2
2.1 ASTM Standards:
D859 Test Method for Silica in Water
D1066 Practice for Sampling Steam
D1129 Terminology Relating to Water
3
D1192 Guide for Equipment for Sampling Water and Steam in Closed Conduits (Withdrawn 2003)
D1193 Specification for Reagent Water
D2777 Practice for Determination of Precision and Bias of Applicable Test Methods of Committee D19 on Water
D3370 Practices for Sampling Water from Closed Conduits
D3919 Practice for Measuring Trace Elements in Water by Graphite Furnace Atomic Absorption Spectrophotometry
D4453 Practice for Handling of High Purity Water Samples
D5810 Guide for Spiking into Aqueous Samples
D5847 Practice for Writing Quality Control Specifications for Standard Test Methods for Water Analysis
3. Terminology
3.1 Definitions—Definitions: For definitions of terms used in this test method, refer to Terminology D1129.
3.1.1 For definitions of terms used in this standard, refer to Terminology D1129.
4. Summary of Test Method
4.1 Total silica is determined using an atomic absorption spectrophotometer in conjunction with a graphite furnace. A sample
is placed in a graphite tube, evaporated to dryness, charred, and atomized. Since the graphite furnace uses the sample much more
efficiently than flame atomization, the detection of low concentrations of elements in small sample volumes is possible. Finally,
1
This test method is under the jurisdiction of ASTM Committee D19 on Water and is the direct responsibility of Subcommittee D19.03 on Sampling Water and
Water-Formed Deposits, Analysis of Water for Power Generation and Process Use, On-Line Water Analysis, and Surveillance of Water.
Current edition approved Oct. 1, 2009Aug. 1, 2015. Published November 2009September 2015. Originally approved in 1985. Last previous edition approved in 20042009
as D4517 – 04.D4517 – 04 (2009). DOI: 10.1520/D4517-04R09.10.1520/D4517-15.
2
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.
3
The last approved version of this historical standard is referenced on www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
D4517 − 15
the absorption signal during atomization is recorded and compared to standards. A general guide for the application of the graphite
furnace is given in Practice D3919. Pretreatment of the graphite tube may be used to enhance the sensitivity and repeatability, or
4
both, of the test.
4.2 Total silica is determined using a freshly ultrasonically treated and shaken aliquot of sample.
4.3 This test method determines low-level total silica in high purity water. Refer to Test Method D859, Test Method B, for
determination of molybdate-reactive silica.
5. Significance and Use
5.1 Control of silica in boiler feedwater and boiler wate
...