GB/T 39701-2020 English PDF (GBT39701-2020)

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GB/T 39701-2020: Limit and test method of ammonium ion content in fly ash
GB/T 39701-2020
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 91.100.10
Q 11
Limit and Test Method of Ammonium Ion Content in
Fly Ash
ISSUED ON: DECEMBER 14, 2020
IMPLEMENTED ON: NOVEMBER 01, 2021
Issued by: State Administration for Market Regulation;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative References ... 5
3 Terms and Definitions ... 5
4 Technical Requirements ... 6
5 Preparation of Sample ... 6
6 Inspection Methods ... 6
7 Inspection Rules ... 6
Appendix A (Normative) Test Method for Ammonium Ion Content in Fly Ash -
Distillation Titration Method ... 8
Appendix B (Normative) Test Method for Ammonium Ion Content in Fly Ash -
Electrode Method ... 14
Appendix C (Normative) Test Method for Ammonium Ion Content in Fly Ash -
Nessler's Reagent Spectrophotometry... 18
Appendix D (Normative) Test Method for Ammonium Ion Content in Fly Ash -
Ion Chromatography ... 21
Limit and Test Method of Ammonium Ion Content in
Fly Ash
1 Scope
This Standard specifies the limit and test method of ammonium ion content in fly ash.
This Standard is applicable to fly ash that is used as cement admixtures, mortar and
concrete admixtures and other materials designated to adopt this Standard.
2 Normative References
The following documents are essential to the application of this document. For the
dated documents, only the versions with the dates indicated are applicable to this
document; for the undated documents, only the latest version (including all the
amendments) is applicable to this document.
GB/T 6682 Water for Analytical Laboratory Use - Specification and Test Methods
GB/T 8170 Rules of Rounding off for Numerical Values and Expression and
Judgement of Limiting Values
GB/T 12573 Sampling Method for Cement
3 Terms and Definitions
For the purposes of this Document, the following terms and definitions apply.
3.1 Ammonium ion in fly ash
Ammonium ions in the form of NH4+ attached to the surface of fly ash.
3.2 Series standard specifications for determining ammonium content of fly ash
Standard samples with different concentrations of ammonium ion content.
NOTE: It is used for comparative analysis to reduce the test error of ammonium ion content in
fly ash.
Appendix A
(Normative)
Test Method for Ammonium Ion Content in Fly Ash -Distillation
Titration Method
A.1 Principle
Mix the fly ash with water; adjust the pH to alkaline; perform distillation; absorb the
distilled NH3 by a dilute sulfuric acid solution; and transfer the ammonium ions in the
fly ash to the distillate. Take methyl red-methylene blue mixed indicator as indicator;
titrate the excessive sulfuric acid by sodium hydroxide standard titration solution; and
calculate the ammonium ion content in fly ash based on the NH4+ content in the
distillate.
A.2 Basic requirements of the test
A.2.1 Test requirements
The number of times for each test is specified as twice; and the difference between the
two test results shall be within the listed tolerance (see Table A.1), and the average of
the two test results is used to indicate the test result.
The blank test specified in this Standard can be carried out every 3 months when the
quality of distilled water remains unchanged.
It is recommended to use series standard specifications for determining ammonium
content of fly ash to reduce test errors.
In all titration processes, the needle-tube weighing method can be used instead of the
burette method of measuring the solution.
A.2.2 Expression of mass, volume and result
The mass is expressed in "grams (g)" and is accurate to 0.001g. The volume of the
burette is expressed in "milliliters (mL)", and the reading is accurate to 0.01mL. Refer
to the burette for the indication of the needle tube.
The ratio of concentration and volume of the standard titration solution retain three
significant figures. Unless otherwise stated, all analysis results are based on mass
fraction. The unit of ammonium ion content in fly ash is mg/kg, and it is retained to one
digit after the decimal point.
The rounding-off of the value is carried out according to GB/T 8170.
A.2.3 Blank test
Do not add fly ash, use the same amount of reagent, and perform the test in
accordance with the same measurement procedures.
A.2.4 General rules of reagents
Unless otherwise specified, the used reagents shall be no lower than the analytical
reagent, and the guaranteed reagent is preferred. The reagent used for calibration
shall be the reference reagent. The used water shall be no lower than the requirements
for Class-III water specified in GB/T 6682; and distilled water is generally used.
The density of commercially available concentrated liquid reagents listed in this
Standard refers to the density (ρ) at 20°C, and the unit is grams per cubic centimetre
(g/cm3).
In chemical analysis, any acid whose concentration is not marked refers to a
commercially available concentrated acid.
Unless otherwise stated, the validity period of the standard titration solution is 3 months.
If it exceeds 3 months, re-calibrate it.
A.3 Reagents and materials
A.3.1 Sulfuric acid (H2SO4)
1.84g/cm3, the mass fraction is 95%~98%.
A.3.2 Sodium hydroxide (NaOH)
Chemically pure.
A.3.3 Potassium hydrogen phthalate (C8H5KO4)
Reference reagent.
A.3.4 Ethanol (C2H5OH)
The volume fraction of ethanol is 95%.
A.3.5 Phenolphthalein indicator solution (10g/L)
Dissolve 1g of phenolphthalein in 100 mL of ethanol (A.3.4).
A.3.6 Sulfuric acid solution c(1/2H2SO4) = 0.1mol/L
Pipette 3mL of sulfuric acid; slowly pour into 1000mL of water; cool and shake well.
A.3.7 Sodium hydroxide standard titration solution c(NaOH)=0.1mol/L
A.4.1.1 Analytical balance: the division value is no more than 0.0001g.
A.4.1.2 Electronic balance: the division value is no more than 0.01g.
A.4.2 Glass volumetric utensils
A.4.2.1 500mL distillation flask.
A.4.2.2 50mL alkali burette.
A.4.2.3 250mL, 300mL beaker.
A.4.2.4 20mL pipette.
NOTE: It is recommended to use a pipette gun.
A.4.2.5 1000mL volumetric flask.
A.4.2.6 250mL graduated cylinder.
A.4.3 1000 W electric jacket
The capacity is 500mL.
A.4.4 Medical syringe
The capacity is no less than 30mL.
A.5 Test procedures
A.5.1 Preparation of distillate
Weigh 10g of fly ash sample (m2), accurate to 0.01g; and put it into a 250mL beaker.
In another graduated cylinder (A.4.2.6), pipette about 210mL of distilled water; mix the
distilled water and fly ash evenly and transfer it into a 500mL distillation flask (A.4.2.1).
In order to transfer all the fly ash into the distillation flask, the beaker shall be rinsed
twice.
Add about 0.2g of sodium hydroxide (A.3.2) in the distillation flask; quickly connect the
distillation device and ensure that it is sealed to prevent ammonia from escaping; and
wait for distillation.
Pipette 20.00mL of sulfuric acid solution (A.3.6) in a 250mL beaker; add 3 ~ 4 drops of
methyl red-methylene blue mixed indicator solution (A.3.8). Insert the glass tube at the
outlet of the distillation flask into the sulfuric acid solution at the bottom of the beaker.
Heating distillation, when the volume of distillate in the beaker reaches 200mL, stop
heating; remove the distillation flask; rinse the condenser by water; and collect the
washing liquid in the beaker.
Appendix B
(Normative)
Test Method for Ammoniu...