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GB/T 2091-2008 (GB/T2091-2008)

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GB/T 2091-2008: PDF in English (GBT 2091-2008)
GB/T 2091-2008
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 71.060.30
G 11
Replacing GB/T 2091-2003
Phosphoric acid for industry use
工业磷酸
ISSUED ON: APRIL 1, 2008
IMPLEMENTED ON: SEPTEMBER 01, 2008
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration of the People’s Republic of
China.
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Normative references ... 4 
3 Molecular formula, molecular weight ... 5 
4 Product classification ... 5 
5 Requirements ... 5 
6 Test method ... 5 
7 Inspection rules ... 13 
8 Marking, labeling ... 14 
9 Packaging, transportation, storage ... 14 
Appendix A (Informative) Technical differences between this Standard and the
Japanese standard ... 15 
Appendix B (Informative) Structural differences between this Standard and the
Japanese standard ... 17 
Foreword
This Standard revises and adopts the Japanese standard JIS K 1449: 1978
(confirmed in 1988) “Phosphoric acid” (Japanese version).
This Standard is redrafted in accordance with the Japanese standard JIS K
1449: 1978 (confirmed in 1988) "Phosphoric acid".
In consideration of China's national conditions, when JIS K 1449:1978 is
adopted, some amendments are made to this Standard. The technical and
structural differences are incorporated into the text; vertical single-lines are
used to mark in the margins of the articles to which they relate. A list of these
technical and structural differences and their causes is given in Appendix A and
Appendix B for reference.
This Standard replaces GB/T 2091-2003.
The main differences between this Standard and GB/T 2091-2003:
-- Revise the indicator parameter of the heavy metal mass fraction of
qualified products from 0.05% to 0.005% (4.2 of version 2003, 5.2 of this
version);
-- Modify chloride and heavy metal test methods;
-- Add Appendix A and Appendix B.
Appendix A and Appendix B of this Standard are informative appendixes.
This Standard was proposed by China Petroleum and Chemical Industry
Federation.
This Standard shall be under the jurisdiction of Subcommittee on Inorganic
Chemical Industry of National Standardization Technical Committee of
Chemical (SAC/TC 63/SC 1).
The main drafting organizations of this Standard: Hubei Xingfa Chemicals
Group Co., Ltd., Tianjin Chemical Research and Design Institute.
The drafters of this Standard: Li Guangming, Wang Xiangsen, Xiong Ping, Wan
Jinzhu, Yang Zhengyong.
The previous versions of the standards which are replaced by this Standard are:
-- GB 2091-1980, GB/T 2091-1992, GB/T 2091-2003.
Phosphoric acid for industry use
1 Scope
This Standard specifies the classification requirements, test methods,
inspection rules, marking, labeling, packaging, transportation and storage of
phosphoric acid for industry use.
This Standard applies to phosphoric acid for industry use which is produced
from industrial yellow phosphorus. This product is mainly used in the production
of electroplating, phosphating solution and industrial phosphate.
2 Normative references
The terms in the following documents become the terms of this Standard by
reference to this Standard. For dated references, all subsequent amendments
(not including errata content) or revisions do not apply to this standard.
However, parties to agreements that are based on this Standard are
encouraged to study whether the latest versions of these documents can be
used. For undated references, the latest edition applies to this Standard.
GB 190-1990, Labels for packages of dangerous goods
GB/T 605, Chemical reagent - General method for the measurement of
colour (GB/T605-2006, ISO 6353-1:1982, EQV)
GB/T 610.1-1988, Chemical reagent - General method for the determination
of arsenic
GB/T 1250, Representation and determination of limit values
GB/T 3049-2006, Chemical products for industrial use - General method for
determination of iron content - 1,10-Phenanthroline spectrophotometric
method (ISO 6685:1982, IDT)
GB/T 6678, General principles for sampling chemical products
GB/T 6682-1992, Water for laboratory use - Specifications (eqv ISO
3696:1987)
HG/T 3696.1, Inorganic chemical products - Preparations of standard
volumetric solutions for chemical analysis
HG/T 3696.2, Inorganic chemical products - Preparations of standard
solutions for chemical analysis
6.2 General provisions
The reagents and water that are used in this Standard, when no other
requirements are specified, refer to analytical reagents and grade-III water
which is specified in GB/T 6682-1992. The standard titration solutions, impurity
standard solutions, preparations and products that are used in the test shall be
prepared in accordance with the provisions of HG/T 3696.1, HG/T 3696.2, HG/T
3696.3, when no other requirements are specified.
6.3 Appearance determination
Determine visually under natural light conditions.
6.4 Color determination
Determine according to the method that is specified in GB/T 605.
6.5 Determination of phosphoric acid content
6.5.1 Gravimetric method (arbitration method)
6.5.1.1 Method summary
In the acidic medium, the phosphate radical in the test solution forms a
precipitate with the added precipitating agent, quinoxaline ketone. Calculate the
phosphoric acid content by filtration, drying, and weighing.
6.5.1.2 Reagents
6.5.1.2.1 Hydrochloric acid;
6.5.1.2.2 Quinoxaline ketone solution.
6.5.1.3 Instrument
6.5.1.3.1 Sintered-glass filter crucible: the hole diameter is 5 μm ~ 15 μm;
6.5.1.3.2 Electric oven: the temperature can be controlled at 180 °C ± 5 °C or
250 °C ± 10 °C.
6.5.1.4 Analysis steps
6.5.1.4.1 Preparation of test solution
Weigh approximately 1 g of the sample, accurate to 0.0002 g, in a 100 mL
beaker; add 5 mL of hydrochloric acid and a small amount of water; cover the
watch glass; boil for 10 min. After cooling, transfer to a 500 mL volumetric flask;
add 10 mL of hydrochloric acid; use water to dilute to the mark; shake well.
6.5.1.4.2 Preparation of blank solution
Except that no sample is added, the amount of other added reagents is exactly
the same as that of the test solution. The same treatment is carried out
simultaneously with the sample.
6.5.1.4.3 Determination
Pipette 10 mL of the test solution and the blank test solution into the 250 mL
beakers respectively; add water to a total volume of about 100 mL. Add 35 mL
of quinoxaline ketone solution; cover the watch glass; heat in a water bath until
the temperature in the cup reaches 75°C ± 5°C; keep for 30 s (do not use open
flame when heating; do not stir when adding reagent or heating, so as to avoid
clot formation). Cool to room temperature; stir 3 ~ 4 times during cooling. Use
the sintered-glass filter crucible, which has been dried to a constant mass at
180°C ± 5°C or 250 °C ± 10 °C in advance, to suction-filter the supernatant;
take decantation to wash the precipitate for 5 ~ 6 times, each with about 20 mL
of water. Transfer the precipitate to the sintered-glass filter crucible; continue to
use water to wash for 3 ~ 4 times. Place the sintered-glass filter crucible in an
electrically heated drying oven at 180 °C ± 5 °C, to bake for 45 min; or bake at
250 °C ± 10 °C for 15 min; take it out; place in a desiccator to cool to room
temperature; weigh to the nearest 0.000 2 g.
6.5.1.5 Result calculation
The phosphoric acid content is calculated by the mass fraction w1 of phosphoric
acid (H3PO4); the value is expressed in %; it is calculated according to Formula
(1):
Where:
m1 -- the value of the mass of the quinoline phosphomolybdate precipitate that
is formed in the test solution, in grams (g);
m2 -- the value of the mass of the quinoline phosphomolybdate precipitate that
is formed in the blank solution, in grams (g);
m -- the value of the mass of the sample, in grams (g);
0.044 28 -- the value of quinoline phosphomolybdate that is converted to
phosphoric acid.
6.7.2.1 Ethanol: 95% (volume fraction);
6.7.2.2 Hydrochloric acid solution: 1+3;
6.7.2.3 Barium chloride (BaCl2·2H2O) solution: 250 g/L;
6.7.2.4 Sulfate standard solution: 1 mL of solution contains 0.010 mg of sulfate
(SO4); prepare when needed.
Pipette 1 mL of the sulfate standard solution that is prepared according to HG/T
3696.2; place it in a 100 mL volumetric flask; use water to dilute to the mark;
shake well.
6.7.3 Analysis steps
For superior and first-class products, weigh 1.00 g ± 0.01 g of samples; for
qualified products, weigh 0.50 g ± 0.01 g of samples; put them in 25 mL
colorimetric tubes; add 10 mL of water, 5 mL of ethanol, 1 mL of hydrochloric
acid solution; add 3 mL of barium chloride solution dropwise when shaking
continuously; use water to dilute to the mark; shake well. Let stand for 10 min;
compare with the sulfate standard turbidimetric solution.
Preparation of sulfate standard turbidimetric solution: for the superior products,
transfer 3.0 mL of sulfate standard solution; for the first-class and qualified
products, transfer 5.0 mL of sulfate standard solution; place in a 25 mL
colorimetric tube; treat at the same time as the sample.
6.8 Determination of iron content
6.8.1 Method summary
Same as Chapter 3 of GB/T 3049-2006.
6.8.2 Reagents
Same as Chapter 4 of GB/T 3049-2006.
6.8.3 Instruments
Same as Chapter 5 of GB/T 3049-2006.
6.8.4 Analysis steps
6.8.4.1 Drawing of the working curve
According to 6.3 of GB/T 3049-2006, use a 2 cm absorption cell and the
corresponding iron standard solution to draw the working curve.
6.8.4.2 Preparation of test solution
Weigh about 3 g, to the nearest 0.01 g, of the sample; put it in a 100 mL
volumetric flask; add water to about 60 mL; use hydrochloric acid solution or
ammonia solution to adjust the pH of the solution to approximately 2 (use
precision pH test paper to check). Add 1 mL of ascorbic acid solution, 20 mL of
buffer solution, 10 mL of phenanthroline solution; use water to dilute to the mark;
shake well.
6.8.4.3 Preparation of blank test solution
Except that no sample is added, the amount of other added reagents is exactly
the same as that of the test solution. The same treatment is carried out
simultaneously with the sample.
6.8.4.4 Determination
Take the test solution and the blank test solution; select a 2 cm absorption cell;
measure the absorbance according to 6.3.3 of GB/T 3049-2006.
Subtract the absorbance of the blank test solution from the absorbance of the
test solution; find out the mass of iron in the test solution according to the
working curve.
6.8.5 Result calculation
The iron content is calculated by the mass fraction w2 of iron (Fe); the value is
expressed in %; it is calculated according to Formula (3):
Where:
m1 -- the value of the mass of iron in the test solution, in milligrams (mg);
m -- the value of the mass of the sample, in grams (g).
Take the arithmetic mean of the parallel determinations as the determination
result. The absolute difference between the results of two parallel
measurements shall not be greater than 0.000 2%.
6.9 Determination of arsenic content
6.9.1 Method summary
Same as Chapter 3 of GB/T 610.1-1988.
6.9.2 Reagents
Same as Chapter 4 of GB/T 610.1-1988.
......
 
(Above excerpt was released on 2020-03-31, modified on 2021-06-07, translated/reviewed by: Wayne Zheng et al.)
Source: https://www.chinesestandard.net/PDF.aspx/GBT2091-2008