GB/T 5686.7-2022 PDF in English
GB/T 5686.7-2022 (GB/T5686.7-2022, GBT 5686.7-2022, GBT5686.7-2022)
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Ferromanganese, ferromanganese-silicon, nitrogen-bearing ferromanganese and manganese metal -- Determination of sulfur content -- Infrared absorption method and combustion-neutralization method
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| GB/T 5686.7-2008 | English | 150 |
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Ferromanganese, ferromanganese-silicon, nitrogen-bearing ferromanganese and manganese metal -- Determination of sulfur content -- Infrared absorption method and combustion-neutralization method
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| GB/T 5686.7-1988 | English | 199 |
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Methods for chemical analysis of silicomanganese alloy--The infrared absorption method for the determination of sulfur content
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Standards related to (historical): GB/T 5686.7-2022
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GB/T 5686.7-2022: PDF in English (GBT 5686.7-2022) GB/T 5686.7-2022
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.100
CCS H 11
Replacing GB/T 5686.7-2008
Ferromanganese, Ferromanganese-silicon, Nitrogen-bearing
Ferromanganese and Manganese Metal - Determination of
Sulfur Content - Infrared Absorption Method and
Combustion-neutralization Method
ISSUED ON: DECEMBER 30, 2022
IMPLEMENTED ON: JULY 1, 2023
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
Introduction ... 6
1 Scope ... 8
2 Normative References ... 8
3 Terms and Definitions ... 9
4 Method 1 - Infrared Absorption Method ... 9
5 Method 2 - Combustion-neutralization Method ... 14
6 Test Report ... 21
Appendix A (normative) Specimen Analysis Result Acceptance Procedure Flow Chart
... 22
Appendix B (informative) Additional Information on Joint Precision Test ... 23
Ferromanganese, Ferromanganese-silicon, Nitrogen-bearing
Ferromanganese and Manganese Metal - Determination of
Sulfur Content - Infrared Absorption Method and
Combustion-neutralization Method
WARNING---the personnel using this document shall have practical experience in formal
laboratory work. This document does not point out all possible safety issues. It is the user’s
responsibility to take appropriate safety and health measures and ensure compliance with
the conditions stipulated in relevant national regulations.
1 Scope
This document describes the method of determining the sulfur content in ferromanganese,
ferromanganese-silicon, nitrogen-bearing ferromanganese and manganese metal, using the
infrared absorption method and combustion-neutralization method.
This document is applicable to the determination of sulfur content in ferromanganese,
ferromanganese-silicon, nitrogen-bearing ferromanganese and manganese metal. For Method
1, the determination range (mass fraction) is: 0.003% ~ 0.120%; for Method 2, the
determination range (mass fraction) is: 0.015% ~ 0.120%. Method 2 is not suitable for the
determination of sulfur content in nitrogen-bearing ferromanganese.
2 Normative References
The contents of the following documents constitute indispensable clauses of this document
through the normative references in the text. In terms of references with a specified date, only
versions with a specified date are applicable to this document. In terms of references without a
specified date, the latest version (including all the modifications) is applicable to this document.
GB/T 4010 Ferroalloys Sampling and Preparation of Samples for Chemical Analysis
GB/T 6379.1 Accuracy (trueness and precision) of Measurement Methods and Results - Part 1:
General Principles and Definitions
GB/T 6379.2 Accuracy (trueness and precision) of Measurement Methods and Results - Part 2:
Basic Method for the Determination of Repeatability and Reproducibility of a Standard
Measurement Method
GB/T 6682 Water for Analytical Laboratory Use - Specification and Test Methods
GB/T 8170 Rules of Rounding off for Numerical Values & Expression and Judgement of
Limiting Values
3 Terms and Definitions
This document does not have terms or definitions that need to be defined.
4 Method 1 - Infrared Absorption Method
4.1 Principle
The test portion is burned in a high-frequency induction furnace with oxygen flow, and the
sulfur is oxidized into sulfur dioxide, which is carried to the infrared absorption cell with the
oxygen flow. The infrared detector measures its absorption of infrared rays of a specific
wavelength. The absorption value is proportional to the flowing sulfur dioxide, and the sulfur
content can be determined in accordance with the changes in energy received by the detector.
4.2 Reagents and Materials
4.2.1 Acetone, the residue after evaporation contains less than 0.0005% sulfur.
4.2.2 Magnesium perchlorate, anhydrous, granular.
4.2.3 Caustic soda asbestos, granular.
4.2.4 Glass wool.
4.2.5 Tungsten particles, with sulfur content less than 0.0005% and a particle size 0.8 mm ~ 1.4
mm.
4.2.6 Tin particles, with sulfur content less than 0.0005% and a particle size 0.4 mm ~ 0.8 mm.
If necessary, acetone (see 4.2.1) shall be used to clean the surface.
4.2.7 Oxygen, with a purity greater than 99.95%. Other grades of oxygen may also be used if a
low and consistent blank can be obtained.
4.2.8 Power gas source, nitrogen, argon or compressed air, with impurity (water and oil) content
less than 0.5%.
4.3 Instruments and Equipment
4.3.1 High-frequency infrared carbon and sulfur analyzer or infrared absorption sulfur
analyzer
4.3.1.1 High-frequency infrared carbon and sulfur analyzer or infrared absorption sulfur
analyzer (with a sensitivity of 0.0001%). The device connection is shown in Figure 1.
4.3.1.2 Gas cleaning bottle, filled with caustic soda asbestos (see 4.2.3).
regulator and a timing control part that ensures appropriate pressure and rated flow.
4.3.3 High-frequency induction furnace
It shall satisfy the requirements for the melting temperature of the test portion.
4.3.4 Control System
4.3.4.1 The microprocessor system includes a central processing unit, memory, keyboard input
device, information center display screen, analysis result display screen and analysis result
printer, etc.
4.3.4.2 The control functions include automatic loading and unloading of crucibles and furnace
table lifting, automatic cleaning, analysis condition selection and setting, analysis process
monitoring and alarm interruption, analysis data collection, calculation, correction and
processing, etc.
4.3.5 Measurement system
It is mainly composed of an electronic balance (with a sensitivity not greater than 0.001 g)
controlled by a microprocessor, an infrared analyzer and electronic measuring elements.
4.3.6 Ceramic crucible
The size of the ceramic crucible is 23 mm 23 mm or 25 mm 25 mm. It is burned in a
high-temperature heating furnace above 1,200 C for 4 hours or burned with oxygen, until the
blank value is the lowest.
4.4 Sampling and Specimen Preparation
In accordance with the stipulations of GB/T 4010, take and prepare specimens. The
ferromanganese-silicon specimens shall pass a 0.125 mm sieve, the ferromanganese and
nitrogen-bearing ferromanganese specimens shall pass a 0.149 mm sieve, and the manganese
metal specimens shall pass a 0.177 mm sieve.
4.5 Analytical Procedures
4.5.1 Number of determinations
For the same specimen, carry out at least 2 independent determinations.
4.5.2 Amount of test portion
The amount of test portion is weighed in accordance with Table 1 and the category of the
specimen to be tested, accurate to 0.001 g.
Table 1 -- Amount of Test Portion
Category Amount of Test Portion
Under the reproducibility conditions, two different operators from different laboratories use the
routine and correct operation of this method to conduct two independent determinations on the
same specimen, the absolute difference shall not be greater than the reproducibility limit R, and
the situation of exceeding the reproducibility limit R shall not exceed 5%.
5 Method 2 - Combustion-neutralization Method
5.1 Principle
The test portion is burned with oxygen at high temperature to oxidize all the sulfur into sulfur
dioxide, which is absorbed into the hydrogen peroxide solution and turned into sulfuric acid,
which is titrated with sodium hydroxide standard solution. Calculate the sulfur content.
5.2 Reagents and Materials
Unless otherwise stated, only reagents confirmed to be analytical pure shall be used in the
analysis, and the test water is distilled water that is Grade-3 or above in compliance with GB/T
6682 and has been boiled to drive out carbon dioxide and cooled.
5.2.1 Oxygen, with a purity greater than 99.5%.
5.2.2 Fluxing agent, tin particles and pure iron, etc. The sulfur content in the fluxing agent shall
be less than 0.001%. The tin particles have a particle size of 0.4 mm ~ 0.8 mm and sulfur content
less than 0.0005%. The pure iron is in the form of chips, has no dust and has sulfur content less
than 0.0005%.
5.2.3 Silica gel, activated alumina or magnesium perchlorate. Silica gel, bead-shaped particles,
no adhesion, consistent in color. Activated alumina has a particle size less than 80 mesh; it is
firstly soaked in 1 mol/L hydrochloric acid for several hours, then, rinsed several times with
clean water. Each time, the fine particles that have not settled within 10 seconds after shaking
are discarded, then, set aside. Magnesium perchlorate, anhydrous, granular.
5.2.4 Soda lime or sodium hydroxide, granular.
5.2.5 For chromic acid-saturated sulfuric acid solution, add potassium dichromate or chromic
anhydride to sulfuric acid (ρ = 1.84 g/mL), until it is saturated, and use the upper part of settled
solution.
5.2.6 Absorption solution: transfer-take 3.5 mL of hydrogen peroxide (ρ = 1.10 g/mL), use
water to dilute it to 1,000 mL and mix it well.
5.2.7 Methyl red-methylene blue mixed indicator: weigh-take 0.1250 g of methyl red and
0.0860 g of methylene blue, use absolute ethanol to dissolve and dilute it to 100 mL, and mix
it well.
5.2.8 Bromothymol blue indicator, (1 g/L). Weigh-take 0.1 g of bromothymol blue and dissolve
it in 50 mL of absolute ethanol, and use water to dilute it to 100 mL.
5.2.9 Sulfamic acid standard solution. Weigh-take 0.2500 g of sulfamic acid (NH2SO3H) that
has been dried in a vacuum sulfuric acid desiccator for about 48 hours and has a purity greater
than 99.90% in a 300 mL beaker, add water to completely dissolve it. Transfer it to a 500 mL
brown volumetric flask, use water to dilute to the scale and mix it well. The concentration of
this solution is about 0.005 mol/L.
5.2.10 Sodium hydroxide standard titration solution, cNaOH = 0.005 mol/L. Weigh-tale 0.2000 g
of sodium hydroxide and dissolve it in 1,000 mL of water. Add 1 mL of newly prepared barium
hydroxide saturated solution, mix it well; isolate the carbon dioxide and leave it for 2 days ~ 3
days. When using, take the upper part of settled solution.
Adopt the following two methods to calibrate the sodium hydroxide standard titration solution:
a) Use sulfamic acid standard solution for calibration. Transfer-take 20.00 mL of
sulfamic acid standard solution (see 5.2.9), place it in a 250 mL conical flask, add 100
mL of water and 10 drops of bromothymol blue indicator (see 5.2.8), and immediately
use sodium hydroxide standard titration solution to titrate it, until the solution changes
from yellow to pure blue and remains unchanged for 30 seconds, which is the end
point.
Transfer-take 120 mL of water into a 250 mL conical flask, add 10 drops of
bromothymol blue indicator (see 5.2.8), and immediately use sodium hydroxide
standard titration solution to titrate it, until the solution changes from yellow to pure
blue and remains unchanged for 30 seconds, which is the end point.
In accordance with Formula (1), calculate the concentration of the sodium hydroxide
standard titration solution:
Where,
c---the concentration of the sodium hydroxide standard titration solution, expressed
in (mol/L);
m---the weighed mass of sulfamic acid, expressed in (g);
f---the purity of sulfamic acid, expressed in (%);
V---the volume of the sodium hydroxide standard titration solution consumed during
calibration, when the range of 3 portions is not greater than 0.10 mL, take the average
value, expressed in (mL);
V0---the volume of the sodium hydroxide standard titration solution consumed by the
reagent blank during calibration, expressed in (mL);
97.093---the molar mass of sulfamic acid, expressed in (g/mol).
continue to use the sodium hydroxide standard titration solution (see 5.2.10) to titrate it to bright
green, then, stop oxygen introduction. Use the above-mentioned absorption solution to wash
the drying tube (see 15 in Figure 2) and the pipelines of the connecting parts; introduce it into
the absorption bottle. If the solution turns red purple, continue to use the sodium hydroxide
standard titration solution (see 5.2.10) to titrate it to bright green, which is the end point.
5.5.5.3 Suitable for ferromanganese: at a flow rate of 200 mL/min, introduce oxygen to burn
the test portion for 5 minutes, then, at a flow rate (inlet flow rate) of 700 mL/min ~ 900 mL/min
of oxygen, introduce into the absorption bottle (see 16 of Figure 2) to allow sulfur dioxide to
be absorbed. After burning for 10 minutes, use the sodium hydroxide standard titration solution
(see 5.2.10) to titrate the solution from red purple to bright green. Then, at a flow rate of 1,000
mL/min ~ 1,200 mL/min of oxygen, use the two-way piston (see 9 in Figure 2) to control
intermittent oxygen introduction for 5 minutes. If the solution turns red purple, continue to use
the sodium hydroxide standard titration solution (see 5.2.10) to titrate it to bright green, then,
stop oxygen introduction. Use the above-mentioned absorption solution to wash the drying tube
(see 15 in Figure 2) and the pipelines of the connecting parts; introduce it into the absorption
bottle. If the solution turns red purple, continue to use the sodium hydroxide standard titration
solution (see 5.2.10) to titrate it to bright green, which is the end point.
5.5.5.4 Suitable for manganese metal: at a flow rate (inlet flow rate) of 700 mL/min ~ 900
mL/min of oxygen, immediately introduce into the absorption bottle (see 16 of Figure 2) to
allow sulfur dioxide to be absorbed. After burning for 10 minutes, use the sodium hydroxide
standard titration solution (see 5.2.10) to titrate the solution from red to bright green. Then, at
a flow rate of 1,000 mL/min ~ 1,200 mL/min of oxygen, use the two-way piston (see 9 in Figure
2) to control intermittent oxygen introduction for 5 minutes. If the solution turns red purple,
continue to use the sodium hydroxide standard titration solution (see 5.2.10) to titrate it to bright
green, then, stop oxygen introduction. Use the above-mentioned absorption solution to wash
the drying tube (see 15 in Figure 2) and the pipelines of the connecting parts; introduce it into
the absorption bottle. If the solution turns red purple, continue to use the sodium hydroxide
standard titration solution (see 5.2.10) to titrate it to bright green, which is the end point.
5.5.6 Expression of analysis results
In accordance with Formula (3), calculate the sulfur content ws in the specimen, expressed in
mass fraction (%):
Where,
c---the concentration of the sodium hydroxide standard titration solution, expressed in (mol/L);
V2---the volume of the sodium hydroxide standard titration solution consumed during the
titration of the test portion solution, expressed in (mL);
V3---the volume of the sodium hydroxide standard titration solution consumed when titrating
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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