GB/T 6730.64-2022_English: PDF (GB/T6730.64-2022)
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Iron ores -- Determination of water soluble chloride content -- Ion-selective electrode method
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Iron ores -- Determination of water soluble chloride content -- Ion-selective electrode method
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| Standard ID | GB/T 6730.64-2022 (GB/T6730.64-2022) | | Description (Translated English) | Iron ores -- Determination of water soluble chloride content -- Ion-selective electrode method | | Sector / Industry | National Standard (Recommended) | | Classification of Chinese Standard | D31 | | Classification of International Standard | 73.060.10 | | Word Count Estimation | 14,121 | | Date of Issue | 2022-10-14 | | Date of Implementation | 2022-10-12 | | Older Standard (superseded by this standard) | GB/T 6730.64-2007 | | Drafting Organization | Ningbo Institute of Inspection and Quarantine Science and Technology, Qingdao Yuancheng Zongheng Technology Co., Ltd., Metallurgical Industry Information Standards Institute | | Administrative Organization | National Iron Ore and Direct Reduced Iron Standardization Technical Committee (SAC/TC 317) | | Proposing organization | China Iron and Steel Association | | Issuing agency(ies) | State Administration for Market Regulation, National Standardization Management Committee | | Standard ID | GB/T 6730.64-2007 (GB/T6730.64-2007) | | Description (Translated English) | Iron ores. Determination of water soluble chloride content. Ion-selective electrode method | | Sector / Industry | National Standard (Recommended) | | Classification of Chinese Standard | D31 | | Classification of International Standard | 73.060.10 | | Word Count Estimation | 12,151 | | Date of Issue | 2007-08-14 | | Date of Implementation | 2008-03-01 | | Adopted Standard | ISO 9517-1989, MOD | | Drafting Organization | Baoshan Iron & Steel Co., Ltd. | | Administrative Organization | Metallurgical Industry Information Standards Institute | | Regulation (derived from) | China National Standard Approval Announcement2007 No.8 (Total No.108) | | Proposing organization | China Iron and Steel Association | | Issuing agency(ies) | Administration of Quality Supervision, Inspection and Quarantine of People's Republic of China; Standardization Administration of China | | Summary | This standard specifies the ion selective electrode method for the determination of water soluble chloride content of iron ore. This section applies to natural iron ore, iron ore, determination of water soluble chloride content of pellets and sinter. Measuring range (mass fraction, chlorine meter): 0. 005% to 0. 1 %. Note: The water soluble chloride refers to the nearly neutral conditions using aqueous leaching, filter, obtained by extraction of iron chloride content portion. |
GB/T 6730.64-2022
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 73.060.10
CCS D 31
Replacing GB/T 6730.64-2007
Iron Ores - Determination of Water Soluble Chloride
Content - Ion-selective Electrode Method
(ISO 9517:2007, Iron Ores - Determination of Water-soluble Chloride - Ion-selective
Electrode Method, MOD)
ISSUED ON: OCTOBER 12, 2022
IMPLEMENTED ON: OCTOBER 12, 2022
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
Introduction ... 5
1 Scope ... 6
2 Normative References ... 6
3 Terms and Definitions ... 7
4 Principle ... 7
5 Reagents and Materials ... 7
6 Instruments ... 9
7 Sampling and Sample Preparation ... 9
8 Analytical Procedures ... 10
9 Result Calculation and Expression ... 13
10 Test Report ... 15
Appendix A (informative) Constituent Documents of GB/T 6730 ... 16
Appendix B (normative) Acceptance Procedures for Specimen Analysis Results ... 21
Appendix C (informative) Specimens Used for Precision ... 22
Iron Ores - Determination of Water Soluble Chloride
Content - Ion-selective Electrode Method
WARNING---the personnel adopting this document shall have practical experience in
regular laboratory work. This document does not point out all possible safety issues. The
user is responsible for taking appropriate safety and health measures and ensuring
compliance with the conditions stipulated in relevant national regulations.
1 Scope
This document specifies the method for the determination of water soluble chloride content in
iron ores using ion-selective electrodes.
This document is applicable to the determination of water soluble chloride content in natural
iron ores, iron ore concentrates, sinters and pellets. The determination range (mass fraction) is:
0.007% ~ 0.1%.
NOTE: the water soluble chloride content in iron ores refers to the chlorine obtained by leaching
iron ores with aqueous solution under near-neutral conditions.
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 6682 Water for Analytical Laboratory Use - Specification and Test Methods (GB/T 6682-
2008, ISO 3696:1987, MOD)
GB/T 6730.1 Iron Ores - Preparation of Predried Test Samples for Chemical Analysis (GB/T
6730.1-2016, ISO 7764:2006, MOD)
GB/T 8170 Rules of Rounding off for Numerical Values & Expression and Judgement of
Limiting Values
GB/T 10322.1 Iron Ores - Sampling and Sample Preparation Procedures (GB/T 10322.1-2014,
ISO 3082:2009, IDT)
GB/T 12805 Laboratory Glassware - Burettes (GB/T 12805-2011, ISO 385:2005, NEQ)
GB/T 12806 Laboratory Glassware - One-mark Volumetric Flasks (GB/T 12806-2011, ISO
1042:1998, NEQ)
GB/T 12808 Laboratory Glassware - One-mark Pipettes
3 Terms and Definitions
This document does not have terms or definitions that need to be defined.
4 Principle
The specimen is leached with potassium sulfate aqueous solution, and the obtained suspension
is transferred to a volumetric flask, diluted to the scale, and dry-filtered. Take part of the filtrate,
add potassium persulfate solution, neutral buffer solution and ionic strength adjustment solution;
use a chloride ion-selective electrode and a double-joint reference electrode to determine the
concentration of chloride ions in the test solution.
5 Reagents and Materials
Unless otherwise stated, only approved analytically pure reagents and distilled water of Grade-
2 or above that complies with the stipulations of GB/T 6682 or water of equivalent purity are
used in the analysis.
The preparation of reagents and calibration solutions, as well as all operations specified in
Chapter 6 ~ Chapter 8, shall be effectively isolated from the place where hydrochloric acid is
used.
5.1 Potassium sulfate (K2SO4) solution, 2 g/L.
5.2 Potassium persulfate (K2S2O8) solution, 15 g/L. Prepare it right before use.
5.3 Sodium nitrate (NaNO3) solution, 5 mol/L. Dissolve 42.5 g of sodium nitrate in about 60
mL of water, transfer it to a 100 mL volumetric flask, use water to dilute to the scale, and mix
it well.
5.4 Phosphate buffer solution. Dissolve 2.72 g of potassium dihydrogen phosphate (KH2PO4)
and 2.84 g of disodium hydrogen phosphate (Na2HPO4) in about 40 mL of water, transfer it to
a 100 mL volumetric flask. Use water to dilute to the scale and mix it well.
5.5 Cleaning fluid. Under constant stirring, carefully and slowly add 150 mL of phosphoric acid
(ρ 1.84 g/mL) and 150 mL of phosphoric acid (ρ 1.7 g/mL) to 700 mL of water, and mix it well.
5.6 Chlorine standard solution A, 1.00 mg/mL. Weigh-take 0.8240 g of sodium chloride
reference material, dissolve it in about 50 mL of water, then, transfer it to a 500 mL volumetric
flask; use water to dilute to the scale and mix it well. Sodium chloride is pre-burned at 500 C
~ 600 C to a constant weight, then, cooled to room temperature.
5.7 Chlorine standard solution B, 100 g/mL. Take 50.00 mL of chlorine standard solution A
Chlorine calibration solutions containing 1.0 g/mL ~ 10.0 g/mL shall be prepared on the
same day.
6 Instruments
6.1 Burettes, one-mark volumetric flasks and one-mark pipettes: shall respectively comply with
the stipulations of GB/T 12805, GB/T 12806 and GB/T 12808.
6.2 Magnetic stirrer.
6.3 Electric heating magnetic stirrer: or water bath with ultrasonic wave. Set the heating power
to maintain 35 mL of water at 90 C ~ 95 C.
6.4 Electric hot plate: set the heating power to rise 50 mL of water to at least 90 C (under non-
boiling conditions) in 25 min.
6.5 Plastic stirring rod: coated with PTFE or polyethylene, length: 25 mm ~ 30 mm. Before use,
the stirring rod shall be cleaned in the cleaning liquid (see 5.5) for 30 min, then, washed with
water for 30 min, to avoid possible chlorine contamination caused by iron ore powder adhesion
or other reasons. The cleaned stirring rod shall be picked up with clean tweezers. Or plastic
magnetic stirrers coated with PTFE or polyethylene can also be used, and the cleaning method
is the same.
6.6 Suction filtration device: diameter 25 mm ~ 50 mm, equipped with glass or polycarbonate
plastic microporous filter membrane with a pore size less than 1 m. The microporous filter
membrane shall only be handled with clean tweezers.
6.7 Ion-selective potentiometer: or high-sensitive pH meter, or high-impedance millivolt meter,
with a reading accuracy of 0.1 mV.
6.8 Chloride ion-selective electrode and independent double salt bridge reference electrode:
both electrodes shall be maintained and used in accordance with the instructions provided by
the manufacturer. The solution in the outer chamber of the reference electrode shall be replaced
as specified and filled when necessary. The flow rate along the nitrate / test solution interface
shall be adjusted, so that the liquid level in the outer chamber maintains a falling speed of
approximately 4 mm/d ~ 5 mm/d.
Chloride ion-selective electrodes are sensitive to light and shall not be used in direct sunlight
or under strong light.
7 Sampling and Sample Preparation
7.1 Laboratory Specimens
In accordance with GB/T 10322.1, take and prepare the specimens. Generally, the particle size
of the specimens shall be less than 100 m. If the content of combined water or readily
oxidizable substances in the specimens is high, the particle size shall be less than 160 m.
The stipulations for high content of combined water and readily oxidizable substances shall
comply with GB/T 6730.1.
7.2 Preparation of Pre-dried Specimens
Thoroughly mix the laboratory specimens and adopt the sample reduction method for sampling.
In accordance with the stipulations of GB/T 6730.1, at 105 C 2 C, dry the specimens, and
cool them to room temperature in a desiccator for later use.
8 Analytical Procedures
8.1 Number of Determinations
In accordance with Appendix B, the same dried specimen shall be independently determined at
least twice.
NOTE: “independent” means that the results of the second and any subsequent determinations are
not affected by the previous one. In this document, this condition means repeated
determinations conducted by the same operator at different times or by different operators,
including the application of appropriate re-calibration.
8.2 Blank Test and Verification Test
8.2.1 Blank test
Due to technical reasons, the conventional blank test does not apply to the ion-selective
electrode method. This method uses the step of 8.3.2 to replace the blank test.
8.2.2 Verification test
Along with each batch of test specimens, under the same conditions, analyze the same type of
reference materials for verification test. The pre-drying of the reference materials shall be
carried out in accordance with the stipulations of 7.2.
If multiple specimens of the same type are simultaneously analyzed, the analysis value of
reference material can be used.
8.3 Preparation before Test
8.3.1 Electrode inspection
Before using the electrode for each test, the electrode performance shall be inspected in
accordance with the following steps.
a) Add 100 mL of water and 2 mL of sodium nitrate solution to a 150 mL or 250 mL
beaker, and add a plastic stirring rod (see 6.5). Put the electrode into the solution, stir
be left for enough time to make the temperature between the test solution and the calibration
solution consistent.
In accordance with the potential value determined in the first round, and the sequence from low
to high concentration, re-arrange the calibration solution and the test solution, then, determine
another set of potential value. Take the second set of data as the determined value.
In accordance with the known chlorine mass concentration and corresponding determined
potential value in the calibration, draw the lg [Cl]E calibration curve. When necessary,
respectively draw the calibration curves for concentration segments that are not of the same
order of magnitude.
From the calibration curve, in accordance with the determined value of electrode potential of
the test solution, calculate the corresponding chlorine mass concentration.
NOTE: when the chlorine mass concentration is lower than 3 g/mL, the curve may bend to a
certain extent. The extent of bending may vary due to differences in electrode performance.
9 Result Calculation and Expression
9.1 Calculation of Water Soluble Chloride Content
In accordance with Formula (1), calculate the water soluble chloride content (mass fraction) wCl
in the specimen, expressed in (%).
Where,
ρCl---the chlorine mass concentration in the test solution obtained from the calibration curve,
expressed in (g/mL);
m---the mass of specimen, expressed in (g).
9.2 General Processing of Analysis Results
9.2.1 Precision
The functional relation of precision in this document is shown in Table 4. The specimen used
for precision test is shown in Appendix C.
Through the C value of the certified reference material (CRM) or reference material (RM)
determined among multiple laboratories, calculate in accordance with Formula (3):
Where,
R---the inter-laboratory reproducibility limit;
r---the intra-laboratory repeatability limit;
n---the number of repeated determinations of the reference material;
u---the uncertainty of the standard value of CRM or RM.
9.2.5 Calculation of final result
The final result of the specimen is the arithmetic mean of the acceptable analysis values, or the
value determined in accordance with the stipulations of Appendix B. The calculation is accurate
to the fifth decimal place, and the report is accurate to the third decimal place. The values shall
be rounded off in accordance with the stipulations of GB/T 8170.
10 Test Report
The test report shall include the following information:
a) Laboratory name and address;
b) Release date of test report;
c) Serial No. of this document;
d) Detailed description necessary for specimen identification;
e) Analysis results;
f) Serial No. corresponding to the analysis results;
g) Any abnormal characteristics during the determination and any operations not
specified in this document that may affect the analysis results of the specimen or
reference material.
......
GB/T 6730.64-2007
Iron ores. Determination of water soluble chloride content. Ion-selective electrode method
ICS 73.060.10
D31
National Standards of People's Republic of China
Determination of water soluble chloride content in iron ore
Ion Selective Electrode
(ISO 9517. 1989, MOD)
Posted 2007-08-14
2008-03-01 implementation
Administration of Quality Supervision, Inspection and Quarantine of People's Republic of China
Standardization Administration of China released
Foreword
GB/T 6730 partial modification of the present international standard ISO 9517. 1989 "Determination of water soluble chloride content of iron ore from
Sub-selective electrode. "
This part of International Standard ISO 9517. 1989 Comparison major amended as follows.
--- "2 Normative references" by our standards instead of the corresponding international standards;
--- "4.6 chlorine standard solution" in this part of sodium chloride drying conditions by the ISO 9517. 1989 in "105 ℃ for 1 hour and dried
Cool to room temperature "with" at 500 ℃ ~ 600 ℃ to constant burning ";
--- This part of ISO 9517. 1989's "4.8 chlorine standard solution B, 50μg/mL" and "4.9 chlorine standard solution C, 20μg/mL"
We merged and adopted the "4.7 chlorine standard solution B, 100μg/mL" formulated series of calibration solutions. Table 2 with calibration solution
The concentration of the lowest point of the system by "2μg/mL" to "1.5μg/mL", equivalent to the chlorine content of the sample was 0.005%, and this section
The lower limit is consistent measurement range;
--- "5.2" the provisions of this section adds, "Note" allows the use of an ultrasonic water bath with ongoing water soluble chloride sample
Leaching;
--- This section "4.8 calibration solution", the potassium concentration of the solution used by the ISO 9517. 1989 in "4g/L" to "2g/L",
Added the same amount. Cancel ISO 9517. 1989 in "4.2 potassium sulfate (K2SO4) solution, 4g/L";
--- This section "7.5 Sample volume" by the ISO 9517. 1989 in "2g" changed to "3.0g". Accordingly, the "test solution at 8.6.3
Reason "by the amount of test solution dispensation" 45mL "changed to" 25mL ";" 9.1 Calculation of water-soluble chloride content "in the calculation formula
Also revised accordingly.
Appendix A of this section is normative appendix, Appendix B and Appendix C are informative appendices.
This part is proposed by the China Iron and Steel Association.
This section is under the jurisdiction of Metallurgical Industry Information Standards Institute.
This section is drafted. Baoshan Iron & Steel Co., Ltd.
The main drafters of this section. Jihong Ling, Liu Xiaoping, Xu Yuan Cai, Wang Weimin.
Determination of water soluble chloride content in iron ore
Ion Selective Electrode
Warning --- Use this section shall be a person experiences regular laboratory work. This section does not point out all possible security asked
question. Users have the responsibility to take appropriate safety and health practices and to ensure compliance with matters relevant national regulations.
1 Scope
GB/T 6730 This section specifies the determination of water-soluble chloride content in iron ore by ion selective electrode method.
This section applies to natural iron ore, iron ore assay, pellets and sinter water-soluble chloride content. Measuring range (mass
Score, chlorine basis). 0.005% to 0.1%.
Note. Water-soluble chloride refers to the near-neutral conditions, with an aqueous leaching, filtration, iron ore extracted in part chlorine content.
2 Normative references
The following documents contain provisions which, through reference to GB/T 6730 to the present, constitute provisions of this section. For dated reference documents
Member, all subsequent amendments (not including errata content) or revisions do not apply to this section, however, encouraged to reach under this section
Parties to research agreement to use the latest versions of these documents. For undated reference documents, the latest versions apply to this
section.
GB/T 6682 analytical laboratory use specifications and test methods (GB/T 6682-1992, neq ISO 3696. 1987)
GB/T 6730.1 Methods for chemical analysis of iron pre-drying of the sample preparation (GB/T 6730.1-1986 use, eqv ISO
7764. 1985)
GB/T 10322.1 mechanical ore sampling and sample preparation method (GB/T 10322.1-2000, idt ISO 3082.1998)
GB/T 12805 Laboratory glassware burette (GB/T 12805-1991, neq ISO 385. 1984)
GB/T 12806 Laboratory glassware Single Groove flask (GB/T 12806-1991, neq ISO 1042. 1983)
GB/T 12808 Laboratory glassware Single Groove pipette (GB/T 12808-1991, neq ISO 648. 1977)
Principle 3
Sample with potassium sulfate solution was stirred 1h at 90 ℃ ~ 95 ℃ water soluble chloride leaching. The suspension was transferred into a volumetric flask, and dilute
Explanation to the mark. Dry filter, aliquot of the test solution, and potassium sulfate solution used after neutral buffer solution, sodium nitrate was added to adjust the ionic strength
Solution, chlorine ion selective electrode and double-joint chloride ion concentration reference measuring electrode.
4 Reagents and materials
Analysis Unless otherwise stated, use only reagents of recognized analytical grade and distilled water or equivalent purity of its water, in line with GB/T 6682
Provisions.
Preparation of reagents and calibration solutions, and all actions in this section as specified in Chapter 6, 7 and using hydrochloric acid to be effective places
isolation.
4.1 sulfate (of K2SO4) solution, 2g/L.
4.2 potassium persulfate (K2S2O8) solution, 15g/L. When using the existing service.
4.3 sodium nitrate (of NaNO3) solution of Ba (NaNO3) = 5mol/L.
The 42.5g of sodium nitrite dissolved in about 60mL of water into the 100mL volumetric flask, dilute with water to volume, and mix.
4.4 phosphate buffer solution.
......
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