Skip to product information
1 of 8

PayPal, credit cards. Download editable-PDF and invoice in 1 second!

GB/T 6730.5-2007 English PDF (GBT6730.5-2007)

GB/T 6730.5-2007 English PDF (GBT6730.5-2007)

Regular price $130.00 USD
Regular price Sale price $130.00 USD
Sale Sold out
Shipping calculated at checkout.
Quotation: 24-hr self-service. Click GB/T 6730.5-2007
See Chinese contents: GB/T 6730.5-2007

GB/T 6730.5-2007: Iron ores -- Determination of total iron content -- Titanium (???) chloride reduction methods

This Part of GB/T 6730 specifies the determination of total iron content by titration of potassium dichromate after reduction of iron with titanium (III) chloride. This Part applies to the determination of total iron content in natural iron ores, iron concentrates, and agglomerations, including sintered products. The determination range (mass fraction): 30.0%~72.0%.
GB/T 6730.5-2007
NATIONAL STANDARD OF THE
PEOPLE REPUBLIC OF CHINA
ICS 73.060.10
D 31
Replacing GB/T 6730.5-1986
Iron ores - Determination of total iron content -
Titanium (III) chloride reduction methods
(ISO 9507:1990, MOD)
ISSUED ON: AUGUST 14, 2007
IMPLEMENTED ON: MARCH 01, 2008
Issued by: General Administration of Quality Supervision, Inspection and Quarantine of the PRC;
Standardization Administration of the PRC.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Principle ... 6
4 Reagents ... 7
5 Apparatus ... 9
6 Sampling and samples ... 9
7 Analytical procedures ... 10
8 Result calculation ... 14
9 Test report ... 16
Appendix A (Normative) Flow chart for acceptance procedure of sample
analysis value ... 18
Appendix B (Informative) Precision expression ... 19
Foreword
This Part of GB/T 6703 modifies and adopts ISO 9507:1990 ?€?Iron ores -
Determination of total iron content - Titanium (III) chloride reduction methods?€?. Compared with ISO 9507:1990, this Part mainly makes the following changes: - In ?€?2 Normative references?€?, replace the corresponding international
standards with Chinese standards;
- In ISO 9507:1990, excess reducing agent is oxidized with dilute potassium dichromate (Method 1) or perchloric acid (Method 2). In this Part, use dilute potassium dichromate to oxidize;
- In ISO 9507:1990, for melting-acidification decomposition samples, use zirconium crucible or glassy carbon crucible; ADD sodium carbonate and
sodium peroxide. In this Part, use platinum crucible; ADD sodium carbonate and boric acid. Temperature and acidification conditions are adjusted
accordingly. The purpose of both is to completely decompose the sample; - In ISO 9507:1990, for melting-filtration decomposition samples, use
zirconium crucible or glassy carbon crucible. This Part uses a corundum crucible;
- In ISO 9507:1990, use isatin as an indicator of redox. This Part uses sodium tungstate. Both have the same effect. Sodium tungstate is currently widely used;
- ISO 9507:1990 does not specify the method used when the copper content is high. This Part specifies the separation method when the copper content is high.
This Part replaces GB/T 6730.5-1986 ?€?Methods for chemical analysis of iron ores - The titanium chloride-potassium dichromate volumetric method for the determination of total iron content?€?. Compared with GB/T 6730.5-1986, the main changes in this Part are as follows:
- ADD melting-acidification and melting-filtration decomposition sample methods;
- GB/T 6730.5-1986 blank titration uses two additions of ammonium ferrous sulfate solution. This Part uses the addition of iron standard solution. Appendix A of this Part is a normative appendix. Appendix B is an informative appendix.
Iron ores - Determination of total iron content -
Titanium (III) chloride reduction methods
WARNING: The personnel using this Part shall have practical experience
in regular laboratory work. This Part does not point out all possible safety problems. It is the responsibility of the user to take appropriate safety and health measures and to ensure compliance with the conditions stipulated by relevant national regulations.
1 Scope
This Part of GB/T 6730 specifies the determination of total iron content by titration of potassium dichromate after reduction of iron with titanium (III) chloride.
This Part applies to the determination of total iron content in natural iron ores, iron concentrates, and agglomerations, including sintered products. The determination range (mass fraction): 30.0%~72.0%.
2 Normative references
The following documents contain provisions which, through reference in this Part of GB/T 6730, constitute provisions of this Part. For the dated references, their subsequent amendments (excluding corrections) or revisions do not apply to this Part. However, the parties who enter into agreement based on this Part are encouraged to investigate whether the latest editions of these documents are applicable. For undated reference documents, the latest editions apply to this Part.
GB/T 6682 Water for analytical laboratory use - Specification and test
methods (GB/T 6682-1992, neq ISO 3696:1987)
GB/T 6730.1 Methods for chemical analysis of iron ores - Preparation of predried test samples for chemical analysis (GB/T 6730.1-1986, eqv ISO
7764:1985)
GB/T 6730.3 Methods for chemical analysis of iron ores - The gravimetric method for the determination of hygroscopic moisture content in analytical samples (GB/T 6730.3-1986, eqv ISO 2596:1984)
GB/T 10322.1 Iron ores - Sampling and sample preparation procedures
4.18 Potassium dichromate solution, 0.25 g/L.
4.19 Stannous chloride solution, 100 g/L.
Dissolve 100 g of stannous chloride crystal (SnCl2 ?€? 2H2O) in 200 mL of hydrochloric acid (4.5); dissolve by heating in a water bath. COOL the solution; USE water to dilute to 1 L. The solution shall be stored in a brown glass bottle with a small number of tin granules.
4.20 Titanium (III) chloride solution, 15 g/L.
USE 9 volumes of hydrochloric acid (4.6) to dilute 1 volume of titanium (III) chloride solution [about 15% titanium (III) chloride solution]. Another method is that: In a beaker with a watch glass, use about 30 mL of hydrochloric acid (4.5) to dissolve 1 g of titanium sponge. COOL the solution; USE water to dilute to 200 mL. Prepare at the time of use.
4.21 Iron standard solution, 0.05 mol/L.
TRANSFER 2.79 g of pure iron to a 500 mL conical beaker and place a filter cone at the neck. ADD 35 mL of hydrochloric acid (4.6) slowly and heat until dissolved. COOL and successively add a small amount of 5 mL of hydrogen peroxide oxidation solution. HEAT to boiling to decompose excess hydrogen peroxide and remove chlorine gas. TRANSFER to a 1000 mL volumetric flask and dilute to the mark.
1.00 mL of this solution is equivalent to 1.00 mL of standard potassium dichromate solution.
4.22 Standard solution of potassium dichromate, 0.01667 mol/L.
WEIGH 4.904 g of potassium dichromate (reference) which is pre-dried at 140??C~150??C for 2 h and cooled to room temperature in a desiccator to dissolve in water. After cooling to 20??C, transfer to a 1000 mL volumetric flask; USE water to dilute to the mark and mix well.
Note 1: The volumetric flask shall be checked first. At 20??C, the mass of the water contained is weighed and then converted into a volume.
Note 2: On the storage bottle, record the temperature at which the solution is diluted (20??C). 4.23 Sodium tungstate solution. WEIGH 25 g of sodium tungstate and dissolve it in an appropriate amount of water (If turbid, it needs to be filtered). ADD 5 mL of phosphoric acid (?? 1.70 g/mL); USE water to dilute to 100 mL.
4.24 Sodium diphenylamine sulfonate indicator solution, 0.2 g/100 mL.
GB/T 6730.3:
a) Processed ore containing metallic iron;
b) Natural or processed ore with a sulfur content greater than 0.2%;
c) Natural or processed ore containing more than 2.5% of combined water. 6.2.2 Ores other than 6.2.1
Thoroughly mix the laboratory samples. USE the increment division method to sample. In accordance with the provisions of GB/T 6730.1, the sample is dried at a temperature of 105??C??2??C.
7 Analytical procedures
7.1 Number of determinations
According to Appendix A, the same sample shall be determined at least twice independently.
Note: ?€?Independent?€? means that the results of the second and any subsequent determinations are not affected by the result of previous determination. In this analytical method, this condition means that the same operator repeats the determination at different times or by different operators, including the use of appropriate recalibration.
7.2 Test portion size
USE a non-magnetic weighing spoon (5.4) to weigh nearly 0.40 g of the test portion (6.2), accurate to 0.0002 g.
7.3 Blank test and verification test
7.3.1 Blank test
DO a blank test along with the test portion (see 7.5.4 for requirements). 7.3.2 Verification test
Along with the analysis of test portion, do a verification test of the same type of standard sample.
7.4 Determination of hygroscopic water
When the ore type meets the requirements of 6.2.1, while taking the total-iron measurement sample, the hygroscopic water content shall be determined
7.5.1.3 Melting-filtration [for samples containing more than 0.05% of vanadium and/or more than 0.1% of molybdenum, but not more than 0.1% of copper]
PUT the test portion (7.2) into a corundum crucible (5.1); ADD 1.3 g of sodium carbonate (4.2) and 2.7 g of sodium peroxide (4.3) and mix thoroughly. PLACE in a muffle furnace at 500??C??10??C for 30 min. TAKE the crucible out of the furnace; PLACE it on the burner to melt the sinter (within 30 s) and turn the crucible from time to time to continue heating for a total of 2 min.
COOL the molten material; PUT the crucible into a 400 mL beaker; ADD about 100 mL of warm water; HEAT for a few minutes to leach the molten material. WASH the crucible; ADD the washings to the solution. Retain the crucible. COOL the solution; USE a medium-speed filter paper to filter. USE sodium hydroxide solution (4.14) to wash the filter paper twice; DISCARD the filtrate. USE spray water to wash the precipitate on the filter paper into the previous beaker; ADD 10 mL of hydrochloric acid (4.5); HEAT to dissolve the precipitate. USE the previous filter paper to filter the solution. USE warm hydrochloric acid (4.6) to wash the filter paper 3 times; USE hydrochloric acid (4.8) to wash several times; finally use warm water to wash until the washings are not acidic. COLLECT the filtrate and washings in a 400 mL beaker (this is the main fluid). In the retained crucible, use hot hydrochloric acid (4.6) to dissolve the residual iron; USE hot water to wash it into the main fluid. Evaporate to about 150 mL without boiling. Continue the operation according to the procedure specified in 7.5.2.
7.5.2 Reduction
7.5.2.1 When the copper content is not more than 0.1%, add 3 drops~5 drops of potassium permanganate solution (4.17) to the solution obtained in 7.5.1; HEAT the solution below the boiling point. Maintain at this temperature for 5 min, to oxidize the arsenic or organic matter. USE a small amount of hot hydrochloric acid (4.7) to wash the watch glass and the inner wall of the beaker. Immediately add dropwise the stannous chloride solution (4.19), to reduce iron (III); agitate the solution in the beaker from time to time, until the solution remains light yellow (ferric trichloride). USE a small amount of hot water to wash the inner wall of the beaker; ADD 15 drops of sodium tungstate solution (4.23) as an indication; then add dropwise the titanium (III) chloride solution (4.20); continuously agitate the solution until the solution turns blue. Then, add dropwise dilute potassium dichromate solution (4.18) until colorless.
7.5.2.2 When the sample contains more than 0.1% of copper, add 3 drops~5 drops of potassium permanganate solution (4.17) to the solution obtained in 7.5.1.1; HEAT the solution below the boiling point. Maintain at this temperature for 5 min, to oxidize the arsenic or organic matter. USE a small amount of hot 8 Result calculation
8.1 Calculation of total iron content
According to formula (1), calculate the total iron content w (mass fraction) in the sample. The value is expressed in %.
Where:
V1 - Volume of dichromic acid standard solution (4.22) consumed by the test portion, in milliliters (mL);
V2 - The volume of the corresponding standard solution of potassium
dichromate consumed by blank test adding iron standard solution in 7.5.4, in milliliters (mL);
m - Sample mass, in grams (g);
0.0055847 - The iron content equivalent to 1 mL (0.01667 mol/L) of standard solution of potassium dichromate, in grams (g);
K - 1.00 for the pre-dried sample (6.2.2). The conversion coefficient of the general sample (6.2.1) is calculated according to formula (2).
Where:
A - Mass fraction of combined water measured in accordance with GB/T 6730.3. 8.2 General treatment of results
8.2.1 Repeatability and tolerance
The precision of this analysis method is shown in Table 1.
8.2.2 Determination of analysis results
According to the procedure in Appendix A, according to formula (1), calculate the independent repeated measurement results. Compare with the repeated measurement tolerance (Rd), to determine the analysis results.
8.2.3 Interlaboratory precision

View full details