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(Methods for chemical analysis of bauxite - Part 4: Determination of iron oxide contents)
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Methods for chemical analysis of bauxite. Part 4: Determination of iron oxide content. Dichromate titrimetric method
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| YS/T 575.4-2006 | English | 239 |
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Methods for chemical analysis of bauxite. Determination of iron oxide content. Dichromate titrimetric method
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Basic data
| Standard ID | YS/T 575.4-2025 (YS/T575.4-2025) |
| Description (Translated English) | (Methods for chemical analysis of bauxite - Part 4: Determination of iron oxide contents) |
| Sector / Industry | Nonferrous Metallurgy Industry Standard (Recommended) |
| Classification of Chinese Standard | H30 |
| Classification of International Standard | 71.040.40 |
| Date of Issue | 2025-08-19 |
| Date of Implementation | 2026-03-01 |
| Older Standard (superseded by this standard) | YS/T 575.4-2007, YS/T 575.5-2007 |
| Issuing agency(ies) | Ministry of Industry and Information Technology |
| Summary | This standard specifies the methods for determining the ferric oxide content in bauxite using the o-phenanthroline spectrophotometric method and the potassium dichromate titration method. This standard is applicable to the determination of ferric oxide content in bauxite. |
YS/T 575.4-2007: Methods for chemical analysis of bauxite. Part 4: Determination of iron oxide content. Dichromate titrimetric method
---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.
Methods for chemical analysis of bauxite. Part 4. Determination of iron oxide content. Dichromate titrimetric method
ICS 71.100.10
Q52
People's Republic of China Nonferrous Metal Industry Standard
YS/T 575.4-2007
Replacing YS/T 575.4-2006
Chemical analysis method of bauxite
Part 4. Determination of iron oxide content
Potassium dichromate titration
Released on.2007-11-11
2008-05-01 implementation
Published by the National Development and Reform Commission
Foreword
QS/T 575-2007 "Chemical Analysis Method for Bauxite Ore" is an amendment to QS/T 575-2006 (formerly GB/T 3257-1999),
There are 24 parts.
--- Part 1. Determination of alumina content EDTA titration method
--- Part 2. Determination of silica content-Molybdenum blue photometric method
--- Part 3. Determination of silica content Molybdenum blue photometric method
--- Part 4. Determination of iron trioxide content potassium dichromate titration method
--- Part 5. Determination of ferric oxide content
--- Part 6. Determination of titanium dioxide content Diantipyroline methane photometric method
--- Part 7. Determination of calcium oxide content by flame atomic absorption spectrometry
--- Part 8. Determination of magnesium oxide content by flame atomic absorption spectrometry
--- Part 9. Determination of potassium oxide and sodium oxide content by flame atomic absorption spectrometry
--- Part 10. Determination of manganese oxide content by flame atomic absorption spectrometry
--- Part 11. Determination of chromium trioxide content by flame atomic absorption spectrometry
--- Part 12. Determination of vanadium pentoxide content
--- Part 13. Determination of zinc content by flame atomic absorption spectrometry
--- Part 14. Determination of total rare earth oxides
--- Part 15. Determination of gallium trioxide content Rhodamine B extraction spectrophotometry
--- Part 16. Determination of phosphorus pentoxide content Molybdenum blue photometric method
--- Part 17. Determination of sulfur content-Combustion-iodine method
--- Part 18. Determination of total carbon content-Combustion-non-aqueous titration method
--- Part 19. Determination of burning loss by gravimetric method
--- Part 20. Preparation of pre-dried samples
--- Part 21. Determination of organic carbon content by titration method
--- Part 22. Determination of wet stored water in analytical samples by gravimetric method
--- Part 23. Determination of chemical composition content X-ray fluorescence spectrometry
--- Part 24. Determination of carbon and sulfur content infrared absorption method
This part is Part 4.
This section replaces YS/T 575.4-2006 (formerly GB/T 32577.4-1999).
This section is a revision of YS/T 575.4-2006. Compared with YS/T 575.4-2006, the main changes are as follows.
--- Unify the drying temperature of the sample to 110 ℃ ± 5 ℃;
--- Increased precision.
This section is proposed and managed by the National Nonferrous Metals Standardization Technical Committee.
This section was drafted by the Aluminum Research Institute of Zhengzhou.
This section was drafted by China Aluminum Corporation Guangxi Branch.
The main drafters of this section. Liu Yuefen, Wei Feng, Yang Yunping, Luo Xiangning.
This section is explained by the National Nonferrous Metals Standardization Technical Committee.
The previous versions of the standards replaced by this section are.
--- QS/T 575.4-2006 (formerly GB/T 32577.4-1999).
YS/T 575.4-2007
Chemical analysis method of bauxite
Part 4. Determination of iron oxide content
Potassium dichromate titration
1 Scope
This section specifies the method for determining the content of ferric oxide in bauxite ores.
This section is applicable to the determination of ferric oxide in bauxite ores. The measurement range is ≥5.0%.
2 Method principle
In the hydrochloric acid medium, most of the trivalent iron was first reduced by tin dichloride, and sodium tritungrate was used as an indicator.
Iron is divalent iron. Excessive titanium trichloride further reduces tungstate to produce "tungsten blue", and potassium chromate is added dropwise until the blue color disappears. Dibenzamide
Sodium was used as an indicator, and divalent iron was titrated with potassium dichromate standard solution.
Vanadium interference. Vanadium pentoxide below 0.6 mg is allowed in the titration solution.
3 reagents
3.1 Potassium hydroxide.
3.2 Sodium peroxide.
3.3 Hydrochloric acid (ρ1.19g/mL).
3.4 Hydrochloric acid (1 + 1).
3.5 Hydrochloric acid (1 + 9).
3.6 Sulfuric acid (ρ 1.84g/mL).
3.7 Phosphoric acid (ρ 1.70g/mL).
3.8 Sulfuric acid-phosphoric acid mixed solution. Slowly add.200mL of sulfuric acid (3.6) to 500mL of water under stirring, cool slightly, and then add 300mL of phosphoric acid
(3.7).
3.9 Titanium trichloride (15% to 20%).
3.10 Titanium trichloride solution. Take a portion of titanium trichloride (3.9) into a brown lower mouth bottle, dilute with nine parts of hydrochloric acid (3.5), and add a layer of liquid stone
Wax protection.
3.11 Tin dichloride solution (5%). Dissolve 5g of tin dichloride in 10mL of hydrochloric acid (3.3), dilute it to 100mL with water, and stir.
3.12 Sodium tungstate solution (25%). Dissolve 25g of sodium tungstate in an appropriate amount of water (if turbid, filter), add 10mL of phosphoric acid (3.7), dilute with water
Release to 100mL and stir well.
3.13 Sodium diphenylamine sulfonate indicator solution (0.2%).
3.14 Ferrous ammonium sulfate solution (0.7%).
3.15 Potassium dichromate standard titration solution (0.02202mol/L). Weigh 0.6735g of potassium dichromate which was dried at 150 ° C for 2h beforehand.
(Reference reagent), dissolved in 100mL of water, transferred to a 1000mL volumetric flask, diluted with water to the mark, and shake well.
４ Sample
Grind the sample with a mortar and pass through a 74 μm sieve. Place the ground sample at 110 ° C ± 5 ° C and dry it for 2h. Place it in a desiccator and cool.
It is reserved at room temperature.
YS/T 575.4-2007
5 Analysis steps
5.1 Sample
Weigh 0.1g to 0.2g sample (4), accurate to 0.0001g.
5.2 Measurement times
The same sample shall be measured twice independently and the average value shall be taken.
5.3 Determination
5.3.1 Place the sample (5.1) in a 30mL silver crucible, add 3g of sodium hydroxide (3.1) to cover it, cover the crucible cover, and place
In a muffle furnace at 750 ° C ± 10 ° C, melt for 20 min (blank melt for 5 min). Take out and rotate the crucible to make the melt adhere to the crucible evenly
Wall, cooling.
5.3.2 Place the silver crucible in a 250mL beaker, add 30mL of hot water, and after the molten material falls off, wash out the crucible with hydrochloric acid (3.5) and hot water.
Add 25mL of hydrochloric acid (3.3) and cover the table. Heat to boiling, add tin dichloride solution (3.11) drop-wise until light yellow, add water to 100mL
On the right, add 1 mL of sodium tungstate solution (3.12) and dropwise add titanium trichloride solution (3.10) until blue appears. Immediately use potassium dichromate standard solution
(3.15) Titrate to colorless (not take reading).
Note. The blank test should be heated and boiled off the hydrogen peroxide before the acidification of hydrochloric acid.
5.3.3 Immediately add 10mL of sulfuric acid-phosphoric acid mixed solution (3.8), 4 drops of sodium diphenylamine sulfonate indicator solution (3.13), and use potassium dichromate to mark
The quasi-solution (3.15) was added dropwise to a stable purple-blue color as the end point.
5.3.4 Reagent blank Follow the analysis steps 5.3.1 to 5.3.2, but before (5.3.3) do not add sulfuric acid-phosphoric acid mixed solution, add
5000mL of ferrous ammonium sulfate solution (3.14), the volume of potassium dichromate standard (3.15) used was A, and then 5.0mL of ferrous sulfate was added to the solution.
Ferric ammonium solution (3.14) was titrated with potassium dichromate standard solution (3.15) to the end point, and the volume was recorded as B. Repeatedly add ammonium ferrous sulfate solution
(3.14), titrate with potassium dichromate standard solution (3.15), when the B value is a certain constant value, then A-B is the potassium dichromate standard used for blank
The volume of the quasi-solution (3.15) (） 0).
6 Calculation of analysis results
Calculate the mass fraction of ferric oxide (%) according to the formula.
(Fe2O3) =
(犞-犞 0) · 犮 × 0.157
In the formula.
犞 --- the volume of the standard titration solution of potassium dichromate consumed when titrating the sample solution, the unit is milliliter (mL);
Q0 --- volume of standard titration solution of potassium dichromate consumed when titrating the blank solution, the unit is ml (mL);
犮 --- the actual concentration of potassium dichromate standard solution, the unit is mole per liter (mol/L);
0.1597 The millimolar mass of ferric oxide, the unit is gram per millimole (g/mmmol).
7 Precision
7.1 Repeatability
Measured values of two independent test results obtained under repeatable conditions, within the range of average values given below, these two test results
Interpolation gives.
Mass fraction of ferric oxide /%. 10.20 19.30 24.90
7.2 Allowable difference
The difference between laboratory analysis results should not be greater than the allowable difference listed in Table 1.
YS/T 575.4-2007
Table 1
Mass fraction of ferric oxide /% Allowable difference /%
≥5.0 ~ 10.00 0.20
＞ 10.00 ～ 20.00 0.30
＞ 20.00 ～ 30.00 0.40
8 Quality Assurance and Control
When analyzing, check with standard or control samples, or check the analysis method with standard or control samples at least once a year
Times. When the process is out of control, the cause should be identified. After correcting the errors, recheck.
YS/T 575.4-2007
