GB/T 18882.2-2017 English PDF (GBT18882.2-2017)

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GB/T 18882.2-2017: Chemical analysis methods for mixed rare earth oxide of ion-absorbed type rare earth ore -- Part 2: Determination of aluminum oxide content
GB/T 18882.2-2017
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.120.99
H 14
Replacing GB/T 18882.2-2008
Chemical analysis methods for mixed rare earth oxide of
ion-absorpted type rare earth ore - Part 2: Determination of
aluminum oxide content
ISSUED ON: OCTOBER 14, 2017
IMPLEMENTED ON: MAY 01, 2018
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 ... 5
2 Method 1: Inductively coupled plasma atomic emission spectrometry (ICP-OES) .. 5
3 Method 2: Titration ... 9
Chemical analysis methods for mixed rare earth oxide of
ion-absorpted type rare earth ore - Part 2: Determination of
aluminum oxide content
1 Scope
This Part of GB/T 18882 specifies the determination method of aluminum oxide content
in mixed rare earth oxide of ion-absorpted type rare earth ore.
This Part applies to the determination of aluminum oxide content in mixed rare earth
oxide of ion-absorpted type rare earth ore, including two methods: Method 1
Inductively coupled plasma atomic emission spectrometry and Method 2 Titration. The
determination range of Method 1 (mass fraction): 0.10% ~ 5.00%, and the
determination range of Method 2 (mass fraction): 4.00% ~ 15.00%.
2 Method 1: Inductively coupled plasma atomic emission
spectrometry (ICP-OES)
2.1 Principle of the method
Decompose the test sample by nitric acid and hydrofluoric acid; after the perchloric
acid has smoked out, dissolve it in hydrochloric acid to make it clear; use approximate
matrix matching to eliminate the rare earth matrix interference; directly excite by argon
plasma light source; perform the spectrum measurement.
2.2 Reagents and materials
Unless otherwise specified, all reagents used in this Part are analytical reagents that
meet national or industry standards, and the water used is grade-II water.
2.2.1 Hydrochloric acid (ρ = 1.19 g/mL).
2.2.2 Hydrofluoric acid (ρ = 1.13 g/mL).
2.2.3 Perchloric acid (ρ = 1.67 g/mL).
2.2.4 Nitric acid (ρ = 1.42 g/mL).
2.2.5 Hydrogen peroxide (30%).
2.2.6 Nitric acid (1+1).
2.3 Instruments and equipment
2.3.1 Inductively coupled plasma atomic emission spectrometer, resolution < 0.006 nm
(at 200 nm).
2.3.2 Light source: argon plasma light source.
2.4 Test sample
2.4.1 The particle size of the test sample is less than 0.074 mm.
2.4.2 Pre-dry the sample at 105 ℃ ~ 110 ℃ for 2 h; then, place it in a desiccator to cool
to room temperature.
2.5 Procedure
2.5.1 Test material
Weigh 0.1g of test sample (2.4), accurate to 0.000 1 g.
2.5.2 Number of determinations
Independently perform two determinations; take the average value.
2.5.3 Blank test
Carry out a blank test together with the test material (2.5.1).
2.5.4 Preparation of analytical solution
Place the test materials (2.5.1) in a 150 mL polytetrafluoroethylene beaker; add a small
amount of water; add 2 mL of nitric acid (2.2.6); heat to decompose for 3 min ~ 5 min;
add 2 mL of hydrofluoric acid (2.2.2) and continue to decompose for 3 min ~ 5 min;
add 3 mL of perchloric acid (2.2.3) to smoke and evaporate to nearly dry; remove and
cool slightly; add 10 mL of hydrochloric acid (2.2.7) and add 3 ~ 5 drops of hydrogen
peroxide (2.2.5); heat to dissolve until clear; transfer the test solution into a 100 mL
volumetric flask; use water to dilute to the mark; mix well; test.
2.5.5 Series standard configuration
According to Table 2, transfer the standard stock solution into six 100 mL volumetric
flasks; use water to dilute to the mark; mix well; test.
Unless otherwise specified, all reagents used in this Part are analytical reagents that
meet national or industry standards, and the water used is grade-II water.
3.2.1 Hydrochloric acid (ρ = 1.19 g/mL).
3.2.2 Hydrofluoric acid (ρ = 1.13 g/mL).
3.2.3 Hydrogen peroxide (30%).
3.2.4 Perchloric acid (ρ = 1.67 g/mL).
3.2.5 Nitric acid (ρ = 1.42 g/mL).
3.2.6 Oxalic acid solution (100 g/L).
3.2.7 Sodium hydroxide solution (200 g/L).
3.2.8 Hydrochloric acid (1+1).
3.2.9 Hydrochloric acid (1+4).
3.2.10 Ammonia water (1+1).
3.2.11 EDTA (Ethylene Diamine Tetraacetic Acid) solution (about 0.05 mol/L): Weigh
20 g of EDTA and dissolve it in a small amount of water; transfer it into a 1 000 mL
volumetric flask; use water to fix the volume; mix well.
3.2.12 Cresol red indicator (2 g/L): Weigh 0.2 g of cresol red and dissolve it in 100 mL
of ethanol solution (1+1).
3.2.13 Phenolphthalein ethanol solution (10 g/L).
3.2.14 Acetic acid-sodium acetate buffer solution (pH 5.5): Weigh 200 g of sodium
acetate and dissolve it in a small amount of water; transfer it into a 1 000 mL volumetric
flask; add 10 mL of glacial acetic acid (w ≥ 99.5%); use water to fix the volume; mix
well.
3.2.15 Xylenol orange indicator (4 g/L): Weigh 0.4 g of xylenol orange and 20 g of
potassium nitrate; dissolve in a small amount of water; transfer to a 100 mL volumetric
flask; use water to fix the volume; mix well. Store in a brown bottle.
3.2.16 Sodium fluoride solution (40 g/L).
3.2.17 Aluminum standard solution: Weigh 1.000 0 g of metallic aluminum (spectrally
pure, remove all surface oxides before use) into a 500 mL beaker; add 50 mL of water;
then, add 40 mL of hydrochloric acid (3.2.1); dissolve at low temperature until clear
(add hydrochloric acid and water in between); cool. Transfer to a 1 000 mL volumetric
flask; use hydrochloric acid (5+95) to dilute to the mark; mix well. This standard
solution contains 1 mg of aluminum in 1 mL.
3.2.18 Zinc sulfate solution (about 0.1 mol/L): Weigh 30 g of zinc sulfate (ZnSO4·7H2O)
and dissolve it in an appropriate amount of water; transfer it into a 1 000 mL volumetric
flask; use water to fix the volume; mix well.
3.2.19 Zinc sulfate standard solution.
3.2.19.1 Preparation: Weigh 2.4 g of zinc sulfate (ZnSO4·7H2O) and dissolve it in a
small amount of water; transfer it into a 1 000 mL volumetric flask; use water to fix the
volume; mix well.
3.2.19.2 Calibration: Pipette 10.00 mL of aluminum standard solution (3.2.17) into a
250 mL conical flask; add 20 mL of LEDTA solution (3.2.11); add 1 ~ 2 drops of
phenolphthalein ethanol solution (3.2.13); use sodium hydroxide solution (3.2.7) to
neutralize until red appears. Use hydrochloric acid (3.2.9) to neutralize until colorless
and add 1 drop in excess; add 20 mL of acetic acid-sodium acetate buffer solution
(3.2.14); boil slightly at low temperature for 1 min ~ 2 min; remove and cool. Perform
the following operations according to the analytical steps (3.4.4).
Calculate the concentration of zinc sulfate standard solution according to Formula (2):
Where:
c – concentration of zinc sulfate, in moles per liter (mol/L);
ρ0 – mass concentration of aluminum standard solution, in milligrams per milliliter
(mg/mL);
V1 – volume of aluminum solution pipetted, in milliliters (mL);
M – molar mass of aluminum, in grams per mole (g/mol);
V2 – volume of zinc sulfate standard solution consumed, in milliliters (mL).
3.3 Test sample
3.3.1 The particle size of the test sample is less than 0.074 mm.
3.3.2 Pre-dry the sample at 105 ℃ ~ 110 ℃ for 2 h; then, place it in a desiccator to cool
to room temperature.
3.4 Procedure
3.4.1 Test material
Weigh 0.25g of test sample (3.3), accurate to 0.000 1 g.
3.4.2 Time of determinations
Independently perform two determ...