YS/T 252.5-2007 English PDF (YST252.5-2007)

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YS/T 252.5-2007: Methods for chemical analysis of nickel matte. Determination of sulfur content. Combustion-neutralization titrimetric method
YS/T 252.5-2007
YS
NONFERROUS INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
ICS 77.120.40
H 13
Replacing YS/T 252.5-1994
Methods for chemical analysis of nickel matte -
Determination of sulfur content - Combustion-neutralization
titrimetric method
ISSUED ON: APRIL 13, 2007
IMPLEMENTED ON: OCTOBER 01, 2007
Issued by: National Development and Reform Commission of PRC
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Method summary ... 5
3 Reagents ... 5
4 Instruments ... 6
5 Analytical procedures ... 7
6 Calculation and expression of analysis results ... 8
7 Precision ... 8
8 Quality assurance and control ... 9
Foreword
YS/T 252 "Methods for chemical analysis of nickel matte" is divided into five parts:
YS/T 252.1 Methods for chemical analysis of nickel matte - Determination of nickel
content - Dimethylglyoxime gravimetric method
YS/T 252.2 Methods for chemical analysis of nickel matte - Determination of iron
content - Sulfosalicylic acid photometric method
YS/T 252.3 Methods for chemical analysis of nickel matte - Determination of cobalt
content - Flame atomic absorption spectrometric method
YS/T 252.4 Methods for chemical analysis of nickel matte - Determination of cobalt
content - Sodium thiosulphate titrimetric method
YS/T 252.5 Methods for chemical analysis of nickel matte - Determination of sulfur
content - Combustion-neutralization titrimetric method
This Part is Part 5.
This Part replaces YS/T 252.5-1994 "Determination of sulfur content by sodium
thiosulphate titrimetric method ". Compared with YS/T 252.5-1994, this Part mainly
has the following changes:
- CHANGE the analysis method from barium sulfate gravimetric method to
combustion-neutralization titration method;
- ADD repeatability limits, supplementing quality assurance and control terms.
This Part was proposed by AND shall be under the jurisdiction of the National Technical
Committee for Standardization of Nonferrous Metals.
Responsible drafting organization of this Part: Jinchuan Group Co., Ltd.
Participated drafting organization of this Part: Beijing General Research Institute of
Mining and Metallurgy, Daye Nonferrous Metals Co., Ltd.
The main drafters of this Part: Liu Haidong, Yu Shengjie, Yang Xiuping, Lin Xiuying,
Zhao Junfeng, Zhu Yuqiang.
The main verifiers of this Part: Xu Xiaoyan, Ruan Guise, Guo Xiaohong, and Li
Haiqiong.
The National Nonferrous Metals Standardization Technical Committee is responsible
for the interpretation of this Part.
Methods for chemical analysis of nickel matte -
Determination of sulfur content - Combustion-neutralization
titrimetric method
1 Scope
This Part specifies the method for determination of sulfur content in high nickel matte.
This Part is applicable to the determination of sulfur content in high nickel matte.
Measuring range: 15% ~ 25%.
2 Method summary
The sample uses copper wire as flux and burns in air flow at 1250 °C ~ 1300 °C, to
convert sulfur into sulfur dioxide. It is absorbed and oxidized into sulfuric acid by
hydrogen peroxide. Methyl red-methylene blue solution is used as a mixed indicator.
Use sodium hydroxide standard titration solution to make titration, until the solution
changes from purple to bright green, which is taken as the end point.
3 Reagents
3.1 Copper wire (mass fraction of copper ≥ 99.95%, diameter 0.25 mm ~ 0.5 mm).
3.2 Acid absorption solution (potassium dichromate-sulfuric acid solution): Heat and
dissolve 5 g of potassium dichromate with a small amount of water. After cooling, add
100 mL of sulfuric acid.
3.3 Desiccant: Anhydrous calcium chloride.
3.4 Alkali absorption solution: Sodium hydroxide (50 g/L).
3.5 Phenolphthalein indicator (10 g/L), ethanol solution.
3.6 Methyl red-methylene blue mixed indicator: Weigh 0.3 g of methyl red and 0.25 g
of methylene blue. Dissolve in 500 mL of absolute ethanol.
3.7 Hydrogen peroxide absorption solution (prepared when used): Take 50 mL of
hydrogen peroxide. Use water to dilute it to 1 L. Add 10 mL of mixed indicator (3.6).
Use sodium hydroxide solution (3.8) to make adjustment, until bright green appears.
3.8 Sodium hydroxide standard titration solution [c(NaOH) ≈ 0.065 mol/L]:
3.8.1 Preparation: Prepare sodium hydroxide into a saturated solution. Place it in a
plastic bottle until the solution is clear. Pipette 32 mL of supernatant. Use carbon
dioxide-free water to dilute it to 10 L. Mix well.
3.8.2 Calibration: Weigh four sets of 0.300 g (accurate to 0.0001 g) of potassium
hydrogen phthalate (standard reagent), that has been dried at 100 °C ~ 105 °C for 2
hours. Place it in a 300 mL Erlenmeyer flask. Use 60 mL of hot water, which does not
contain carbon dioxide, to dissolve it. After cooling, add 2 drops of phenolphthalein
indicator (3.5). Use sodium hydroxide standard titration solution to make titration, until
it shows light red, which is taken as end point.
Do a blank test along with the calibration.
Calculate the titration coefficient of sodium hydroxide standard titration solution for
sulfur, according to formula (1):
Where:
FS - Titration coefficient, the mass of sulfur equivalent to 1.00 mL of sodium
hydroxide standard titration solution, in milligrams per milliliter (mg/mL);
m1 - The mass of potassium hydrogen phthalate, in grams (g);
V1 - During calibration, the volume of sodium hydroxide standard titration solution
consumed in titrating potassium hydrogen phthalate solution, in milliliters (mL);
V0 - During calibration, the volume of sodium hydroxide standard titration solution
consumed by titrating the blank test solution, in milliliters (mL);
204.2 - Molar mass of potassium hydrogen phthalate [M(C8H5KO4)], in grams per
mole (g/mol);
16.03 - Molar mass of sulfur [M(1/2S)], in grams per mole (g/mol).
Take the average of four results. The range of the four calibration results is not greater
than 0.0060 mg/mL; otherwise, the measurement will be repeated.
4 Instruments
4.1 Tubular combustion furnace: The maximum temperature 1350 °C, common
temperature 1300 °C, equipped with resistance furnace temperature controller (0 °C ~
1600 °C).