YS/T 252.4-2007 English PDF (YST252.4-2007)

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YS/T 252.4-2007: Methods for chemical analysis of nickel matte. Determination of copper content. Sodium thiosulphate titrimetric method
YS/T 252.4-2007
YS
NONFERROUS INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
ICS 77.120.40
H 13
Replacing YS/T 252.4-1994
Methods for chemical analysis of nickel matte -
Determination of copper content - Sodium thiosulphate
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 Analytical procedures ... 7
5 Calculation of analysis results ... 7
6 Precision ... 8
7 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 4.
This Part replaces YS/T 252.4-1994 "Determination of copper content by sodium
thiosulphate titrimetric method ". Compared with YS/T 252.4-1994, this Part mainly
has the following changes:
- ADJUST the measurement range from 6.00% ~ 30.00% to 6% ~ 55%;
- ADJUST the sample amount from 0.200 g to 0.400 g;
- ADJUST the concentration of sodium thiosulfate standard solution from 0.02 mol/L
to 0.01 mol/L;
- ADD the 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: Guangzhou Nonferrous Metals Research
Institute, Beijing General Research Institute of Mining and Metallurgy.
The main drafters of this Part: Liu Haidong, Yu Shengjie, Wang Zhong, Lin Xiuying,
Zhao Junfeng, Zhu Yuqiang.
The main verifiers of this Part: Dai Fengying, Zhang Yongjin, Mai Libi, Tang Shufang,
and Yu Li.
Methods for chemical analysis of nickel matte -
Determination of copper content - Sodium thiosulphate
titrimetric method
1 Scope
This standard specifies the method for determination of copper content in high nickel
matte.
This standard is applicable to the determination of copper content in high nickel matte.
Measuring range: 6% ~ 55%.
2 Method summary
The sample is decomposed with hydrochloric acid and nitric acid-potassium chlorate
saturated solution. The ammonium bifluoride is used to mask the iron and the solution
is controlled at pH3.5 ~ pH4. Potassium iodide is added, to cause the copper to
precipitate copper iodide and precipitate an equal amount of iodine. Use the starch
solution as an indicator; use sodium thiosulfate standard titration solution to indirectly
determine the amount of copper.
3 Reagents
3.1 Ammonium bifluoride.
3.2 Potassium iodide.
3.3 Ammonia water (ρ0.90 g/mL).
3.4 Hydrochloric acid (ρ1.19 g/mL).
3.5 Nitric acid (ρ1.42 g/mL).
3.6 Nitric acid (1 + 1).
3.7 Sulfuric acid (1 + 1).
3.8 Urea saturated solution.
3.9 Potassium sulfate solution (100 g/L).
3.10 Nitric acid-potassium chlorate saturated solution: Dissolve potassium chlorate in
nitric acid (3.5) until saturated.
3.11 Starch solution (5 g/L).
3.12 Copper standard solution: Accurately weigh 1.0000 g of metallic copper (mass
fraction of copper ≥ 99.95%). Place it in a 400 mL beaker. Add 20 mL of nitric acid
(3.6). Dissolve at low temperature and evaporate to a viscous state. Cool it. Add 5 mL
of sulfuric acid (3.7). Heat until a lot of white smoke comes out. Cool it slightly. Add
water to boil to dissolve the salts. Cool to room temperature. Pipette it into a 1000 mL
volumetric flask. Use water to make the volume reach to the mark. 1 mL of this solution
contains 1.0 mg of copper.
3.13 Sodium thiosulfate standard titration solution [c (Na2S2O3) ≈ 0.01 mol/L]:
3.13.1 Preparation: Weigh 2.5 g of sodium thiosulfate (Na2S2O3•5H2O). Dissolve it in
newly boiled water and cool it to room temperature. Add 0.1 g of anhydrous sodium
carbonate. Dissolve it and transfer it to a 1000 mL brown bottle. Use water to make the
volume reach to the mark. Calibrate after standing for one week.
3.13.2 Calibration: Pipette 25.00 mL of copper standard solution (3.12) into a 300 mL
triangular beaker. Add ammonia water (3.3) dropwise, until it turns dark blue. Proceed
the subsequent steps according to 4.3.3.
Calculate the titration coefficient of sodium thiosulfate standard titration solution for
copper, according to formula (1):
Where:
FCu - Titration coefficient, the unit volume of sodium thiosulfate standard titration
solution is equivalent to the mass of copper, in milligrams per milliliter (mg/mL);
ρ - The mass concentration of the copper standard solution, in milligrams per
milliliter (mg/mL);
V1 - The volume of the copper standard solution dispensed, in milliliters (mL);
V2 - The volume of the sodium thiosulfate standard titration solution consumed
when titrating the copper standard solution, in milliliters (mL).
Take the average of four results. The difference in the volume of the standard titration
solution, which is consumed during the four calibrations, shall not be greater than 0.10
mL; otherwise, the calibration will be re-calibrated.
Note: The sodium thiosulfate standard titration solution must be recalibrated every one week.