YS/T 1149.1-2016 PDF in English
YS/T 1149.1-2016 (YS/T1149.1-2016, YST 1149.1-2016, YST1149.1-2016)
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Methods for chemical analysis of zinc concentrate roasting--Part 1: Determination of zinc content--Na2EDTA titration method
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Standards related to (historical): YS/T 1149.1-2016
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YS/T 1149.1-2016: PDF in English (YST 1149.1-2016) YS/T 1149.1-2016
YS
NONFERROUS METAL INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
ICS 77.120.60
H 13
Methods for chemical analysis of zinc concentrate
roasting - Part 1: Determination of zinc content -
Na2EDTA titration method
ISSUED ON: JULY 11, 2016
IMPLEMENTED ON: JANUARY 01, 2017
Issued by: Ministry of Industry and Information Technology of PRC
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Method summary ... 4
4 Reagents ... 5
5 Specimens ... 7
6 Analytical procedures ... 7
7 Calculation of analysis results ... 8
8 Precision ... 9
9 Test report ... 10
Methods for chemical analysis of zinc concentrate
roasting - Part 1: Determination of zinc content -
Na2EDTA titration method
1 Scope
This Part of YS/T 1149 specifies the method for the determination of zinc
content, in zinc concentrate roasting.
This Part applies to the determination of zinc content in zinc concentrate
roasting. The measurement range is 30.00% ~ 70.00%.
2 Normative references
The following documents are essential to the application of this document. For
the dated documents, only the versions with the dates indicated are applicable
to this document; for the undated documents, only the latest version (including
all the amendments) is applicable to this standard.
GB/T 8151.8 Methods for chemical analysis of zinc concentrates - Part 8:
Determination of cadmium content - The flame atomic absorption
spectrometric method
3 Method summary
The sample is dissolved by hydrochloric acid, nitric acid, sulfuric acid; lead in
the sulfuric acid medium produces lead sulfate precipitation; it is filtered and
separated from coexisting elements; the filtrate is precipitated by ammonia
water, to separate coexisting elements, such as iron and manganese. In the
filtrate, thiourea is added to mask copper; ammonium fluoride is added to
eliminate the interference of a small amount of elements, such as iron and
aluminum. In acetic acid-sodium acetate buffer solution of pH5 ~ pH6, use
xylenol orange as indicator; use Na2EDTA standard titration solution to titrate it,
until the solution changes from purple red to bright yellow, which is used as the
end point. Calculate the combined amount of zinc and cadmium, according to
the volume of the Na2EDTA standard titration solution consumed. After
deducting the amount of cadmium, it is the amount of zinc.
4 Reagents
Unless otherwise specified, the reagents used in this Part are analytical
reagents AND distilled water or deionized water or water of equivalent purity,
that meet national standards or industry standards.
4.1 Zinc oxide (reference material).
4.2 Ammonium chloride.
4.3 Ammonium fluoride.
4.4 Ascorbic acid.
4.5 Anhydrous sodium acetate.
4.6 Hydrochloric acid (ρ1.19 g/mL).
4.7 Sulfuric acid (ρ1.84 g/mL).
4.8 Nitric acid (ρ1.42 g/mL).
4.9 Ammonia (ρ0.90 g/mL).
4.10 Acetic acid (ρ1.049 g/mL).
4.11 Hydrochloric acid (1 + 1).
4.12 Sulfuric acid (1 + 1).
4.13 Sulfuric acid (1 + 9).
4.14 Sulfuric acid (2 + 98).
4.15 Ammonia (1 + 1).
4.16 Washing solution: Dissolve 2 g of ammonium chloride (4.2) in 100 mL of
water. Add 1 mL of ammonia water (4.9). Mix well.
4.17 Ammonium persulfate solution (200 g/L): It is prepared on the day when it
is used.
4.18 Thiourea saturated solution.
4.19 Ferric sulfate solution (10 g/L): Weigh 10 g of ferric sulfate; dissolve it in
1000 mL of sulfuric acid (4.13).
4.20 Acetic acid-sodium acetate buffer solution (pH 5.5): Weigh 150 g of sodium
Use water to rinse the watch glass and the wall of the beaker. Dilute to about
50 mL. Heat to a slight boil for 10 min. Cool to room temperature. Let it stand
for 1 h. Use slow quantitative filter paper to filter. Use a beaker to collect the
filtrate. Use sulfuric acid (4.14) to wash the beaker and the precipitate 5 times
each. Use water to rinse the beaker and the precipitate once each. Keep the
filtrate. Discard the precipitate.
6.4.4 Add 3 g ~ 5 g of ammonium chloride (4.2) and 5 mL of ammonium
persulfate solution (4.17), to the solution of 6.4.2 or the filtrate of 6.4.3. Use
ammonia water (4.9) to neutralize it, until the precipitation is complete. Then
add another 10 mL. Heat for a slight boiling, for 1 min ~ 2 min. While it is hot,
use fast qualitative filter paper to filter it. Use hot washing solution (4.16) to
wash the beaker and precipitate 2 ~ 3 times each. Keep the filtrate.
6.4.5 Use hot hydrochloric acid (4.11) to dissolve the precipitation in the original
beaker. Use hot water to wash the filter paper clean. Add 5 mL of ammonium
persulfate solution (4.17). Use ammonia water (4.9) to neutralize it, until the
precipitation is complete. Add another 10 mL. Heat to slight boiling for 1 min ~
2 min. Remove it. Filter it through the original filter paper in the beaker of the
retained solution in 6.4.4. Use hot washing solution (4.16), to wash the beaker
and the precipitate for 3 ~ 4 times each.
6.4.6 Boil and concentrate the filtrate (6.4.5) to a volume of about 100 mL.
Completely destroy the excess ammonium persulfate. Remove it for cooling.
6.4.7 Add 0.1 g of ascorbic acid (4.4), 0.2 g of ammonium fluoride (4.3), 5 mL
of thiourea saturated solution (4.18). Shake well for each reagent added. Add 1
drop of methyl orange indicator (4.22). Use ammonia water (4.15) and
hydrochloric acid (4.11), to adjust the solution, until it just turns red. Add 1 ~ 2
drops of xylenol orange indicator (4.23). Add 20 mL of acetic acid-sodium
acetate buffer solution (4.20). Use Na2EDTA standard titration solution (4.21) to
titrate it, until the solution just changes from purple to bright yellow, which is
taken as the end point.
7 Calculation of analysis results
The amount of zinc is calculated in terms of the mass fraction of zinc, wZn; the
value is expressed in %; it is calculated according to formula (2):
Where:
c - The concentration of Na2EDTA standard titration solution, in moles per
milliliter (mol/L);
65.38 - The molar mass of zinc, in grams per mole (g/mol);
V3 - The volume of Na2EDTA standard titration solution, which is consumed
by the test solution, in milliliters (mL);
V2 - The volume of Na2EDTA standard titration solution, which is consumed
by blank test solution, in milliliter (mL);
m2 - The mass of the sample, in grams (g);
wCd - The mass fraction of cadmium, which is measured by GB/T 8151.8;
0.5816 - The coefficient of converting the amount of cadmium to the amount
of zinc.
The calculation result is expressed to two decimal places.
8 Precision
8.1 Repeatability
For the measured values of two independent test results, which are obtained
under repeatability conditions, within the average range given in Table 2, the
absolute difference between the two test results does not exceed the
repeatability limit r; the case where it exceeds the repeatability limit r is not more
than 5%. The repeatability limit r is obtained, by linear interpolation and epitaxy,
according to the data in Table 2.
Table 2 -- Repeatability limits
8.2 Reproducibility
For the measured values of the two independent test results, which are
obtained under reproducibility conditions, within the average range given in
Table 3, the absolute difference between the two test results does not exceed
the reproducibility limit R; the case where it exceeds the reproducibility limit R
is not more than 5%. The reproducibility limit R is obtained by linear
interpolation and epitaxy, according to the data in Table 3.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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