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YS/T 1149.5-2016 PDF in English


YS/T 1149.5-2016 (YS/T1149.5-2016, YST 1149.5-2016, YST1149.5-2016)
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YS/T 1149.5-2016: PDF in English (YST 1149.5-2016)

YS/T 1149.5-2016
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 5: Determination of iron content -
Na2EDTA titrimetric 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 Method summary ... 4 
3 Reagents ... 4 
4 Specimens ... 6 
5 Analytical procedures ... 6 
6 Calculation of analysis results ... 7 
7 Precision ... 8 
8 Test report ... 8 
Methods for chemical analysis of zinc concentrate
roasting - Part 5: Determination of iron content -
Na2EDTA titrimetric method
1 Scope
This Part of YS/T 1149 specifies the method for the determination of iron content,
in zinc concentrate roasting.
This Part applies to the determination of iron content in zinc concentrate
roasting, which has a tin content < 0.40%. The measurement range is 2.00% ~
20.00%.
2 Method summary
The sample is dissolved in hydrochloric acid, nitric acid, sulfuric acid. It is
evaporated to near dryness. The salts are dissolved by hydrochloric acid;
ammonia water is added to precipitate iron into ferric hydroxide; it is filtered, to
separate coexisting elements. The precipitate is dissolved by diluted
hydrochloric acid; the acidity is adjusted. The temperature is controlled at 60 °C
~ 80 °C; the sulfosalicylic acid is used as an indicator; the Na2EDTA standard
titration solution is used for titration, until the solution changes from brown to
bright yellow, which is taken as the end point.
3 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.
3.1 Ammonium chloride.
3.2 Hydrochloric acid (ρ1.19 g/mL).
3.3 Nitric acid (ρ1.42 g/mL).
3.4 Sulfuric acid (ρ1.84 g/mL).
3.5 Ammonia (ρ0.90 g/mL).
3.6 Hydrochloric acid (1 + 1).
3.7 Hydrochloric acid (1 + 11).
3.8 Ammonia (1+1).
3.9 Washing solution: Weigh 25 g of ammonium chloride (3.1). Dissolve it in
500 mL of water. Add 20 mL of ammonia water (3.5). Mix well.
3.10 Sulfosalicylic acid solution (100 g/L).
3.11 Iron standard solution (0.01 g/mL): Weigh 1.4297 g of ferric oxide
reference material (pre-dried at 100 °C ~110 °C for 1 h ~ 2 h and cooled to room
temperature). Put it in a 300 mL beaker. Add 10 mL of hydrochloric acid (3.6).
Heat it at low temperature, until it is completely dissolved. Cool it. Add 10 mL of
hydrochloric acid (3.6). Transfer it into a 100 mL volumetric flask. Use water to
dilute it to the mark. Mix well. 1 mL of this solution contains 0.01 g of iron.
3.12 Disodium ethylenediaminetetraacetate (Na2EDTA) standard titration
solution (about 0.025 mol/L).
3.12.1 Preparation: Weigh 10 g of Na2EDTA (C10H4N2O8Na2·2H2O) in a beaker.
Add about 400 mL of hot water to dissolve it. Cool it to room temperature.
Transfer it into a 1000 mL volumetric flask. Use water to dilute it to the mark.
Mix well. Let it stand for 3 days, before calibration.
3.12.2 Calibration: Pipette three parts of 5.00 mL of iron standard solution (3.11)
into 300 mL beakers, respectively. Add water to about 120 mL. Use ammonia
water (3.8) to neutralize it, until ferric hydroxide precipitate appears. Add 10 mL
of hydrochloric acid (3.7). Heat to 60 °C ~ 80 °C. Add 1 mL of sulfosalicylic acid
solution (3.10). Use Na2EDTA standard titration solution to titrate it, until the
solution changes from brown to bright yellow, which is taken as the end point.
A blank test is performed along with the calibration.
The actual concentration of Na2EDTA standard titration solution is calculated,
according to formula (1):
Where:
c - The concentration of Na2EDTA standard titration solution, in mole per liter
(mol/L);
5.4.1 Put the sample (5.1) in a 300 mL beaker. Use a small amount of water to
wet it (if the sample contains high silica, add 0.2 g of ammonium fluoride). Add
10 mL of hydrochloric acid (3.2). Dissolve it at low temperature for 5 min. Add
10 mL of nitric acid (3.3). Continue to heat to dissolve it completely. Add 5 mL
of sulfuric acid (3.4). Heat it until thick white smoke appears. Evaporate it to 2
mL. Remove and cool it. Add 2 mL ~ 3 mL of hydrochloric acid (3.2). Use water
to wash the watch glass and the wall of the beaker. Heat to dissolve the salts.
Add 4 g ~ 5 g of ammonium chloride (3.1). Add water to a volume of 70 mL ~
80 mL. Use ammonia water (3.5) to neutralize it, until ferric hydroxide is
completely precipitated. Add another 3 mL. Heat it to slight boiling, for 3 min ~
5 min. Remove it. Add 3 mL of ammonia water (3.5). Use fast filter paper to filter
it. Use hot washing solution (3.9) to wash the beaker and filter paper 4 times
each. Then use water to wash them once each.
5.4.2 Use hot hydrochloric acid (3.6) to dissolve the precipitate in the original
beaker. Then use water and hydrochloric acid (3.6) to alternately wash it, until
the filter paper is colorless. Put the solution at a low temperature, to evaporate
it to 1 mL ~ 2 mL. Remove it. Add water to about 120 mL. Use ammonia water
(3.8) to neutralize it, until ferric hydroxide precipitates. Add 10 mL of
hydrochloric acid (3.7). Heat it to 60 °C ~ 80 °C. Add 1 mL of sulfosalicylic acid
solution (3.10). Use Na2EDTA standard titration solution (3.12) to titrate it, until
the solution changes from brown to bright yellow, which is taken as the end
point.
6 Calculation of analysis results
The amount of iron is expressed as the mass fraction of iron wFe; the value is
expressed as %; it is calculated according to formula (2):
Where:
c - The concentration of Na2EDTA standard titration solution, in mole per liter
(mol/L);
V3 - The volume of Na2EDTA standard titration solution, which is consumed
by the titrating the sample solution, in milliliter (mL);
V0 - The volume of Na2EDTA standard titration solution, which is consumed
by the titrating the blank test solution, in milliliters (mL);
55.85 - The molar mass of iron, in grams per mole (g/mol);
m - The mass of the sample, in grams (g).
......
 
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.