GB/T 3884.1-2012 PDF in English
GB/T 3884.1-2012 (GB/T3884.1-2012, GBT 3884.1-2012, GBT3884.1-2012)
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| GB/T 3884.1-2012 | English | 125 |
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Methods for chemical analysis of copper concentrates -- Part 1: Determination of copper content -- Iodine titration method
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| GB/T 3884.1-2000 | English | 279 |
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Methods for chemical analysis of copper concentrates. Determination of copper content
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| GB/T 3884.1-1983 | English | RFQ |
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Methods for chemical analysis of copper concentrates--The thiosulfate-iodometric method for the determination of copper content
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Standards related to (historical): GB/T 3884.1-2012
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GB/T 3884.1-2012: PDF in English (GBT 3884.1-2012) GB/T 3884.1-2012
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.120.60
H 13
Replacing GB/T 3884.1-2000
Methods for chemical analysis of copper concentrates
- Part 1: Determination of copper content - Iodine
titration method
ISSUED ON: DECEMBER 31, 2012
IMPLEMENTED ON: OCTOBER 01, 2013
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 summary ... 5
3 Reagents ... 5
4 Instruments ... 8
5 Samples ... 9
6 Analysis steps ... 9
7 Calculation of analysis results ... 12
8 Precision ... 13
9 Test report ... 14
Methods for chemical analysis of copper concentrates
- Part 1: Determination of copper content - Iodine
titration method
1 Scope
This Part of GB/T 3884 specifies the method of determination of copper content
in copper concentrates: long iodine titration method (Method One) and short
iodine titration method (Method Two), hereinafter referred to as Method One
and Method Two.
This Part is applicable to the determination of copper content in copper
concentrates. The determination range: 13.00%~50.00%.
2 Method summary
2.1 Method One
The test material is decomposed by hydrochloric acid, nitric acid and sulfuric
acid. Add sodium thiosulfate solution to dilute sulfuric acid solution to separate
copper ions from the solution in the state of copper sulfide. The precipitation is
dissolved with mixed acid. Adjust the pH of the solution to 3.0~4.0. Use
ammonium bifluoride to mask iron. Add potassium iodide to interact with
divalent copper. The precipitated iodine uses starch as an indicator. Use sodium
thiosulfate standard titration solution to titrate. The filtrate after the separation
of copper is used to determine the amount of copper by atomic absorption
spectrometry.
2.2 Method Two
After the test material is decomposed by hydrochloric acid and nitric acid, use
ammonium acetate solution to adjust the pH of the solution to 3.0~4.0. Use
ammonium bifluoride to mask iron. Add potassium iodide to interact with
divalent copper. The precipitated iodine uses starch as an indicator. Use sodium
thiosulfate standard titration solution to titrate.
3 Reagents
Unless otherwise specified, only reagents and distilled water or deionized water
3.22 Saturated solution of ammonium bifluoride (stored in polyethylene bottle).
3.23 Ammonium acetate solution (300g/L): Weigh 90g of ammonium acetate in
a 400mL beaker. Add 150mL of water and 100mL of glacial acetic acid (3.13).
After dissolving, use water to dilute to 300mL. Mix well. The pH value of this
solution is 5.
3.24 Potassium thiocyanate solution (100g/L): Weigh 10g of potassium
thiocyanate in a 400mL beaker. After adding 100mL of water to dissolve, add
2g of potassium iodide (3.2) to dissolve. Add 2mL of starch solution (3.28). Add
iodine solution (3.18) dropwise to just blue. Then use sodium thiosulfate
standard titration solution (3.25) to titrate until the blue color just disappears.
3.25 Sodium thiosulfate standard titration solution
[c(Na2S2O3·5H2O≈0.04mol/L].
3.25.1 Preparation: Weigh 100g of sodium thiosulfate (Na2S2O3·5H2O) in a
1000mL beaker. Add 500mL of sodium carbonate solution (3.19). Transfer to a
10L brown reagent bottle. Use boiled and cooled distilled water to dilute to about
10L. Add 1mL of chloroform (3.5). Place still for two weeks. Filter when in use.
Add 1mL of chloroform (3.5). Mix well. Place for 2h.
3.25.2 Calibration: Weigh three portions of 0.080g (to the nearest of 0.00001g)
of treated pure copper (3.1) to respectively place in 500mL triangular beakers.
Add 10mL of nitric acid (3.9). Cover the watch glass. Heat on an electric heating
plate at a low temperature to completely dissolve. Remove. Use water to wash
the watch glass and beaker wall. Add 5mL of sulfuric acid (3.11). Continue to
heat and steam until it is dry. Remove to cool for a while. Rinse the wall of the
beaker with 40mL of water. Heat till it is boiling. Completely dissolve the salt.
Remove to cool to room temperature. Add 1mL of glacial acetic acid (3.13). Add
3mL of saturated ammonium bifluoride solution (3.22). Shake well. Add 2g~3g
of potassium iodide (3.2). Shake to dissolve. Immediately use sodium
thiosulfate standard titration solution (3.25) to titrate to light yellow. Add 2mL of
starch solution (3.28). Continue to titrate to light blue. Add 5mL of potassium
thiocyanate solution (3.24). Shake vigorously to deepen the blue. Titrate again
until the blue just disappears as the end point. Conduct the blank test with the
calibration.
Calculate the actual concentration of sodium thiosulfate standard titration
solution according to formula (1):
Where,
Add 15mL of nitrosulfur mixed acid (3.15) and 0.5mL~1mL of bromine (3.6).
Cover the watch glass. Shake well. Heat at a low temperature. After the test
material is completely decomposed, continue to heat and steam dry. Cool.
6.4.1.2 Separation of copper
Use 90mL of water to wash the watch glass and the wall. Add 10mL of sulfuric
acid (3.11) on the heating plate and boil. Under stirring, slowly add 25mL of
sodium thiosulfate solution (3.21). Boil 5min. Keep warm and boil until the
sediments coagulate. Filter while hot and wash the sediment with hot water
more than three times. The washing liquid and the separated copper sulfide
filtrate are combined and used for atomic absorption spectrometry to determine
copper content.
6.4.1.3 Decomposition of copper deposits
Return the sediment and filter paper to the original triangular beaker. Add 20mL
of mixed acid (3.16). Decompose precipitation and filter paper by heating (if
there is still carbon and sulfur that have not been decomposed, add mixed acid
appropriately, and then heat to complete decomposition). And smoke until
nearly dry. Cool.
6.4.1.4 Titration
Use 30mL of water to rinse the watch glass and the beaker wall. Cover the
watch glass. Place on the heating plate to boil to dissolve soluble salts. Remove
and cool to room temperature. Add ammonia (3.17) dropwise until the
precipitate is formed. Then add acetic acid (3.14) dropwise until the precipitate
disappears. Excess by 4mL. Add 3mL of saturated ammonium bifluoride
solution (3.22). Shake well. Add 2g~3g of potassium iodide (3.2). Shake to
dissolve. Immediately use sodium thiosulfate standard titration solution (3.25)
to titrate to light yellow. Add 2mL of starch solution (3.28). Continue to titrate to
light blue. Add 5mL of potassium thiocyanate solution (3.24). Shake vigorously
to deepen the blue. Titrate again until the blue just disappears as the end point.
6.4.1.5 Determination of copper content in the filtrate
Steam the filtrate after separating the copper to nearly dry. Remove to cool. Add
100mL of water and boil on the heating plate. Dissolve the soluble salts.
Remove to cool. Transfer to a 200mL volumetric flask. Use water to dilute to the
scale. Mix well. Place 2h.
Use air-acetylene flame, at 324.7nm wavelength of atomic absorption
spectrometer, to adjust the zero with water at the same time as the
measurement series standard solution. Measure the absorbance of the solution.
Subtract the absorbance of the blank solution of the test material. Find the
corresponding copper mass concentration (ρ) from the working curve.
6.4.1.6 Drawing of working curve
6.4.1.6.1 Pipette 0mL, 1.00mL, 2.00mL, 3.00mL, 4.00mL, 5.00mL of copper
standard solution (3.27) into a set of 200mL volumetric flasks. Add 1.0mL of
sulfuric acid (3.10). Use water to dilute to the scale. Mix well.
6.4.1.6.2 Use air-acetylene flame, at 324.7nm wavelength of atomic absorption
spectrometer, to zero with water. Measure the absorbance of the solution.
Subtract the absorbance of the "zero" concentration solution. Use the
concentration of copper as the abscissa and absorbance as the ordinate to
draw the working curve.
6.4.2 Method Two
6.4.2.1 Processing of test material
Place the test material (6.1) in a 500mL triangular beaker. Use a little water to
moisten. Add 10mL of hydrochloric acid (3.7). Place it on the electric heating
plate and heat it at low temperature for 3min~5min. Remove to cool for a while.
Add 5mL of nitric acid (3.8) and 0.5mL~1mL of bromine (3.6). Cover the watch
glass. Mix well. Heat at a low temperature. After the test material is completely
decomposed, remove it and let it cool slightly. Use a little water to wash the
watch glass. Continue to heat and steam until nearly dry. Cool.
NOTE 1: When the silicon content in the test material is high, 0.5g of ammonium bifluoride
(3.3) needs to be added.
NOTE 2: If the carbon content in the test material is high, add 2mL of sulfuric acid (3.10)
and 2mL~5mL of perchloric acid (3.12). Heat to dissolve until there is no black residue and
evaporate to dryness.
NOTE 3: If the test material contains high silicon and carbon, add 0.5g of ammonium
bifluoride (3.3) and 5mL~10mL of perchloric acid (3.12).
NOTE 4: If the chromium content in the test material is high, add perchloric acid to smoke.
When the solution appears brick red, add hydrochloric acid or solid sodium chloride.
Repeat twice. Steam to nearly dry. Add 5mL of hydrochloric acid (3.7). Heat to dissolve.
NOTE 5: If the content of calcium and magnesium in the test material is high, use Method
One to determine copper.
6.4.2.2 Titration
Use 30mL of water to rinse the watch glass and beaker wall. Cover the watch
glass. Place on the heating plate to boil. Dissolve the soluble salts completely.
Remove to cool to room temperature. Drop ammonium acetate solution (3.23)
until the red color no longer deepens and excess by 3mL~5mL. Then add
dropwise saturated ammonium bifluoride solution (3.22) until the red color
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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