GB/T 223.19-1989 English PDF (GBT223.19-1989)

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GB/T 223.19-1989: Methods for chemical analysis of iron, steel and alloy. The neocuproine-chloroform extraction photometric method for the determination of copper content
GB/T 223.19-89
GB
NATIONAL STANDARD OF
THE PEOPLE’S REPUBLIC OF CHINA
UDC 223.14/.15.543.06
H 11
Replacing GB 223.19-82
Methods for chemical analysis of iron, steel and alloy
The neocuproine-chloroform extraction photometric
method for the determination of copper content
ISSUED ON. MARCH 31, 1989
IMPLEMENTED ON. JULY 1, 1990
Issued by. China Bureau of Technical Supervision.
Approved by. China Bureau of Technical Supervision, February 21, 1989
Table of Contents
Additional Information ... 3 
1 Subject and scope ... 4 
2 Method summary ... 4 
3 Reagents ... 4 
4 Analysis steps ... 5 
5 Calculation of analysis results ... 6 
6 Precisions ... 7 
Additional Information
This Standard shall be under the technical jurisdiction of Metallurgical
Industry Research Institute of Iron and Steel.
Main drafting organization of this Standard. Metallurgical Industry Research
Institute of Iron and Steel.
The drafting organizations of this Standard. Wuhan Iron and Steel Company
and Metallurgical Industry Research Institute of Iron and Steel.
Main drafter of this Standard. Cao Hongyan, Ke Ruihua, Yang Wenqiu.
This Standard level mark. GB 223.19-89 I
Methods for chemical analysis of iron, steel and alloy
The neocuproine-chloroform extraction photometric
method for the determination of copper content
1 Subject and scope
This Standard specifies the neocuproine-chloroform extraction photometric
method for the determination of copper content.
This Standard is applicable to the determination of copper content in pig iron,
carbon steel, alloy steel, super alloy and precision alloys. The determination
range. 0.010% ~ 1.00%.
2 Method summary
After the sample is acid-solubilized, the copper is reduced to monovalent with
hydroxylamine hydrochloride in the presence of citric acid. In the range of PH
5~6, neocuproine and copper generate 2.1 insoluble yellow complex. Extract
with chloroform and measure its absorbance. Chromium has negative
interference when it is more than 4 mg in the extraction solution; other
common coexisting elements have no interference.
3 Reagents
3.1 Absolute ethanol.
3.2 Trichloromethane.
3.3 Hydrochloric acid (ρ 1.19 g/mL).
3.4 Nitric acid (ρ 1.42 g/mL).
3.5 Nitric acid (1+3).
3.6 Perchloric acid (ρ 1.67 g/mL).
3.7 Hydrofluoric acid (ρ 1.15 g/mL).
3.8 Hydrochloric acid-nitric acid mixed acid. mix hydrochloric acid (3.3),
nitric acid (3.4) and water according to a proportion of 3+1+3.
3.9 Sodium citrate solution (30%).
3.10 Hydroxylamine hydrochloride solution (10%).
3.11 2,9-dimethyl-1,10-phenanthroline (neocuproine) ethanol solution
(0.1%). weigh 1 g of neocuproine and dissolve in 1000 mL of absolute ethanol
(3.1); store in a brown bottle.
3.12 Copper standard solution
3.12.1 Weigh 0.1000 g of copper metal (99.9% above) in a 250 mL beaker.
Add 10 mL of nitric acid (3.4). Cover the watch glass. Slightly heat and
dissolve. Add 5 mL of perchloric acid (3.6). Continue heating and evaporation
till high perchloric acid smokes. Cool for a little while. Add a small amount of
water to dissolve the salt. Move the solution into a 1000 mL flask. Use water
to dilute to scale. Well mix. This solution shall contain 100 µg of copper per 1
mL.
3.12.2 Pipette 50.00 mL of copper standard solution (3.12.1) into a 500 mL
flask. Use water to dilute to scale. Well mix. This solution shall contain 10 µg
of copper per 1 mL.
4 Analysis steps
4.1 Sample quantity
Weigh the sample according to Table 1.
Table 1
Copper content, % Sample amount, g
0.010 ~ 0.100 0.5000
>0.100 ~ 1.00 0.2500
4.2 Blank test
Perform the blank test with sample.
4.3 Determination
4.3.1 General sample. place the sample (4.1) in a 150 mL conical flask; add
20 mL of hydrochloric acid-nitric acid mixed acid (3.8); heat till the sample is
dissolved [high silicon sample is added with an appropriate amount of
hydrofluoric acid (3.7) to assist dissolving]; add 5 mL of high-fluoride acid
(3.6), continue heating and evaporation to till high-fluoride acid smokes; high
fluoride residue is less than 1 mL; cool for a little while.
4.3.2 High chromium sample. place the sample (4.1) in a 150 mL conical
flask; add 15 mL of hydrochloric acid (3.3); heat and dissolve; add nitric acid
(3.4) in drops for oxidation; add 10 mL of high-fluoride acid (3.6); continue
heating till high-fluoride acid smokes and chromium is oxidized to high price;
add hydrochloric acid (3.4) in drops to remove chromium as chromium
fluoride; high fluoride residue is less than 1 mL; cool for a little while.
4.3.3 In 4.3.1 or 4.3.2 solution, add into 20 mL of water. Heat to dissolve the
salt. Cool to room temperature. Move the test solution into a 100 mL flask.
Use water to dilute to scale. Well mix (If graphite carbon, tungstic acid and
other insoluble matter exit, use medium-speed filter paper for dry filtration and
removal).
4.3.4 Pipette 10.00 mL of test solution [pipette 5.00 mL when copper
content is 0.50% ~ 1.00%] into a 125 mL separating funnel. Use water to
dilute to about 25 mL.
4.3.5 Add 10 mL of sodium citrate solution (3.9), 5 mL of hydroxylamine
hydrochloride solution (3.10) and mix well. Add 5 mL of neocuproine ethanol
solution (3.11) and mix well. Add 10 mL of chloroform (3.2). After shaking for
30 s, laying for stratification, use cotton wool to filter the organic phase into a
25 mL flask that has been dried and is filled with 5 mL of absolute ethanol
(3.1). In the separating funnel, add into 5 mL of chloroform (3.2). After shaking
for 15 s, laying for stratification, combine the organic phase into a 25 mL flask.
Use absolute ethanol (3.1) to dilute to scale; well mix.
4.3.6 Pipette the color liquid into the absorption dish (use 3 cm absorption
dish when copper content is 0.01% ~ 1.00%, 1 cm absorption dish for copper
content greater than 0.01% ~ 1.00%). Take the blank solution that is with
sample as reference. Measure its absorbance at a wavelength of 456 nm on
spectrophotometer. Check the corresponding copper content in the color
liquid from the working curve.
4.4 Drawing of working curve
Pipette 0, 1.00, 2.00, 3.00, 4.00, 5.00 mL (pipette 0, 2.50, 5.00, 7.50, 10.00,
12.50 mL when copper content is greater than 0.10% ~ 1.00%) of copper
standard solution (3.12.2) into 125 mL separating funnels, respectively. Add
water to dilute to about 25 mL. The followings shall be carried out according
to 4.3.5, 4.3.6. Use reagent blank solution as reference. Measure its
absorbance. Take copper as abscissa and absorbance as ordinate to draw
working curve.
5 Calculation of analysis results
Calculate the percentage of copper by the following formula.
where,
m1 - copper content checked from working curve, g;
V1 - volume of sub-test solution, mL;
V - total volume of test solution, mL;
m - sample amount, g.
6 Precisions
The precisions of this Standard were determined in 1988 by a joint test of ten
laboratories at six levels. The precisions are shown in the following table.
Level rang, % (m/m) Repeatability r Reproducibility R
0.010 ~ 1.00 lgr = -1.5993 + 0.6856 lgm lgR = -1.1792 + 0.7367 lgm
If the difference between two independent test results exceeds the
repeatability or reproducibility value calculated by the precision function listed
in the table, the two results shall be considered suspicious.