BS 7317-7-1990 Methods for analysis of high purity copper cathode Cu-CATH-1 - Method for determination of lead by lanthanum hydroxide separation and atomic absorption spectrophotom.pdf

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1、BSI BSX7337: PART*7 90 Lb24bb9 0303738 O W BS 7317 : Part 7 : 1990 UDC 669.3.015.4 : 543.422.062 : 546.8151.819 British Standards Institution. No part of this publication may be photocopied or otherwise reproduced without prior permission in writing of BSI British Standard Methods for Analysis of hi

2、gh purity copper cathode Cu-CATH-I Part Z Method for determination of lead by lanthanum hydroxide separation and atomic absorption spectrophotometry British Standards Institution BSI BSw7317: PART*7 90 W 3624bb 0303439 2 W BS 7317 : Part 7 : 1990 Foreword BS 7317 has been prepared under the directio

3、n of the Non-ferrous Metals Standards Policy Committee. It des- cribes methods for the determination of impurity elements in high purity copper cathode designated Cu-CATH-I, each method being published as a separate Part. The methods are based on those previously issued in the Draft for Development

4、series DD 95 : Parts 1 to 7. The information and experience gained from the practical application of DD 95 have been taken into account in the methods in BS 7317. This Part of BS 7317 supersedes DD 95 : Part 7 : 1986, which is withdrawn. It is one of a series of methods in BS 7317, the others being

5、as follows: Part 1 Method for determination of cadmium, manganese and silver (screening procedure for chromium, cobalt, iron, nickel and zinc) by atomic absorption spectrophotometry Method for determination of chromium, cobalt, iron, nickel and zinc by discrete volume nebuliza- tion atomic absorptio

6、n spectrophotometry Method for determination of antimony, arsenic, bismuth, selenium, tellurium and tin by hydride generation and atomic absorption spectrophoto- metry Method for determination of antimony, arsenic, bismuth, lead, selenium, tellurium and tin by electrothermal atomization atomic absor

7、ption spectrophotometry Method for determination of sulphur by hydrogen sulphide evolution and spectrophotometry Part 2 Part 3 Part 4 Part 5 Part 6 The atomic absorption spectrophotometric procedures in Parts 1 and 2 are complementary. A sample solution concentration found to be satisfactory for neb

8、ulizers in standard atomic absorptiometers was 20 g/L. At this concentration the precision obtainable, using the method described in Part 1, is only sufficient to allow the determination of cadmium, manganese and silver. Results would be obtained for chromium, cobalt, iron, nickel and zinc that woul

9、d prove useful in detecting impurities grossly in excess of the requirements for chemical composition specified in BS 6017 for Cu-CATH-I and would give a guide to the levels to be determined by Part 2. The discrete volume nebulization procedure in Part 2 was developed to enable a higher equivalent s

10、ample solution concentration of 100 g/L to be used without nebulizer blockage. The method involves no chemical separation, which can give rise to contamination problems, and the extra sensitivity obtained enables the impurities to be determined to an adequate accuracy for the requirements for chemic

11、al composition specified in BS 6017 for Parts 1 and 2 essentially cover the same impurities. Part 4 covers the electrothermal atomization atomic absorption spectrophotometric method and is recommended where the facility is available. Parts 1, 2, 3 and 7 are included for use where the electrothermal

12、atomization equipment is not available. Compliance with a British Standard does not of itself confer immunity from legal obligations. Method for determination of phosphorus and sil icon by spectrophotometry CU-CATH-I. - BSI BS*7337: PART*7 90 = 3624667 0303740 9 = BS 7317 : Part 7 : 1990 Contents Fo

13、reword Committees responsible Method 1 Scope 2 Principle 3 Reagents 4 Apparatus 5 Procedure 6 Calculation and expression of results 7 Repeatability and reproducibility 8 Test report Table 1 Calibration solutions Page Inside front cover Back cover 2 1 BSL BS*7317: PART*? 90 9 1624669 03034411 O 9 BS

14、7317 : Part 7 : 1990 Method 1 Scope This Part of BS 7317 describes a method for the deter- mination of the actual amount of the impurity element lead present in high purity copper cathode (designated Cu-CATH-I), by atomic absorption spectrophotometry. It is applicable to concentrations of lead not e

15、xceeding the following limit. 8 pg/g (0.0008 % mlm) maximum NOTE. The titles of the publications referred to in this Part of BS 7317 are listed on the inside back cover. Lead 2 Principle Test solutions are prepared by separating the impurity element from the analysis sample of Cu-CATH-I by double co

16、-precipitation with lanthanum hydroxide. The deter- mination of lead is carried out by flame atomic absorption spectrophotometry using matching calibration solutions. NOTE. The separation procedure is similar to that given in BS 7317 : Part 3. 3 Reagents 3.1 General During the analysis, use only rea

17、gents of recognized analytical quality or higher purity and only distilled water, deionized water, or water of equivalent purity that has no detectable level of lead. NOTE. Unless crtherwise stated all solutions are aqueous solutions. 3.2 Copper*, a certified reference material of a minimum of 99.99

18、9 % of copper, containing less than 0.5 pglg of each of the impurity elements. 3.3 Hydrochloric acid, p 1 .I8 glm L. 3.4 Hydrochloric acid, p 1 .I8 g/mL, 50 % VIV solution. 3.5 Nitric acid, p 1.42 glm L. 3.6 Nitric acid, p 1.42 g/mL, 50 % VIV solution. 3.7 Lanthanum nitrate solution, 0.05 g1mL. Diss

19、olve 25 g lanthanum nitrate in 500 mL water. 3.8 Ammonia solution, p 0.880 g/mL. 3.9 Ammonia solution, p 0.880 g/mL, 10 % VIV solution. 3.10 Primary calibration solution. Dissolve 1 .O00 g lead in 200 mL of nitric acid solution (3.6). Cool, transfer to a 1 L volumetric flask and dilute to the mark w

20、ith water. 3.11 Acetone 4 Apparatus 4.1 Atomic absorption spectrophotometer, incorporating a x 10 scale expansion facility and fitted with a burner for use with acetylenelair and an electrodeless discharge (ED) lamp, or a hollow cathode (HC) lamp. 4.2 Laboratory glassware NOTE. It is recommended tha

21、t new glassware, dedicated to this specific purpose, is used. 4.3 Paper pulp pad 4.4 1 1 O mm hardened, rapid filter paper 5 Procedure 5.1 General Scrupulously clean all glassware in aqua regia, .e. 1 part of concentrated nitric acid (3.5) and 3 parts of concentrated hydrochloric acid (3.3) for 16 h

22、, and rinse with water immediately before use. 5.2 Preparation of solutions 5.2.1 Stock reference solution. Prepare a stock reference solution by the following method and use within 24 h to avoid deterioration. Into a 1 L volumetric flask transfer, using a pipette, 10 mL of primary calibration solut

23、ion (3.10). Dilute to the mark with water and mix well. NOTE. The concentration of the resulting stock reference solution will be such that 1 mL is equivalent to 10 pg of lead. 5.2.2 Calibration solutions. Prepare six calibration solutions (solutions 5.2.2.1 to 5.2.2.6) by the following method, and

24、use them in the same time period as that in which the test portions (see 5.2.4) and the reagent blanks (see 5.2.5) are prepared and measured. Weigh and transfer approximately 35 g of copper (3.2) into a 1 L beaker, add 250 mb of 50 % VIV hydrochloric acid solution (3.4), cover and boil for 1 min. De

25、cant the acid solution and wash the copper several times with water, followed by acetone (3.11), and dry using gentle heat. Table 1. Calibration solutions Calibration solution 1 5.2.2.1 5.2.2.2 5.2.2.3 5.2.2.4 5.2.2.5 5.2.2.6 Addition of stock reference solution mL 0.00 1 .o0 1.50 2.00 2.50 3.00 Equ

26、ivalent concentration for a 5 g sample Pglg 0.00 2 .o0 3.00 4.00 5.00 6.00 *For information on the availability of copper of suitable purity,apply to Enquiry Section, BSI, Linford Wood, Milton Keynes MK14 6LE. enclosing a stamped addressed envelope for reply. 2 BSI BS*7317: PARTS7 Weigh and transfer

27、 six 5.0 g portions of the cleaned and dried copper (3.2) into separate 600 mL beakers. Add 40 mL nitric acid solution (3.6) and heat gently to dissolve. Boil gently to expel nitrous fumes and dilute to approximately 200 mL with water. Add to each beaker the amount of stock reference solution (5.2.1

28、) given in table 1. 5.2.3 Separation procedures 5.2.3.1 Carry out the procedures in 5.2.3.2 to 5.2.3.4 for each calibration solution (5.2.2.1 to 5.2.2.61, for each test portion (5.2.4.1 to 5.2.4.6) and for each reagent blank (5.2.5.1 to 5.2.5.3). 5.2.3.2 Add 10 mL of lanthanum nitrate solution (3.7)

29、 and mix well. Add 40 mL of ammonia solution (3.8) while stirring; heat to boiling and simmer for 1 min. Allow to settle for 1 min. Decant the solution through a paper pulp pad (4.3) in a 62 mm diameter funnel. Transfer the precipitate to the pad with ammonia solution (3.9) and wash with the same so

30、lution until no further copper blue is removed from the pad. Discard the filtrate. 5.2.3.3 Dissolve the precipitate back into the original beaker with 20 mL of hot 50 % VIV hydrochloric acid solution (3.4) added in small portions. Wash the pad with water until the volume of the filtrate is approxima

31、tely 150 mL. Add 15 mL of ammonia solution (3.81, heat to boiling, simmer for 1 min and allow the precipitate to settle for 1 min. 5.2.3.4 Filter through a 110 mm hardened, rapid filter paper (4.4), washing well with ammonia solution (3.9) and finally once with water. Discard the filtrate. Dissolve

32、the precipitate carefully into the original beaker with small portions of hot 50 % VIV hydrochloric acid solution (3.4) to a total of 20 mL. Wash with water. Evaporate until just dry. Re-dissolve in about 15 mL of water. Transfer to a 25 mL volumetric flask, dilute to volume and mix well. 5.2.4 Test

33、 portions. Prepare six test portions (solutions 5.2.4.1 to 5.2.4.6) by the following method. Weigh and transfer six 5.0 g portions of the analysis sample, previously cleaned by the procedure described in 5.2.2, into separate 600 mL beakers. To each beaker add 40 mL of nitric acid solution (3.6) and

34、heat gently to dissolve the sample. Boil gently to expel nitrous fumes and dilute to approximately 200 mL with water. Carry out the separation procedure described in 5.2.3.2 to 5.2.3.4. 5.2.5 Reagent blanks. Prepare three reagent blanks (solutions 5.2.5.1 to 5.2.5.3) by the following method. Into se

35、parate 600 mL beakers add 40 mL of nitric acid solution (3.6) and boil gently to expel any nitrous fumes. Dilute to approximately 200 mL with water. Carry out the separation procedure described in 5.2.3.2 to 5.2.3.4. 5.3 Adjustment of apparatus Adjust the atomic absorption spectrophotometer (4.1), i

36、n accordance with the recommendations of the instrument BS 7317 : Part 7 : 1990 supplier, to give the maximum sensitivity for lead determination. Use automatic background correction, if available. Choose a scale expansion that gives the best balance between readability and stability over the range o

37、f reference so I ut ions. 5.4 Determination Using the 283 nm spectral line, measure the absorbance values three times for each of the calibration solutions (5.2.2.1 to 5.2.2.6), six times for each of the test portions (5.2.4.1 to 5.2.4.6) and six times for the reagent blanks (5.2.5.1 to 5.2.5.3). Re

38、cord the absorbance values to 0.0001. 6 Calculation and expression of results 6.1 Calibration calculations Calculate the arithmetic means of the three absorbance value measurements for each of the calibration solutions (5.2.2.1 to 5.2.2.6). Construct or calculate a straight line calibration (mean ab

39、sorbance plotted against calibration solution concen- tration) using a least squares (firstorder) fit. From the calibration read off or calculate an apparent lead concentration, in pg/g (% mlrn), corresponding to each of the measured absorbance values. Calculate the differences between the apparent

40、concentrations and the true concentrations (see table 1). Sum these differences arithmetically, .e. ignoring the signs, and divide the sum by the number of measurements (18) to give the mean difference (2). If the mean difference (4) exceeds 0.1 pg/g (0.00001 % mlm), check the procedure, instrumenta

41、l adjustments and test conditions, and then repeat the determinations in 5.4. 6.2 Calculation of the lead concentration in the analysis sample Correct the calibration for the calibration blank solution (5.2.2.1) using the arithmetic means of the measurements in triplicate made in accordance with 5.4

42、. Calculate the arithmetic means of the absorbance values for lead obtained from the measurements on each of the six test portions (5.2.4.1 to 5.2.4.6) and correct for the arithmetic mean of the nine absorbance values obtained from the measurements on the reagent blanks (5.2.5.1 to 5.2.5.3). Using t

43、he mean values, read off or calculate from the calibration the lead concentration in pglg (% mlm) for each of the six test portions (5.2.4.1 to 5.2.4.6). Calculate the arithmetic mean and standard deviation (u) for the lead concentration in pglg (% mlrn). 7 Repeatability and reproducibility 7.1 Repe

44、atability When successive determinations of the lead concentration for a given sample using the method described have been made in a short interval by the same operator, using the same apparatus in the same laboratory, the standard deviation calculated for the successively determined concentrations

45、has been found to be 0.1 pglg (0.00001 % mlm) at the 6 pg/g (0.0006 % mlm) lead level. 3 _ BSI BS*7317: PART*? 90 9 lb24669 U303743 4 m BS 7317 : Part 7 : 1990 7.2 Reproducibility 8 Testreport When determinations of the lead concentration for a given cathode using the method described have been repe

46、ated, using samples from the same material, by operators in different laboratories, the reproducibility at the 95 % confidence limit has been found to be 0.6 pg/g (0.00006 % m/m) at the 6 pg/g (0.0006 % m/m) lead level. The test report shall include the following: (a) an identification of the sample

47、; (b) the reference of the method used; (c) the results and the method of expression used; (d) any unusual features noted during the determination; (e) details of any operation not included in this Part of BS 7317 or regarded as optional. BSI BSr7317: PARTS7 90 LbZ4bh 0303744 b Publications referred

48、 to BS 6017 BS 7317 Specification for copper refinery shapes Methods for analysis of high purity copper cathode CU-CATH-1 *Part 1 Method for defermination of cadmium, manganese and silver (screening procedure for chromium, cobalt, iron, nickel and zinc) by atomic absorption spectrophotometry *Part 2

49、 Method for determination of chromium, cobalt, iron, nickel and zinc by discrete volume nebulization atomic absorption spectrophotometry Part 3 Method for determination of antimony, arsenic, bismuth, selenium, tellurium and tin by hydride generation and atomic absorption spectrophotometry atomization atomic absorption spectrophotometry *Part 4 Method for determination of antimony, arsenic, bismuth, lead, selenium, tellurium and tin by electrothermal *Part 5 Method for determination of sulphur by hydrogen sulphide evolution and spectrophotometry *Part 6 Method for determination of ph