ISO 3980:1977 pdf download – Aluminium and aluminium alloys – Determination of copper – Atomic absorption spectrophotometric method
4.6 Aluminium, 20 g/l base solution. Weigh, to the nearest 0,Ol g, 20 g of aluminium free from copper (purity > 99,99 %) previously pickled; transfer it to a 1 000 ml beaker (for example) and cover. Add, in small portions, 600 ml of the hydrochloric acid solution (4.1) and if necessary a drop of metallic mercury to facilitate the attack. If necessary, warm gently to assist the dissolution; then add some drops of the hydrogen peroxide solution (4.2)‘ and boil some minutes to remove the excess of hydrogen peroxide. After cooling, transfer the solution thus obtained quanti- tatively to a 1 000 ml volumetric flask; make up to volume and mix. 50 ml of this solution contains 1 g of aluminium and 30 ml of hydrochloric acid solution (4.1). 5 ml of this solution contains 0.1 g of aluminium and 3 ml of hydrochloric acid solution (4.1). 2 ml of this solution contains 0,04 g of aluminium and I,2 ml of hydrochloric acid solution (4.1).
4.7 Copper, standard solution corresponding to 0,l g of Cu per litre. Transfer 1 + 0,001 g of electrolytic copper (purity > 99,95 %) to a 250 ml beaker (for example) and cover. Add 5 ml of water and 5 ml of the nitric acid solution (4.5) and warm gently until the dissolution is complete and crystalliz- ation begins. Take up with water, and heat, if necessary, to complete the dissolution of the salts. Cool, transfer quanti- tatively to a 1 000 ml volumetric flask; make up to volume and mix. Transfer 1 00,O ml of this solution to a 1 000 ml volumetric flask; make up to volume with water and mix. 1 ml of this standard solution contains 0,l mg of Cu.
4.8 Copper, standard solution corresponding to 0,Ol g of Cu per litre. Transfer 10.0 ml of the standard copper solution (4.7) to a 1 00 ml volumetric flask; make up to volume and mix. 1 ml of this standard solution contains 0,Ol mg of copper.
7.3.1 Preparation of the test solution Transfer the test portion (7.1) to a 250 ml beaker (for example) and cover. Add about 30 to 40 ml of water, then, in small portions, 30 ml of the hydrochloric acid solution (4.11, heating gently, if necessary, to complete the dissol- ution. Add some drops of the hydrogen peroxide solution (4.2) and heat for about IO min to remove the excess of hydrogen peroxide. Filter if necessary. NOTE – For silicon contents greater than 1 % proceed as follows : Transfer the filter containing the silicon to a platinum crucible and ignite it taking care that it does not inflame, then heat at about 550 ‘C. After cooling add 2 ml of the sulphuric acid solution (4.3). 5 ml of the hydrofluoric acid solution (4.4) and, drop by drop, the nitric acid solution (4.5) until a clear solution is obtained (about 1 ml). Evaporate to dryness and heat again, at about 700 “C for some minutes, to volatilize the silicon completely. After cooling, bring the non-volatile matter into solution with the least possible quantity of the hydrochloric acid solution (4.1). filter if necessan/ and add this filtrate quantitatively to the previous filtrate.