1、BRITISH STANDARD CONFIRMED OCTOBER 1995 BS 5658:1979 Specification for Gold potassium cyanide for electroplating UDC546.5932267386:661.859.8:621.357.7.035.4BS5658:1979 This British Standard, having been prepared under the directionof the Surface Coatings(other than paints) Standards Committee, was p
2、ublished under the authorityofthe Executive Boardand came into effect on 28 February1979 BSI 11-1999 The following BSI references relate to the work on this standard: Committee reference SRC/8 Draft for comment76/52450 DC ISBN 0 580 10456 7 Cooperating organizations The Surface Coatings (other than
3、paints) Standards Committee, under whose direction this British Standard was prepared, consists of representatives from the following Government department and scientific and industrial organizations: Aluminium Federation Assay Offices Committee of GreatBritain Association of Metal Sprayers BNF Meta
4、ls Technology Centre British Jewellery and Giftware Federation Limited British Metal Finishing Suppliers Association* British Steel Industry Chemical Industries Association* Copper Development Association Electricity Supply Industry in England and Wales Electronic Engineering Association* Engineerin
5、g Equipment Users Association Greater London Council Institute of Metal Finishing* Institute of Sheet Metal Engineering Institute of Vitreous Enamellers Institution of Corrosion Technology Metal Finishing Association* Ministry of Defence Motor Cycle Association of GreatBritain* Society of Motor Manu
6、facturers and Traders Limited Vitreous Enamel Development Council The organizations marked with an asterisk in the above list, together with the following, were directly represented on the committee entrusted with the preparation of this British Standard: Bicycle Association of GreatBritain Cutlery
7、and Silverware Association Institution of Chemical Engineers International Tin Research Institute Society of Chemical Industry Zinc Development Association Amendments issued since publication Amd. No. Date of issue CommentsBS5658:1979 BSI 11-1999 i Contents Page Cooperating organizations Inside fron
8、t cover Foreword ii 1 Scope 1 2 References 1 3 Precautions 1 4 Appearance 1 5 Composition 1 6 Turbidity 1 7 Insoluble matter 1 8 Loss on drying 1 9 Impurities 1 10 Containers and marking 1 11 Sampling and size of sample 1 Appendix A Determination of gold content 3 Appendix B Determination of turbidi
9、ty 3 Appendix C Determination of insoluble matter 3 Appendix D Loss in mass on drying 4 Appendix E Determination of impurities 4 Figure 1 Sample electrode 5 Figure 2 Counter electrode 5 Table 1 Permitted impurity levels 2 Table 2 Analytical lines 6 Table 3 Atomic absorption method: spectrophotometer
10、 operating conditions 7 Table 4 X-ray fluorescence method: spectrophotometer operating conditions 8 Table 5 Goniometer2 settings 9 Publications referred to Inside back coverBS5658:1979 ii BSI 11-1999 Foreword This British Standard has been prepared under the direction of the Surface Coatings (other
11、than paints) Standards Committee to provide requirements and methods of test for gold potassium cyanide for use in electroplating. This British Standard is one of a series covering chemicals used in this industry, others in the series being as follows. BS 558 drying and weighing of any insoluble res
12、idue. C.2 Reagent During the analysis, use only water complying with the requirements ofBS3978. C.3 Apparatus Ordinary laboratory apparatus with the addition ofC.3.1 andC.3.2. C.3.1 Sintered glass crucible, porosity grade2 complying with the requirements ofBS1752. C.3.2 Oven, capable of being mainta
13、ined at105 2 C. M 1 is the mass of the test portion (in g) M 2 is the mass of residue after heating (in g). M 2 M 1 -100 BS5658:1979 4 BSI 11-1999 C.4 Procedure Filter the solution retained from the method described inAppendix B through the dry, tared sintered glass crucible(C.3.1). Wash the crucibl
14、e and residue five times with50ml portions of water at60 2 C. Dry the crucible and contents in the oven(C.3.2), maintained at105 2 C, for1h. Remove the crucible and allow it to cool in a desiccator and weigh to the nearest0.0005g. Repeat the operations of heating, cooling and weighing until two succ
15、essive weighings do not differ by more than0.0005g. C.5 Expression of results The insoluble matter content, expressed as a percentage by mass, is given by the expression: where M 3is the mass of the test portion taken as described inB.4 (in g) M 4is the mass of the crucible (C.3.1) (in g) M 5is the
16、mass of the crucible and contents (in g). Appendix D Loss in mass on drying D.1 Principle Drying at105 C, weighing and determination of loss in mass. D.2 Apparatus Ordinary laboratory apparatus with the addition ofD.2.1. D.2.1 Oven, capable of being maintained at105 2 C. D.3 Procedure Weigh, to the
17、nearest0.0005g, a test portion of about10g, in a clean, dry tared weighing bottle. Dry the bottle and contents in the oven(D.2.1), maintained at105 2 C, for1h. Remove, allow to cool in a desiccator and weigh to the nearest0.0005g. Repeat the processes of heating, cooling and weighing until two succe
18、ssive weighings do not differ by more than0.0005g. D.4 Expression of results The loss in mass on drying, expressed as a percentage by mass, is given by the expression: where Appendix E Determination of impurities E.1 Emission spectrographic method E.1.1 Applicability. This method is applicable to th
19、e determination of aluminium, chromium, copper, cobalt, iron, lead, magnesium, nickel, silicon, silver, tin and zinc in gold potassium cyanide within the limits specified in this standard. E.1.2 Principle. Photographic recording of spectra produced by d.c.arc excitation followed by determination of
20、the impurity concentration by densitometric examination of the appropriate analytical lines. E.1.3 Reagents. During the analysis use only reagents of a recognized analytical grade and water complying with the requirements ofBS3978. E.1.3.1 Gold potassium cyanide. High purity material, containing non
21、-detectable levels of the impurities listed in and analysed according to the methods described in this specification. E.1.3.2 Silicon dioxide 1) E.1.3.3 Sodium carbonate, anhydrous 1) . E.1.3.4 Nitric acid, approximately1.42g/ml, about70% (m/m) solution. E.1.3.5 Chromium nitrate nonahydrate 1) E.1.3
22、.6 Metals 1) . Aluminium, copper, cobalt, iron, lead, magnesium, nickel, silver and zinc. E.1.3.7 Stannic oxide 1) E.1.3.8 Sodium hydroxide 1) E.1.4 Apparatus. Ordinary laboratory apparatus with the addition ofE.1.4.1 toE.1.4.7. E.1.4.1 Excitation unit. A d.c.arc unit capable of providing5A at a pot
23、ential of70V. E.1.4.2 Spectograph, with resolving power and dispersion capable of separating the analytical lines from other lines in the spectrum in the region of250nm to500nm, with ancillary equipment according to the manufacturers recommendations. E.1.4.3 Photographic plate, with medium speed and
24、 medium high contrast, when processed according to the manufacturers instructions. E.1.4.4 Microphotometer, with a precision of 10% for transmittance readings between5% and95%. M 5 M 4 M 3 -100 M 6 M 7 M 6 -100 M 6 is the mass of the test portion before drying (in g) M 7 is the mass of the test port
25、ion after drying (in g). 1) Johnson Matthey “Specpure” materials are suitable.BS5658:1979 BSI 11-1999 5 E.1.4.5 Electrodes 2) E.1.4.5.1 Sample electrode. High purity graphite cup as shown inFigure 1. E.1.4.5.2 Counter electrode. High purity graphite cup as shown inFigure 2. E.1.4.6 Polymethyl penten
26、e beakers, capacity50ml. E.1.4.7 Platinum crucibles E.1.5 Procedure E.1.5.1 Preparation of standard solutions E.1.5.1.1 Metals and metal salt solution. Dissolve125mg of each of the nine metals(E.1.3.6) and963mg of the chromium nitrate nonahydrate(E.1.3.5) in the minimum quantity of the nitric acid(E
27、.1.3.4) (diluted1:1 with water). Transfer the solution to a250ml one-mark volumetric flask and dilute to the mark with water. 1ml N 0.5 mg of each element. Make dilutions of the stock solution with water to contain0.05mg and0.005mg of each element per millilitre. E.1.5.1.2 Silicon solution. (Sodium
28、metasilicate solution.) Weigh out accurately267.4mg of the silicon dioxide(E.1.3.2) in the platinum crucible(E.1.4.7) and fuse with approximately5g the sodium carbonate(E.1.3.3). Dissolve in water, transfer the solution to a250ml one-mark volumetric flask and dilute to the mark with water. Transfer
29、the solution to a plastics bottle. 1ml N 0.5mg of Si. Make dilutions of the silicon stock solution with water to contain0.05mg and0.005mg of silicon per millilitre. E.1.5.1.3 Tin solution (sodium stannate solution). Weigh out accurately158.7mg of the stannic oxide(E.1.3.7) in the platinum crucible(E
30、.1.4.7) and fuse with approximately5g of the sodium hydroxide(E.1.3.8). Dissolve in water, transfer the solution to a250ml one-mark volumetric flask and dilute to the mark with water. Transfer the solution to a plastics bottle. 1 ml N 0.5 mg of Sn. Make dilutions of the tin stock solution with water
31、 to contain0.05mg and0.005mg of tin per millilitre. E.1.5.2 Preparation of calibration curves. Into each of a duplicate series of five of the polymethyl pentene beakers(E.1.4.6) place equal portions of the pure gold potassium cyanide(E.1.3.1) and measured volumes of the standard solutions(E.1.5.1.1,
32、 E.1.5.1.2 andE.1.5.1.3) to give concentrations relative to gold potassium cyanide of0.0,5.0,10.0,20.0 and50.0mg of each element per kilogram. Evaporate each of the solutions to dryness on a water bath and then heat all the standards for2h in an oven maintained at110 2 C. Allow to cool in a desiccator, if necessary grind each of the standards to a fine powder and store in tightly capped plastics bottles. 2) Johnson Matthey gradesJM21/25 andJM21/26 have been found satisfactory. Dimensions are in millimetres Figure 1 Sample electrode Dimensions are in millimetres Figure 2 Counter electrode
