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है”ह”ह

IS 5761-2 (1984): Gold cyanide and gold potassium cyanidefor electroplating, Part 2: For special applications [CHD5: Electroplating Chemicals and Photographic Materials]

IS : 5761 (Part2)- 1984

Indian Standard SPECIFICATION FOR

GOLD CYANIDE AND GOLD POTASSIUM CYANIDE FOR ELECTROPLATING

PART 2 FOR SPECI’AL APPLICATIONS

( First Revision )

Electroplating Chemicals Sectional Committee, CDC 43

Chairman

DR K. S. RAJMOPALAN

Members

Representing

Central Ekctrochemical Research Institute (CSIR), Karaikudi

SHRX B. A. SHENOI (Alternate to Dr K. S. Rajagopalan )

DR R. P. DAMBAL Indian Telephone Industries Ltd, Bangalore SHRI R. VEERARAGIIA~AN ( Alternate )

SHRI E. D. DWARMARAJ Platewcl Processes & Chamicals L td, Vadodara SHRI M. R. KAM~AR Metal Finishers Association of India, Bombay

SHRI II. M. MEHTA ( Alternate) SHRI GIRI~H KAPUR The Atlas Cycle Industries Ltd, Sonepat

DR KESHAV NARAI N ( Alternate ) SHRI R. D. KAWATRA Directorate General of Technical Development,

New Delhi SHRI M. A. KOTIBXASKAR Canning Mitra Phoenix Ltd, Bombay

SHRI M. A. CHUNEKAR( Alfrmafr ) DR S. KRISHNAUURTHY In personal capacity ( ‘SHUBHODATA’ 38,

Main Road, Mallcrwaram, Bangalore- )

&RI H. R. KRISIXNA~WAMY HMT Ltd (Watch Factory), Bangalore SHRI H. SIVANANDA PATEL ( Altdrnata I ) SHRI A. SHANTH~RAM (Alternate11 1

’ SHRZ P. A. MBXON Golden Chemicals Pvt Ltd, Bombay SHRI Y. M. RAVAL (Alternate)

SRRI K. L. MUTHU T.I. Cycles of India, Madras SHRI N. VASJDEVAN ( Alternate)

( Continued on pngc 2 )

iNS.?IAN STANDARDS This publication is protected under the Indian Copyr&ht Acf (XIV of 1957 ) acd rqvoduction in whole or in part by any means except with written publisbcr &al? be deemed to be an infringement of copyright u

v

IS : 5761 (Part 2) _ 1984

( Continued /mm page 1 )

Mem bcrs Reprecenting

DR V. N. NIQAM Ministry of Defence (DGI)

SHRI J. P. SHUKLA ( Altsrnatc ) DR T. P. RADHAKRISHNAN Bhabha Atomic Research Centre, Trombay REPRESENTATIVE Bharat Heavy Electricals Ltd, Bhopal

SHRI S. KAMESWAR RAO ( Alternate I) SHRI RAJ KUMAR ( Alternate II )

SENIOR CHEMIST AND METALLUR- Research, Designs and Standards Organization QIST DLW, VARANASI ( Mmistry of Railways ), Lucknow CHEMIST AND MeTALLURorST S. RAILWAY, MADRAS ( Alternate )

SHRl R. A. SHAH Ronuk Industries Ltd, Bombay KUMARI MRIDULA A. SHAH ( Altcraatc)

SHRIP. SATYANARAYANAN Devekp;;e;hommissioner ( Small Scale Industries ), e

SHRI J. P. NIOAM ( Altmate) SHRI S. K. MATHUR,

Director (Chem) Director General, IS1 ( Ex-oflcio AIembm )

Secretary SHRI M. S. DATTA

Deputy Director (Chem), IS1

Precious Metal Salts Subcommittee, CDC 43 : 1

Convener DR S. K. SONAWALA Machsons Pvt Ltd, Bombay

Members

SHR~ MULCHAND MANILAL ( Alternate to DR S. K. Sonawala)

SHRI J. P. AGARWAL Ministry of Defence (DGI) SHRI MADAN LAL ( Alternate)

SHRIB. P. ARORA Arora Matthey Ltd, Calcutta SHRI S. P. ARORA ( Altarnate)

DR S. KRISHNAMURTHY In personal capacity ( ‘S HUB HO DA TA’ 38, Main Road, Mallowaram, Bangalore 560055 )

SHRI K. NA~ESH Bharat Electronics Ltd, Bangalore SHRI N. RAVI BHUSHAN (Alternate )

SHRI S. R. NATARAJAN Central Electrochemical Research Institute (CSIR), Karaikudi

DR T. P. RADHAKRISHNAN Bhabha Atomic Research Centre, Trombay SHRI S. RAMACHANDRAN HM I‘ Ltd (Watch Factory), Bangalore SHRI R. A. SNAH Ronuk Industries Ltd, Bombay

2

IS : 5761 (Part 2) - 1984

Indian Standard SPECIFICATION FOR

GOLD CYANIDE AND GOLD POTASSIUM CYANIDE FOR ELECTROPLATING

PART 2 FOR SPECIAL APPLICATIONS

( First Revision )

0. FOREWORD

0.1 This Indian Standard ( Part 2 ) ( First Revision ) was adopted by the Indian Standards Institution on 31 July 1984, after-the draft finalized by the Electroplating Chemicals Sectional Committee had been approved by the Chemical Division Council.

0.2 This standard was originally published in 1970. Since electroplating industry was facing~problems due to the presence of various impurities in gold cyanide and gold potassium cyanide, the committee responsible~for the preparation of the standard felt necessary to revise it. In this revision ( Part 2 ), various impurities normally present in gold cyanide and gold potassium cyanide have been incorporated including the content of copper which adversely affects the quality of plating process and photoresist used in the fabrication of electroplated printed circuit board. This revision is being issued into two parts. Commercial/engineering applications of the items are covered under Part 1 of this revised standard. Part 2 deals with the material used for electroplating items for special purpose like electronic applications.

0.3 For the purpose of deciding whether a particular requirement of this standard is complied with, the final value, observed or calculated, express- ing the result of a test or analysis, shall be rounded off in accordance with IS : 2 - 1960”. The number of significant places retained in the rounded off value should be the same as that of the specified value in this standard.

1. SCOPE 1.1 This standard ( Part 2 ) prescribes the requirements, the methods of sampling and tests for gold cyanide and gold potassium cyanide for use in

*Ruler for rounding off numerical values (reuiscd) .

3

IS : 5761 (Part 2) - 1984

electroplating and allied solutions, for example, those used in autocatalytic or immersion processes for special applications.

2. REQUIREMENTS

2.1 Description

2.1.1 Gold Cyanide - Gold cyanide shall be in the form of yellow powder, free from dirt, foreign matter and visible impurities, and shall correspond essentially to the formula AuCN.

2.1.2 Gold Potassium Cyanide - Gold potassium cyanide shall be in the form of colourless white crystals, free from dirt, foreign matter and visible impurities, and shall correspond essentially to the formula K Au(CN),.

2.2 Gold cyanide and gold potassium cyanide shall also comply with the requirements prescribed in Table 1 when tested according to the methods given in Appendix A. References to the relevant clauses of Appendix A are given in column 5 of the table.

3. SAFETY PRECAUTIONS IN HANDLING GOLD CYANIDE AND GOLD POTASSIUM CYANIDE FOR SPECIAL APPLICATIONS

3.1 Gold cyanide and gold potassium cyanide are highly poisonous and shall be handled with extreme caution. Useful information on this subject is given in Appendix B.

4. PACKING AND MARKING

4.1 Packing - Gold cyanide and gold potassium cyanide shall be packed in air-tight containers preferably with a replaceable closure. The container shall therefore, have an opening of such a size that the material can be easily withdrawn without any loss.

4.2 Marking - The containers shall be marked with the following details :

4 b)

c> d) 4 f)

Name of the material; Mass of the material along with the mass of equivalent gold (as Au) in brackets; Name of the manufacturer or its recognized trade-mark, if any; Batch number; Date of manufacture; and The word “POISON” along with the appropriate symbol [see Fig. 11 of IS : 1260 (Part 1) - 1973”].

*Pictorial markings for handling and labelling of dangerous goods : Part 1 goods (Jirst rsvision).

Dangerous

A

IS : 5761 (Part 2) - 1984

TABLE 1 REQUIREMENTS FOR GOLD CYANIDE AND GOLD X’OTASSIUM CYANIDE FOR ELECTROPLATING FOR SPECIAL APPLICATIONS

( Clause 2.2 )

SL CHARACTERISTIC METHODOP NO.

REQUlKBMENT C------h----- TEST (REPTO Gold Gold Potas- CL 60. IN Cyanide sium Cyanide APPENDIX A)

(3) (4) (5)

88.0 68.1 A-2

To pass the To pass the A-3 test test

0.1 0.1 A-4

(1) (2) i) Gold (as Au), percent by mass, Min

ii) Turbidity

iii) Insoluble matter, percent by mass, Max

iv) Loss on drying, percent by mass, Max

v) Silver (as Ag), percent by mass, &fax

vi) Copper (as Cu), percent by mass, MC-W

vii) Iron (as Fe), percent by mass, MQX

viii) Nickel (as Ni), percent by mass, Max

ix) Cobalt (as Co), percent hy mass, MU

x) Zinc (as Zn), percent by mass, MUX

xi) Lead (as Pb), percent by mass, Max

xii) Sodium + calcium f magnesium+ aluminium (as NafCat Mg+Al), percent by mass, Max

xiii) Arsenic f antimony + bismuth + selenium (as As + Sh + Bi + Se), percent by mass, Max

xiv) Chromium (as Cr), percent by mass, Max

xv) Silicon (as Si), percent by mass, MU

xvi) Tin (as Sn), percent by mass, Mm

0.25

0.005

0.002

0.001

0.003

0.003

0.001

O*OOl

o-05

oXIo2*

0.001

0.001

0.00 1

0.25 A-5

0.005 A-6

0.002 A-6

O-001 A-6

0.003 A-6

0’003 A-6

0.00 1 A-6

0~001 A-6

0’05 A-6

0.002*

0.001

0.001

0.001

A-7

A-6

A-8

A-9

*The total of impurities, arsenic+antimony+hisn.uth+selenium shall not exceed 0.002 percent by mass, but mdividually, none of these should exceed WOO1 percent by mass.

5

IS : 5761 (Part 2) - 1984

4.2.1 The containers may also be marked with the IS1 Certification Mark.

NOTE - The use of the IS1 Certification Mark is governed by the provisions of the Indian Standards Institution (Certification Marks) Act and the Rules and Regulations made thereunder. The IS1 Mark on Products covered by an Indian Standard conveys the assurance that they have been produced to comply with the requirements of that standard under a well-defined system of inspection, testing and quality control which is devised and supervised by IS1 and operated by the producer. IS1 marked products are also continuously cheked by IS1 for conformity to that standard as a further safeguard. Details of conditions, under which a licence for the use of the IS1 Certification Mark may be granted to manufacturers or processors may be obtained from the Indian Standards Institution.

5. SAMPLING

5.1 The method of preparing representative samples of the material and the criteria for conformity to this standard shall be prescribed in Appendix C.

APPENDIX A

( Clause 2.2 )

METHOD OF TEST FOR GOLD CYANIDE AND GOLD POTASSIUM CYANIDE FOR ELECTROPLATING

FOR SPECIAL APPLICATIONS

A-l. QUALITY OF REAGENTS

A-l.1 Unless specified otherwise, pure chemicals and distilled water (see IS : 1070-1977*) shall be used in tests.

NOTE - ‘Pure Chemicals’ shall mean chemicals that do not contain impuritirs which affect the results of analysis.

A-2. DETERMINATION OF GOLD IN GOLD CYANIDE AND GOLD POTASSIUM CYANIDE

A-2.1 Principle

A-2.1.1 This method is based on decomposition of the cyanide with sulphuric acid followed by filtration and weighing of the precipitated gold.

A-2.2 Reagents

A-2.2.1 Concentrated Sulphuric Acid - Relative density 1.84 approxi- mately (see IS : 266-1977t).

*Specification for water for general laboratory use ( second revision ).

@pecification for sulphuric acid ( second revision ).

6

IS : 5761 (Part 2) - 1984

A-2.3 Apparatus

A-2.3.1 Porcelain crucible with loose fitting aid.

A-2.3.2 Furnace, capable of being maintained at 900” f 10°C.

A-2.4 Procedure

A-2.4.1 Weigh accurately 1 g of the material and transfer the sample to a 250-ml conical flask. Transfer the flask to a fume cupboard and add about 20 ml of concentrated sulphuric acid. Loosely cover the flask to prevent spitting and heat on asbestos mat over a Bunsen flame (or any other suitable heating device) and allow the contents to boil for about 20 minutes. Remove the flask from the heat source and allow it to cool (the flask and the contents may now be removed from the fume cupboard). Dilute the contents of the flask to about 100 ml with water and heat to boiling for about 1 minute or until all salts other than gold have dissolved. By this process, gold is thrown down as precipitate. Cool the solution and filter through a filter paper (Whatman No. 42 or 44) and wash the precipi- tate thoroughly with hot water until the filtrates are free of dissolved salts. Retain the combined filtrate and washings for the determination of other impurities. Transfer the filter paper and contents to a pre-weighed por- celain crucible, and carefully ignite, and finally transfer to a furnace maintained at 900” * 10°C for 1 hour. Remove the crucible from the furnace, allow it to cool in a desiccator, and weigh to the nearest O*OOO 2 g. Repeat the operations of heating, cooling and weighing until a constant mass is obtained.

WARNING - It is essential that the first stage of this process should be carried out in an adequately ventilated fume cupboard as lethal hydrogen cyanide gas is evolved when sulphuric acid is added.

A-2.5 Calculation

Gold (as Au), percent by mass= TX 100

where

M = mass in g of the material taken for the test, and M, = mass in g of the precipitated gold.

A-3. DETERMINATION OF TURBIDiTY

A-3.1 Principle

A-3.1.1 Turbidity in the material is determined by visual inspection of a solution of known concentration.

7

IS: 5761 (Part 2) i 1984

A-3.2 Procedure

A-3.2.1 Weigh accurately 10 g of the material and-transfer the sample to a 500:ml conical flask and dilute it to about 200 ml with water. Shake the flask and contents for 5 minutes, taking care to avoid splashing of the contents. Allow the flask to stand for 2 minutes and inspect the solution for clarity, and observe the presence of undissolved impurities. Retain the flask and the contents for use in the determination of insoluble matter described in A-4.

A-3.2.2 The requirements of the test shall be taken as having been satisfied if no turbidity is produced and the solution should be clear to the naked eye.

NOTE - As gold cyanide is not soluble in water, it should be dissolved in saturated solution of potassium cyanide and the resultant solution is diluted to about 200 ml with water.

A-4. DETERMINATION OF INSOLUBLE MATTER

A-4.1 Principle - This method is based on altering the solution of known concentration, drying and weighing of any insoluble matter left behind.

A-4.2 Apparatus

A-4.2.1 Sintered Glass Crucible - G. No. 4

A-4.2.2 Oven - capable of being maintained at 105 -f 2°C.

A-4.3 Procedure

A-4.3.1 Filter the solution retained from the method A-3, through a dry, pre-weighed sintered glass crucible. Wash the crucible and the residue with hot water at 60 & 2°C. Dry the crucible and contents in the oven maintained at 105 f 2°C for 1 hour. Remove the crucible from the oven and allow it to cool in a desiccator and weigh. Repeat the operations of heating, cooling and drying until constant mass is obtained.

A-4.4 Calculatiou

Insoluble matter, percent by mass = M2-M1 x 100 M

where

Ad =mass in g of the material taken as described in A-3.2,

MI-mass in g of the crucible, and

M,=mass in g of the crucible and the residue.

8

IS : 5761 (Part 2) - 1984

A-§. DETERMINATION OF LOSS IN MASS ON -DRYING

A-5.1 Principle

A-5.1.1 This method is based on drying the material at 105°C and subsequent weighing.

A-S.2 Apparatus

A-9.2.1 Oven-capable of being maintained at 105 f 2°C.

A-S.3 Procedure

A-5.3.1 Weigh accurately 10 g of the material into a clean, dry and pre-weighed bottle. Dry the bottle and the contents in the oven maintain- ed at 105 f 2°C for 1 hour. Remove the bottle from the oven and allow it to cool in a desiccator and weigh. Repeat the operations of heating, cooling and weighing until constant mass is obtained.

A-§.4 Calculation

Loss in mass on drying, = M-M1 x 100 M

percent by mass where

M = mass in g of the material before drying, and n/i, -= mass in g of the material after drying.

A-6. DETERMINATION OF SILVER, COPPER, IRON, NICKEL, COBALT, ZINC, LEAD, SODIUM, CALCIUM, MAGNESIUM, ALUMINIUM AND CHROMIUM BY ATOMIC ABSORPTION SPECTROPHOTOMETRIC METHOD

A-6.1 Outline of the Method (Atomic Absorption Spectrometer)

A-6.1.1 The metallic elements in the ground state will absorb light of the same wavelength they emit when excited. When a radiation from a given excited element is passed through a flame containing ground state atoms of that element, the intensity of the transmitted radiation will decrease in proportion to the amount of the ground state element in the flame. A hollow cathode lamp, whose cathode is made up of the element to be determined provides the radiation. The metal atoms to be measured are placed in the beam of radiation by aspirating the specimen into an oxidant-fuel flame. A monochromator isolates the characteristic radiation from the hollow cathode lamp and a photo sensitive device measures the attentuated transmitted radiation.

9

ES : 5761 (Part 2) - 1984

A-6.2 Apparatus

A-6.2.1 Atomic Absorption Spectrophotometer - The instrument shall consist of an atomizer and a burner with suitable pressure regulating devices capable of maintaining a constant oxidant-fuel pressure for the test. It shall also consist of:

a) A hollow cathode lamp for each metal to be tested, b) An optical system capable of isolating the desired line of

radiation, c) An adjustable slit, d) A photomultiplier tube or any other photo-sensitive device as a

light measuring and amplifying device, and e) A read-out mechanism for indicating the amount of absorbed

radiation.

NOTE - Multi-element hollow cathode lamps are available and found satisfactory.

A-6.3 Oxidant

A-6.3.1 Air is the usual oxidant used and it shall be cleaned and dried through a suitable filter to remove oil, water and other foreign substances.

A-6.3.2 Nitrous oxide may be required as an oxidant for refractory type of metals such as silicon and calcium.

A-6.4 Fuel (Acetylene)

A-6.4.1 Commercially available acetylene is the usual fuel used.

A-6.5 Reagents

A-6.5.1 Concentrated Hydrochloric Acid - Relative density 1.19 approxi- mately (see IS : 265-1976”).

A-6.5.2 Concentrated Nitric Acid - Relative density 1.42 approximately (see IS : 264-1976t).

A-6.6 Standard Solutions

A-6.6.1 Silver (1 ml =O*l mg of Ag) -Dissolve 100 mg of pure silver metal in a minimum quantity of nitric acid ( 1 : 1 by volume). Transfer the solution to a 1-litre volumetric flask and dilute up to the mark with water.

A-6.6.2 Copper (1 ml = 0.1 mg of Cu) - Dissolve 100 mg of pure electrolytic copper in a minimum quantity of nitric acid (1 : 1 by volume). Transfer the solution to a I-litre volumetric flask and dilute up to the mark with water.

*Specification for hydrochloric acid (second revision). TSpecification for nitric acid (second r&ion).

10

IS : 5761 (Part 2) - 1984

A-6.6.3 Iron (1 ml =0*5 mg of Fe) - Dissolve 500 mg of iron in a mini- mum quantity of nitric acid (1 : 1 by volume). Transfer the solution to a I-We volumetric flask and dilute up to the mark with water.

A-6.6.4 Nickel (1 ml = 0.5 mg of Ni) - Dissolve 500 mg of nickel in a minimum quantity of nitric acid (1 : 1 by volume). Transfer the solution to a 1-litre volumetric flask and dilute up to the mark with water.

A-6.6.5 Cobalt (1 ml =Os5 mg of Co) - Dissolve 500 mg of cobalt in a minimum quantity of nitric acid (1 : 1 by volume). Transfer the solution to a I-litre volumetric flask and dilute up to the mark with water.

A-6.6.6 Zinc (I ml = 0-Z mg of Zn) - Dissolve 100 mg of zinc in a minimum quantity of nitric acid (1 : 1 by volume). Transfer the solution to a I-litre volumetric flask and dilute up to the mark with water.

A-6.6.7 Lead (1 ml = 0.5 mg of Pb) - Dissolve 500 mg of lead in a minimum quantity of nitric acid (1 : 1 by volume). Transfer the solution to a I-litre volumetric flask and dilute up to the mark with water.

A-6.6.8 Chromium (I ml = 0.5 mg of Cr) - Dissolve 3.848 g of chro- mium nitrate nanohydrate [Cr(NO,),, 9H,O] in a minimum quantity of nitric acid (1 : 1 by volume). Transfer the solution to a I-litre volumetric flask and dilute up to the mark with water.

A-6.6.9 Sodium (I ml = 1.0 mg of Na) - Dissolve 370 g of sodium nitrate (NaNO,) in I-litre of water in a volumetric flask.

A-6.6.10 Calcium (I ml = 1.0 mg of Cu) - Dissolve 4.10 g of calcium nitrate [Ca(NO&] in a minimum quantity of nitric acid (1 : 1 by volume). Transfer the solution to a 1-litre volumetric flask and dilute up to the mark with water.

A-6.6.11 Magnesium (I ml = 0.5 mg of Mg) - Dissolve 500 mg of magnesium in a minimum quantity of nitric acid (1 : 1 by volume). Trans- fer the solution to a 1-litre volumetric flaskand dilute up to the mark with water.

A-6.6.12 Aluminium (I ml = 0.5 mg of Al) - Dissolve 500 mg of alu- minium in a minimum quantity of nitric acid (1 : 1 by volume). Transfer the solution to a 1-litre volumetric flask and dilute up to the mark with water.

A-6.7 Calibration

A-6.7.1 Prepare at least four standard solutions to bracket the expected metal concentration in the sample, by diluting the standard metal solutions with water as described in A-6.6.

11

IS : 5761 (Part 2) - 1984

A-6.7.2 Optimize the response of the instrument by adjusting the burner height and flame. Apply the current to the cathode lamp as suggested by the manufacturer. Allow the instrument to warm up until the energy source stabilizes. The time required for this process may vary from 10 to 20 minutes.

A-6.7.3 Set the slit width for the metal of interest based on the manufac- turer’s instructions. Feed the fuel and the oxidant for the metal of interest as indicated in Table 2 to the burner and ignite the emitted mixture. Adjust the fuel and the oxidant pressure in accordance with the procedure given by the manufacturer to give maximum sensitivity for a given concentration of the metal.

A-6.7.4 Atomize the water and check the aspiration rate for a period of 2 minutes. Normally, an aspiration rate of 4 to 5 ml per minute is satis- factory. The standard and samples of the metal of interest should have the same aspiration rate.

A-6.7.5 Set the wavelength to the approximate value as given in Table 2 depending on the metal of interest. Atomize the standard solution and select the most sensitive wavelength setting for maximum absorption. The wavelength indicated in Table 2 are the most sensitive recommended values for the respective metals. Once the atomization is completed, record the absorbance reading. This procedure has to be repeated for each standard solution.

A-6.7.6 Prepare a calibration curve relating the absorbance and the amount of metal in microgrammes present in the standard solutions.

A-6.8 Procedure

A-6.8.1 Proceed in accordance with A-6.7.1 to A-6.7.5 for preparing the calibration curve. This procedure has to be repeated for each metal.

A-6.8.2 Rinse the atomizer by aspirating water.

A-6.8.3 Take the filtrate from A-2.4 and atomize the metal of interest from the above solution at a wavelength and operating conditions listed in Table 2 and determine its absorbance.

Then determine the mass of metal in microgrammes using the cali- bration curve prepared as in A-6.7.

A-6.9 Calculation

Metal, percent by mass = $ x 100

12

IS : S76i (Part 2) - 1984

M = mass in g of the sample taken, and MI = mass in g of the metal found from the calibration curve.

TABLE 2 OPERATING CONDITIONS FOR ATOMIC ABSORPTION SPECTROPHOTOMETER

( Clause A-6.8.3 )

SL

No.

(1)

i) ii)

iii)

iv)

v) vi)

vii)

viii)

ix)

x) xi)

Xii)

METAL

(2) Silver

Copper Iron

Nickel

Cobalt

Zinc

Lead

Sodium

Calcium

Magnesium

Aluminium

Chromium

WAVELENGTH

(11m)

(3)

328-l

3247

248.3

232-O

240.7

213.8

283.3

589-o

422.7

285-2

399.3

357.9

FUEL

(4)

Acetylene

Acetylene

Acetylene

Acetylene

Acetylene

Acetylene

Acetylene

Acetylene

Acetylene

Acetylene

Acetylene

Acetylene

OXIDANT

(5)

Air

Air

Air

Air

Air

Air

Air

Air

Nitrous oxide

Air

Nitrous oxide

Air

A-7. DETERMINATION OF ARSENIC, ANTIMONY, BISMUTH AND SELENJUM

A-7.1 Determination of Arsenic

A-1.1.1 Principle

A-7.1.1.1 Arsenic is liberated as arsine (ASH,) from the sample and it is passed through a column containing a roll of cotton moistened with lead acetate solution. It is then absorbed in sodium hypobromite solution and oxidized to the pentavalent state. The oxidized arsenic is then reacted with ammonium molybdenum acid solution in the presence of hydrazine sulphate as reducing agent and the blue colour formed is used for calorimetric estimation.

A-7.1.2 Apparatus

A-7.1.2.1 Gutzeit generator - The generator along with the assembly of the apparatus is shown in Fig. 1.

13

IS : 5761 (Part 2) - 1984

GLASS BEADS SOAKED IN SODIUM HY POBROMITE SOLUTION

\

CONNECTION

FIG. 1 APPARATUS FOR DETERMINATTON OF ARSENIC

A-7.1.2.2 Glass beads - 2 to 3 mm in diameter and absorbent cotton,

A-7.1.3 Reagents

A-7.1.3.1 Lead acetate solution (10 percent mfv) - Dissolve 10 g of lead acetate [Pb(CH,COO),, 3H,OJ in 100 ml of water.

A-7.1.3.2 Sodium hypobromite solution - Add 2 ml of bromine io 470 ml of water in an amber-coloured glass-stoppered bottle. Add 30 ml of 6 N sodium hydroxide and immediately shake thoroughly until the bromine dissolves. Solution should be prepared afresh when required.

A-7.1.3.3 Dilute sulphuric acid (I : I by volume) - Cautiously mix one volume of concentrated sulphuric acid (see IS : 266-1977*, relative density 1.84) with one volume of water.

*Specification for sulphuric acid (second revision),

14

IS : 5761 (Part 2 ) - 1984

A-7.1.3.4 Potassium iodide solution (15 percent m/v) - Dissolve 15 g of potassium iodide in water, and dilute it to 100 ml with water. Store the solution in amber coloured bottle and discard the solution when distinct yellow colour develops.

A-7.1.3.5 Stannous chloride solution - Dissolve 40 g of arsenic free stannous chloride (SnCI,, 2H,O) in 25 ml of concentrated hydrochloric acid and dilute up to 100 ml with water.

A-7.1.3.6 Zinc granules - Must be arsenic-free and capable of passing through 5.60 mm IS Sieve and shall be retained on 2.80 mm IS Sieve [see IS : 460 (Part l)-1978*].

A-7.1.3.7 Sulphuric acid - 1 N. Cautiously add 27.9 ml of concentrat- ed sulphuric acid to water, and dilute it to 1 litre with water.

A-7.1.3.8 Ammonium molybdate solution - Add cautiously 310_ml of concentrated sulphuric acid to 400 ml of water and allow to cool. Dissolve 50 g of ammonium moIybdate in 200 ml with water. Mix the two solutions and dilute the mixture to I-litre of water.

A-7.1.3.9 Hydrazine sulphate solution - Dissolve I.5 g of hydrazine sulphate in 100 ml of water.

A-7.1.4 Standard Arsenic Solutions

A-7.1.4.1 Arsenic standard stock solution (I ml = 0.1 mg qf As) - Dissolve 0.132 g of arsenic trioxide in 10 ml of 1N sodium hydroxide solution. Add 10 ml of 1N sulphuric acid and dilute to 1-litre with water.

A-7.1.4.2 Arsenic standard working solution (1 ml = 0.01 mg of As) - Dilute 10 ml of stock arsenic solution to 100 ml with water in a volumetric flask. Solution should be prepared afresh when required.

A-1.1.5 Calibration

A-7.1.5.1 Clean all glassware before use by rinsing first in hot nitric acid (1 : 1 by volume) and then with water. The absorbers must be finally rinsed with acetone and then air-dried. Dip one end of a 25-mm long roll of absorbent cotton into the lead acetate solution and transfer into the glass column as shown in Fig. 1. Pack the absorption tube with glass beads to a depth of about 8 cm and add 3 ml of sodium hypobromite solution.

A-7.1.5.2 Prepare a series of standard solutions, to bracket the expect- ed arsenic concentration in the sample, by proper dilution of the standard arsenic working solution and treat each of them as follows.

*Specification for test sieves : Part 1 Wire cloth test sieves (wand reoision).

15

IS : 5761 (Part 2) - 1984

A-7.1.5.3 Transfer 25 ml of the standard solution prepared as in A-7.1.5.2 into a Gutzeit generator. Add 10 ml of dilute sulphuric acid and allow to cool. Then add 5 ml of-potassium iodide solution and add 4 drops of stannous chloride solution. Introduce about 2 to 5 g of zinc shots and at once connect the absorption assembly containing sodium hypobromite solution to the generator. Keep the generator at a temperature of 20 to 25°C by placing it in a water bath and allow the reaction to complete during a period of 1 to 1.5 hours. After the complete absorption of arsenic evolved, wash the contents of the absorption tube using six 2-ml portions of water and transfer them to the spectrophotometric cells. To the wash- ings add accurately using a pipette, 5 ml of 1N sulphuric acid, 1 ml of ammonium molybdate solution and 1 ml of hydrazine sulphate solution, mixing after each addition. Dilute the mixture to 25 ml with water and allow to stand for 1 hour. Simultaneously prepare a blank solution using the same quantities of reagents. Using the spectrophotometer measure the absorbance of the blank and the standard solutions at a wavelength of 650 or 820 nm using water in the reference cell. Subtract the absorbance of the blank solution from that of the standard arsenic solutions and cons- truct a calibration curve relating the absorbance with the amount of arsenic in microgrammes.

A-7.1.6 Procedure

A-7.1.6.1 Weigh accurately 1.0 g of the material and proceed by the method A-2.4 to decompose the cyanide and to remove the gold as precipi- tate. Take the filtrate and reduce the volume to 25 ml by evaporating the solution. Proceed by the method given in A-7.1.5.3 and measure the absorbance of the solution at a wavelength of 650 or 820 nm using water in the reference cell. Subtract the absorbance of the blank solution from that of the sample solution and read the mass of arsenic in microgrammes from the calibration curve.

A-7.1.7 Calculation M

Arsenic, percent by mass =M x 100 1

where Ml = mass in g of the sample taken, and M = mass in g of arsenic.

A-7.2 Determination of Antimony and Bismuth by Atomic Absorption Spectrophotometric Method

A-7.2.1 Standard Solutions

A-7.2.1.1 Antimony (1 ml = 1.0 mg of Sb) - Dissolve 2.743 g of potassium atimonyl tartrate hemi-hydrate in 500 ml of hydrochloric acid

16

IS : 5761 (Part 2) - 1984

(1 : 1 by volume). Transfer the solution to a 1-litre volumetric flask and dilute up to the mark with hydrochloric acid (1 : 1 by volume).

A-7.2.1.2 Bismuth (1 ml = 1.0 mg of Bi) - Dissolve 1.0 g bismuth in 50 ml of nitric acid (1 : 1 by volume) with a gentle heating. Cool and transfer the solution to a 1-litre volumetric flask and dilute up to the mark with water.

A-7.2.2 Procedure - Using the operating conditions and wavelength as given in Table 3 and proceed by the method A-6.7 to A-6.8 to determine the content of antimony and bismuth.

TABLE 3 OPERATING CONDITIONS FOR THE DETERMINATION OF ANTIMONY AND BISMUTH BY ATOMIC ABSORPTION

SPECTROPHOTOMETRIC METHOD

SL METAL WAVELENGTH FUEL OXIDANT No. nm

(1) (2) (31 (4) (5)

i) Antimony

ii) Bismuth

217.6 Acetylene

223.1 Acetylene

Air

Air

A-7.3 Determination of Selenium by Spectrophotometris Method

A-7.3.1. Principle

A-7.3.1.1 The determination of selenium in the material is carried out by dissolving the compound in sulphuric acid followed by decomposition of the cyanide and the gold is removed by precipitation. Selenium in the filtrate is converted to a yellow complex using .diamino benzidine. Formic acid is used to reduce all selenium to selenite (IV).

. EDTA is used to mask interfering polyvalent metals. The complex is then extracted with toluene at a pH between 6.0 and 7.0 followed by spec- trophotometric determination of the selenium diamino benzidine complex.

A-7.3.2 Reagents

A-7.3.2.1 Ammonium hydroxide (1 : 1 by volume) - Mix one volume of ammonium hydroxide (see IS : 799-1978’“) with one volume of water.

*Specification for ammonia, liquor (second fcZGJn).

17

IS : 5761 (Part 2) - 1984

A-7.3.2.2 Diamino benzidine solution (IO g/litre) - Dissolve 100 mg of 3-3 diamino benzidine hydrochloride in 10 ml of water. This solution is unstable and must be prepared afresh when required.

A-7.3.2.3 EDTA solution (0-I M)- Dissolve 37.22 g of disodium ethylene diamine tetra acetate dihydrate (Na, EDTA. 2H,O) in water and dilute it to 1 litre using water.

A-7.3.2.4 Formic acid solution (1 : 9 by volume) - Mix one volume of formic acid (HCOOH, 89 to 91 percent Min) with 9 volumes of water.

A-7.3.2.5 Hydrochloric acid (1 : 1 by volume) - Mix one volume of concentrated hydrochloric acid (relative density 1.19 approximately) (see IS : 265-1976*) with one volume of water.

A-7.3.2.6 Concentrated nitric acid - see IS : 264-1976t

A-7.3.2.7 Sodium sulphate, anhydrous - (Na,SO,).

A-7.3.2.8 Toluene

A-7.3.3 Standard Selenium Solutions

A-7.3.3.1 Solution I (1 mZ-lOO/ug of Se) -Accurately weigh 100 mg of metallic selenium and place it in a beaker. Add 5 ml of concentrated nitric acid and warm the solution until the reaction is completed. Cau- tiously evaporate the solution just to dryness. Then transfer the solution to a 1-litre volumetric flask and dilute up to the mark with water.

A-7.3.3.2 Solution II (I ml= 1 lpg of Se) - Transfer 10 ml of selenium standard solution I to a I-litre volumetric flask and dilute up to the mark with water.

A-7.3.4 Apparatus

A-7.3.4.1 Spectrophotometer - Suitable for measuring the absorbance of the solution at a wavelength of 420 nm.

Ai7.3.4.2 pH meter

A-7.3.5 Calibration

A-7.3.5.1 Prepare a series of standard solutions, to bracket the expected selenium concentration in the sample, by proper addition of the standard selenium solution II with water and treat each of them as follows.

*Specification for hydrochloric acid (second rstisim).

tSpccification for nitric acid (suond rcvisim).

18

IS : 5761 (Part 2) - 1984

A-7.3.5.2 Transfer 100 ml of the standard solution prepared as in A-7.3.5.1 into a 250 ml beaker and add 10 ml of EDTA solution. Adjust the pH between 2.3 to 2.7 using ammonium hydroxide or hydrochloric acid and stir well. Add 2 ml of diamino benzidine solution and stir until the contents are thoroughly mixed. Allow the solution to stand for 30 minutes.

NolX - A slight precipitate of EDTA may form, but it will dissolve when the W is adjusted.

A-7.3.5.3 Adjust thepH of the solution between 6.0 to 7.0 using ammonium hydroxide. Transfer the solution to a graduated cylinder and adjust the volume to 120 f 2 ml using the washings from the beaker.

A-7.3.5.4 Pour the contents of the cylinder into a 250-ml separating funnel and add 20 ml of toluene. Shake the solution for 30 seconds. Discard the aqueous layer and transfer the organic layer to a 25- or 50-ml centrifugal tube. Centrifuge briefly to remove water from toluene. Simul- taneously prepare a blank solution using the same quantity of reagents. Using the spectrophotometer measure the absorbance of the blank and standard solutions at a wavelength of 420 nm using toluene in the refer- ence cell. Subtract the absorbance of the blank solution from that of the standard selenium solutions and construct a calibration curve relating the absorbance with the amount of selenium in microgrammes.

A-7.3.6 Procedure

A-7.3.6.1 Weigh accurately 1 *O g of the material and proceed by the method A-2.4 to decompose the cyanide and to remove the gold as preci- pitate. Take the filtrate and adjust the volume to 100 ml. Transfer the solution to a 250-ml beaker and proceed by method A-7.3.5.2 to A-7.3.5.4 and measure the absorbance of the solution at a wavelength of 420 nm using toluene in the reference cell. For measuring the absorbance of the solution use a 5 cm cell for concentrations of selenjum from 1 to 400 pg and 1 cm cell for higher concentrations of selenium. Subtract the absor; bance of the blank solution from that of the sample solutions and read the mass of selenium in microgrammes from the calibration curve.

A-7.3.7 Calculation

Selenium, percent by mass= $ x 100

where

114 = mass in g of the sample taken, and

Mi = mass in g of selenium.

19

fS : 5761 (Part 2) - -1984

A-8. DETERMINATION OF SIEICON BY SPECTROPHOTOMETRIC METHOD

A-8.1 Principle

A-8.1.1 The determination of silicon in the material is carried out by dissolving the compound in sulphuric acid followed by decomposition of the cyanide and the gold is removed by precipitation. Silicon in the filtrate is converted to a greenish-yellow complex with ammonium molyb- date solution. The complex is then converted to a blue complex by reduction with 1-amino-2-napthol-4 sulphonic acid followed by spectro- photometric determination of the blue coloured silicon complex.

A-8.2 -Reagents

A-8.2.1 Amino h’apthol Sulphonic Acid Solution - Dissolve 0.5 g of I- amino-2-napthol-4 sulphonic acid in 50 ml of water containing 1 g of sodium sulphite (Na,SO,). Then add the above solution to 100 ml of water containing 30 g of sodium hydrogen sulphite (NaHSO,). Dilute the solution to 200 ml with water and store in a dark plastic bottle.

A-8.2.2 Ammonium Mol.vbdate Solution (100 gllitre) - Dissolve 10 g of ammonium molybdate (NH& MO,O,d, 4Ha0) in 100 ml of water.

A-8.2.3 Hydrochloric acid (1 : I by volume) - Mix one volume of con- centrated hydrochloric acid (relative density 1 .I9 approximately), (see IS : 265-1976”) with one volume of water.

A-8.2.4 Oxalic Acid &h&ion (100 g[litre) - Dissolve 10 g oxalic acid (H&,0,, 2H,O) in 100 ml of water.

A-S.3 Standard Silicon Solution (1 ml = O-5 mg of Si)

A-8.3.1 Weigh accurately 267.4 mg of silicon dioxide into a platinum crucible and fuse with approximately 5 g of sodium carbonate. Dissolve in water and transfer the solution to a 250-ml volumetric flask and dilute up to the mark with water. Store in a plastic or polyethylene bottle.

A-8.4 Apparatus

A-8.4.1 Spectrophotometer - Suitable for measuring the absorbance~of the solution at a wavelength of 810 nm.

A-S.5 CaIibration

A-8.5.1 Prepare a series of standard silicon solutions, to bracket the expected silicon concentration in the sample, by proper dilution of the standard silicon solution with water and treat each of them as follows.

*Specification for hydrochloric acid (second revision).

20

IS : 5761 (Part 2) - 1984

A-8.5.2 Transfer 50 ml of the slandard solution prepared as in A-8.5.1 into apolyethylene or any suitable plastic container and add immediately 1 ml of hydrochloric acid and 2 ml of ammonium molybdate solution, and mix the contents thoroughly. After 5 minutes add 1.5 ml of oxalic acid solution and again mix thoroughly.

A-8.5.3 After I minulc add 2 ml of amino-napthol-sulphonic acid, mix well and allow the solution to stand for 10 minutes. Simultaneously prepare a blank solution using the same quantities of reagents. Using the spectrophotometer measure the absorbance of the blank and standard solutions at a wavelength of 810 nm using silicon free water in the refe- rence cell. Subtract the absorbance of the blank solution from that of the standard silicon solutions and construct a calibration curve relating the absorbance with the amount of silicon in microgrammes.

A-8.6 Procedure

A-8.6.1 Weigh accurately 1.0 g of the material and proceed by the method A-2.4 to decompose the cyanide and to remove the gold as preci- pitate. Take the filtrate and reduce the volume to 50 ml by evaporating the solution. Transfer the solution to a polyethylene or any suitable plastic container and proceed by method A-8.5.2 to A-8.5.3 and measure the absorbance of the solution at a wavelength of 810 nm using silicon free water in the reference cell. Subtract the absorbance of the blank solution from that of the sample solution and read the mass of silicon in micro- gtammes from the calibration curve.

A-8.6.2 Calculation

Silicon, percent by mass =-& 100 1

where

M1 = mass in g of the sample taken, and

M= mass in g of silicon.

A-9. DETERMINATION OF TIN BY SPECTROPHOTOMETRIC METHOD

A-9.1 Principle ’

A-9.1.1 The determination of tin in the material is carried out by dis- solving the compound in sulphuric acid and the gold is removed by precipitation. Tin from the filtrate is extracted as stannic iodide using toluene followed by spectrophotometric determination of tinlcatechol violet complex.

21

IS : 5761 (Part 2) i 1984

A-9.2 Reagents

A-9.2.1 Ammonia Solution - Approximately 5 M solution.

A-9.2.2 Ascorbic Acid - 5 percent m/v solution. This solution should be prepared afresh when required.

A-9.2.3 Catechol Violet - 0.05 percent m/v aqueous solution prepared 1 afresh when required.

A-9.2.4 Hydrochloric Acid - Approximately 5 M solution. Cautiously mix 160 ml of concentrated hydrochloric acid relative density 1.19 approximately (see IS : 265-1976*) with water. Cool the solution to room temperature and dilute to 1-litre with water.

A-9.2.5 Potassium Iodide - Approximately 5 M solution. Dissolve 83 g ~of potassium iodide in water and dilute to 100 ml with water. This solution should be prepared afresh when required.

A-9.2.6 Sodium Hydroxide - Approximately 5 M solution.

A-9.2.7 Sodium Hydroxide - Approximately 0.1 M solution.

A-9.2.8 Sodium Acetate Trihydrate - 20 percent m/v, aqueous solution.

A-9.2.9 Sulphuric Acid - Approximately 9 M solution. Cautiously mix 500 ml of concentrated sulphuric acid of relative density l-84 approximately (see IS : 266-1977t) with water. Cool the solution to room temperature and dilute to 1-litre with water.

A-9.2.10 Sulphuric Acid - Approximately 4.5 M solution. Cautiously mix 250-ml of concentrated sulphuric acid with water. Cool the solution to room temperature and dilute to I-litre with water.

A-9.2.11 Toluene (low in benzene)

A-9.3 Standard Tin Solutions

A-9.3.1 Solution I (I ml = 200 p g ofSn) - Dissolve O-1 g of pure granulated tin in 20 ml of concentrated sulphuric acid by heating until fumes appear. Allow the solution to cool, cautiously dilute to 150 ml with water, and cool again. Add 130 ml of sulphuric acid solution (A-9.2.9), and transfer the solution to a 500-ml volumetric flask and dilute up to the mark with water.

A-9.3.2 Solution II (1 ml=IO p g of Sn) - Take 5 ml of solution pre- pared as in A-9.3.1 and dilute it to 100 ml with water. This solution should be prepared afresh when required.

*Specification for hydrochloric acid ( second revision ) . jSpeci6cation for sulphuric acid ( second rtvisivn ).

22

IS : 5761 (Part 2) - 1984

A-9.4 Apparatw

A-9.4.1 Spectrophotometer - Suitable for measuring the absorbance of the solution at a wavelength of 552 nm.

A-9.4.2 pH Meter

A-9.5 Calibration

A-9.5.1 Prepare a series of standard tin solutions to cover the range of 0 to 30 pg of tin and add suitable volume of the solutions to a series of 50 ml beakers and treat each of them as follows.

A-9.5.2 Dilute the solution II with 7 ml of water, add 1 ml of sodium hydroxide solution (A-9.2.6) and mix the solutions thoroughly.

Add 2.5 ml of hydrochloric acid (A-9.2.4) and again mix thoroughly. Add 2 ml of catechol violet solution, stir well and add 5 ml of sodium acetate solution. Adjust the pH of the solution to 3.8 f 0.1 using ammonia solution. Transfer the solution to a 25-ml volumetric flask and dilute up to the mark with water and set aside the flask for 30 minutes.

Simultaneously prepare a blank solution using the same quantity of reagents. Using the spectrophotometor measure the absorbance of the blank and the standard solutions at a wavelength of 552 nm using water in the reference cell. Subtract the absorbance of the blank solution from that of the standard tin solutions and construct a calibration curve relating the absorbance with the amount of tin in microgrammes.

A-9.6 Procedure

A-9.6.1 Weigh accurately 1.0 g of the material and proceed by the method A-2.4 to decompose the cyanide and to remove the gold as pre- cipitate. Take the filtrate and reduce its volume approximately to 70 ml by evaporating the solution. Cool and transfer the solution to a loo-ml volumetric flask and dilute up to the mark with water.

A-9.6.2 Transfer a suitable portion of the solution containing not more than 30 p g of tin to a separating funnel and dilute the solution approxi- mately to 4.5 M solution and allow to cool. For each 25 ml of the solution add 2.5 ml of potassium iodide solution, mix thoroughly and add 10 ml of toluene. Shake vigorously for 2 minutes, allow the layers to separate and discard the aqueous layer. Wash the toluene layer (without shaking) with 5 ml of a solution prepared by mixing 25 ml of sulphuric acid (A-9.2.10) with 2.5 ml of potassium iodide solution and discard the washings. The toluene layer should be coloured pink with extracted iodine.

A-9.63 Add 5 ml of water to the toluene extract and add sodium hydro- xide solution (A-9.2.6) drop by drop with shaking, until the toluene layer becomes colourless. Add a few drops of sodium hydroxide solution in

23

IS : 5761 (Part 2)1984

excess (usually 8 to 10 drops). Shake the solution for 30 seconds, allow the layers to separate and transfer the aqueous layer to a 50-ml beaker. Shake the toluene layer with 3 ml of sodium hydroxide solution (A-9.2.7) for 30 seconds, allow the layers to separate, and add the aqueous layer to the contents of the 50-ml beaker. Retain the toluene layer.

A-9.6.4 Acidify the aqueous solution in the beaker with 2.5 ml of hydro- chloric acid and decolourize the liberated iodine by adding ascorbic acid solution drop by drop. Add 2 ml of catechol violet solution and mix thoroughly. Wash the retained toluene layer as in A-9.6.3 without shaking with 5 ml of sodium acetate solution. Add the washings to the contents of the beaker, mix thoroughly and adjust the pH to 3.8 & 0.1 by padding ammonia solution. Transfer the solution to a 25-ml volumetric flask and dilute up to the mark with water and set aside for 30 minutes. Simulta- neously prepare a blank solution using the same quantity of reagents. Using the spectrophotometer measure the absorbance of the blank and the solution at a wavelength of 552 nm using water in the reference cell. Sub- tract the absorbance of the blank solution from that of the sample solution and read the mass of tin in microgrammes from the calibration curve.

A-9.7 Calculation

Tin, percent by mass =$$- x 100 1

where

MI - mass in g of the sample taken, and

M = mass in g of tin.

APPENDIX B ( Clause 3.1 )

SAFETY PRECAUTIONS FOR HANDLING GOLD CYANIDE AND GOLD POTASSIUM CYANIDE FOR ELECTROPLATING

FOR SPECIAL APPLICATIONS

B-l. SAFETY PRECAUTIONS

B-l.1 As gold cyanide and gold potassium cyanide are highly poisonous, they should never be touched with unprotected -hands. Gloves should always be worn during crushing operations, and during crushing, gogles fitted with a face cloth should~also be worn.

24

IS : 5761 (Part 2) - 1984

B-l.2 Solutions containing cyanides should never be pipetted by mouth suction. A safety pipette should always be used to draw the liquid into the pipette. A burette may also be used for drawing measured quantity of the solution.

B-l.3 On account of highly poisonous character of hydrogen cyanide, all operations involving the decomposition of gold cyanide and gold potassium cyanide should be conducted in a well-ventilated fume cupboard.

B-2. HYD~ROCYANIC AClID AND CYANIDE POISONING

B-2.1 Symptoms-The symptoms are giddiness, staggering, and insensibi- lity accompanied by fanting and respiration, followed by profound collapse with convulsions.

The action is extremely rapid

B-2.2 First Aid

B-2.2.1 Remove the patient from cause of trouble, and take him to fresh air. Make the patient lie down, keep him warm and do not allow him to move more than necessary.

B-2.2.2 If breathing has ceased, apply artificial respiration.

B-2.2.3 Admitzister Amyl Nitrite - This is purchased in the form of small ampoules and one of these is broken and held under the nose so that the patient will inhale the vapour. It should be administered for 15 to 30 seconds every 2 to 3 minutes.

NOTE - Amy1 nitrite is scmitive to light and’ wrrrmlh, and should, t’lerefore, he kept in dark at a ttmperature less than 15%. All wn~~oul~s s ou!d be dixarded every 2 yeara.

B-2.2.4 If available, administer oxygen through a face mask and call for a medical practitioner.

B-2.3 Antidote

B-2.3.1 The following antidote has been found useful when cyanide is swallowed:

a) Solutim A-Dissolve 158 g of ferrous sulphate (FeS0,,7H,O) and 3 g of citric acid in one litre of water. The solution should be regularly inspected and replaced whenever any deterioration occurs.

b) Solution B-Dissolve 60 g of anhydrous sodium carbonate in one litre of water.

25

IS : 5761 (Part 2) - 1984

B-2.3.2 Take 50 ml each of solution A and B and keep them in separate 175 ml wide necked bottles with a polyethylene closure. Mark the bottles as ‘cyanide antidote A and ‘cyanide antidote B’. Both the bottles should bear the following legend.

“Mix the whole contents of bottles A and B, and swallow the mixture”.

B-2.4 Medical Treatment

B-2.4.1 The treatment consists of the injection into the blood stream of sodium nitrite and sodium thiosulphate and should be carried out only by qualified medical practitioner.

Details of treatment are as follows:

a) Intravenous injection of 0.3 g of sodium nitrite dissolved in 10 ml of sterile distilled water. This should be given slowly at the rate of 2.5 to 5 ml per minute.

b) Immediately following this and through the same needle an intra- venous injection of 25 g sodium thiosulphate in 150 ml sterile distilled water is given at the same rate. Leakage of material out- side the vein should be avoided.

B-2.4.2 A temporary improvement is not a criterion of recovery. If the symptoms persist or recur after an hour, a second injection of the two substances should be given. It is suggested that electroplating shops using cyanide should keep a supply of these two substances in ampoule form and two sterilized syringes, one with a total capacity of 10 ml and the second with a total capacity of 50 ml, together with particulars of the treat- ment (as above).

B-2.4.3 Since it is unlikely that the average general practitioner or hospi- tal would have such material ready for use, the patient be sent to hospital along with these materials and during the Journey the first aid procedures already prescribed should be continued.

B-2.4.4 Some patients may respond to the first aid treatment alone, but in many cases it will be advisable to give the intravenous injection. This should be done as soon as possible, and in any case it is desirable that it should be administered within 15 minutes. It is, therefore, essential that, if medical help cannot immediately be obtained, the patient should be sent without delay to the nearest hospital.

26

IS :5761 @'i&2)-1984

APPENDIX C

(CZause 5.1)

SAMPLING OF GOLD CYANIDE AND GOLD POTASSIUM CYANIDE FOR SPECIAL APPLICATIONS

C-l. GENERAL REQUIREMENTS OF SAMPLING

C-l.1 In drawing, preparing, handling and storing samples all the precau- tions prescribed in Appendix B shall be strictly observed.

C-l.2 The sampling implement shall be preferably the one used by the plater for drawing the material.

C-l.3 To draw a representative sample, the contents of each container selected for sampling shall be mixed thoroughly by suitable means.

C-l.4 The samples shall be placed in suitable, clean, dry and air-tight containers on which the material has no action.

C-2. SCALE OF SAMPLING

C-2.1 All the containers in a single consignment of the material drawn from a single batch of manufacture shall constitute the lot.

C-2.2 For ascertaining the conformity of the material in any lot to the requirements of this specification, samples shall be tested from each lot separately. The number of containers to be selected at random from lots of different sizes shall be in accordance with Table 4.

TABLE 4 NUMBER OF CONTAINERS TO BE SELECTED FROM LOTS OF DIFFERENT SIZES

LOT SlZB SAMPLB SIZE

x 72

Up to 25 2

26 to 50 3

51 to 100 4

101ax~dabove .5

C-2.3 In order to ensure randomness of selection, random number tables shall be used. If such tables are not available the following procedure is recommended.

IS: 5761 (Part 2)-19&d

Arrange all containers in the lot in one order starting from any one of them, count them as 1,2,3, . . . . . . . . . . . up to r and so on, where r is the integral part of N/n (N being the lot size and n the sample size respec- tively). Every rth container thus counted shall be withdrawn to constitute the sample.

C-3. PREPARATION OF SAMPLES

C-3.1 From each of the containers selected according to C-2.3, about 30 g material shall be withdrawn taking all the necessary precautions. -These portions shall be kept separately in suitable containers with relevant details of sampling. These shall be called individual samples.

C-3.2 From each of the individual samples a small but equal quantity of the material shall be taken and thoroughly mixed to form composite samples weighing about 30 g.

C-4. NUMBER OF TESTS AND CRITERIA FOR CONFORMITY

C-4.1 Tests for gold content shall be conducted separately on any two of the individual samples. Tests for other characteristics shall be made on the composite sample.

C-4.2 The lot shall be deemed to conform to this specification if the test results on individual and composite samples satisfy the corresponding requirements given in Table 1.

28