sodium carbonate april prd 155 2011 3 · 3 technical anhydrous sodium carbonate: 3.1 requirements...

DKS 155: 2011

© KEBS 2011 – All Rights Reserved

KENYA STANDARD

SODIUM CARBONATE (TECHNICAL GRADE) —SPECIFICATION

DKS 155: 2011


KENYA BUREAU OF STANDARDS (KEBS)

TECHNICAL COMMITTEE REPRESENTATION

The following organizations were represented on the Technical Committee:

University of Nairobi

Government Chemist

MOR-Materials Dept.

Agro Chemical and Food Company

Kenyatta University

Spectre International

Associated Battery Manufacturers

Marshall Fowler

KIRDI

Athi River Mining Ltd

Eastern Chemicals Ltd

Betachem

Unilever (K) Ltd

Pan Africa Chemicals Ltd

Kenya Bureau of Standards Secretariat

REVISION OF KENYA STANDARDS

In order keep abreast of progress in industry, Kenya standards shall be regularly reviewed. Suggestion for improvements to published standards addressed to the Managing Director, Kenya Bureau of Standards, are welcome.

© Kenya Bureau of Standards, 2011

DKS 155: 2011


Copyright. Users are reminded that by virtue of section of the Copyright Act, Cap. 12 of 2001 of the Laws of Kenya, copyright subsists in all Kenya Standards and except as provided under section 26 of this Act, no Kenya Standard produced by Kenya Bureau of Standards may be reproduced, stored in a retrieval system in any form or transmitted by any means without prior permission in writing from the Managing Director.

KENYA BUREAU OF STANDARDS (KEBS)

Head Office: P.O. Box 54974 Nairobi, Tel.: (+254 02 ) 502211-10, 502543/45, Fax: (+254 02) 503293

E-Mail: [email protected] , Web: http://www.kebs.org

Coast Regional Office Western Kenya Region Office R ift valley Regional Office P.O. Box 99376, Mombasa P.O. Box 2949, Kisumu P.O. Box 8111, Eldoret

Tel.: (+254 011) 229563, 230939/40 Tel.: (+254 035) 23549, 22396 Tel.: (+254 0321) 3151,63377

Fax: (+254 011) 229448 Fax: (+254 035) 21814 Fax: (+254 0321) 33150

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P R E F A C E This second edition of this Kenya Standard was prepared by the Technical Committee on Industrial solvents and chemicals under the authority of Kenya Bureau of Standards. Revision of this standard was necessitated by the fact that new technologies have come up and safer alternative laboratory chemicals are also available. 1,10-phenonthralene has been introduced as an alternative to 2,2-bipyridyl in the determination of iron content. In the determination of fluoride content, Thorium Nitrate method has been removed as it is no longer applicable. AAS method has been introduced in the determination of Iron content. During the preparation of this standard, reference was made to the following publications and acknowledgement is made for their assistance with thanks:

• Information gathered from the industry and KEBS laboratory

DKS 155: 2011


KENYA STANDARD

SODIUM CARBONATE (TECHNICAL GRADE)—SPECIFICATION

SODIUM CARBONATE (TECHNICAL

GRADE) — SPECIFICATION

1. Scope:

This Kenya Standard prescribes the requirements, methods of test and sampling of sodium carbonate decahydrate and anhydrous sodium carbonate of technical grade for general industrial uses.

This specification does not apply to material intended for medicinal, AR and photographic use which have separate specifications.

2. Technical sodium carbonate dacahydrate 2.1 Requirements

2.1.1 Description- The material shall consist essentially of sodium carbonate

decahydrate, Na 2CO 3.10H 2O. It shall be in the form of almost colourless crystals which efflorescence in dry air and shall be free from impurities.

2.1.2 Chemical characteristics- The material shall conform to the requirements outlined in Table 1, when tested according to the appropriate method given in the annexes.

TABLE 1: REQUIREMENTS FOR SODIUM CARBONATE DECAHYDR ATE SL NO. CHARACTERISTICS REQUIREMENTS METHOD OF TEST

1 Total alkali content, as Na2CO3 per cent by mass

35.7 min ANNEX B

2 Matter Insoluble in water per cent by mass

0.2 max ANNEX C

3 Sulphate content, as Na2SO4 per cent by mass of sulphate

0.3 max ANNEX D

4 Chloride content, as NaCl, per cent by mass of chloride

0.3 max ANNEX E

5 Iron content, as Fe2O3 per cent by mass iron

0.007max ANNEX F

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3 TECHNICAL ANHYDROUS SODIUM CARBONATE:

3.1 Requirements 3.1.1 The material shall consist essentially of anhydrous sodium carbonate,Na2CO3. in

the form of white uniform powder or granules free from impurities.The material shall be of two commercial grades, namely dense grade and light grade, both having the same chemical composition.

3.1.2 Bulk density- The commercial product grades may vary in bulk density and shall

be as given below when tested as prescribed in annex A

a) Dense Grade 950 to 1250g/l

b) Light Grade 500 to 750g/l

3.1.3 The sieve analysis of the grades of the material shall be as agreed to between

the purchaser and supplier.

3.1.4 Chemical characteristics –The material shall conform to the requirements

outlined in table 2 when tested according to the appropriate method given in the

appendices.

TABLE 2: REQUIREMENTS FOR SODIUM CARBONATE (SODA AS H).

SL NO.

CHARACTERISTICS REQUIREMENTS METHOD OF TEST

1 Total alkali content, as Na2CO3 per cent by mass

97.0 min B

2 Matter Insoluble in water per cent by mass

0.35max C

3 Sulphate content, as Na2SO4 per cent by mass of sulphate

0.35max D

4 Chloride content, as NaCl, per cent by mass of chloride

0.5max E

5 Iron content, as Fe2O3 per cent by mass iron

0.025 max F

6 Flouride content, as NaF, per cent by mass

0.90 max G

4. Packaging and Marking 4.1 Packaging 4.1.2 The material, either the decahydrate or the anhydrous, shall be supplied in intact, clean and dry packages or containers, securely closed.

4.1.2 Marking – Each package or container shall be marked with the following information:

a) Name and grade of material;

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b) Manufacturer's name or recognized trademark c) The net weight of the content of the package or container d) Each consignment shall be accompanied by a certificate of analysis e) Year of manufacture f) Batch/Lot number g) Country of origin

5. SAMPLING To test for the compliance of the sodium carbonate to the requirements of this standard a sample of at least 750g shall be taken and stored in an air-tight container.

Caution: In taking samples from a container or a package, care shall be taken to exclude portions where caking is noticeable (due to absorption of moisture and carbon dioxide). This may be done by removing from the top about 20cm of the material in the container and then taking out sample from the center of the remaining portion.

ANNEX A

DETERMINATION OF BULK DENSITY

A.1 APPARATUS A.1.1 Assemble the apparatus as shown in figure 1

The base of the measuring cylinder A shall be ground flat and the empty measuring cylinder together with the rubber bung shall weigh 250 ± 5g. It shall be accurately calibrated to 250ml. The distance between the zero and 250ml graduation on the measuring cylinder A shall be not less than 220mm and not more than 240mm. The distance between the flat-ground part of the base of the cylinder and the rubber base pad B, when the measuring cylinder A is raised to the full height shall be 50 ± 2mm.

A.1.2 Funnel – Made of glass, with an angle of 60 0

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Fig. 1 APPARATUS FOR DETERMINATION OF BULK DENSITY

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A.2 Procedure

Take a sufficient quantity of the material on a glazed paper and slip it gently and smoothly through the funnel into the measuring cylinder A up to 100ml mark without knocking. With the thumb and fingers of one hand, grasp the upper portion of the cylinder and lift it as far as 50 mm height; release the cylinder on the table. Repeat this knocking a second time. Again slip more of the material into the cylinder gently and smoothly as before up to 200-ml mark and give two knocks as before by lifting the cylinder to 50 mm height. Finally, slip more of the material up to 250-ml mark an give two more knocks of 50 mm height. Level the cylinder with the material without any further knocking. Empty out the material from the cylinder and weigh the material to the nearest 0.1 g.

A3. Calculation Bulk density, mlg 4/ = Where, m = mass in grams of the material in the cylinder.

ANNEX B

DETERMINATION OF TOTAL ALKALI CONTENT

B1. REAGENTS

B1.1 Standard Sulphuric Acid or Standard Hydrochloric Acid – Approximately I N.

B1.2 Methyl Orange Indicator Solution – dissolve 0.01 g of methyl orange in 100 ml of distilled

water.

B2. PROCEDURE

Weigh to the nearest 0.001 g. about 5 g of the decahydrate or about 2 g of the

anhydrous material in a stoppered weighing bottle. Transfer it completely into a 250-ml

conical flask and dissolve in the minimum volume of water. Add 4 drops of the methyl

orange indicator and titrate with the standard hydrochloric acid (or sulphuric acid)

solution.

B3. CALCULATION Total alkali content, as Na2CO3 per cent by mass = 5.3 VN

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m

Where

V = Volume in milliliters of the standard hydrochloric or sulphuric

acid solution used in titration

N = normality of standard acid, and

M = mass in grams of the sample taken for the test.

ANNEX C

DETERMINATION OF MATTER INSOLUBLE IN WATER

C1. PROCEDURE

Weigh accurately 2-5g of the sample. Transfer it into a 400-ml beaker, add about 200 ml

of distilled water and boil the solution for about 10 minutes. Allow to stand for one hour

and filter the solution through a weighed sintered glass crucible No. 3 or Gooch crucible,

transferring any insoluble matter into the crucible with a jet of distilled water. Wash the

residue five times with 5-ml portions of distilled water at room temperature. Dry the

crucible in an oven at 1000C to 105oC for one hour, cool in a desiccator and and weigh

to the nearest 0.1mg.

C2. CALCULATION

Matter insoluble in water, per cent by mass

m1 ×100

m 2

Where,

m1 = mass in grams of the residue,

m2 = mass in grams of the sample taken for the test

ANNEX D

DETERMINATION OF SULPHATE CONTENT

D1. APPARATUS

D.1.1 Porcelain or silica crucible

D.1.2 Filter paper (whatman No. 542)

D2. REAGENTS

D2.1 Distilled water, or water of at least equal purity.

D2.2 Hydrochloric acid, concentrated, (d= 1.18)

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D2.3 Barium chloride, 10 per cent (w/v) solution.

D2.4 Methyl orange indicator, 0.05 per cent (w/v) solution.

D3. PROCEDURE

Weigh 50 g of the sample, transfer it to a 600-ml beaker and dissolve in 250 ml of

distilled water. Add 3 drops of the methyl orange indicator, neutralize the solution with

concentrated hydrochloric acid and add 2 ml of the acid in excess. Filter through a

hardened acid-washed filter paper (Whatman No. 542), into one-litre beaker and add

barium chloride solution to the boiling solution. Place the solution on a boiling-water bath

for 2 hours, then remove and allow to stand for 4 hours. Filter through filter paper

(whatman No. 542), wash with hot water until the washings are free from chloride,

transfer the residue to a tared porcelain or silica crucible, dry and ignite at 900oC. Cool

in a desiccator and weigh to the nearest milligram.

D4. CALCULATION

Sulphate content, as Na2SO4, per cent by mass = 1.22 m

Where

m= mass in grams of barium sulphate found.

ANNEX E

DETERMINATION OF CHLORIDE CONTENT

E1 REAGENTS

E1.1 Nitric acid, concentrated, d= 1.42.

E1.2 Standard silver nitrate, 0.1 N solution.

E1.3 Standard ammonium thiocyanate, 0.1 N solution

E1.4 Ferric Ammonium Sulphate Indicator Solution – Dissolve 150 g of ferric ammonium

sulphate in 800 ml of deionized water and add 200 ml of concentrated nitric acid.

E2. PROCEDURE

Weigh, to the nearest 0.01 g, about 20 g of the decahydrate or about 10g of the

anhydrous material and transfer to a 400-ml beaker. Add about 30 ml of deionized

water. Carefully neutralize with concentrated nitric acid and then add 5 ml of the acid in

excess. Cool to room temperature, add 0.1 ml of the standard ammonium thiocyanate

solution and 5ml of the standard ferric ammonium solution.

Add the standard silver nitrate solution from a burette until the silver nitrate is in excess.

Record the volume of the standard silver nitrate solution added and then titrate the

excess silver nitrate with the standard ammonium thiocyanate solution until the solution

assumes a slightly red tinge.

E3 CALCULATION

Chloride content, as NaCl, per cent by mass.

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=)

m

NVNV 2211(85.5 −

m

where

V1 = volume in ml of standard silver nitrate solution used. N1= exact normality of the silver nitrate solution. V2 =volume in ml of standard ammonium thiocyanate solution used in titration

N2.= exact normality of the standard ammonium m = mass in g of the sample taken for the test.

ANNEX F

DETERMINATION OF IRON CONTENT F.1 PRINCIPLE The iron present in the sample is reduced to the ferrous state and determined visually using 2,2-bipyridyl / 1,10-phenanthroline spectrophotometrically; or by Atomic bsorption Spectroscopy (AAS) method.

F.2 SPECTROPHOTOMETRIC METHOD F.2.1 APPARATUS F.2.1.1 Spectrophotometer with 1 cm cells, or alternatively Nessler cylinders. F.2.2.2 Twelve one-mark volumetric flasks, 100 ml capacity. F.2.2.3. One-mark volumetric flask, 250 ml capacity. F.2.2. REAGENTS F.2.2.1 Hydrochloric acid, concentrated, d=1.18. free from iron. F.2.2.2 Hydrochloric acid, approximately, N solution free from iron F.2.2.3 Hydroxyammonium chloride, 10 per cent (w/v) solution F.2.2.4 Ammonium acetate, 20 per cent (w/v) solution. F.2.2.5 Bromine water, saturated. F.2.2.6 2,2-bipyridyl / 1,10-phenanthroline, 0.1 per cent (w/v) solution – Dissolve 0.1 g of the reagent in 50 ml of water containing 2 ml of N hydrochloric acid and dilute to 100 ml. F.2.2.7 Standard Iron Solution – Dissolve 7.022 g of ammonium ferrous sulphate in a mixture of 600 ml of water and 350 ml of concentrated sulphuric acid, d = 1.84. Dilute to 1000 ml with deionizedwater and further dilute 10 ml of the solution so obtained to 1 000 ml with water. 1 ml of the solution contains 10 micrograms of iron (10 µg of iron).

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F.2.2.8 Methyl orange indicator, 0.05 per cent (w/v) solution. F.2.3 PROCEDURE F.2.3.1 Preparation of Standard Iron Solutions (Colour Standards) – Into eleven of the 100-ml

one-mark volumetric flasks, each containing 50 ml of water, and 2 ml of N hydrochloric acid, transfer amounts of the standard iron solution, containing from 0 to 100 micrograms of iron (o g to 100 g of iron) increasing by stages 10 micrograms (10 µg ) and treat each solution as follows:

Add 2 ml of the hydroammonium chloride solution and allow to stand for one minute, add 10 ml of the ammonium acetate solution and 3 ml of the 2,2 – bipyridyl/1,10-phenanthroline solution. Diluted the contents of the flask to 100 ml and mix thoroughly. These standard solutions are used directly for visual comparison of the colour with that of the sample.

If an instrument is to be used, measure the optical density of each solution at a wavelength of 515 nm and prepare a calibration chart.

F.2.3.2 Determination – Weigh accurately to the nearest 0.01g, about 25g of the sample and

transfer to a 400-ml beaker. Add 100 ml of water one drop of methyl orange indicator and acidify with concentrated hydrochloric acid adding 2 ml in excess. Boil the solution for a few minutes. Add a few drops of bromine water to destroy the colour of the indicator and boil the solution to expel excess bromine. Cool the solution transfer to the 250-ml one-mark volumetric flask, add 2 ml of the hydroxyammonium chloride solution and allow to stand for one minute. Add 10 ml of the ammonium acetate solution mix and add 3 ml of the 2.2 – bipyridly/1,10-phenanthroline solution, Dilute to 100 ml with water and thoroughly mix.

At the same time carry out a blank test on the reagents alone. Measure the optical density of the solution at wavelength of 515 nm and read the

amount of iron present from the calibration chart prepared in F4.1. Alternatively compare the colour of the sample solution in matched Nessler cylinders with the series of the prepared standard iron solutions

F.2.4 CALCULATION Iron content, AS Fe parts per million by mass = 25 M2

M1

Where,

m2 = mass in micrograms, of iron found, and

m1 = mass in grams of sample taken

F.3 ATOMIC ABSORPTION SPECTROSCOPY METHOD

F.3.1 Apparatus:

F.3.1.1 Atomic Absorption Spectrometer

F.3.1.2 100ml beaker

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F.3.1.3 Filter paper No. 1

F.3.1.4 Analytical balance

F.3.1.5 100ml volumetric flask

F.3.2 Reagents

F.3.2.1 Conc. Nitric acid d= 1.42.

F.3.3 Procedure

F.3.3.1 Take 2 g of the sample and add 6 ml of conc. Nitric acid and dissolve. Filter the solution through filter paper No 1, into 100 ml beaker Wash the filter paper using distilled water. Transfer the filtrate to the 100ml volumetric flask. Top up to the mark with distilled water. Use this solution to determine the iron content in sodium carbonate using AAS F.3.3.2 Calculations Fe content, mg/l = reading x volume x dilution factor (if any) weight of sample taken

ANNEX G

G1. DETERMINATION OF FLUORIDE CONTENT

G1.1 Principle - The fluoride content is determined as fluoride concentration as mg/l fluoride

by ion-selective electrode procedure using specific ion meter.

G1.2 Ion-Selective Method (Electrode method )

G1.2.1 Principle — The fluoride is determined by ion-selective electrode procedure

using specific ion meter. The fluoride electrode is a selective ion sensor. The

electrode, commonly called a probe, is designed to be used with a standard

calomel reference electrode and any modern pH meter having an expanded

millivolt scale. The fluoride ion-selective electrode can be used to measure the

activity or the concentration of fluoride in aqueous samples by use of an

appropriate calibration curve.

G1.2.2 Apparatus

G1.2.2.1 Expanded scale or digital pH meter or ion-selective meter

G1.2.2.2. Sleeve-type reference electrode (Orion # # 90-01-00, Beckman # 40463 or

Corning ≠ ≠ 476012). Fiber-tip reference electrodes should not be used; they

exhibit erratic behavior in very dilute solutions

G1.2.2.3 Fluoride electrode (Orion ≠ ≠ 94-09).

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G1.2.2.4 Magnetic stirrer, with Teflon-coated sirring bar.

G1.2.2.5 Stop watch or timer.

G1.2.3 Reagents

G1.2.3.1 Stock fluoride solution — Dissolve 221.0 mg anhydrous sodium fluoride, NaF, in

distilled water and dilute to 1 litre; 1.00 ml of this solution contains 100/µg F.

G1.2.3.3 Total ionic strength adjustment buffer (TISAB) — Place approximately 500 ml

distilled water in a l – litre beaker and add 57 ml glacial acetic acid, 58 g sodium

chloride, and 4.0 g 1.2 cyclohexylene diamine tetraacetic acid (CDTA). Stir to

dissolve. Place the beaker with its contents in a cool water bath and add slowly

6N sodium hydroxide (about 125 ml) with sirring, until pH is between 5.0 and 5.5

Transfer to 1-litre volumetric flask and add distilled water to the mark.

G1.2.4 Procedure

G1.2.4.1 Instrument calibration — No major adjustment of any of the instruments is

normally required to use the electrodes in the fluoride range of 0.2 to 2.0

mg/litre. For Those instruments with zero at centre scale (e.g. most Beckman or

leeds and Northup meters) adjust the calibration control so that the 1.0 mg/litre

F standard reads at the centre zero (100 m2) when the meter is in the expanded

scale position. This cannot be done on some meters, such as the corning

model 12, which do not have a millivolt calibration control. To use a selective-ion

meter follow instructions of the manufacturer for calibration.

G1.2.4.2 Preparation of fluoride standards — Prepare a series of standards by adding,

respectively, 2.5, 5.0 and 10.0 ml standard fluoride solution (G1.3.3.2) to each

of three 100-ml volumetric flasks. To each flask, add by pipette 50 ml of pH 5.0

to 5.5 TISAB solution (G1.3.3.3) and dilute to 100 ml with distilled water: mix

well. These standards are equivalent to 0.5, 1.0 and 2.0 mg/litre fluoride.

(Because the concentration of the sample is reduced by half by the addition of

TISAB solution doubling the standards’ true concentration enables the analyst to

read the samples’ original concentration directly)

G1.2.4.3 Treatment of the sample place 50 ml TISAB in 150-ml volumetric plastic

beaker, add 50 ml distilled water, then add 1 gram of the sample. Stir to

dissolve. Bring the standard and the sample to the same temperature.

Preferably room temperature.

G1.2.4.4 Measurement with electrode — Transfer each standard and sample to a series

of 150-ml beakers. Immerse the electrodes and measure the developed

potential while stirring the test solution on a magnetic stirrer. Avoid stirring the

solution before immersing the electrodes because entrapped air around the

crystal can produce erroneous reading or needle fluctuations. Let the

electrodes remain in the solution for 3 minutes before taking a final positive

millivolt reading. Rinse the electrodes with distilled water and blot dry between

readings.

When using an expanded-scale pH meter or selective-ion meter, recalibrate the

electrode frequently by checking the potential reading of the 1.00 mg/l fluoride

DKS 155: 2011


standard and adjust the calibration control. If necessary, until the meter reads as

before. Confirm the calibration after each unknown and also after reading each

standard when preparing the standard curve.

Plot the potential measurement of the fluoride standards against concentration

on two-cycle semilogarithmic graph paper. Plot milligrams per litre fluoride on

the logarithmic axis. With the lowest concentrations at the bottom of the page.

Using the potential measurement for each unknown sample read the

corresponding fluoride concentration from the standard curve.

DKS 155: 2011


sodium carbonate april prd 155 2011 3 · 3 technical anhydrous sodium carbonate: 3.1 requirements...

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