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UDC 661.833.622 : 620.1
Ref. No. iSO/R 745-1968 (E)
IS0
INTERN AT1 ON A L O R G A N IZAT I O N FOR S TA N DARD IZATl O N
IS0 RECOMMENDATION
R 745
SODIUM CARBONATE FOR INDUSTRIAL USE
DETERMINATION OF LOSS OF MASS
AND OF NON-VOLATILE MATTER AT 250 "C
1st EDITION
May 1968
c
COPYRIGHT RESERVED
The copyright of IS0 Recommendations and IS0 Standards
belongs to IS0 Member Bodies. Reproduction of these
documents, in any country, may be authorized therefore only
by the national standards organization of that country, being
a member of ISO.
For each individual country the only valid standard is the national standard of that country.
Printed in Switzerland
Also issued in French and Russian. Copies to be obtained through the national standards organizations.
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BRIEF HISTORY
The IS0 Recommendation R 745, Sodium carbonate for industrial use - Determination of
loss o,f'mass and of non-volatile matter at 250 "C, was drawn up by Technical Committee
ISO/TC 47, Chemistry, the Secretariat of which is held by the Ente Nazionale Italian0
di Unificazione (UNI).
Work on this question by the Technical Committee began in 1951 and led, in
1956. to the adoption of a Draft IS0 Recommendation.
In June 1966, this Draft IS0 Recommendation (No. 101 I) was circulated to all
the IS0 Member Bodies for enquiry. It was approved, subject to a few modifications
of an editorial nature, by the following Member Bodies :
Argentina Italy Switzerland
Japan Turkey
Austria
Belgium Korea, Rep. of U.A.R.
Brazil Netherlands United Kingdom
Chile New Zealand U.S.A.
Poland U.S.S.R.
Czechoslovakia
France Portugal Yugoslavia
Romania
Germany
South Africa,
Hungary
India Rep. of
Israel Spain
No Member Body opposed the approval of the Draft.
The Draft IS0 Recommendation was then submitted by correspondence to the
Council, which decided, in May 1968, to accept it as an IS0 RECOMMENDATION.
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ISO/R 745-1968 (E
--
IS0 Recommendation R 745 May 1968
SODIUM CARBONATE FOR INDUSTRIAL USE
DETERMINATION OF LOSS OF MASS
AND OF NON-VOLATILE MATTER AT 250 "C
This IS0 Recommendation describes a method for the determination of loss of mass
and of non-volatile matter at a temperature of 250 'C.
2. FIELD OF APP1,ICATION
The method is applicable to the determination of the loss of mass and of non-volatile
matter at ZL50 'C in anhydrous sodium carbonate for industrial use.
2.1 Special case
Sodium carbonate decahydrate,
3. PRINCIPLE
Heating of thin layers of a test portion to constant mass at a temperature of 2%) 'C.
The loss of mass represents water in its various forms plus half the carbon dioxide
content of the hydrogen carbonate present.
The residue constitutes the non-volatile matter at 250 'C.
4. APP AR ATüS
Ordinary laboratory apparatus and
4.1 Weighing hottle.approxiniately 100 ml capacityand 75 mm in diameter,
...