|
UDC 666.1 : 620.1
IS0
I N T E RN AT I ON A L O R G A N I Z AT I ON FOR S TA N DARD 1 ZATl O N
IS0 RECOMMENDATION
R 719
DETERMINATION OF THE HYDROLYTIC RESISTANCE
OF GLASS GRAINS AT 98 "C
1st EDITION
May 1968
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.
---------------------- Page: 1 ----------------------
BRIEF HISTORY
The IS0 Recommendation R 719, Determination of the hydrolytic resistance of glass grains at
98 OC, was drawn up by Technical Committee ISO/TC 48, Laboratory glassware and related apparatus,
the Secretariat of which is held by the British Standards Institution (BSI).
Work on this question by the Technical Committee began in 1950 and led, in 1961, to the
adoption of a Draft IS0 Recommendation.
In December 1963, this Draft IS0 Recommendation (No. 718) was circulated to ail the IS0
Member Bodies for enquiry. It was approved, subject to a few modifications of an editorial nature, by
the following Member Bodies :
Argentina Greece Spain
Sweden
Australia Hungary
India Switzerland
Austria
Brazil Israel Turkey
Canada Italy U.A.R.
Chile Japan United Kingdom
Colombia Korea, Rep. of U.S.S.R.
Czechoslovakia Netherlands Yugoslavia
France New Zealand
Germany Poland
Two Member Bodies opposed the approval of the Draft :
Belgium
U.S.A.
The Draft IS0 Recommendation was then submitted by correspondence to the IS0 Council
which decided, in May 1968, to accept it as an IS0 RECOMMENDATION.
-2-
---------------------- Page: 2 ----------------------
ISO/R 719-1968 (1
IS0 Recommendation R 719 May 1968
DETERMINATION OF THE HYDROLYTIC RESISTANCE
OF GLASS GRAINS AT 98 "C
1. SCOPE
The purpose of this IS0 Recommendation is to describe a method for determining the hydrolytic
resistance of glass grains at 98 OC. The resistance is measured inversely by the volume of acid required
for titration of the alkali extracted from unit mass of glass, and is expressed by the amount of sodium
oxide equivalent to this volume of acid.
This method is recommended for use on the less resistant types of glass. For the more resistant
glasses, the method described in IS0 Recommendation R 720, Determination of the hydrolytic resis-
tance of glass grains at 121 "C, is preferable.
2. APPARATUS
2.1 Balance, accuracy f 5 mg or better.
2.2 Burettes, 10 ml, graduated in 0.05 ml, and 1 or 2 ml, graduated in 0.01 ml.
2.3 Cooling bath, of capacity sufficient to contain 1 litre of water for each flask used in the test.
2.4 Conicaf flasks, 100 ml capacity, made of chemically resistant glass and pre-treated by fiiling to
the base of the neck with water and heating as described in clause 2.5 below.
2.5 Volumetric flasks, 50 ml capacity, made of chemically resistant giass and with giass stoppers. It
is advisable to select flasks with the graduation line in the lower half of the neck. Before use,
each flask should be pre-treated by filing to above the graduation mark with water and heating
to 100 OC in the heating bath for three separate periods of 1 hour, using a fresh quantity of
water in the flask each time.
NOTE. - Flasks made from vitreous silica may also be used, in which case the pre-treatment is not requifed.
2.6 Hammer, weighing about 1 kg.
2.7 Mortar and pestle, made of hardened steel and of the design and approximate dimensions shown
in the Figure, page 4.
2.8 Pipette, 25 ml.
-3-
---------------------- Page: 3 ----------------------
ISO/R 719-1968 (I
Approximate dimensions
in millimetres
FIGURE - Hardened steel mortar and pestle
-4-
---------------------- Page: 4 ----------------------
ISO/R 719-1968 (E)
Sieves. A set of 200 mm diameter square-aperture sieves, with stainless steel mesh, including :
2.9
- a sieve (A) of 500 pm aperture,
- a sieve (B)* of 300 pm aperture,
- a sieve (O)** of a convenient aperture between 600 and 1000 pm.
The cover, pan, and especially the rings should be of stainless steel or lacquered wood.
2.10 Thermometer, covering the range of 90 to 110 OC, capable of being read to an accuracy of
2 0.2 Oc.
2.1 1 Heating bath, gas or electrically heated, thermostatically controlled, of capacity sufficient to
contain 1 litre of liquid for each flask used in the test and capable of carrying out the heating
cycle described in section 6.
2.12 Stoppered storage vessel.
3. REAGENTS
Analytical grade reagents should be used throughout.
3.1 Distilled water or deionized water, of high purity complying with the following requirements
when tested immediately before use : it should be free from dissolved gases and heavy metals,
particularly copper, as shown by the dithizone test; it should have a specific conductivity not
exceeding 1 X 10
...