ISO 3262-19:2021 pdf free download.Extenders – Specifications and methods of test Part 19 : Precipitated silica.
1 Scope
ISO 3262-19 specifies requirements and corresponding methods of test for precipitated silica.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of ISO 3262-19. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 787-2. General methods of test for pigments and extenders — Part 2: Determination of matter volatile at 105
ISO 787-5, General methods of test for pigments and extenders — Part 5: Determination of oil absorption value
ISO 787-9. General methods of test for pigments and extenders — Part 9: Determination of pH value of an aqueous suspension
ISO 787-11, General methods of test for pigments and extenders — Part 11: Determination of tamped volume and apparent density after tam ping
ISO 3262-1, Extenders — Specifications and methods of test — Part 1: introduction and general test methods
ISO 3696, Water for analytical laboratory use — Specification and test methods
ISO 5794-1:2010, Rubber compounding ingredients — Silica, precipitated, hydrated — Part 1: Non-rubber tests
ISO 15528, Paints, varnishes and raw materials for paints and varnishes — Sampling
ISO 18451-1, Pigments, dyestuffs and extenders — Terminology — Part 1: General terms
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 1845 1-1 and the following apply.
The precipitate is ignited at 11)00 °C, giving impure silicon dioxide, which is treated with sulfuric and hydrofluoric acid. The silicon tetralluoride formed Is evaporated off and the silica content Is calculated from the resulting loss in mass
6.2 Reagents
WARNING — Hydrofluoric acid is corrosive and toxic. The related operations shall be performed In fume hood. This document does not point out all possible safety problems. It is the responsibility of the user to take proper safety and health measures, and to determine the applicability of regulatory limitations prior to use.
Use only reagents of recognized analytical grade and only water of at least grade 3 purIty according to
ISO 3696.
6.2.1 Hydrochloric acid (HCl), CAS.No 7647.01.011. concentrated, approximately 32% mass fraction. px 1,16g/mI.
6.2.2 Hydrochloric acid (HCl). CASNo 7647.01.0. diluted 1 + 1.
Add I part by volume of concentrated hydrochloric acid (6.21) to I part by volume of water.
6.2.3 Sulfuric acid (H2SOj, CAS-No 7664-93-9. diluted I + 1.
Add 1 part by volume of concentrated sulfuric acid, approximately 96 % mass fraction, p x 1,84 g/ml, slowly to I part by volume of water.
6.2.4 Hydrufluoric acid (HF), CAS-No 7664-39-3, concentrated, approximately 40 % mass fraction, p 1.13 gJml.
6.3 Apparatus
Use ordinary laboratory apparatus and glassware, together with the following.
6.3.1 Dish.
6.3.2 Platinum crucible.
6.3.3 Water bath, capable of being maintained at 100 C.
6.3.4 Infrared evaporator.
6.3.5 Muffle furnace, capable of being maintained at (1 000 * 20) °C.
6.3.6 Drying oven, capable of being maintained at (140 * 5) °C.
6.3.7 Filter paper.
The filter paper used for filtration of the silica shall be of such texture as to retain the smallest particles of precipitate and nevertheless permit rapid filtration2).
6.3.8 DesIccator, containing for example magnesium perchiorate as desiccant.
6.4 Procedure
6.4.1 Number of determinations
Carry out the determination In duplicate.
6.4.2 Test portion
Weigh, to the nearest 0,2 mg. approximately I g (in9) of the sample (see Ciau.se5) into a dish (6.3.1).
6.4.3 DeterminatIon
Slowly add 20 ml of concentrated hydrochloric acid (62.1) and evaporate to dryness under the infrared evaporator (63A). Add again 20 ml of concentrated hydrochloric acid and evaporate to dryness. Repeat this step once more. After the third evaporation, place the dish in the drying oven (6.16). maintained at (140 ± 5) °C. and leave for 2 h.
Remove the dish from the oven and allow to cool. Add SO ml of I + I hydrochloric acid (6.2.2) to the residue In the dish and warm It For approximately 20 mm on the water bath (6.33) at 100 °C. Filter through a suitable filter paper (6.31) and wash the residue on the filter with hot water until the washings are neutral.
Pour the filtrate and washings into the original dish and evaporate to dryness. Repeat this evaporation step another two times, adding each time 10 ml of concentrated hydrochloric acid to the residue. After the third evaporation, heat at (140 ± 5) °C for 2 h in the drying oven.
Add 20 ml of I + 1 hydrochloric acid to the residue in the dish and warm it for approximately 10 mm on the water bath at 100 °C. Filter through a fresh filter paper and wash the residue on the filter with hot water until the washings are neutral.
II necessary, check the filtrate for any silicon which may have passed through the filter.
Place the two filter papers with the washed precipitates In the platinum crucible (6.32). Dry, char at low temperature, ignite in the muffle furnace (6.15) at (1 000 ± 20) °C to constant mass (this should take approximately 1 h) and allow to cool in the desiccator (6.3.8). Weigh the ignited precipitate to the nearest 0.2 mg (in1).
Wet the ignited precipitate in the platinum crucible with 2 ml to 3 ml of water, add 1 ml of I + 1 sulfuric acid (6.23) and 15 ml of hydrolluoric acid (6.L4) and evaporate to a syrup, taking care to avoid loss by spitting. Allow to cool and wash the sides down with small quantities of water. Then add a further 10 ml of hydrofluoric acid and evaporate to dryness. If the evaporation of the silicon tetrafluoride Is not complete, add a further 10 ml of hydrolluoric acid and evaporate to dryness again.
Heat the residue until white fumes are no longer evolved, then ignite for 30 mm in the muffle furnace at (1 000 ± 20) °C. Remove from the furnace, allow to cool in the desiccator and weigh to the nearest 0,2 mg (in2).
6.4.4 DeterminatIon of the total loss on ignition
Weigh, to the nearest 0,2 mg. approximately 1 g (m3) of the sample (see Clause 5) into a platinum crucible.
NOTE Weighing out the test portions for the determination of the silica content (see 6.42) and the total loss on ignition can be carried out at the same time.
Ignite the test portion to constant mass in the muffle furnace at (1 000 ±20) °C (this takes approximately 2 Ii) and allow to cool in the desiccator. Weigh the ignited test portion to the nearest 0,2 mg (m4).
Calculate the mean of the two determinations and report the result to the nearest 0.1 %.
8.6 Precision
No precision data are available at the time of pubhcatlon.
9 Test report
The test report shall contain at least the Following information:
a) all details necessary to identify the product tested;
b) a reference to ISO 3262-19. I.e. ISO 3262-19:2021;
c) the results of the tests and whether or not the product complies with the relevant specification limits;
d) the type of residue on the sieve;
e) any deviation from the test methods specified;
f) any unusual features (anomalies) observed during the test;
g) the date of the tests.