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BS ISO 18843:2015 pdf free

BS ISO 18843:2015 pdf free.Aluminium oxide primarily used for the production of aluminium – Method for the determination of flow time.
The standard funnel is loaded with a specified mass of alumina. The time for the alumina to flow out of the funnel is determined.
4 Apparatus
4.1 General
The test maybe carried out using manual or automatic timing. An automatic device is shown in Figure 1.
4.2 Funnel, precisely constructed of a corrosion resistant metal, e.g. brass or aluminium, as shown in Figure 2 with an abrasion resistant material, e.g. hardened stainless steel, insert with an outlet diameter of (3,95 to 4,00) mm; this diameter is critical.
4.3 Stand, a suitable device for supporting the funnel.
4.4 Timing device, either a stop watch or automated device capable of an accuracy of 1 s.
4.5 Top-loading balance, capable of weighing 100 g to the nearest 0,1 g.
4.6 SIeve, with apertures within the range (300 to 400) .im to remove abnormal oversize material.
4.7 Container, suitable for containing the test sample.
4.8 Sealable container, suitable for containing and storing the funnel.
5 Sample preparation
The analytical sample shall be conditioned by exposure to the laboratory atmosphere for a minimum of 2 h in a layer of 5 mm maximum thickness. The sample shall then be split as per AS 4538.2 into three portions of approximately (105 to 120) g for testing. The sample shall then be screened through a sieve (4.6) and the oversize material discarded.
6 Procedure
6.1 General
This procedure is for manually timed determinations.
6.2 Number of determinations
Three determinations shall be carried out.
6.3 Determination
Each determination shall be carried out as follows.
a) Ensure the funnel is clean with no surface oxides present and dry prior to use; otherwise flow times will not be reproducible. Frequent use has usually been found to be an adequate cleaning method.
b) Set up the apparatus by placing the funnel (4.2) on the stand (4) in a vibration-free environment.
c) Ensure that the funnel is secure on the stand and that the upper surface is precisely level.
d) For apparatus not in frequent use, clean the funnel by passing several portions of alumina through it [see a)]. Discard this material prior to testing.
e) Take one of the prepared samples (see Clause 5) and accurately weigh a test portion of (100 ± 0,1) g and place into the container (41). (See Clause 5.)
1) Pour the test portion uniformly into the funnel while manually obstructing the outlet.
g) Start the flow by removing the outlet obstruction and immediately commence timing. Stop the timing as soon as all the sample has passed through the funnel. Never tap the funnel.
h) Repeat the procedure with the other two test portions (Clause 5).
I) Remove the funnel from the stand and wipe the funnel clean with a dry cloth. Replace it in the sealable container (4.8) to prevent damage to the outlet orifice and minimize atmospheric oxidation of the inner surface.BS ISO 18843 pdf free download.

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