BS ISO 7992:2015 pdf free

BS ISO 7992:2015 pdf free.lron ores for blast furnace feedstocks – Determination of reduction under load.
Nitrogen (N2) shall be used as the heating and cooling gas. Impurities shall not exceed 0,1 % (volume fraction).
The flow rate of N2 shall be maintained at 50 L/min until the test portion reaches 1 050 °C and at 83 L/min during temperature-equilibration period. If desired, the test portion may be cooled under nitrogen to below 100 °C. During cooling, it shall be maintained at 5 L/min.
7.4 Temperature of the test portion
The temperature of the entire test portion shall he maintained at 1 050 °C ± 10 °C during the entire reducing period and, as such, the reducing gas shall be preheated before entering the test portion.
7.5 Loading of the test portion
During the entire heating and reducing periods, the test portion shall be subjected to a constant load of 50 kPa ± 2 kPa applied over the surface of the bed.
8 Procedure
8.1 Number of determinations for the test
Carry out the test as many times as required by the procedure in Annex A.
8.2 Chemical analysis
Take, at random, one of the test portions prepared in and use it for the determination ot the iron(iIJ oxide content (wi) in accordance with ISO 9035 and the total iron content (wa) in accordance with
ISO 2597-1 or ISO 2597-2.
8.3 Reduction
In order to achieve a more uniform gas flow, place a double-layer bed of porcelain balls () in the reduction tube () on the perforated plate and level its surface. Measure the height of the top surface of the porcelain layer.
Take, at random, another test portion prepared in 2 and record its mass (mo). Place it on the bed of porcelain balls and level its surface.
Place a further double layer of the porcelain balls upon the test portion and level its surface. Measure the height of the top surface of this porcelain layer.
Close the top of the reduction tube by connecting the heating assembly containing the loading device () to the reduction tube. Insert the reduction tube assembly into the furnace (hi) and suspend it centrally from the balance (), ensuring that there is no contact with the furnace wall or heating elements.
Connect the thermocouple, ensuring that its tip is at the central position, as shown in Figure 2. Connect the measurement devices for the differential pressure (j) and for the change in the height of the test bed ).
Connect the gas-supply system (9), the discharge line and the compressed air to the loading device. Apply a load of 50 kPa ± 2 kPa.BS ISO 7992 pdf free download.