ISO 4696-2:2015 pdf download.Iron ores for blast furnace feedstocks - Determination of low-
temperature reduction-disintegration indices by static method
1 Scope
This part of ISO 4696 specifies a method to provide a relative measure for evaluating the degree of size degradation of iron ores when reduced with carbon monoxide and nitrogen, under conditions resembling those prevailing in the low-temperature reduction zone of a blast furnace.
This part of ISO 4696 is applicable to lump ores, sinters and hot-bonded pellets.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 3082, Iron ores — Sampling and sample preparation procedures
ISO 3310-1, Test sieves — Technical requirements and testing — Part 1: Test sieves of metal wire cloth ISO 3310-2, Test sieves — Technical requirements and testing — Part 2: Test sieves of perforated metal plate
150 11323, Iron ore and direct reduced iron — Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 11323 apply.
4 Principle
The test portion is isothermally reduced in a fixed bed, at 550 °C, using a reducing gas consisting of CO and N2, for 30 mm. The reduced test portion is tumbled in a specific tumble drum for 900 revolutions and then sieved with a sieve having square openings of 2,8 mm. The reduction-disintegration index (RDI) is calculated as the mass percentage of material —2,8 mm.
6.2 Reduction tube, made of non-scaling, heat-resistant metal to withstand temperatures higher than 600 °C, and resistant to deformation. The internal diameter shall be 75 mm±1 mm. A removable perforated plate made of non-scaling, heat-resistant metal to withstand temperatures higher than 600 °C shall be mounted in the reduction tube to support the test portion and to ensure uniform gas flow through it. The perforated plate shall be 4 mm thick, with its diameter 1 mm less than the internal diameter of the tube. The holes in the plate shall be 2 mm to 3 mm in diameter at a pitch centre distance of 4 mm to 5 mm.
Figure 2 shows an example of a reduction tube.
6.3 Furnace, having a heating capacity and temperature control able to maintain the entire test portion, as well as the gas entering the bed at 550 °C±5 °C.
6.4 Gas-supply system, capable of supplying the gases and regulating gas flow rates.
6.5 Tumble drum, made of steel, at least 5 mm thick, having an internal diameter of 130 mm and an inside length of 200 mm. Two equally spaced steel lifters (200 mm long, 20 mm high, and 2 mm thick)shall be mounted longitudinally inside the drum. These can be mounted on a frame that can be inserted inside the vessel from one end. One end of the drum shall be closed and the other open. A close-fitting lid shall be held in place on the opening to ensure a dust-tight seal. The drum shall be replaced in any case when the thickness of the vessel wall is reduced to 3 mm in any area, and the lifters when their height is reduced to less than 18 mm.
Figure 3 shows an example of a tumble drum.ISO 4696-2 pdf download.