ISO 4695:2021 pdf download – Iron ores for blast furnace feedstocks — Determination of the reducibility by the rate of reduction index.
1 Scope This document specifies a method to provide a relative measure for evaluating the extent to and ease with which oxygen can be removed from iron ores, when reduced under conditions resembling those prevailing in the reduction zone of a blast furnace. This document is applicable to lump ores, sinters and hot-bonded pellets. 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 this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 2597-1, Iron ores — Determination of total iron content — Part 1: Titrimetric method after tin(II) chloride reduction ISO 2597-2, Iron ores — Determination of total iron content — Part 2: Titrimetric methods after titanium(III) chloride reduction ISO 3082, Iron ores — Sampling and sample preparation procedures ISO 9035, Iron ores — Determination of acid-soluble iron(II) content — Titrimetric method ISO 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. ISO and IEC maintain terminology databases for use in standardization at the following addresses: — ISO Online browsing platform: available at https:// www .iso .org/ obp — IEC Electropedia: available at https:// www .electropedia .org/ 4 Principle The test portion is isothermally reduced in a fixed bed, at 950 °C, using a reducing gas consisting of CO and N 2 , and the mass loss of the test portion is recorded continuously or at specified time intervals until its degree of reduction reaches 65 %. The rate of reduction is calculated at the oxygen/iron ratio of 0,9.
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 950 °C ± 10 °C. 6.4 Balance, capable of weighing the reduction tube assembly, including the test portion, to an accuracy of 1 g. The balance shall have an appropriate device to suspend the reduction tube assembly. 6.5 Gas-supply system, capable of supplying the gases and regulating gas flow rates. It shall be ensured that a frictionless connection between the gas-supply system and the reduction tube does not affect the weight loss determination during reduction.