| Relating Physical and Metallurgical Properties of Kumba Lump Ore to the behaviour in processes Kobus Vreugdenburg1; Jacques Muller1; 1ANGLO AMERICAN, Pretoria, South Africa; PAPER: 74/Iron/Regular (Oral) SCHEDULED: 14:50/Tue. 29 Nov. 2022/Arcadia 1 ABSTRACT: <p>The standard physical and metallurgical tests are designed to differentiate between iron bearing materials. The standard tests prescribe the equipment and test conditions to compare test results across laboratories. Standard tests are widely accepted and used by suppliers and consumers of the materials for commercial purposes and process control. The conditions in blast furnaces and direct reduction processes are dynamic while the standard tests subject the iron bearing material to fixed conditions, making it difficult to relate the impact of standard properties on process performance. [1]<br />The ISO 3271 standard specifies a method for evaluating the resistance of iron ores to size degradation by impact and abrasion. ISO 3271 prescribes 200 revolutions in a tumble drum to obtain the tumble index (TI), the size degradation Kumba Lump ore from load port to discharge port was correlated with the number of revolutions needed in the ISO tumble drum to obtain similar degradation.<br />ISO 4696 and ISO 11257 standards are used to evaluate the degree of size degradation of iron ores due to low temperature reduction-disintegration in blast furnaces and direct reduction processes respectively. The use of isothermal reduction does not reflect the dynamic conditions in the processes and the reduction disintegration index (RDI) does not always reflect the actual size degradation [1][2]. The ISO tests are done on one size fraction, and the reduction disintegration size fractions experience are different. The effect of test temperature and size fraction on reduction disintegration were evaluated. <br />ISO 4695 and ISO 7215 standards are used to evaluate the relative reducibility of iron ores under blast furnace conditions. The standard tests are done on the 10 to 12.5 mm size fraction or on the 18 to 20mm size fraction, depending on which of the two ISO standards are used. The result is expressed as the reducibility index (RI). The rate at which oxygen can be removed from the ore is dependent on the available surface area - coarser particles will be reduced at a lower rate than finer particles. The actual size fraction of the lump ores used in the blast furnace is around 6.3 to 40mm, the mean reducibility of the lump ore considering the particle size distribution were investigated. <br />The relevance of physical and metallurgical properties of Kumba Lump Ore on the performance in practice were investigated.</p> References: <p>[1] C.E. Loo, N.J. Bristow, Properties of iron bearing materials under simulated blast furnace indirect reduction conditions Part 1 Review and experimental procedure, Ironmaking & Steelmaking 25(3):222-232 (January 1998)<br />[2] C.E. Loo, N.J. Bristow, Properties of iron bearing materials under simulated blast furnace indirect reduction conditions Part 2 Reduction Degradation, Ironmaking & Steelmaking 25(4):287-295 (January 1998)</p> |
