Sinters were produced in the pilot plant using four different ore mixtures with varying proportions of iron ores, fluxes and coke. All the resulting sinters were characterised by chemical and granulometric analysis, degradation testing during reduction in the blast furnace (RDI test), cold resistance testing (Tumbler test), reducibility testing, determination of softening and melting temperatures, and determination of the sinter structure by electron microscopy. The obtained result allow for the establishment of better operation conditions to manufacture sinters.KEY WORDS: sintering; quality of sinter; ore mixtures; iron ores; blast furnace. 1089© 2010 ISIJ line with the ores present, but is three percentage points lower in mixtures 3 and 4 due to the inclusion of 'Goa Silicioso' ore with its lower total iron content. The ferrous content between 3.1 and 4.8 % can be considered as low as correspond to the hematitic nature of the iron ores that make up part of the mixtures. The alkalis content is low. Granulometric AnalysisGranulometric analysis has been performed using a ROT-TAP unit, which combines reciprocating eccentric rotary screening with a percussion system on the screen column. Figure 1 displays the granulometric curve for ore mixture 1, with an average particle size of 1.69 mm. Table 5 lists these values for the four different mixes. Granulation FitnessThe ore mixtures are subjected to granulation treatment prior to sintering in order to increase the average size of the very fine grained ores, with the aim of improving their dynamic behaviour during sintering.The granulation treatment is of basic importance in iron ore sintering, because good sinter bed permeability to a large extent determines the sintering rate and thus the plant's productivity.Granulation fitness testing of each iron ore and each ore mixture has been carried out following the SAFE (Size Analysis on Frozen Elements) standard procedure established by Centro Sviluppo Materiali (CSM) of Italy. Figure 2 shows the granulometry curve of ore mixture 1 before and after the SAFE test. Table 5 indicates the average particle size of the ore mix- ISIJ International, Vol. 50 (2010), No. 8 4) 1090© 2010 ISIJ Table 1. Chemical analysis of iron ores (wt%). Table 2. Chemical analysis of fluxes (wt%). Table 3. Composition of ore mixtures (wt%). Table 4. Chemical analysis of ore mixtures (wt%). tures after undergoing the SAFE test. All the mixtures present good granulation fitness. ReducibilityA reducibility test has been performed at 900°C following the ISO standard for sinters, adapted for ore mixtures of the 3.3-2.0 mm fraction.5) The results are displayed in Table 5. The R 60 value ranges between 50-56 % and may be considered good. Softening and Melting TemperaturesThe test to determine softening and melting temperatures of the ore mixtures has been carried out using a LECO AF-600 unit, with an oven that reaches a maximum temperature of 1 650°C, in which the following parameters have been fixed with the help of a computer: ASTM standard with inert ...

ores and of an ore mixture. The ore mixture is used in Spain, and Drs Ferná ndez Pello, Mené ndez, and Muñ iz are with CENIM's pilot plant to manufacture a series of sinters, ACERALIA Corporació n Siderú rgica. Apartado 570, 33280 Gijó n, whose chemical compositions and quality indices are deterSpain. Manuscript

The most radical method for saving coke in ironmaking is to inject gaseous, Iiquid Table 2. Chemical analysis of coals. (wto/o)

No abstract

In this paper the possibility is demonstrated of producing microalloyed steels with Ti