COREX用碱性球团制备及其预还原性能

Preparation and Pre-reduction Behavior of Alkaline Pellets for COREX

研究了熔剂类型、碱度及原料铁品位对COREX用碱性球团预还原性能的影响。结果表明:生石灰能提高生球性能,铁品位对生球性能影响小。在基准热工制度下,碱度升高至0.8时,石灰石作熔剂的碱性球团抗压强度降低至2 812 N/个,生石灰作熔剂的碱性球团的抗压强度升高至3 227 N/个;铁品位提高时,焙烧球抗压强度出现小幅升高。在预还原条件下,随着碱度升高,石灰石作熔剂的碱性球团RI升高,SI_2下降,RDI_(+3.15 mm)、RSI变化不大;生石灰作熔剂的碱性球团RSI、RI均有升高,RDI_(+3.15 mm)下降,SI_2较大;提高精矿铁品位能改善石灰石作熔剂碱性球团的预还原性能。其中以精矿b为原料、石灰石作熔剂、碱度0.8的球团,其预还原后的RDI_(+3.15 mm)>96.90%,RSI<4.62%,RI>93.15%,SI_2<4.23%,是一种优质的COREX用碱性球团。

The effects of flux types,basicity and total iron content( TFe) of raw materials on preparation and pre-reduction behavior of pellets for COREX were investigated. Experiment showed that the quicklime improved the green pellet quality,while TFe content had little influence on quality of green pellets. Under the same heating condition,the compression strength of the pellets prepared with limestone and quicklime as flux were 2 812 N/a and 3 227 N/a,respectively,with basicity of 0. 8. It is found that the compression strength of pellet can be slightly enhanced with an improvement in TFe of raw materials. With the same pre-reduction condition,an increase in the basicity can result in RI increased but SI_2 decreased for the pellets prepared with addition of limestone,while both RDI_(+ 3. 15 mm) and RSI keeping constant. In contrast,an addition of quicklime can result in an increase in both RSI and RI,a decrease in its RDI_(+ 3. 15 mm),and SI_2 keeping at a high level. It is shown that increasing TFe content in the concentrate can improve pre-reduction behavior of the pellets with limestone as flux. With concentrate b as raw material,limestone as flux,the pellet with the basicity of 0. 8 was subjected to pre-reduction process,leading to RDI_(+ 3. 15 mm)> 96. 90%,RSI < 4. 62%,RI > 93. 15% and SI_2< 4. 23%,which can be regarded as a kind of high-quality alkaline pellets for COREX.