Study Of Increasing Strength Of Vanadium-titanium Magnetite Sinter By Pre-reduction

For the vanadium-titanium magnet sinter produced by Chenggang,its low temperature reduction degradation is so serious.To solve this problem,the mechanism of RDI of vanadium-titanium magnet sinter is studied.The results show that:Severe pulverization will happen in vanadium-titanium magnet sinter during reduction at 500?.The reason is that it is a process of expanding volume and increasing internal stress from Fe₂O₃ to Fe₃O_4.The sinter is not withstanding the destruction of such high intensity internal stress.When vanadium-titanium magnetite sinter is reduced at 900?,the pulverization rate is very low.The restore process contains two stages.In the first stage,the sinter can be also cracked.In the second stage,FeO is increasing and keeps crystallizing,which makes up the destruction of the sinter.Therefore the strength of the sinter is increasing.Based on the analysis,a vision is put forward:reduce the sinter in shaft furnace before entering it into blast furnace.The results of pre-restore tests show that:The variation range of the CO content is 20%⁵0%.In the condition that the initial temperature is 800?and the cooling rate is 10?/min,the higher the CO content is,the better the performance of RDI will be.When the CO content is 50%,the performance of RDI is the best.RDI_+3.15of vanadium-titanium magnet sinter is 68.62%.The variation range of the initial temperature is 750?⁹00?.In the condition that the CO content is 30%and the cooling rate is 10?/min,the higher the initial temperature is,the better the performance of RDI will be.When the initial temperature is 900?,the performance of RDI is the best.RDI_+3.15of vanadium-titanium magnet sinter is 47.03%.The variation range of the cooling rate is 5?/min¹0?/min.In the condition that the CO content is 30%and the initial temperature is 800?,the slower the cooling rate is,the better the performance of RDI will be.When the cooling rate is 5?/min,the performance of RDI is the best.RDI_+3.15of vanadium-titanium magnet sinter is 69.83%.