Study On The Performance And Reduction Behavior Of Cold-bonded Briquette Prepared By Sinter Return Ore

As a big iron and steel country,China consumes a large amount of sinter every year,and sintering will produce 30～40%of sintering return ore.Sintering re-sintering will cause energy consumption,greenhouse gas and pollutant emissions.In response to the national"double carbon"strategy,how to achieve green and pollution-free treatment of sintering return ore has become a key issue.Based on this,a method of preparing cold briquetting by sintering return ore is proposed.This paper mainly studies the physical and chemical properties of different binders on the cold briquetting of sintered return ore,and finds a new composite binder suitable for the cold briquetting of sintered return ore.The following main conclusions are obtained:The experimental results of using corn starch as a binder to prepare sintered ore cold briquetting show that with the increase of binder content,the falling strength of wet briquetting,the compressive strength of wet briquetting,the falling strength of dry briquetting and the compressive strength of dry briquetting increase.With the increase of water content,the strength of each level increased first and then decreased.With the increase of stirring time,the strength of each level increases first and then tends to be stable.The optimum scheme is that the amount of binder added is 2.5%,the amount of water added is 7%,and the stirring time is 7 min.At this time,the falling strength of the wet briquette is 10.5 times/0.5m,the compressive strength of the wet briquette is82.85 N,the falling strength of the dry briquette is 115.5 times/0.5m,and the compressive strength of the dry briquette is 2915.58 N.The experimental results of cold briquetting of sintered ore with composite binder show that the optimum binder ratio is 6%inorganic binder D+0.15%organic binder（HPMC）.At this time,the falling strength of the wet block is 3.9 times/0.5m,the compressive strength of the dry block is 2018.23N,the low temperature reduction pulverization performance RDI_+3.15is 86.07%,the compressive strength after RDI is1133.77N,the reduction degree RI is 61.21%,and the compressive strength after RI is336.18N.Meet the quality requirements of industrial production.The experimental results of isothermal reduction kinetics show that the reduction rate of the cold briquetting of the sintered return ore increases with the increase of temperature.When the temperature is 1050°C,the reduction rate is 74.80%.With the increase of temperature,the metal iron phase in the external area of the cold briquette gradually accumulates and increases,and the iron oxide phase in the internal area of the cold briquette gradually becomes smooth.The reduction process is controlled by interfacial chemical reaction in the early stage,and is controlled by interfacial chemical reaction and internal diffusion in the middle and late stages of reduction.The apparent activation energy is 20.04 k J/mol and 27.10 k J/mol.