Experimental Study On Sintering Of Yangxian Vanadium Titanium Magnetite

Vanadium titanium magnetite,as an ore closely associated with iron,vanadium and titanium,contains rich metal elements.Yangxian County,Shaanxi Province is rich in vanadium titanium magnetite resources,and the ore price is far lower than other iron concentrates,which has a high cost performance ratio.However,after adding vanadium titanium magnetite,the sintering index and metallurgical performance of sinter show a trend of deterioration,and the low-temperature reduction pulverization performance of sinter declines significantly,which seriously affects the smooth operation of blast furnace smelting.In order to make use of the vanadium titanium magnetite resources in Yangxian County and improve the quality of vanadium titanium sinter,Yangxian vanadium titanium magnets were selected as the main raw materials in this experiment.The main factors affecting the quality of sinter,such as vanadium titanium ore ratio,carbon content and alkalinity,were tested in a sintering cup,and then reasonable sintering process parameters were determined.The experimental results indicate that:(1)The sintering parameters of Yangxian vanadium titanium magnetite are as follows: the ratio of vanadium titanium magnetite should be controlled within 30%～40%;The carbon allocation should be in the range of 5.0% to 5.5%,which is more appropriate;The alkalinity of sintered ore should be controlled at around 2.2,and the moisture content of the mixture should be controlled at 8%～9%.The yield of vanadium titanium sintered ore is 85.91%,the drum strength is 56.94%,the low-temperature reduction performance(RDI+3.15mm)is 54.49%,the reduction degree is 59.3%,the softening start temperature is1167℃and the final temperature is 1252℃,with a softening temperature range of 85 ℃.(2)When the ratio of vanadium titanium ore is 20%,30%,40%,and 50%,the drum strength of vanadium titanium sintering ore is 57.55%,57.16%,56.94%,and 53.31%;The yield is 86.73%,86.18%,85.91%,and 74.65%;The vertical sintering speeds are23.13mm/min,25mm/min,28.67mm/min,and 26.62mm/min.The low-temperature reduction pulverization index(RDI+3.15mm)is 56.24%,55.12%,54.49%,and 45.40%;The reduction degree is 65.1%,63.8%,59.3%,and 53.1%.With the increase of vanadium titanium ratio,the proportion of small particle size(5mm～10mm)increases,and the softening temperature range widens.When the ratio is 50%,the performance indicators of vanadium titanium sintered ore decrease significantly.(3)When the carbon content is 4.0%,4.5%,5.0%,and 5.5%,the drum strength of vanadium titanium sintered ore is 50.34%,53.11%,56.94%,and 56.37%;The yield rates are 74.46%,83.49%,85.91%,and 84.12%;The vertical sintering speeds are 17.14mm/min,24.00 mm/min,28.67 mm/min,and 27.00 mm/min.The low-temperature reduction pulverization index(RDI+3.15mm)is 45.40%,50.29%,51.40%,54.49%,and the reduction degree is 62.1%,60.8%,59.3%,and 58.4%.With the increase of carbon content,the proportion of small particle size(5mm～10mm)decreases,the softening range narrows,and the performance of vanadium titanium sintered ore improves.(4)When the alkalinity is 1.8,2.0,2.2,2.4,the drum strength of vanadium titanium sintered ore is 50.97%,55.31%,56.94%,56.48%;The yield is 86.67%,86.12%,85.91%,and 83.83%;The vertical sintering speed is 20.67%,25.62%,28.67%,28.94;,The lowtemperature reduction pulverization index(RDI+3.15mm)is 41.29%,50.34%,54.49%,55.42%,and the reduction degree is 52.4%,55.6%,59.3%,and 61.2%.With the increase of alkalinity,the proportion of small particles(5mm～10mm)decreases,the softening range narrows,and various performance indicators are significantly improved.(5)The microstructure and phase composition of vanadium titanium sinter were studied by X-ray diffractometer,mineral phase microscope and scanning electron microscope.The results show that the metal phase in sinter is mainly magnetite and hematite,and the bonding phase is mainly silicate phase and calcium ferrite phase.When the proportion of vanadium titanium ore increases,the microstructure of the sintered ore shows a granular interweaving erosion granular change,with an increase in pores;The microstructure with different carbon content and alkalinity is a granular porphyritic structure,with an increased degree of homogenization.The number of pores is inversely proportional to the carbon content of the sintered ore and directly proportional to the alkalinity of the sintered ore.