Study On High Temperature Carbothermal Reduction Of Oolitic Hematite With Additives

The Oolitic hematite is rich in China.it is proven reserves of 3.72 billion tons and is one of the most important resources for iron ore resources in China.Most of this type of ore in China is concentrated in the southwest and central provinces.Because of characteristics of the Oolitic hematite,At present,new methods for the study of Oolitic hematite are proposed: re-election,flotation,magnetization roasting,chemical leaching,microwave reduction and other means.These methods provide a new direction for the study of Oolitic hematite,but do not achieve a high reduction effect.Li selected a combination of borax and sodium sulfate to study the separation of iron and phosphorus from a hematite.It was found that the combination additive can enhance the reduction and promote the separation of iron and phosphorus.Therefore,the selection of suitable additives is the study.Applied to the actual key.There is from the preliminary theoretical analysis.Adding CaO can effectively improve the reduction effect and facilitate the aggregation and growth of iron particles.This paper takes Guizhou Hezhang Oolitic hematite as experimental material,the effect of reduction was studied when adding boron oxide,borax and sodium carbonate into high-phosphorus Oolitic hematite.In this paper,optical microscopy,SEM-EDS,XRD and chemical analysis were used to study the effects of reduction and sodium carbonate on the metallization rate and microstructure when adding boron oxide,borax and sodium carbonate into high-phosphorus Oolitic hematite in two different temperature(950°C,1150°C),the effect of different reduction conditions on the phase composition of the reduction product was also studied.The results show that the elevated temperature is beneficial to the positive reaction of the reduction reaction and promote the nucleation growth of the iron particles.The metallization rate of the reduction product after the addition of boron oxide at the reduction temperature of 950°C is increased from 11.3% to 78.19%.The metallization rate of the reduced product after borax increased from 11.3% to85.76%.The metallization rate of the reduced product increased from 11.3% to 14.2%after adding sodium carbonate.The borax have the best effect.All three additives can promote the decomposition of iron slag phase olivine and iron spinel reducing agent into iron,so the metallization rate was promoted.The metallization rate increases as the additives(sodium carbonate,borax)gradually increase.The metallization rate of boron oxide at the content of 2% is up to 78.19%,and the metallization rate decreases with the increase of boron oxide after the content exceeds 4%.When the temperature is 1150°C,the effect of the additive is not great,and the increase of the metallization rate is not obvious.In summary,the optimum temperature is 950°C,the best additive is borax,the best addition content is 2% borax,the metallization rate reaches 90.1%.