Experimental Study On Nb Fe Alloy From Iron Ore Bearing Nb By Direct Carbon Reduction

This experiment mainly using Bayan Obo niobium containing iron ore was used as raw material,and hydrogen was used as reducing agent to explore the optimum conditions for simultaneous removal of sulfur,phosphorus and iron.Acontaining niobium ore powder possible reaction and the direction and can balance conditions,orthogonal experiment to determine the different in the process of selective reduction of hydrogen reduction temperature,reduction time and the optimal working condition of the hydrogen content.The orthogonal table is L16(4~3),four levels and three factors.The variation of 940-970?is discussed at 10?interval,the variation of 2-3.5 h is discussed at 0.5 h interval,and the variation of 60-90 L/h is discussed at 10 L/h interval.The optimum conditions are as follows:reduction temperature 95?,reduction time 3h and hydrogen flux 90L/h.According to the melting point of iron and the melting temperature of slag,the experimental conditions are determined as melting temperature 1550?and holding time 25 min.Under these conditions,the calculated niobium yield and iron removal rate are more than 97%,the desulfurization rate is 99%,and the dephosphorization rate is 96%.It can be seen that the yield and iron removal rate of niobium are very high.It shows that the enrichment effect of niobium is very good and all the iron is in the slag phase,and the desulfurization rate can reach 99%,indicating that the sulfur is removed,and the dephosphorization rate is 96%,indicating that most of the phosphorus is removed,and the overall melting effect is good.Finally,Niobium-rich slag obtained by melting of slag and gold is used to prepare Niobium-rich Ferroalloy by direct carbon reduction method.According to thermodynamic calculation,the temperature of carbon direct reduction method must reach 1500?.The experimental conditions are selected as reduction temperature interval of 50?.The variation of temperature between 1500?and 1600?is compared.The holding time is determined to be 25 minutes.Finally,the content of niobium-rich ferroalloy pellets is determined.The results show that the reduction effect is better when the temperature is 1550?and the holding time is 25 min.The niobium content in the niobium-iron alloy pellets is 1.39g,and the calculated niobium yield is 73.94%.