Comparative Study On Reduction Of Phosphate Ore By Fixed Bed And Fluidized Bed

With the rapid development of the economy,resources are also becoming scarce,which leads us to develop new energy or technology.Today,our country which is rich in phosphate rock resources is also faced with the dilemma,and the phosphoric acid occupies very important position in national economy,which is a important raw material of many base products.At present,the process of the production of phosphoric acid including Wet-process phosphoric acid,tunnel kiln-method phosphoric acid,furnace-process phosphoric acid.In view of the development prospects of furnace-process phosphoric acid is bigger,In this paper,the reduction of phosphate ore is analyzed from the Angle of phosphate reduction equipment.First of all,using fixed bed of high temperature furnace molten to study the reduction process conditions of phosphate rock,for example the temperature,reaction time and dosage of carbon,the influence of slag basicity of phosphate rock reduction rate,the best reduction process condition is that temperature is 1350 ?,reaction time is 60 min,excess carbon coefficient is 1.6,slag basicity is 2.2,the reduction rate of phosphate rock is 96.61%.Secondly,using fixed bed reactor to simulate phosphate rock pretreatment device to obtain the best temperature is 800 ?,the time of pretreatment of phosphate rock is 20 min,reduction temperature is 1300 ?,and without pretreatment conditions of the same other conditions,reduction rate can reach 93.09%.By TGA,XRD and SEM analysis,the most dolomite and calcite in phosphate rock are broken down at 800 ?,which makes the phosphate rock iin the reduction reaction rapidly accelerate the process of the reduction reaction in liquid phase formation,so as to achieve the purpose of lowering the temperature.by the comparison and analysis,the effect of by preprocessing of the phosphorous reduction is obviously better than that of without pretreatment.Again,using the fluidized bed reactor in our laboratory to explore the various reduction factors in a fluidized bed reactor,and compared with fixed bed reactor to conduct an experiment.The experimental results show that the temperature is 1300?,nitrogen gas flow is 500 L/h,silicon calcium ratio 2.2,excess carbon coefficient is 1.6,the reaction time is 60 min conditions,reduction rate can reach 95%,much higher than 1300 ? reduction rate of phosphate rock in a fixed bed reactor.By XRD and SEM analysis,think phosphate rock collision more intense in the fluidized bed,heat transfer and mass transfer effect is better,and makes the reduction of phosphate rock reaction rate higher,so the reduction rate is higher.Due to phosphate rock in fluidized bed at 1150 ? had higher reduction rate,which fully shows the fluidized bed reactor is beneficial to lower the temperature of the reduction reaction of phosphate rock,so the prospects of the development of fluidized bed is better.Finally,the contrast analysis of the fixed bed and fluidized bed reduction about the kinetics of phosphate rock,the results show that the phosphate rock in the fixed bed without pretreatment is far lower than the first order reaction,after pretreatment of phosphate rock close to level 3 reaction,reduction reaction of phosphate rock in the fluidized bed close to the first order reaction;While the activation energy in the fluidized bed reactor is far lower than the fixed bed reactor,the activation energy,which theoretically explains the phosphate rock reaction rate is quicker in the fluidized bed,and heat transfer and mass transfer efficiency is also higher Which further indicates that the fluidized bed reactor is more suitable for the reduction of phosphate rock than the fixed bed reactor.The experiment provides the necessary basic data for the industrial development in the future.