Study On The Thermal Reduction Process Of Chromite Siliceous In A Microwave Field

Ferrochromium alloy,as an indispensable material for the addition of steel,can be used to produce special steel with high strength.There are two main processes in traditional smelting of low carbon ferrochromium alloy:converter and electric furnace smelting.However,there are some problems in the two smelting methods.Because of the high smelting temperature?1800²000^oC?,the converter has high energy consumption and high demand for equipment.Because the electrode used in smelting process is carbon electrode,the consumption of carbon electrode will cause the increase of carbon content in ferrochromium smelting.Facing of these problems,it is necessary to explore a new process for smelting low carbon ferrochromium.As a new type of clean and efficient heating energy,microwave energy has been paid more and more attention in recent years.Compared with the traditional heating methods,it has the following advantages:selective heating materials,fast heating,high heating efficiency;have catalytic effect on the chemical reaction,reduce the reaction temperature,shorten the reaction time,promote energy saving;itself does not produce any gas.So it is one of the effective ways to realize the clean production of metallurgical industry make the material?This paper analyzed the application status of chromite and chromite alloy at home and abroad was comprehensively,and the current research status of smelting low carbon ferrochrome with chromite was also introduced.The principle,characteristics,advantages and application status of microwave heating at home and abroad were briefly described.On this basis,the study on the preparation of ferrochromium alloy by silicon thermal reduction of ferrochrome ore powder in microwave field was carried out.1?In this paper,South Africa's chromite powder supplied by Jinzhou,Liaoning was used as raw material,ferrosilicon powder as reducing agent and calcium oxide powder as a cosolvent.Studied the material's absorbing properties and found they all had good absorbing property.2?The process of the reduction of chromite fines on silicon thermal did simple thermodynamic analysis and thermal gravimetric analysis,made the following conclusions:Fe₂O₃ was firstly reduced;followed by Fe O was reduced and finally Cr₂O₃ was reduced,and the microwave field silicon thermal reduction process of Cr₂O₃ in the restore sequence according to the Cr₂O₃-CrO-Cr.3?The influence of raw material size,reducation time,reduction temperature,microwave power,reducing agent dosage and material thickness on the heating performance and the conversion rate of chromite with microwave heating was studied.The optimum process parameters are as follows:microwave power:1500W,reduction time:60min,raw material size:-200 mesh,reducing agent dosage:40%;1300?at temperature,heat preservation at 60min,and 1450?for bulk reduction.The reduction product has been made the SEM analysis and phase analysis,low carbon ferrochrome prepared chromite reduction method that microwave thermal field of silicon,the main chemical components to meet the requirements of Fe Cr₅₅C₂₅ II?GB5683-87?.4?The product of the reduction by scanning electron microscopy at different reduction temperatures were analyzed.The results showed that when the temperature in 1100?nucleation surface chromite particle has scattered bright white metal forming,broken phenomenon slight;when the temperature reached 1200?,the fragmentation increased,a large number of the bright white metal;when the temperature is as high as 1300?,the edge has massive bright white,chrome alloy forming process basically has ended.In summary,the use of single factor test method,discussed some key problems in the microwave field in the thermal process control of chromite reduction,analyzed of microwave reduction of chromite process and principle of residue analysis,revealed the process and mechanism of slag metal separation.Providing some new ideas for the future to study the low carbon and chromium ore smelting the chrome alloy.