Study On Microwave Sintering Of Magnetite Concentrates

Sinter is one of the main raw materials in blast furnace iron-making process, which takes about 70% in the iron-bearing materials. Generally, with an air-exhausted or air-blast method, the iron ore and other materials such as calcium are sintered to meet the request of processing. But two problems can not be overcame.Firstly, the conventional sintering process needs 3～5 percent carbon, and it will exhausted a large mounts of coal resource. Secondly, a large amount of polluted gases would be produced due to the use of coal, and this is opponent to the"clean production".So it is necessary to develop a process that may overcome the problems, while the microwave is a valuable method.Microwave heating is a novel heating method, which has many potential properties, such as selective heating, volumetric heating, clean, easy to control and rapid heating, and it has applied in many fields,especially, it has attained a great achievement in some aspects. As for magnetic concentrates-one of the raw materials mentioned, whose main composition is Fe3O4, is microwave-absorbing material, and can be heated rapidly under microwave irradiation. For the goal to overcome the problems due to the fuel and pollution of conventional sintering, a primary study about microwave sintering of magnetite concentrates has been done.The mechanism of microwave heating was introduced, and in lab-scale,with a microwave oven (2.45GHz,100W) and periodical temperature measurement,in the condition of different irradiation time,carbon addition,basicity,sample mass,inert atmosphere and Fe3O4 addition,the microwave sintering properties of three magnetite concentrates(Local concentrates,ZhiLi concentrates,V-Ti concentrates )were studied.It was shown that:in the process of microwave heating magnetite concentrates,the temperature can reach 1200℃in 15 minutes,and the average temperature rate was about 67℃/min,then the temperature change became lower in this temperature;With a same irradiation time(20min),all the temperature of the sample with 1%,2%,3% carbon were lower than 1000℃,the temperature of 3% carbon sample,comparaed with the sample with 1% carbon, the temperature change is about 600℃, 30℃, 10℃for local concentrates, ZhiLi concentrates,V-Ti concentrates respectively.To add CaO to magnetite concentrates to form the sample with 1.5～2.5 basicity,with a heating time of 20min, the temperature is among 1000 to 1300℃,especially,the local concntreates with...