Research Of On Reasonable Methods On For Using Of Pyrite Cinder In The Ironmaking Process

With the development of modern steel industry, shortage of iron ore resource becomes more and more severe. Shortage of iron ore resource has seriously restricted the development of iron and steel industry. It is significant to utilize the secondary resources which are rich of iron, such as pytite cinder, comprehensively. Pyrite cinder, also containing considerable nonferrous metals, is a kind of important secondary resources which are difficult to upgrade and smelt. Tens of millions of tons of pyrite cinder are discharged in chemical industry annually. In addition, there are more than 100 million tons of the accumulated waste cinder in storage that cannot be efficiently utilized. It is significant to research of on reasonable methods on for using of pyrite cinder in the ironmaking process. In the document, pyrite cinder can be utilized to obtain clay brick, cement, iron series pigments, ironmaking raw materials and so on. In consideration of the yeild of pyrite cinder, it will be mainly used in ironmaking process in the future.Reasonable methods on for using of pyrite cinder in the ironmaking process should consider quality of sinter, equipment corrosion, exhaust emission and so on. In order to provide reasonable methods on for using of pyrite cinder in the ironmaking process, this paper studied the utilization of pyrite cinder in sintering process and pelletizing process. Several conclusions were shown as follow:① The main phase of pyrite cinder are hematite(Fe2O3), magnetite(Fe3O4) and magnesioferrite. The main phase of Australian iron ore are hematite(Fe2O3), a certain amount of hydroxide radical and little kaoline. The particle size of pyrite cinder less than 0.2mm is close to 80%, as adhesion particles in granulating process. The particle size of Australian iron ore is bigger than other iron ores, as nucleation particles exist in granulating process.Moisture capacity of pyrite cinder is 37.25%, contact angle of it is 73.6°, Moisture capacity of Australian iron ore is 22.01%, contact angle of it is 69.8°. It can be seen from the microstructure of pyrite cinder that the most of particles look like a round ball and surface of particles have a lot of minute porosity. It results poorly balling property in granulating process.② The actual water content of pyrite cinder sintering mixture should be controlled 10±0.3% in basicity 1.2, carbon content 5.0%, 50% pyrite cinder. The water content of pyrite cinder is higher than ordinary iron ores sintering mixture, this is because pyrite cinder is poor balling property in granulating process, incresing water content could improve balling property. The basicity of pyrite cinder sintering mixture should be controlled 1.5 in carbon content 5.0%, 50 pyrite cinder, water content 10%. The carbon content of pyrite cinder sintering mixture should be controlled 5.0% in basicity 1.5, 50 pyrite cinder, water content 10%. So the optimal scheme is water content 10%, basicity 1.5, carbon content 5.0%.③ Researching sinter indexes versus different ratios of pyrite cinder in basicity 1.5, carbon content 5.0%, water content 10%. Experimental investigation shows that sinter indexes became badly with improvement ratios of pyrite cinder. Increasing ratios of pyrite cinder in sintering mixture, the percent of nucleation particles will decrease in sintering mixture, it is bad for sintering mixture to pelletize, permeability of sintering mixture became bad because of increasing ratios of pyrite cinder, and so the quality of sinter became badly. the optimal scheme:basicity 1.5, carbon content 5.0%, ratios of pyrite cinder 50%, sinter return proportioning 20%, water content 10%), the yield is 85%, the shatter index is 68%, the drum strength is 48%, the abrasion index is under 4.4%. doing metallurgical performance test for the optimal scheme, the results were as follows. RDI+3.15=86.16%, Rt=77.5%, RVI=45.14%, softening temperature range △Tsa=TsTa=128 ℃, Tm=1420 ℃. The sinter of optimal scheme can satisfy requirement ironmaking in blast furnace. In sintering process some sulfur and arsenic can be removed, but sintering equipment should be propect.④ The experiment of briquetting pyrite cinder show that the best roasting temperature is 1260℃ and the best roasting time is 12 min. pyrite cinder should be grinded before pelleting. The effects of pyrite cinder pellet is poor without grinded. Shatter strength of green pellet is very low. The particle size become samll with grinded grinding can increase surface energy and improve balling property, Shatter strength of green pellet increase with adding ball-milling time. Increasing the percent of bentonite can improve balling property It can reduce total iron grade of pellets when the percent of bentonite is high.⑤ Studied the grinding time and bentonite content have effect on pellet of pyrite cinder. Experimental investigation shows that compressive strength of the pellet has reached 3.458 k N in bentonite content 2.0%, grinding time 40 min, it can satisfy requirement of ironmaking in blast furnace.