Study On Modification Of Iron Powder

Iron powder is largely used in powder metallurgy, welding rod making and flame incising. With quick development of powder metallurgy, a lot of powder products are needed. Iron powders are formed during steel refining by oxygen blasting and reaction of oxygen with impurities in the steel solution. Mechanism of forming powder and figuration of particle are similar to pulverization powder. Some smog with iron powder converter ash come into the system of powder integration, then turn into sludge of converter. It indicates that there are 20% iron powder in the converter residue. Pangang iron powder of ash from converter would arrive at eighty thousand tons, whose MFe is 20%～25%, and the MFe of the powder dust will arrive at more than 90% by magnetic enrichment, ball milling, gravitational rocking.However,this kind of iron powder has some bad properties, such as rule particle , lubricity surface with silicate film, high foreign substance, which result in high apparent density, bad figuration and bad sintering character.It can be used as reducing iron powder in vitriol method titanic powder production ,but can not be used in powder metallurgical directly because it has not been modified enough.In order to modify iron powder to raw material of powder metallurgy by milling and modificating, we modify the characters of the iron powder by corrupt ball milling and fine secondary reduction process, and compare the effects of technical parameters between lab and expansile product line. The results of research indicate that using corrupt ball milling with ball mill can improve the apparent density and particle size of iron powder ,reduce the percentages of Ca,Mn,Si ,make spherical particle into erose particle, turn the slick surface into crude, and thus have meet physical requirements of reconstructing iron powder. It also shows the percentages of C,S,O decrease and chemical purity has been developed by reverting iron powder in a reduction furnace using pure hydrogen as reducing agent.At last, we get the best technical parameters:FeCl₃(s)/iron powder(w/w)= 1.2/100,muriatic acid/iron powder(w/w)=0.5/100,iron powder /steel ball(w/w)=1/5,iron powder /wate(rv/v)=1/1,diameter of the steel ballΦ:3-10mm,ball milling time:3h,hydrogen reverting temperature :850℃,reducing time:2 h. The final quality of the product: purity of the iron powder is 98.72%, with 0.036% C, 0.015% Si,0.003% S, 0.029% Ca, 0.027% Mn。The best technical parameters for ampliative experiment: iron powder/steel ball(w/w)= 1/9;iron powder/water(w/w)=1/1; FeCl3(s)/iron powder(w/w)= 0.3/100; muriatic acid/iron powder(w/w)=0.5/100;ratio of different steel ball:φ6(mm)/φ9(mm)=4/9; ball milling time:3h;reducing medium is mixed hydrogen and nitrogen from ammonia, hydrogen- reduced temperature: 900℃,reducing time :2 h. The final quality of the product: purity of the iron powder is 99.16%, with 0.029% C, 0.016% Si,0.005% S, 0.032% Ca, 0.037% Mn,0.079%P.Characterization of molding,sintering,sintered sample of modified iron powder proves that modified iron powder can be used as middle,low water atomization iron powder,the iron powder has been modified,this technology has been used in production and created benefits. Acidic waste water from process can be cycled which meets the requirement of environmental protection...