Study On The Recovering Iron Nanopowder From The Magnetic Filter Product Of Cold Rolling Plant

Magnetic filter product as one of considerable industrial wastes is produced in the thin steel plate production process in cold rolling plant.Its character is rich of oil and sticky.Now it is mainly buried or burnt to cause environment pollution easily.Magnetic filter product consisting of rolling oil,water and iron powder particle is obtained from cold rolling emulsion circulated through magnetic filter.Iron nanopowder could be recovered by removing the emulsible oil off the particle surface.Iron nanopowder of small size,large specific surface area and high surface energy has physical and chemical properties different from general iron powder.It is of high economic value and widely used in metallurgy,catalysis,water treatment,medical treatment and other fields.In this paper,the valuable pure iron nanopowder was recovered from the industrial waste magnetic filter product.Magnetic filter product was pretreated with centrifugal separation to get oily iron powder.In the coaction of ultrasonic cavitation and aqueous-base metal detergent,oily iron powder was cleaned and rinsed.Pure iron powder product was obtained through vacuum dryness.Magnetic filter product was centrifugally separated at the speed of 12000 r/min and room temperature for 40 minutes to remove most emulsible oil.Oily iron powder was washed three times with ultrasonic wave in aqueous-base metal detergent and rinsed in deionized water until the liquid was clarified.Magnet was used to separate iron powder and liquid.Iron powder product was dried 5 hours at low temperature and vacuum.In the experiment,the iron content of the iron powder product was detected using1,10-Phenanthroline spectrophotometry and the oil in liquid from the iron powder surface was showed by the area beneath the absorbeny curve.The mass fraction of each matter in aqueous-base metal detergent was TX-10 0.7%,AEO-9 0.5%,surfactant F 0.05%,Na₂SiO₃ 2%,n-butanol 0.1%,EDTA 0.1%and water.The cleaning condition was the ultrasonic frequency 40 kHz,power 200 W,temperature40℃and liquid-solid ratio 20 to 1 for 3 times of 12 min,8 min,3 min respectively.The iron content of the iron powder product reached 97.14%detected using1,10-Phenanthroline spectrophotometry.The iron powder product was 19.5 nm in size and contained Fe 84.16%,Fe₂C 3.09%and Fe₃O₄ 12.75%detected with XRD.