Synthesis of Iron Nanopowder from FeCl3Solution by Chemical Reduction Method for Recycling of Spent Neodymium Magnet

Recycling process of iron should be developed for efficient recovery of neodymium(Nd), rare metal, from acid-leaching solution of neodymium magnet. In this study, FeCl3 solution as iron source was used for synthesis of iron nanoparticle with the condition of various factors, etc, reductant, surfactant. Na4O7P2 and polyvinylpyrrolidone(PVP) as surfactants, NaBH4 as reductant, and palladium chloride(PdCl2) as a nucleation seed were used. Iron powder was analyzed with instruments of XRD, SEM and PSA for measuring shape and size. Iron nanoparticles were made at the ratio of 1 : 5(Fe (III) : NaBH4) after 30 min of reduction time. Size and shape of iron particles synthesized were round-form and 50 nm ~ 100 nm size. Zeta-potential of iron at the 100 mg/L of Na4O7P2 was negative value, which is good for dispersion of metal particle. When Na4O7P2(100 mg/L), PVP(FeCl3 : PVP = 1 : 4, w/w) and Pd(FeCl3 : PdCl2 = 1 : 0.001, w/w) were used, iron nanoparticles which are round-shape, well-dispersed, near 100 nm-sized can be made.