Study On The Electromagnetic Properties Of Fe Components In Melting Oxidation Nickel Slag

In recent years,with the vigorous popularization of smart wearable electronic devices and the rapid development of communication technology,the research of excellent microwave absorption materials have become more and more urgent.As a kind of industrial smelting waste,nickel slag contains various valuable metals,including iron,nickel,cobalt,and copper.Due to the iron content in nickel slag could up to 40%,the recycling of iron has attracted much attention.The molten oxidation method is a common method for extracting iron from nickel slag.In this process,the fayatite in the nickel slag is transformed into magnetite to achieve the purpose of iron recovery.At the same time,the formation of magnesium ferrate and silicates such as pyroxene will produce heterostructures,which make it have potential application value in the field of microwave absorption.In this paper,the magnetite particles extracted from molten nickel oxide slag are used as raw material to prepare the microwave absorption material,and the electromagnetic parameters of the material are optimized by ball milling,heat treatment,and the introduction of carbon materials.The main contents include:?1?The ball-milling method is used to grind magnetite particles obtained by magnetic separation in nickel slag,and the electromagnetic parameters of materials under different ball milling time is studied.The results show that the particle size of magnetite can be significantly reduced by ball milling.When the ball milling time is12 h,the average particle size of magnetite particles decreases from 40?m to 1?m.At the same time,the silicate such as pyroxene contained in magnetite particles will be separated.When the ball milling time up to 6 h,the minimum reflection loss of magnetite particles will reach-34.0 dB at 16.7 GHz,the effective bandwidth is 2.3GHz,the matching thickness is 5.0 mm.?2?In order to eliminate the internal stress introduced by the ball milling process,the magnetic powder of the ball milling for 12 h was heat-treated at different temperatures.The results show when the heat treatment temperature is 700?,the internal stress of magnetite particles decreases from 0.288%to 0.005%,and the coercivity decreases from 264.2 Oe to 137.3 Oe.The microwave absorption propertities of different samples show that the heat treatment process can optimize the microwave absorption capacity of magnetite particles at low frequency.When the annealing temperature is 700?,the minimum reflection loss of the material will reach-38.7 dB at 6.9 GHz,the corresponding matching thickness is 3.5 mm,and the effective bandwidth is 2.2 GHz.?3?Polyurethane foam was used as template,phenolic resin and magnetite particles milled for 12 h are used as raw materials to prepare Fe₃O₄/C porous composites by impregnation-carbonization.The results indicate that when the carbonization temperature up to 600?,the minimum reflection loss of the material can reach-39.9 due to the existence of porous conductive network structure,and the corresponding matching thickness,resonance frequency and effective bandwidth are4.5 mm,5.4 GHz,and 3.4 GHz,respectively.