Method for preparing magnetically soft composite powder by grinding waste scrap irons

Abstract

The invention belongs to the technical fields of magnetic materials and circular economy, and in particular a method for preparing magnetically soft composite powder by grinding waste scrap irons. The method comprises the following steps: executing thermal base reaction of the grinding waste scrap irons with sodium hydroxide (NaOH) particles at 500-900 degrees centigrade to generate a ferric saltand an aluminium salt; then putting the ferric salt and the aluminium salt in water at 50-100 degrees centigrade for hydrolysis so as to synthesize a compound rubber of ferrous hydroxide (Fe(OH)2), iron hydroxide (Fe(OH)3) and aluminium hydroxide (Al(OH)3); next, heating the compound rubber to 150-500 degrees centigrade for decomposition so as to form compound particles of aluminium oxide (Al2O3)and ferric oxide (Fe2O3); at last, adding 0.2%-5% by mass ratio of aluminium oxide rubber and the compound particles, feeding hydrogen or decomposition ammonia gases at 500-1, 000 degrees centigrade for reduction for 0.5-8 hours to obtain magnetically soft compound powders of aluminium oxide clad ferrous powders. The invention provides a harmless, recycling and high-value reuse way for solid iron-containing wastes, so that not only is environment burden reduced effectively but additional value of waste resources is increased also.

Description

Technical field [0001] The invention provides a method for preparing soft magnetic composite powder by grinding scrap iron filings, which belongs to the technical field of magnetic materials and circular economy. Background technique [0002] my country produces a large amount of grinding scrap iron every year. This kind of grinding scrap iron is produced by grinding, such as machining of mechanical parts, steel cold roll grinding and finishing, tool grinding, etc. Grinding scrap iron usually contains not only a large amount of ferroalloy particles, but also a large amount of cooling oil and grinding wheel particles (Al 2 O 3 ), grinding wheel binder (high-temperature resin and asbestos), and the abrasive, grinding wheel additives and ferroalloy particles are embedded in each other, which makes subsequent sorting very difficult and difficult to be used. Normal centrifugal separation, ball milling, high temperature (1200°C) and other methods can not achieve the separation of metal...

AI Technical Summary

Problems solved by technology

Grinding waste iron chips usually contain not only a large number of ferroalloy particles, but also a large amount of cooling oil and grinding wheel particles (Al 2 o 3 ), grinding wheel binders (high-temperature resin and asbestos), etc., and abrasives, grinding wheel additives and ferroalloy particles are embedded with each other, making subsequent sorting very difficult and difficult to be used

Usual centrifugation, ball milling, high temperature (1200°C) and other methods cannot achieve the separation of metals and non-metals, and cannot obtain pure iron scraps for high value-added reuse

In my country's mechanical processing industry and metallurgical industry, this kind of scrap iron scrap that is difficult to dispose of is treated as waste, which not only occupies land, pollutes the environment, but also causes a great waste of resources.

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