Ultrafine iron powder as an oxygen adsorbent for argon purification. Activation of iron by milling

Ultrafine reactive iron powder was prepared by a high-performance milling p rocedure using commercially available iron powder. The milled iron material was found to have very high affinity to oxygen. The activated powder react ed at very mild conditions even with traces of oxygen in argon. The deactiv ated iron material can be easily reactivated by reduction in a stream of di luted hydrogen. The activation occurred at mild conditions. The sorption ac tivity of the iron reactive powder do es not change substantially over seve ral cycles of adsorption - desorption. Iron powder was characterized by the surface area measured by nitrogen adsorption at -196 degreesC. Oxygen capa cities were determined in an argon gas flow system. The process described h ere can be scaled up for industrial use.