Effect of hydrogen atmosphere on iron powder in secondary reduction process

Preparation of reducing agent hydrogen

The reduction of iron oxide by hydrogen is an endothermic reaction. Therefore, from the point of view of thermodynamics, the higher the temperature of the secondary reduction, the more conducive to the deoxidation reaction. Hydrogen industry, as a reducing agent, usually takes liquid ammonia as the raw material to produce hydrogen through ammonia decomposition.It is the liquid ammonia gasification entered with catalyst decomposition after preheating furnace, under a certain temperature and pressure and catalyst ammonia is decomposed to produce contains 75% nitrogen and 25% hydrogen mixture, gas after heat exchanger and cooler, into the dryer with UOP zeolite molecular sieve as adsorbent, by adsorption purification after the effective removal of residual ammonia and moisture in mixture.

Effect of hydrogen composition on reduction of iron powder

In a certain content of H2 atmosphere at high temperature in the reduction potential (make) in the direction of the reduction reaction, but in the process of cooling is becoming oxidizing atmosphere, can make instead have reduction of iron powder to oxidation In 800, for example, with nearly 30% of water vapor H2 atmosphere can make the FeO reduction for Fe, but such as cooling to 150, the same of H2 atmosphere makes have reduction of iron powder to oxidation;Therefore, in the process of secondary reduction, to control the content of water vapor in hydrogen, it is necessary to make the content of water vapor in hydrogen atmosphere less than 5% of its equilibrium gas phase composition, so as to avoid the oxidation of reduced iron powder in the later stage of reduction as much as possible, affecting the quality of the final reduced iron powder.