Effect of hydrogen atmosphere on iron powder in secondary reduction process.

The preparation of reducing agent hydrogen.

The hydrogen reduction is an endothermic reaction, so the higher the temperature of the secondary reduction is beneficial to the deoxygenation reaction.
Hydrogen is usually produced by ammonia decomposition in the hydrogen industry, which is used as reducing agent.
It is the liquid ammonia gasification entered with catalyst decomposition after preheating furnace, under a certain temperature and pressure and catalyst ammonia decomposition namely mixture containing 75% 75% hydrogen, nitrogen, 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.

The effect of hydrogen composition on iron powder reduction.

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.
At 800 ℃, for example, with nearly 30% of the H2 atmosphere of water vapor can make FeO reduction for Fe, but such as cooling to 150 ℃, the same of H2 atmosphere makes have reduction of iron powder to oxidation;
So to control the hydrogen in the process of secondary reduction of water vapor in the content, must make hydrogen atmosphere of water vapor content in 5% less than the equilibrium gas phase composition, as much as possible to avoid the late reduction has oxidation reduction of iron powder, influence the final quality of the reduced iron powder.