Kinetics of manganese ore reduction by carbon monoxide

A step has been made in the direction of understanding the fundamental chem ical processes taking place inside electric are furnaces producing manganes e alloys. The reduction of higher manganese oxides to MnO by carbon monoxid e has been studied in the temperature range 700 degrees C to 1100 degrees C . A topochemical pattern with a single shrinking core inside the ore partic les has been observed in most cases. It has been found that the reduction o f some manganese silicates (braunite minerals) is influenced by reaction in terface kinetics, whereas the reduction rate of manganese oxides (bixbyite and hausmannite) is mostly determined by product shell pore diffusion. Sint ering kinetics and the extent of natural porosity determine the product she ll pore diffusivity. As the melting point of the reaction product is approa ched, rapid sintering leads to a decrease in diffusivity.