Novel Efficient Reduction Route for Magnesium Production Using Silicothermic Process.

Area of Science:

• Materials Science
• Chemical Engineering
• Metallurgy

Background:

• Magnesium production relies on efficient reduction processes.
• Improving mass transfer in pellet reactants is crucial for higher yields.
• Porous structures can enhance reaction kinetics.

Purpose of the Study:

• To develop an efficient reduction route for magnesium production using porous pellets.
• To investigate the impact of varying pore-forming agent concentrations on pellet performance.
• To optimize pellet composition for enhanced magnesium reduction efficiency.

Main Methods:

• A novel porous pellet precursor was synthesized using ammonium bicarbonate (NH₄HCO₃) as a pore-forming agent at 150 MPa.
• Pellets with varying NH₄HCO₃ content (0-30%) were heat-treated from 100 °C to 1400 °C under high vacuum (approx. 10 Pa).
• Reaction characteristics, including reduction rate and efficiency, were measured at different conversion levels.

Main Results:

• The instantaneous maximum reduction rate initially increased and then decreased with higher pore-forming agent content.
• Pellets with 5% NH₄HCO₃ showed a 36% increase in reduction efficiency at 80% conversion compared to non-porous pellets.
• At 90% conversion, a 29% efficiency improvement was observed with 5% NH₄HCO₃.

Conclusions:

• Adding an optimal ratio of NH₄HCO₃ significantly enhances magnesium vapor diffusion within pellets.
• The time to reach chemical reaction equilibrium is reduced, leading to faster kinetics.
• The developed porous pellet route effectively increases magnesium production efficiency.