| Abstract: | The mechanism of formation of zirconium sponge in the production of zirconium by the magnesothermic process has been investigated by introducing into the reducing agent a very soluble but not very volatile additive (aluminum, tin) acting as marked atoms. It was found that the growth of the zirconium sponge on the wall of the reaction crucible above the level of the molten bath is the result of the reaction of zirconium chloride vapor with molten magnesium as the latter ascends by capillary action through the previously formed sponge. The amount of zirconium chloride reacting with magnesium in unit time depends more upon the perimeter of the crucible than upon the surface area of the bath. To intensify the reduction of zirconium chloride by magnesium, it is recommended that partitions be placed in the crucible to act practically in the same way as the crucible wall. |
