Method for fluxing molten metal

An improved method for treating a body of molten aluminum using an impeller suitable for dispersing a material selected from fluxing gas, solid particles and an immiscible liquid in the body of molten aluminum, the method including increasing shear forces in the body of molten aluminum and reducing vortex formation, the method comprising the steps of:

• (a) providing a body of molten aluminum;
• (b) projecting an impeller on a shaft into said body, said impeller comprising a rectangular-shaped body having a first rectangular-shaped face and a second rectangular-shaped face disposed substantially opposite said first face, said faces substantially parallel to said shaft and defined by a length L and a height H wherein said length L to height H ratio is in a range of 1.6:1 to 12:1, said body having a width W wherein said height H to width W ratio is in a range of about 6:1 to 1:1;
• (c) dispersing said material in said body by:
• (i) rotating said impeller in one direction;
• and thereafter
• (ii) reversing said direction of rotation of said impeller to a counter direction;
• and
• (iii) the direction of rotation of said impeller being reversed periodically to provide increased shear forces in said body for improved dispersion of said gas or said particles in said body.

An improved method for treating a body of molten aluminum using an impeller suitable for dispersing a material selected from fluxing gas, solid particles and an immiscible liquid in the body of molten aluminum, the method producing increased shear forces in the body of molten aluminum and reducing vortex formation, the method comprising the steps of:

• (a) providing a body of molten aluminum;
• (b) projecting an impeller on a shaft into said body, said impeller having a paddle-shaped configuration;
• (c) dispersing said fluxing gas or said particles in said body by:
• (i) rotating said impeller in one direction;
• and thereafter
• (ii) reversing said direction of rotation of said impeller to a counter direction;
• and
• (iii) the direction of rotation of said impeller being reversed periodically to provide increased shear forces in said body for improved dispersion of said gas or said particles in said body.