US 12,338,507 B2
Methods of recycling aluminum alloys and purification thereof
Xinyan Yan, Murrysville, PA (US); and Francis Caron, Portneuf (CA)
Assigned to ALCOA USA CORP., Pittsburgh, PA (US)
Filed by ALCOA USA CORP., Pittsburgh, PA (US)
Filed on Dec. 28, 2018, as Appl. No. 16/235,875.
Application 16/235,875 is a continuation of application No. PCT/US2018/000178, filed on Aug. 16, 2018.
Claims priority of provisional application 62/546,491, filed on Aug. 16, 2017.
Prior Publication US 2019/0136342 A1, May 9, 2019
Int. Cl. C22B 21/00 (2006.01); C22B 1/00 (2006.01); C22B 21/06 (2006.01)
CPC C22B 21/0092 (2013.01) [C22B 1/005 (2013.01); C22B 21/0069 (2013.01); C22B 21/06 (2013.01); C22B 21/066 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method comprising:
(a) melting aluminum alloy scrap, thereby producing a melt, wherein the aluminum alloy scrap comprises an initial iron content, wherein the initial iron content is at least 0.20 wt. % iron (Fe);
(b) adding an excess of manganese (Mn) to the melt, wherein the excess of manganese is an amount of manganese sufficient to produce both (i) iron-bearing intermetallic particles in the melt and (ii) a Mn-based aluminum alloy from the melt;
(c) forming iron-bearing intermetallic particles in the melt, wherein a first amount of manganese reacts with iron of the melt to form the iron-bearing intermetallic particles, and wherein a second amount of manganese remains in the melt in unreacted form, the second amount of manganese corresponding to an amount of the excess manganese employed in the adding step (b) required to create the Mn-based aluminum alloy from the melt;
(d) removing at least some of the iron-bearing intermetallic particles from the melt, thereby producing a low-iron melt with the second amount of manganese therein;
(e) solidifying the low-iron melt, thereby producing the Mn-based aluminum alloy having the second amount of manganese therein, wherein the Mn-based aluminum alloy comprises a purified iron content, wherein the purified iron content is less than the initial iron content and not greater than 0.5 wt. % Fe, and wherein the Mn-based aluminum alloy includes manganese as the predominate alloying ingredient besides aluminum.