US 11,992,903 B2
Solder and method for producing high purity lead
Koen Govaerts, Beerse (BE); Pelle Lemmens, Beerse (BE); Kris Mannaerts, Beerse (BE); Jan Dirk A. Goris, Beerse (BE); Yves De Visscher, Beerse (BE); Charles Geenen, Beerse (BE); and Bert Coletti, Beerse (BE)
Assigned to METALLO BELGIUM, Beerse (BE)
Filed by METALLO BELGIUM, Beerse (BE)
Filed on Mar. 17, 2022, as Appl. No. 17/697,649.
Application 17/697,649 is a division of application No. 16/335,892, filed on Mar. 22, 2019.
Claims priority of application No. 16190907 (EP), filed on Sep. 27, 2016.
Prior Publication US 2022/0203482 A1, Jun. 30, 2022
Int. Cl. B23K 35/26 (2006.01); C22C 11/10 (2006.01); B01D 3/10 (2006.01)
CPC B23K 35/268 (2013.01) [B01D 3/10 (2013.01); C22C 11/10 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A process for the separation by distillation of a metal mixture containing lead (Pb) and tin (Sn), the process comprising the step of pre-treating a liquid molten metal feed composition,
a) the feed composition containing substantial portions of tin and lead and comprising at least 0.16% wt of the total of chromium (Cr), manganese (Mn), vanadium (V), titanium (Ti), tungsten (W), copper (Cu), nickel (Ni), iron (Fe), aluminium (Al) and/or zinc (Zn),
the feed composition having a temperature of at least 500° C.,
the pre-treatment step comprising the steps of:
b) cooling the feed composition down to a temperature of at most 825° C., to produce a bath containing a first supernatant dross which by gravity becomes floating upon a first liquid molten metal phase,
c) adding a compound selected from the group consisting of an alkali metal, an earth alkali metal, a chemical compound comprising an alkali metal, a chemical compound comprising an earth alkali metal, and combinations thereof, to the first liquid molten metal phase to form a bath containing a second supernatant dross which by gravity comes floating on top of a second liquid molten metal phase, and
d) removing the second dross from the second liquid molten metal phase,
whereby the liquid molten metal phase which is obtained as product from the pre-treatment forms the metal mixture containing lead (Pb) and tin (Sn) and further comprising, on a weight basis
at least 10% tin,
at least 45% lead,
at least 90% of tin and lead together,
more lead than tin,
at least 1 ppm and at most 5000 ppm of copper,
at least 0.42% of antimony (Sb),
at least 0.0001% wt of sulphur (S), and
at most 0.1% of the total of chromium (Cr), manganese (Mn), vanadium (V), titanium (Ti) and tungsten (W),
at most 0.1% of aluminium (Al),
at most 0.1% of nickel (Ni),
at most 0.1% of iron (Fe), and
at most 0.1% of zinc (Zn),
the process further comprising the step of subjecting the metal mixture to a distillation step wherein lead (Pb) is removed from the metal mixture by evaporation and a bottom product is obtained which comprises at least 0.6% wt of lead.