US2133327A - Process for refining lead which contains bismuth - Google Patents

Description

Patented a. 18, 1938 V UNITED STATES PATENT OFFICE PROCESS FOR REFINING LEAD'WHICH CON- TAINS BISMUTH Leon Eugene Jollivet, Marseille LEstaque, France, minor to Socit Miniere ct Mtallurgique de Penarroya, Paris, France France, a corporation of No Drawing. Application November 30, 1937, Serial No. 177,301. In France January 11, 1937 7 Claims. (01. 75-63) duces a partial elimination of bismuth in alloys v containing a high contentthereof.

The process which forms the subject of the present invention thus consists essentially in adding to lead which contains bismuth and which has been previously molten, magnesium and potassium in suitable quantities and then allowing the metal bath to cool' to near its temperature of solidi'lcation.

There is thus formed'a floating crust containing bismuth, magnesium, potassium and lead and which is separated from the bath of metal by any known process. I

This floating crust will contain, according to the proportions of magnesium and potassium used, the desired part of the bismuth contained, and up to the whole of the bismuth content, the bismuth content of the fused metallic lead being thus able practically to be brought to 0.001%.

After this treatment the lead always contains an excess of magnesium and potassium from which it can be freed by any known treatment for example with chlorine or water vapour.

For putting the process according to the invention into eflect, the magnesium and potassium may be employed in the state of pure metals or of alloys with lead or with other metals, and be added successively or simulteously to the bath of impure metal to be trea v If desired the proportion of magnesium or potassium utilized maybe diminished and this diminution be compensatedby an increase of potassium or magnesium taking care always to provide a simultaneous or successive addition of potassiumand magnesium; one may thus in particular confer upon the refining process additional advantages such for example as minimum cost of the reagents employed, greater ease in the treatment of the dresses, etc.

It should be noted that if thelead from which the bismuth isto be removed contains, besides bismuth, other impurities these may be partly or wholly contained in the dross with the bismuth.

However as at present there are eflicacious means for the separation of these other current impurities from impure lead, it may be more economical to separate from the lead to be treated the greater part of its other impurities before applying the process of the invention for the removal of bismuth. I

The-invention is illustrated in the following non-limiting examples.

Example 1 A lead containing 1350 grams of bismuth per metric ton is treated in the fused state with an addition of magnesium equal to 1520 grams per metric ton and an addition oil potassium equal to 975 grams per metric ton. After agitation and cooling to the neighbourhood of the temperature of solidification, the floating crust is separated. The lead obtained only contains 130 grams of bismuth per metric ton.

v I Example 2 A lead containing 590 grams of bismuth pe metric ton is treated as above with an addition of magnesium equal to 2220 grams per metric ton and an addition of potassium equal to 1240 grams per metric ton. After, cooling and separation of the'floating crust the lead obtained only contains'14 grams of bismuth per metric ton.

What I claim is:

'1. Process for refining .lead which contains bismuth, consisting in adding to the lead in the molten state magnesium and potassium, cooling the metallic bath to the neighbourhood of its solidification point and then separating therefrom the floating crust in which the bismuth has collected.

2. Process for refining H lead which contains bismuth, consisting in adding simultaneously to the lead in the molten state magnesium and potassium, cooling the metallic bath ,to the neighbourhood of its solidification point and then separating therefrom the floating crust in which the bismuth has collected.

3. Process for refining lead which contains bismuth, consisting in adding successively in either sequence to the lead in the molten state magnesium and potassium, cooling the metallic bath to the neighbourhood of its soli'dflcation point and then separating therefrom the floating crust in which the bismuth has collected. 7

4. Process for refining lead which contains bismuth, consisting in adding to the lead in the molten state magnesium and potassium. in the state of alloys with lead, cooling the metallic bath to the neighbourhood of its solidification point and then separating therefrom the floating crust in which the bismuth has collected.

5. Process for refining lead which contains bismuth, consisting in adding to the lead in the molten state magnesium and potassium in the state of alloys with other metals, cooling the metallic bath to theneighbourhood of its solidification point and then separating therefrom the floating crust in which the bismuth has collected.

6. Process for refining lead which contains bismuth consisting in adding to the lead in the molten state magnesium and potassium, cooling the metallic bath to the neighbourhood of its 1 solidification point, and then separating therefrom the floating crustin which the bismuth has collected, the proportions of magnesium and potassium being coordinated in the sense that the proportion of one may be varied within certain limits, this variation being compensated by a corresponding variation in the opposite sense in the proportion of the other. r

7. Process for refining lead which contains bismuth, consisting in bringing to simultaneous action on the lead in molten state magnesium and potassium, cooling the metallic bath to the neighbourhood of its solidification point and then separating therefrom the floating crust in which the bismuth has'collected.

LEON EUGENE JOLLIVET.