US1693642A - Method of treating metallic particles - Google Patents

Description

Patented Dec. 4, 1928.

UNITED-STATES eeann career caries.

GEORGE E. DALBEY, OF EAST BERLIN, AND THOMAS P. HANFORD, OF BERLIN, CON- NECTICUT, ASSIGNORS TO THE STANLEY CHEMICAL COMPANY, OF EAST BERLIN, CONNECTICUT, A CORPORATION OF CONNECTICUT.

METHOD OF TREATING METALLIC PARTICLES.

No Drawing.

This invention relates to a method of treating metallic particles.

More particularly the invention relates to the treatment of metallic particles of lead alloys containing arsenic, tin and antimony, or one or more of such metals. It is to be understood that the term alloy is intended to include impure lead in which the arsenic, tin or antimony appear as impurities.

l0 The metallic'particles to be treated may be derived from various sources and in various ways. For example, certain metallic dresses, which are subject to reclamation treatment, consist largely of alloys of arsenic, tin, an-

timony and lead. By known methods of concentration it is possible to separate the metallic particles. from these drosses. Such a source of metallic particles is referred to in a copending application filed of even date herewith, Serial No. 161,236.

i It is an object'of the present invention to provide a commercially economical method of treating the metallic particles referred to, to separate them into their component metals or into chemical compounds of such metals, thereby obtaining products of commercial value;

With this general object in view, the invention consists in the method which is here- 0 inafter described and then more particularly pointed out in the claims.

In carrying out the method of the invention, the metallic particles are subjected to the influence of an alkali metal hydroxide in 5 the presence of an oxidizing agent. In carrying out the invention to what is now considered the best advantage the metallic particles are continuously agitated in a water solution of caustic soda to which has been 40 added an oxidizing agent. This may be done in a rolling barrel or by other suitable means.

While various oxidizing agents may be used sodium nitrate or oxide of lead, e. g. litharge, have been found suitable.

In the use of sodium nitrate the metallics are oxidized and the resulting oxides combine with the caustic soda to form sodiummetal salts, e. g. sodium arsenate, sodium stannate, sodium antimonate and sodium plumbate.

In the use of an oxide of lead, such as litharge, the metals other than lead, e. g. arsenic, tin and antimony, are oxidized with Application filed January 14, 1927. Serial No. 161,235.

the consequent reduction of the lead oxide to metallic lead. It is probable that a certain amount of the lead oxide is reacted upon by the caustic soda to form some sodium plumbate or plumbite. The latter, however, itself reacts with the metallic arsenic, tin and antimony to cause reduction of the sodium plumbate or plumbite to metallic lead. And there is formed sodium salts of the other metals, e. g. sodium arsenate, sodium stannate and sodium antimonate.

Vhile the conditions under which these reactions are carried out may vary as to temperatures and pressures, room temperatures and atmospheric pressure have been found suitable. Such conditions, moreover, make for simplicity of apparatus and operation.

lVhatever the means of oxidation the results are the same except that metallic lead is precipitated when lead oxide is used.

As a result of the steps described the metallic particles are separated into their component metals or chemical compounds of these metals. The resulting solution or suspension of the sodium compounds, which may include free uncombined caustic soda, is capable of further treatment for the recovery of valuable products, for example, by the process disclosedin a copending application filed of even date herewith, Serial No. 161,238. Likewise the resulting sludge which may contain metallic lead can be further treated for the recovery of values.

What is claimed is:

1. The method of treating metallic particles of lead alloys containing one or more of the metals tin, antimony, arsenic, which comprises subjecting the particles, at temperatures substantially below the fusing oint thereof, to the influence of a water soution of an alkali metal in the presence of an oxidizing agent. i

2. The method of treating metallic particles of lead alloys containing one or more of the metals tin, antimony, arsenic, which comprises oxidizing the particles and causing the resulting oxides to react with caustic soda to form sodium salts of the metals, all at temperatures substantially below the ins ing: point of the metal particles.

3. The method of treating metallic particles of lead alloys containing one or more Mai 2 meson of the metals tin, antimony, arsenic, which all at temperatures substantially below the comprises subjecting the particles to the infusing point of the metal particles. fluence of a Water solution of caustic soda In testimony whereof, We have hereunto in the presence of an oxide of lead, whereby set our hands.

5 the oxide of lead is reduced to metallic lead and the oxides of the other metals react with GEORGE E. the caustic soda to form sodium-metal salts, THOMAS P, HANFORD.