METHOD FOR CONCENTRATION OF NOBLE METALS BY CUPELLATION MELTING AND METHOD FOR CUPEL MANUFACTURE Russian patent published in 1998 - IPC

FIELD: metallurgy; may be used in separation from crude lead of concentrated alloy of noble metals, such as, gold, silver and other. SUBSTANCE: method of concentration of noble metals includes oxidizing melting of crude lead in cupel from porous refractory material. Concentrated noble metals in the form of regulus are sent for separation of metals, and cupel is ground and subjected to reduction melting for separation of alloy part of noble metals got into cupel, and also of lead for its repeated use. The method of cupel manufacture for cupellation melting provides for porosity required for execution of the above-described method of concentration of noble metals. The method consists in that mixture of magnesite and kaoline is ground, mixed and placed into mold, moistened with sulfuric acid and pressed. EFFECT: reduced losses of noble metals, especially, in small volumes of melting. 4 cl