US 5,023,059 A · Recovery of metal values and hydrofluoric acid from tantalum and columbium waste sludge

Abstract

A metallurgical processing system for economically recovering metal values, such as columbium, tantalum, thorium, and uranium from dilute source solids, such as digestion sludges, by a series of steps including: 1) slurrying the source solids with dilute hydrofluoric acid to produce a solid phase and a liquid phase containing dissolved tantalum and columbium, then extracting tantalum and/or columbium from the liquid phase by means of a liquid ion-exchange process and then, additionally; 2) roasting the solid phase with sulfuric acid to recover and recycle hydrofluoric acid, leaching the roasted solids with dilute sulfuric acid to produce a disposable solid phase and a liquid phase containing thorium and uranium, and extracting thorium and uranium from the liquid phase by means of a liquid-liquid amine extraction process.

Claims44

Dependent claims

A process for recovering metal values from a source material containing at least tantalum and columbium which comprises:

(a) digesting the source material in concentrated hydrofluoric acid to form a slurry comprising a first aqueous phase containing tantalum and columbium values and a sludge containing entrained therein dissolved tantalum and columbium values along with insolubles;
(b) separating the first aqueous phase from the sludge;
(c) extracting the tantalum and columbium values from the separated first aqueous phase by ketone extraction;
(d) slurrying the sludge with dilute hydrofluoric acid to form a second slurry comprising a second aqueous phase containing the dissolved tantalum and columbium values and a residual slurry;
(e) separating the second aqueous phase from the residual slurry;
and
(f) extracting the dissolved tantalum and columbium values from the second aqueous phase using a liquid amine exchange agent.

4 more elements

Dependencies are inferred from the claim text.

Recovery of metal values and hydrofluoric acid from tantalum and columbium waste sludge

Life of this patent

Recovery of metal values and hydrofluoric acid from tantalum and columbium waste sludge

Life of this patent

Abstract

Claims44