Process of preparing a solution of cesium and rubidium salts

US5900221A · kind A · utility

Assignee

• Metallgesellschaft AG · DE

Inventors

• Hartmut Hofmann · Frankfurt am Main, DE
• Klaus Kobele · Dietzenbach, DE
• Horst Prinz · Friedberg, DE
• Klaus Schade · Wiesbaden, DE

Key dates

• Filing date: Sep 18, 1996
• Grant date: May 4, 1999
• Expiry date: Sep 18, 2016

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02P40/18
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

The process for preparing a cesium and rubidium salt-containing solution includes a hydrothermal digestion of an uncalcined pollucite and/or calcined lepidolite particulate having an average particle size up to 0.5 mm with an aqueous solution of Ca(OH).sub.2 in a suspension with a mole ratio of SiO.sub.2 to CaO of from 1:2.5 to 1:1.25 in a rotary tubular autoclave at a digestion temperature of 200 to 280.degree. C., under a pressure of from 15 to 65 bar and at a suspension density between 8 and 18% by weight for from 0.5 to 3 hours; filtering the suspension to remove insoluble solids and to form a digestion filtrate; adding at least one acid or acid anhydride to the digestion filtrate to adjust its pH to 6 and to form the cesium and rubidium salt-containing solution; and performing an evaporation after the hydrothermal digestion to obtain an increase in concentration of cesium salts and rubidium salts in the cesium and rubidium salt-containing solution and to adjust a density of the cesium and rubidium salt-containing solution to from 1.6 to 3.3 g/cm.sup.3. An optional aeration of the digestion filtrate with carbon dioxide to remove lithium and calcium ions in precipitated carbonat…