PROCESS OF PREPARING A CAESIUM AND RUBIDIUM SALT SOLUTION HAVING A HIGH DENSITY

摘要

The invention relates to a process for producing a high-density concentrated caesium and rubidium salt solution. According to the invention, uncalcined pollucite and/or calcined epidolite are ground to a grain size < 0.1 mm, hydrothermally dissolve with Ca(OH)2 at a temperature of 200 to 280 .degree. C, a pressure of 20 to 40 bar and a suspension density of 4 to 15 % wt. in a period of one to three hours and a mol ratio of SiO2 to CaO ~ 1:2. The insoluble solids are filtered off and washed, calcium and lithium are removed by introducing carbon dioxide and filtering the deposited carbonates from the dissolution filtrate, the remaining solution is concentrated and the salts of caesium and rubidium are formed by the addition of an acid or acid anhydride up to a pH of about 6, the filtrate separated off after dissolution being us ed several times in the hydrothermal dissolution process.