Extraction And Separation Of Rubidium And Cesium Ion From The Lepidolite

The feed solutions were prepared by refluxing the calcined and uncalcined lepidolite with sulfuric acid. With ICP-OES and AAS determination, the concentration of rubidium and cesium ion in the latter increased 150 times and 80 times, but the concentration of lithium ion lowered by 20%. The main reason is phase structural transformation of calcined lepidolite ore. A sol-gel method was used to synthesize 35% ammonium tungstophosphate supported silicon oxide and the same loading amount ammonium phosphomolybdate. We made a contrast about their static adsorptive capability of rubidium and cesium ion, the results showed AWP/SiO2 was superior to AMP/SiO2. In dynamic experiments, impact factors of rubidium and cesium ion adsorption, dosage and loading amount of ammonium tungstophosphate supported silicon oxide, and concentration of the eluent (NH4)2SO4, were studied. We confirmed optimal conditions containing 0.7g and 35% 80～100mesh AWP/SiO2, 0.1mol·L-1 and 2 mol·L-1 (NH4)2SO4 for eluting rubidium and cesium ion, respectively. Under optimal conditions, the elution rates of Rb+ and Cs+ ions both reached up to 90% above.35% AWP/SiO2 still maintained a good adsorption effect on rubidium and cesium ion after three times used. Non-supported Prussian blue and 55% Prussian blue supported SiO2 were also synthesized through a sol-gel method. The effects of contact time, initial ion content, concentration of hydrogen ion, interfering cations K+ and NH4+ on rubidium and cesium ion static adsorption were investigated using non-supported Prussian blue and stimulant liquid in detail, and the results showed that distribution coefficients of rubidium and cesium ion both increased with the extension of contact time and were less affected by three other factors. Due to good dispersing performance of pure Prussian blue in water,55% PB supported SiO2 was selected in the column experiment. The results identified that 55% PB supported SiO2 had an excellent exchange capacity toward rubidium and cesium ion, but the maximum elution rates of them were 7% below using 0.5 mol·L-1 and 3.0 mol·L-1 H2SO4 as the eluents, and it indicated that the ion exchange interaction between them was basically irreversible. Eventually crude extraction rate of lithium ion in the feed solution was investigated. It was found that it was not proportional between crude extraction rate of lithium ion and volume of feed solution. The reason was that volume of feed solution was not controlled freely and that sodium sulfate and potassium sulfate couldn’t be thoroughly separated out when evaporated.