A method for extracting rubidium chloride from kaolin tailings, comprising the following steps:
(1) add the ore sample to the vibrating disc mill for vibrating grinding for 4min, pass through a 300-mesh screen to obtain 95% mineral powder of -300 mesh; carry out disc grinding and crush the leaching agent CaF2, and pass through a 300-mesh screen; take 200g of ore The powder is mixed with 30g CaF2 leaching agent, and then added to 400ml of sulfuric acid solution with a mass fraction of 40%;
(2) Leaching conditions: leaching with 40% mass fraction of sulfuric acid and 15% mass fraction of calcium fluoride (the mass ratio of calcium fluoride and mineral powder), adding calcium fluoride and sulfuric acid to react to release F-, F- to mineral powder Decomposition occurs, the liquid-solid ratio (sulfuric acid: (mineral powder + calcium fluoride)) is 2:1, the leaching temperature is 95°C, and the leaching time is 6h, (the mass of sulfuric acid and calcium fluoride added is based on the mass of rubidium-containing minerals ), so that the rubidium ions in the mixture are fully leached; using calcium fluoride and sulfuric acid as leaching agents in the high temperature zone may be:
(3) the solution obtained in step (2) is subjected to vacuum filtration under the condition of incomplete cooling, and the obtained leaching residue is beaten and washed once (liquid-solid volume ratio 1.5:1), time 30min, and then the second pumping is carried out Vacuum filtration, rinsed twice with hot water (each rinse is about 50 mL) to obtain a colorless and transparent leachate;
(4) NaOH is added to the leachate obtained in step (3), and the leachate is neutralized to PH=7;
(5) Take 400 mL of leachate and slowly add soda ash solution while stirring, gradually adjust the pH of the solution to be slightly greater than 7.0, control the pH of the end point, continue to stir for 50 minutes after stabilization, let stand for 10 minutes, then vacuum filter, and rinse the calcium-removing residue with a total of 100 mL of water wash three times;
(6) 500 mL of the obtained leachate in (5) was evaporated and concentrated to 50mL to obtain a rubidium-enriched leachate;
(7) Through the process of crushing-acid leaching-washing-neutralization-decalcification-evaporation, the recovery rate of rubidium reaches 83%, which has a relatively high metal rate;
(8) The concentrated solution was mixed with 20 g/L of sodium hydroxide and alkalized as an extraction feed liquid. The organic phase was composed of t-BAMBP and sulfonated kerosene, and the concentration of t-BAMBP was 1.2 mol/L. Prepare 450mL extraction phase according to the above formula, and prepare 200mL of 5g/L NaOH solution as detergent and 300mL of 1mol/L HCl back-extract at the same time;
(9) the extractant and concentrated solution of above-mentioned preparation are mixed and stirred according to volume ratio O/A=1:3, after standing for stratification, respectively collect water phase and organic phase, then new organic phase and water phase are in proportion 1:3 mixing and stirring, standing for stratification, collecting the aqueous phase and the organic phase respectively, and repeating the countercurrent extraction for 3 times to obtain the loaded organic phase;
(10) The loaded organic phase obtained in (9) and the detergent prepared in (8) are mixed and washed according to O/A=8:1, the washing time is 5min, the washing is repeated twice, and the washing water is returned to step (6) for crystallization ;
(11) the organic phase after washing and the back extraction liquid obtained in step (8) were mixed and stirred for 5 min according to the volume ratio O/A=3:1, after standing for stratification, the aqueous phase and the organic phase were collected respectively, and the new The back-extraction liquid and the organic phase were mixed and stirred for 5min, and the aqueous phase and the organic phase were collected after standing for stratification, and the countercurrent back-extraction was repeated 3 times to obtain a rubidium-enriched water phase;
(12) through multistage countercurrent extraction-washing-countercurrent back-extraction, the recovery rate of rubidium reaches 97%, and the loss of rubidium in the extraction process is very small;
(13) the water phase obtained in the step (11) is subjected to evaporative crystallization, to obtain the crude rubidium chloride with higher impurity content compared to the purified rubidium chloride;
(14) the crude rubidium salt product obtained in the step (13) is added with water to heat up and dissolve, alkalization, extraction, and back-extraction are obtained to obtain the back-extract after concentrating, crystallization and filtration, so that most of sodium chloride and potassium remain in the mother liquor . Using the principle that potassium chloride and sodium chloride can dissolve in a small amount while rubidium chloride is insoluble in anhydrous alcohol, the rubidium chloride crystals are soaked and washed twice with anhydrous alcohol to obtain refined rubidium chloride.
