Recovery of lithium from brines

Lithium carbonate from brines (i.e., solar evaporation processf. The recovery of lithium from brines is a less energy-intensive process and it is therefore extensively used where natural brines are found. Nevertheless, the methods of recovery used vary with the nature of the brines, especially the lithium concentration and the concentration of interfering cations such as magnesium and calcium. Brines are pumped from natural ponds (e.g., Chile, Argentina,... 

R.L. Retallack, Electrolytic recovery of lithium from brines, US Patent No. 

Production of Lithium Salts from Salar de Atacama Brine. Informacion Tecnologica 9(2), 245-251. Bukowsky, H., Uhlemann, E., and Steinbom, D. (1991). The Recovery of Lithium from Brines Containing more Calcium than Magnesium. Hydrometallurgy 27, 317-325. 

Recovery from Brines. Natural lithium brines are predominately chloride brines varying widely in composition. The economical recovery of lithium from such sources depends not only on the lithium content but on the concentration of interfering ions, especially calcium and magnesium. If the magnesium content is low, its removal by lime precipitation is feasible. Location and avadabiHty of solar evaporation (qv) are also important factors. 

The types of lithium - containing brines and technical solutions. Industrial technologies of the lithium recovery from brines. The selective extraction methods of lithium from brines and liquid wastes... 

Barrett, W. T., and O Neill, J. O. (1970). Recovery of Lithium from Saline Brines Using Solar Evaporation. Third Symp. Salt 2, 47-50. 

Vergara-Edwards, L., Parada-Frederick, N., and Pavlovic-Zuvic, P. (1985). Recovery of Lithium from Crystallized Salts in the Solar Evaporation of Salar de Atacama Brines. Lithium Current Appl. Sci., Med. Tech., pp. 47-59. Wiley, New York. 

Holdorf, H., Ziegenbalg, G., and Schmidt, B. (1993). Recovery of Lithium Compounds from Natural Salt Brines. Seventh Symposium on Salt 1, 571-595. 

Recovery Process. Lithium is extracted from brine at Silver Peak Marsh, Nevada, and at the Salar de Atacama, Chile. Both processes were developed by Foote Mineral Corp. The process at Silver Peak consists of pumping shallow underground wells to solar ponds where brines are concentrated to over 5000 ppm. Lithium ion is then removed by precipitation with soda ash to form a high purity lithium carbonate [554-13-2]. At the Atacama, virgin brine with nearly 3000 ppm lithium is concentrated to near saturation in lithium chloride [7447-41 -8]. This brine is then shipped to Antofagasta, Chile where it is combined with soda ash to form lithium carbonate. 

Trona concentrate is not technically classified as a mineral, but is rather the by-product of potassium and borax recovery from Searles Lake brine in California. The concentration of lithium in this brine is low (approximately 0.03% LiCl), and it would be uneconomical to process this brine for lithium values alone. The name Trona comes from the mixed crystal NaHCOs. Na2C03.2H2O, which is one of the products of Searles Lake. 

The Dead Sea is one of the world s largest and lowest inland lakes, containing a concentrated calcium-magnesium-sodium-potassium chloride brine, with about 10 ppm Li (Table 1.9) and reserves of about 2 milUon tons of Li. The brine is commercially evaporated in large solar ponds to produce potash in both Israel and Jordan, and their pond end-liquors often contain about 30 ppm Li. Some of this brine is processed for bromine and magnesia recovery, but most of it is merely returned to the sea. Because of its ready availability and potential value several laboratory studies have been made on lithium recovery from it, but without economic success. 

C to precipitate lithium carbonate. The end-liquor was next treated with a small amount of phosphoric acid and evaporated to nearly sodium sulfate s crystallization point, precipitating trisodium phosphate that was recycled to the licons leach step. The final solution then only contained <0.07% Li instead of its original 0.28% Li, and it was sent to the soda products plant. The operation produced about 900 mt/yr of lithium carbonate, with an overall recovery from the lithium in the brine entering the evaporators of about 30% (Rykken, 1976 Williams, 1976). The operation was terminated in 1978 after 40 years of production when the soda products plant was closed. 

With -butanol the Uthium extraction was the same at pH values from 1 to 11, although pH > 8 reduced the calcium extraction. The optimum ratio of solvent to brine was 1/1, among the ratios of 1/5 to 3.2/1 that were tested. As high as a 90% lithium recovery was obtained in four mixer-settler stages from solutions containing from 30-300 g/1 Uthium. 

Precipitating lithium from low-lithium brines with sodium phosphate has also been tested, after the model of licons being precipitated from Searles Lake brine. Tandy and Canfy (1993) smdied the precipitation of lithium phosphate from Dead Sea potash pond end-liquor, and found that perhaps a 70% Li recovery could be obtained. By adding over a 30-fold molar excess of disodium phosphate to the lithium in the brine, adjusting the pH to 6-7, heating to 80°C, and with a 20-30 min residence time about 76% of the lithium would be precipitated along with dicalcium phosphate and the excess disodium phosphate. The precipitate contained about 0.3% Li, and could be leached with water to recover over 90% of the Li, with the remainder being in the residual phosphate precipitate. The filtrate contained about 1440 ppm Li in a sodium phosphate-chloride solution (Table 1.34). 

Lithium may be recovered from natural chloride brines. Such recovery processes may require additional steps depending on the magnesium and calcium content of the brine. The process involves evaporation of brine, followed by removal of sodium chloride and interferring ions such as calcium and magnesium. Calcium is removed by precipitation as sulfate while magnesium is removed by treating the solution with lime upon which insoluble magnesium hydroxide separates out. Addition of sodium carbonate to the filtrate solution precipitates hthium carbonate. 

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