Lithium recovery from seawater

Several alternative methods proposed for lithium recovery from seawater use ion exchange after solar evaporation and fractional crystallization of NaCl, CaS04 and KCl MClj. In these instances, polymeric ion exchangers, such as highly cross-linked Dowex 50 (16% DVB) [110] or Retardion Ag II, A8 (copolymer of styrene and acrylic acid cross-linked... 

It is worth emphasizing the fact that the number of publications on lithium recovery from seawater is rising steadily. 

Abe, M., Chitrakar, R., and Tsiyi, M. (1993). Lithium Recovery from Seawater with Various Inorganic Ion Exchangers. Seventh Symposium on Salt 2, 17-21. 

The problem of lithium recovery from land-based hydromineral sources is very similar to the problem encountered in its recovery from seawater. Coprecipitation, extraction, and ion exchange, the methods used in both instances are practically the same. 

According to the latest estimates of Skinner [18], elements potentially recoverable from seawater are sodium, potassium, magnesium, calcium, strontium, chlorine, bromine, boron, and phosphorus because of their practically unlimited presence in the ocean. After improving respective technologies, recovery of the following elements is expected to become profitable as well lithium, rubidium, uranium, vanadium, and molybdenum. Additional profit can be gained since desalinated water will probably be obtained as a by-product. This could be important for countries with a very limited number of freshwater sources (e.g., Israel, Saudi Arabia). 

Lithium concentration in seawater does not exceed 0.17 mg/L. Nevertheless, the ocean is considered to be the most promising source of this element in the near future [107]. The overall inventory of lithium in the world s oceans is approximately 2.6x 10 tons [2]. With lithium so accessible, continual growth of lithium demand depends solely on new developments and expansion of its recovery from sea. 

Figure 10 Scheme of pilot unit for twtxtage recovery of lithium from seawater (see text). 

Ooi, K., Miyai, Y., and Katoh, S., Recovery of lithium from seawater by manganese oxide adsorbent, Separ. Sci. Technol., 21, 755, 1986. 

Y. Miyai et al, Recovery of lithium from seawater using a new type of ion-sieve adsorbent based on MgMn204 , Separation Science and Technology, 23(1-3), pp. 179-191, 1988. 

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