Lake Zabuye, Tibetan Plateau

Lake Zabuye lies in the ET Köppen high-altitude tundra zone  in the Gangdisi Mountains in the interior of the Tibetan Plateau The name of Zabuye Lake is also spelt as Drangyer, Zabayu, Zhabuye, Chabyêr or Chabyer, Tabie or Tchapia, sometimes with an additional suffix of "Tsaka" or "caka", which means "salt lake" in Tibetan.

The lake is fed by a combination of rain, groundwater and ice melt. The catchment area is 6,680 km², and the lake is surrounded by mountains with a height of 4,600–5,200 m above sea level. The northern part of the lake sump is fed via two inlets on its east and on the west, funnelling snow melt from the Rianglinag Mountains (6,364 metres). Current climate in this intermontane sump is cold and very dry, with annual precipitation of 199 mm and evaporation of 2342 mm.

Today, the lake is shrinking as indicated by terrace deposits above the present lake level with up to 14 terraces visible, but only the bottom seven have been evaluated via radiocarbon dating; terrace age increase from around 5,000 in the lowermost to 24,000 years at the top. Terrace layers from 10 to 14 rise to above 4,600 meters and suggest that earlier in the Quaternary the lake was open with a much larger area.

The lake is geologically interesting as the lithium content of the lake waters are so elevated that it is the only known lacustrine location in the world where lithium carbonate, zabuyelite, is a natural brine precipitate. When artificially concentrated, the crystallisation sequence of primary salts from a Zabuye lake brine at 25°C is :
halite (NaCl) --> aphthitalite (3K2SO4·Na2SO4) --> zabuyelite (Li2CO3) --> sylvite (KCl) --> trona (Na2CO3·NaHCO3·2H2O) and thermonatrite (Na2CO3·H2O)

The lake’s brine is naturally supersaturated with NaCl and other salts, so millions of metric tons of halite, potash, trona, and other minerals have accumulated on the bottom of the lake in the past few thousand years.

Aside from lithium carbonate, the lake brine has a high content of borax and also is saturated with respect to mirabilite and other alkali metal salts with a total content of 360-410 g/L. The approximate elemental concentrations in the brine in g/L are as follows: Na (160), K (60), Li (1.5), Rb (0.25), Cs (0.1), SO4 (20), CO3 (90), Cl (120), Br (3), I (0.02), B (3). Brine density is around 1.4 g/cm3 and pH about 10.

The lithium content of the lake brine is around 1.53 g/L, which nearly corresponds to the solubility limit of lithium carbonate in water and is the second-highest known Li value in a brine worldwide.

Production of zabuyelite from the salt lake brines began in 2004–2005, after exploration work for the mineral was initiated in 1982. In 1984, lithium was found in micro-fine lake sedimentsthat were considered amenable to refining in large quantities. Production started from a brine with 0.12% Li. The company involved with the extraction, Zabuye (Shenzhen) Lithium Trading Co., Ltd., was established in 1999, and currently employs 11–50 people with an annual  sales volume in excess of  $10 million. The plant on the lake edge (see inset) has a total annual capacity in excess of 5,000 tonnes and in 2008 produced 1,556.5 tonnes of lithium carbonate.


Crystal of zabuyelite


Pilot plant


Edge of lake Zabuye

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