Development Prospect of Salt Lake Resources.

Salt lake resources in China are mainly distributed in the northwestern areas. The three famous salt lakes in China are Inner Mongolia Salt Lake, Xinjiang Salt Lake and Qinghai-Tibet Plateau Salt Lake. There are 731 salt lakes with an area of over 1 [km.sup.2] and the total area reaches 27 834 1 [km.sup.2]. In salt lakes in China, lithium reserves hold the first place in the world, boron and magnesium reserves hold a leading position in the world.

Although quite a lot of salt lakes have been developed, both the production scale and the product variety are small. Qinghai Potassic Fertilizer Plant is mainly engaged in potassium chloride production and also uses brine to produce bischofite. Useful substances in the brine such as boron, magnesium and bromine have not yet been utilized. Xinjiang Salt Lake is famous for halite, mirabilite, thenardite, nitratine and kentite and is mainly engaged in the production of edible salt, trona, heavy soda and granular soda. Resources of Qinghai-Tibet Salt Lake mainly include halite, carnallite, borate salt, trona, mirabilite, water-based magnesium mineral and bischofite, but the comprehensive utilization of associated resources such as lithium, bromine and sulfur has not yet been made.

China has a serious lack of soluble potash. The proven potash reserves only account for 0.002% of the world total. Charhan Salt Lake is China's biggest potash salt lake with potassium chloride reserves of several hundred million tons. Other resources to be developed include solid potash mineral in Yunnan Simao, large-scale brine potash mineral recently discovered at lopnur and underground brine potash mineral in Sichuan. The annual consumption of potassic fertilizers in China has reached 3.0 million tons, accounting for 13.27% of the world total. Domestic products can only meet 5 - 6% of the demand and great quantities have to be imported from abroad each year. The import amount is expected to increase to 5.1 - 5.2 million tons in 2000. Based on the 3% grain output growth rate and the world average NPK ratio, the amount of 100% potassium chloride converted from the consumption of potassic fertilizers in 2020 will reach over 17.0 million tons. Even if the 1.0 million t/a second phase project of Qinghai Potass ic Fertilizer Plant is completed, the output can only meet one-quarter of the demand. There is therefore huge potential and market space for the development of salt lake potash resources.

The application of lithium and lithium salts in high-tech fields is ever expanding in the recent years. It is imperative to speed up the development of lithium resources. The proven lithium resources in China hold the second place in the world, only next to Bolivia. Brine lithium resources account for 79% of the total. The prospected brine lithium resources in Qinghai Salt Lake and Ximao Salt Lake alone are equivalent to the total proven resources in other countries. Abundant resources are the basis for the development of the lithium industry. The development of the lithium industry and the participation in international competition will bring new hope to the development of salt lakes in China.

The development of salt lake magnesium resources also has a bright prospect. Potash in Qinghai Salt Lake is the main potash source in China. There is 10 tons of magnesium oxide as byproduct for one ton of potassium chloride. The failure to make a comprehensive utilization of magnesium has caused waste of resources and pollution to environment. The conversion of the advantage in magnesium resources to the product advantage and the economic advantage also has a bright prospect.