II. Salt Lake Structure and Meteorology and Hydrology
The Lower Paleozoic metamorphic rock series, Mesozoic Jurassic and Cenozoic Tertiary are widely distributed in Laoshan, the periphery of Keke Salt Lake, and Hercynian granite and various dikes are also exposed. The periphery of the lake area is quaternary loose deposits such as diluvial, alluvial, aeolian and lacustrine deposits. The central part of the lake area is mainly composed of gypsum and rock salt deposited in the lake. The main strata exposed horizontally in the mining area are Quaternary gravel layer, sandstone layer, loam and clayey silt fine sand layer. Rock salt is a tilted bed of rock salt ore with solid and liquid phases, and there are 6 known rock salt ore bodies at most. The main seam is the first seam, which is layered in shape, with a length of Z3 km from east to west and a width of more than 4 km from north to south, covering an area of about 95 square kilometers. The seam is 1 ~ 15 meters thick, with a maximum thickness of Z7 meters, and most of the NaCL content is above 8%.
the lake surface of Keke Salt Lake is flat, with an altitude of about 31m, which is suitable for mechanized mining. The climate is continental arid, with annual evaporation (2152.2mm) much larger than annual precipitation (21.1mm), low relative humidity and large temperature difference. The annual maximum temperature is 22.9℃ from July to August, and the minimum temperature is-19℃ ~-23℃ from December last year to January next year, with an annual temperature difference of 41.9℃ ~ 46℃. The annual average relative humidity is 34% ~ 37%, which provides superior conditions for the formation and exploitation of reclaimed salt. It is an ideal salt chemical base with great development prospects and comprehensive development conditions of lake salt.
III. Formation of Salt Lake and Its Surrounding Environment
About 15 million years ago, when the Qaidam Basin was initially formed, it was originally a green kingdom with humid climate, abundant rainfall and lush plants. The Himalaya Mountain rises sharply, which is like an indestructible barrier, blocking the moist air in the northern Indian Ocean from the Qinghai-Tibet Plateau mercilessly, and the climate in the Qaidam Basin changes from wet to dry, and a large area of salt lakes is formed in the basin. The basin is an inland centripetal water system, which originates from the rivers in the surrounding mountains. Some of them leak into the basin edge and disappear, while others flow into the lowlands of the basin as lakes, which evaporate strongly, making the lakes become salt marshes or salt lakes. There are two kinds of brines in Keke Salt Lake: surface brines and intergranular brines. The lake water is only distributed in a small area in the northeast and southwest corner of the salt lake, and there is only temporary surface brines in the vast lake during the rainstorm. In general, the lake area is only 1.5 square kilometers. The porosity of the halite layer becomes 2% ~ 3%, which contains intergranular brine.
Because of rational development, emphasis on sustainable development, and protection of ecological environment, natural pastures are still preserved around Keke Salt Lake. In summer, herders graze by the salt lake, and there are various birds flying around in the wetland near the lake. Sometimes, wild antelope are seen inhabiting by the lake in groups, and the blue sky, snow-capped mountains, grasslands, sheep and salt lake form a beautiful picture. Here people can enjoy the natural beauty endowed by nature. Keke Salt Lake is slightly different from other salt lakes because it belongs to a "dry lake". Every year, except in summer, the lake is basically dry, and vehicles can gallop in the lake without any worries and enjoy the beautiful scenery of the salt lake. Here you can also see the patented three-stage washing production line of lake salt, the production of Wang Yi and the production process.
IV. Salt Lake Mining and Technological Development
The mining area of Keke Salt Lake is covered with accumulated sand or clay, with a thickness of 3. About centimeters. When mining every year, firstly, sand is removed, the salt cover is uncovered, and the salt is loosened by blasting, and then the primary salt layer with a thickness of 5-8 cm is broken for excavation production.
There is surface brine in the lake of Keke Salt Lake in summer and autumn, and the mining of primary salt is open-air operation. The salt fished out is washed in the brine in the salt pit nearby and piled on the salt cover, and shipped after the water is naturally dried, without going through the beach drying process. The production period is generally from April to September every year, and it can also be produced in March and October in good weather years. At that time, the production scale was very small, the equipment was simple, and the salt mining technology was very backward. The production tools used for salt mining are "three pieces", namely, shovel, spoon and rake. Manual operation is slow and inefficient, and only relying on manual salt fishing is backward, which directly affects the improvement of production level and product quality.
after p>2, after technical transformation and innovation, excavators were used in the production of Wang Yi, and the production efficiency was greatly improved. Mechanized mining technology has been realized and the production capacity has reached 1 million tons. It fundamentally improves the working environment, lightens the labor intensity and reduces the production cost.
in recent years, in the face of market changes, with the increasing demand for industrial salt, backward production technology can no longer meet the market demand. On the basis of introduction, digestion and absorption, through technical transformation and continuous innovation, the company has realized mechanization in mining, collection, irrigation and loading. The technological process is as follows: digging with a excavator in the lake-transportation when the car is short-washing-car transportation-washing and dehydration-lump collection-package filling-loading. Excavators enter the salt mining operation area for mining. After the first brine washing, water-insoluble substances such as sediment and silt are washed, and the contents of water-soluble impurities such as sulfate and calcium are reduced. After three-stage spray washing (fresh water spray washing industrial salt), the finished product is transported, and the whole production process is completed. After several months of brine control, all physical and chemical indexes can reach the national standard.
With the saturated evaporation of brine, new salt crystals are formed and deposited on the surface of salt lake in the pit where the raw salt has been fished under the conditions of dry climate, strong evaporation and no rain, snow and surface water supply. After a few years, it is filled with new salt, and the salt can be directly mined without peeling off the cover, which reduces the mining process of the new salt. As the raw salt for edible salt production, recycled salt is crystal white, with less water-insoluble substances and other impurities, good sense and pure taste. After washing and processing, it is a truly pollution-free natural green food.
v. Development prospects of salt lakes
(1) Accelerating the protective development of salt lakes is a long-term strategic goal in the future. At present, Keke Salt Lake is rich in resources (with a reserve of 1.26 billion tons), with a high content (with an average content of more than 9% of sodium chloride), and has a broad development prospect (it is one of the first green food production bases in China). The salt products in the salt lake are rich in trace elements (such as potassium sulfate, magnesium sulfate, calcium sulfate, gypsum, etc.), and the salt chemical industry (potassium chloride, magnesium chloride, etc.) has comprehensive utilization development value and economic and practical value. It is an ideal production base of high-end edible salt and edible salt green salt (containing various trace elements in human body), and it is a high-quality raw material salt and a real green food. In the future, we should adhere to the principles of resource conservation, scientific planning and sustainable development, rationally develop and utilize resources, improve the production skills and raise the technical level to ensure the long-term, sustainable development and effective utilization of salt resources.
(2) we should continue to accelerate the pace of industrial upgrading and product structure adjustment. Continue to intensify technological transformation, rely on scientific and technological progress, extend industrial chain, improve technical level and deep processing capacity, increase varieties of salt products, and form a diversified salt chemical product system.
(3) relying on rich resource advantages, accelerate the development of enterprises. The salt industry system will face major reforms, and the market economy situation will be unpredictable. In addition, during the "Twelfth Five-Year Plan" period, the expansion, integration and reorganization of large domestic enterprises will intensify. These new changes and new features also put forward new requirements and new hopes for us. We will rely on rich resource advantages and location advantages to intensify technological transformation, increase new products and comprehensively utilize and develop. Make full use of the preferential policies of the country to develop the western region, boldly forge ahead, seek a stronger and bigger development road, strive for new breakthroughs in the company's various economies, realize the goals of sustainable development and green development, and make Keke Salt Lake shine continuously.