What is the law of salt field distribution?

Great changes have taken place in the production mode of sea salt in China: from inefficient seawater drying to efficient brine drying. In 2004, China's sea salt output was more than 2 1 10,000 tons, including more than 7 million tons of sun-baked brine, making it the first sea salt producer in the world.

Due to the increasing output of basic chemical raw materials such as caustic soda and soda ash in China, the demand for sea salt is also increasing. It is estimated that the annual gap will be about100000 tons in the next few years.

The application and discovery of modern technology came into being.

Since ancient times, the production of sea salt in China has been based on seawater, and the practice of drying salt on the beach has been implemented. However, the production method of drying salt on the beach covers a large area, has a long production cycle, low output and low benefit. Especially in recent decades, coastal beach culture has swept the north and south, and sea salt production has been challenged.

Laizhou Bay Salt Area in Shandong Province is the earliest area in China and even in the world to use this kind of underground brine resources, which has a history of thousands of years, but it was in the stage of spontaneous exploitation before 1980s. Except for shallow exploration in a small area of Shouguang Yangkou Salt Field in 1957, only the salt industry department has studied the technology of making salt from underground brine, but has not done geological research. Since the late 1970s, China's coastal economy has developed greatly, and the supply of raw salt is in short supply. In the past, the drying of beach salt with low concentration seawater always relied on expanding the area of salt pan to increase the output, but this was bound to be restricted by the area of beach. However, the technical transformation of the old saltworks has large investment, slow effect and low efficiency, which can not meet the needs of development.

Therefore, the road to the great development of salt industry has turned to "drying salt on the beach" with obvious advantages.

The scientific research of underground brine came into being, and the comprehensive utilization of brine had a solid foundation.

1979, Shandong Province initiated a project for the first time to study the comprehensive utilization of underground brine along the coast of Laizhou Bay.

From then on, Han Yousong, a researcher at the Institute of Oceanography of China Academy of Sciences, founded the first Quaternary underground brine research group at home and abroad, and began to carry out geological basic research on underground brine in combination with production and development.

From 65438 to 0987, Han Yousong presided over the research of the experimental area, and with the support of the national fund and the provincial and municipal salt departments, on the one hand, he improved the theoretical research, on the other hand, he began to turn to the development and application research.

By 1993, they have basically completed the investigation and study of two coastal types in the northern coastal areas, and achieved considerable results: they found that underground brine distributed in the coastal plane, formed a large-scale ore belt around the coast, and concentrated in patches in the bay sedimentary basins in the coastal areas of the harbor, confirming its universal distribution characteristics.

Brine is produced in marine-continental sediments and belongs to coastal facies, which existed from late Pleistocene to Holocene.

Brine comes from seawater, formed in the regressive stage of transgression, and is formed by evaporation, concentration, aggregation, land-sea change and burial.

They found that modern coastal beaches are still producing brine, which was confirmed by field simulation tests. Based on this, they put forward the theory of "brine formation in coastal beach" and the hypothesis of "brine formation in shelf plain due to freezing" according to the evolution of quaternary paleomarine environment in shelf shallow sea and the paleoenvironmental characteristics of shelf plain during glacial low sea level, and finally completed the monograph "Introduction to Quaternary Coastal Underground Brine" published in 1996.

The output of raw salt quadrupled, and the problem of salt shortage was solved in one fell swoop.

Regarding the actual development and utilization, they also have quite clear medium-and long-term goals: the scenic spot of 1500 square kilometers has been demarcated along the coast of Laizhou Bay, which provides a basis for the site selection of three large-scale new and expanded salt fields; The original spontaneous depth expanded from 30 ~ 50 meters to 60 ~ 80 meters, which is the transgression layer of the third Quaternary. As a result, it has promoted the rapid expansion of the number and scale of development in salt areas, and realized the "well beach" in the whole region.

A series of effective scientific research, technical application and practical development have been carried out in an orderly manner, which has quadrupled the crude salt production in Shandong from 2 million tons since the 1980s to 8 million tons, and the annual output has reached 50% of the national sea salt production, which has reversed the contradiction between the supply and demand of crude salt in the coastal areas of China and played an active role in building the first salt industry and salt chemical production base in China in Laizhou Bay.

The theory gained from practice has brought about a successful new development of 100%.

The theory summarized from the production practice in Laizhou Bay, Shandong Province, and the successful experience in guiding the development prompted the research group to adapt to the reform of scientific research system, go out of Shandong from 65438 to 0988, turn from theoretical research to forecasting and discovering new brine distribution areas, and enter the second stage of combining theory with production.

Their forecast delineates the coastal plain of Bohai Bay 1000 square kilometers, and predicts the distribution area of Qingdao coastal prospect.

After investigation and exploration in cooperation with the geological and mineral departments, valuable brine was found in 13 saltworks, with a success rate of 100%. Among them, 2.5 billion cubic meters of brine reserves have been obtained, equivalent to 65.438+600 million tons of sodium chloride reserves.

Now, 30% of the newly discovered areas have been successfully developed. At the same time, Dalian Salt Industry Department also cited the theoretical achievements and development experience of Laizhou Bay Salt Area, and also found brine resources in Liaodong Peninsula, which have been successfully developed.

Theoretically, the output of crude salt increased by 20 million tons, creating benefits of 654.38 billion yuan.

It is a leap from Laizhou Bay to Bohai Sea. The discovery of brine in the coastal areas of ports is a breakthrough.

Previously, many marine geologists believed that the Quaternary paleoenvironment between the coastal plain and the harbor coast was quite different. There was only one transgression in the coastal area of the port in Holocene, and the Quaternary sediments were shallow and there was no valuable brine.

However, new research and findings have reached new conclusions and practical results.

199 1 year, in order to solve the serious salt shortage problem in Qingdao, the research group ventured to predict this scenic spot. It is based on the fact that although there is only a transgression layer with a thickness of 10 m or more on the coast of the harbor, and the formation time is less than 1 10,000 years, there is a Pleistocene continental layer with a thickness of 10 m or more ~ 20 m below it, which may be a favorable brine reservoir.

Practice has proved that this theoretical analysis is correct.

It is precisely because of this theoretical analysis that brine resources were found for Qingdao, which promoted the successful development in that year, promoted the development of salt industry and solved a major problem in economic construction.

With successful experience, they predicted several brine prospective distribution areas along the coast of East China and South China from 1993.

After preliminary investigation and exploration, brine has been found in Guangdong, Fujian and Guangxi.

During the period from 1995 to 10, the application of underground brine theory has guided the development and predicted the discovery and expansion of new deposits. According to preliminary statistics, the output of raw salt was increased by nearly 20 million tons, and the benefits were more than 654.38 billion yuan.

This achievement won the first prize of scientific and technological progress of China Academy of Sciences 1994 and the third prize of national scientific and technological progress 1995.

The second technological revolution in sea salt production has solved the Millennium problem of using salt in people's daily life, and also provided raw material guarantee for modern chemical industry.

A study by Han Yousong, a researcher at the Institute of Oceanography of China Academy of Sciences, proved that underground brine resources are widely distributed along the coast of China. The width of brine ore belt reaches 10 ~ 30 kilometers from the coastline to the land, and the buried depth is within 100 meters.

Using this research result, underground brine deposits 13 have been discovered along the coast of Bohai Bay and the coast of Jiaodong and Liaodong Peninsula, with brine reserves of 2.5 billion cubic meters, equivalent to salt reserves10.60 billion tons.

Groundwater with salinity greater than 50g/L is called brine, which is a liquid sedimentary deposit, mainly including deep ancient brine distributed in inland sedimentary basins (such as Triassic Zigong brine in Sichuan Basin), modern salt lake brine and shallow Quaternary coastal underground brine distributed in coastal areas.

The exploitation and utilization of underground brine resources in coastal zone is of great value and significance. It has changed the production mode of sea salt with seawater as raw material that has been used for thousands of years and opened up a new road for the development of salt industry.

Because it is known that the concentration of underground brine is 2 ~ 6 times higher than that of seawater, it can save 60% ~ 80% of the brine area of salt field, shorten the technological process by 40% ~ 60%, improve the disaster resistance, and increase the yield of raw salt exponentially, thus achieving the goal of high and stable yield.

The "well-beach salt drying" using underground brine is considered as the second technological revolution in sea salt production (the first revolution changed from seawater boiling to beach salt drying). At present, the development and utilization of underground brine in China has gradually expanded from Laizhou Bay salt area to Shandong, Hebei, Tianjin, Liaoning and other salt areas, and has been extended to coastal provinces and cities in East China and South China.

Researcher Han Yousong and his research group have made great achievements in the research on the distribution law, enrichment conditions and causes of underground brine resources in coastal areas. At first, they put forward the theory of "brine generation in coastal beach" and the hypothesis of "frozen brine generation in shelf plain", and successfully used these theories to guide production and development from 1988, predicted and delineated six prospective distribution areas of underground brine in China, including Qingdao, and determined 13. Among them, the prospective reserve of underground brine in Qingdao coastal area 135 square kilometers is about 220 million cubic meters, equivalent to about100000 tons of sodium chloride. After 1993, Huangdao Yantian made full use of underground brine to produce raw salt, and the output was more than twice as high as before. After Jimoqiao saltworks in Shandong and Huanghai saltworks in Jiaonan switched to underground brine to produce crude salt, the output also doubled.

The exploitation and utilization of underground brine resources has greatly promoted the development of sea salt production in China. This research achievement won the first prize of 1994 Scientific and Technological Progress Award of China Academy of Sciences.