Human beings first collected brine and salt that existed in nature, including natural brine and rock salt on the surface, as well as salt naturally crystallized in seaside depressions, for consumption. More than 5,000 years ago, China began to scrape the salty soil from the seaside and pour brine and fry the salt. In areas with natural brine, the production method of "burning charcoal first, pouring it with salt well water, and scraping the salt" was used.
At the end of the Warring States Period, Sichuan began to dig wells, collect brine, and fry salt. Qi Guanzhong implemented the "official mountain and sea" policy, that is, salt was jointly produced by the government and the people, and all products were transported and sold by the government.
From the Han Dynasty to the Ming Dynasty, except for the period from the third year of the founding of Emperor Wen of the Sui Dynasty to the tenth year of the founding of Emperor Xuanzong of the Tang Dynasty, beaches, salt wells, and salt lakes across the country were opened. Although during the Sui and Tang Dynasties, the production of lake salt in Shanxi had formed a new process of "cultivating the border and watering in the sun". During the Song and Yuan Dynasties, the production of sea salt in Fujian had partially adopted the sun salt method. However, the production scale was small, the tools and equipment were simple, and the producers There is only simple collaboration between them, and they have always stayed in the state of small-scale production one by one.
During the Qianlong and Jiaqing years of the Qing Dynasty, the Zigong salt industry had entered the stage of capitalist factory handicrafts. After 1835, black brine wells, rock salt wells, and deep natural gas wells were successively dug, providing the salt industry with abundant raw materials and energy. Rock salt wells naturally dissolve and penetrate through the cavity. One well is filled with water and multiple wells are brine. This has promoted the cooperation of related well owners and greatly promoted the development of the handicraft industry in the salt area.
After the middle of the 19th century, some countries with relatively developed technology began to dig wells, collect brine, and make salt from mine salts; receive tides, make brine, crystallize, collect salt, and collect and transport sea salt; and lake salt. , mining of mineral salt, mechanical equipment has been adopted one after another, and the scale of production is expanding day by day.
In 1912, steam locomotives were used to draw brine. In 1925, Tianjin Hangu Salt Farm used diesel engines to drive water pumps to lift water. Some other sea salt areas also gradually began to use machinery, but the development was slow.
Extended information:
Raw materials for the salt industry
1. Sea water
The ocean area accounts for 70.8% of the earth’s total surface area. The average depth is about 3800m. More than 80 chemical elements have been found in seawater, forming a variety of dissolved salts, with a total salt content of about 3.5%. The content of sodium chloride is about 2.7%, which is an important raw material for salt production.
2. Rock salt
Solid phase sediment of sodium chloride in the earth's crust. It is formed by the gradual evaporation, concentration and deposition of salt-rich water bodies in closed or semi-closed sedimentary basins under favorable geological structures and arid climate conditions.
3. Salt Lake
Halite and brine deposits formed since the Quaternary period are distributed in the arid inland closed-flow areas of the world and are divided into two salt lake belts in the southern and northern hemispheres. The equatorial salt lake area is dominated by the salt lake belt in the northern hemisphere. Generally, they exist in solid phase and liquid phase, and there are also brine lakes and dry salt lakes.
4. Underground natural brine
When sedimentary rocks are formed, seawater sealed in mineral or rock gaps and cracks, brine condensed when underground salty mud cools, or underground dissolved filter salt A brine formed from similar minerals.
Baidu Encyclopedia-Salt Making