Chemical Engineering in Daily Life – Question 32: Why did our ancestors dry salt in pools rather than cooking it in pots? Standard answer already available
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This post was last edited by yjqin1 on 2015-9-24 22:31. Humans are salt-loving; no other land animal enjoys salt as much as humans do or relies on it in the same way. When asked about the secret to cooking well, a famous chef replied: Use good salt. Do you know why, during the Western and Eastern Zhou dynasties (the Spring and Autumn and Warring States periods), the states of Qi and Jin (Wei in the early Warring States period, and Zhao in the later period) were powerful? The answer is that they all produce salt. The people of Jin dried salt from Jiechi, while those of Qi dried salt from the underground brine in Laizhou Bay. Men are iron and food is steel; without salt, there’s no worry. During the Song and Liao dynasties, the Bai gou River served as a boundary; the Liao people could not obtain salt from Laizhou Bay in the Song dynasty, so they had to use water from the Bohai Bay to produce salt. Therefore, the salt fields in Hangu have been in use for over a thousand years. Here’s the question: why didn’t ancient people use large pots to produce salt, when they could have used salt pans for evaporation? It’s much slower that way, isn’t it? Salt can be harvested only once or twice a year. If a tsunami comes, or even just heavy rain, everything is ruined. Moreover, both the ancients and people today use several ponds connected together, gradually increasing the salinity of the water through repeated processes, with salt being collected only in the final pond. Why do we need to do this?
Increase the evaporation area; the larger the evaporation area, the higher the efficiency. Together with the effect of wind, the evaporation rate is further increased.
Increasing the evaporation area and enhancing the evaporation intensity aims to boost production capacity.
One more thing to add about teachers: In the southwestern region, due to the high humidity, there isn’t enough land available for salt pans, and the sunlight is insufficient; therefore, in ancient times salt was produced by boiling methods. Typical examples are the Sanghai Well in Zigong, Sichuan, and Heijing Town in Yunnan. As one moves towards the plateaus, where the sunlight is stronger, salt production by evaporation became possible. It’s a small town located in the Grand Canyon area, but I’m not sure of the exact location
I think it’s based on the principle of progressive concentration to reduce the workload
Thank you! I understand these. The Consulate General in New York has been sending me **geography magazines. We are working on a project for removing hydrogen sulfide using the gas-phase membrane method in wells. I also know the secrets of “tofu dipping sauce”. By the way, the salt well in my doctoral supervisor, Mr. Wang’s grandfather’s family, has been in use for over 400 years; it is called \"Si Jian Ban\". That well was dug after our ancestors sold four and a half pieces of property to fund its construction.
There is a Salt Industry History Museum in Zigong, Sichuan. In the early days, salt was also extracted by digging wells in Yunyang; back then, salt traders were all very wealthy people
Natural utilization of seawater for salt production: One method is to use infertile saline-alkali lands and natural evaporation to produce edible salt； Secondly, seawater contains not only sodium chloride but also other impurities such as magnesium chloride, magnesium sulfate, and sodium sulfate; if it is boiled in a large pot, won’t all these salts get precipitated along with sodium chloride? There are significant differences in their taste and the body’s needs for them: lol
A large proportion of table salt should be mineral salt; I think a lot of salt is produced through solar evaporation
Yes, when drying, a larger initial investment is required, such as for digging pits, whereas the manufacturing cost is relatively much lower. Just think about using boiling in a pot: depending on the solubility of salt, how much water needs to be evaporated for one ton of salt, and how much fuel will be consumed.
In the inland areas of ancient China, people used well salt, which was produced by boiling it in large pots. Sea salt in coastal areas is produced in the open air, relying on the thermal radiation of the sun to gradually concentrate seawater and precipitate salt through natural evaporation in large salt pans. Per product, more than 100 m3 of water needs to be evaporated to produce 1 ton of salt. The meteorological factors that affect sea salt production include evaporation, rainfall, temperature, humidity, as well as wind speed and direction.