Extracting Salt From Inland Pans: A Natural Process

Salt is essential for human survival, and while it is easy to extract from seawater, it is less practical for those who live far from the coast. There are several methods for extracting salt inland, including harvesting it from rock salt deposits, brine springs, salt lakes, and even certain plants. One traditional method of inland salt production is the use of salt pans, where brine from natural brine streams is pumped from the ground and evaporated using the open-pan technique. This process has been used in various parts of the world, including the UK, France, Germany, Portugal, and the USA. Today, only a few complexes of inland open-pan salt works survive globally, showcasing the evolution of salt extraction techniques over time.

Extracting salt from sand

Salt is a crucial mineral for human survival, and while it is relatively easy to extract salt from seawater, this is only practical if you live near the coast. However, there are other methods of salt extraction, including from plants and inland salt pans.

Salt can be extracted from sand through a straightforward process. Here is a step-by-step guide:

• Mix equal parts of sand and salt: Measure out your portions carefully, as salt and sand mix very well. You can mix them by shaking or stirring the mixture.
• Add water: For every 10 grams of the sand-salt mixture, add about 100 millilitres of water, or just enough to cover the mixture.
• Heat the mixture: Place the mixture on a stovetop over medium heat. This will cause the salt to dissolve in the water. Stir the mixture if the salt forms clumps. Do not let the water reach its boiling point, as this will cause the water to evaporate.
• Strain the saltwater: Use a coffee filter and funnel to separate the saltwater from the sand. Set a funnel into a glass, and place a coffee filter inside. Pour the sand-water mixture into the filter and let it drain.
• Boil the saltwater: Return the salt to its original state by boiling the water. Continue boiling until all the water has evaporated, leaving the salt behind in the pan.

Other Methods of Salt Extraction

In addition to the above method, salt can also be extracted from brine using open pans. This method involves pumping brine from underground salt deposits and evaporating it using the open-pan technique. This process was traditionally used in a few locations where geological conditions preserved layers of salt beneath the ground.

Additionally, beyond natural deposits, salt can also be extracted from certain plants, especially those that are salt-tolerant. For example, Coltsfoot leaves can be dried, burned, and the resulting ash can be used as a salty seasoning for food.

Harvesting rock salt

Rock salt is mined from the ground. There are two main methods of mining rock salt: deep-shaft mining and solution mining.

Deep-Shaft Mining

This method of mining is similar to mining for other minerals. The salt exists as deposits in ancient underground seabeds, which were buried through tectonic changes over thousands of years. Many salt mines use the "room and pillar" system of mining. Shafts are sunk down to the floor of the mine, and rooms are carefully constructed by drilling, cutting and blasting between the shafts, creating a checkerboard pattern. After the salt is removed and crushed, a conveyor belt hauls it to the surface. Most salt produced this way is used as rock salt.

Solution Mining

Solution mining involves erecting wells over salt beds or domes (deposits of salt forced up out of the earth by tectonic pressure) and injecting water to dissolve the salt. The salt solution, or brine, is then pumped out and taken to a plant for evaporation. At the plant, the brine is treated to remove minerals and pumped into vacuum pans—sealed containers in which the brine is boiled and then evaporated until the salt is left behind. It is then dried and refined. Depending on the type of salt, iodine and an anti-clumping agent are added. Most table salt is produced this way.

Harvesting salt from brine springs and salt lakes

Salt is harvested from brine springs and salt lakes using solar evaporation ponds. These are shallow, artificial basins designed to extract salt from seawater, salty lakes, or mineral-rich springs through natural evaporation. Salt evaporation ponds are almost entirely located in warm climates with high evaporation and low precipitation.

Salt is traditionally made in two ways: rock salt is mined from the ground, and white salt is made by the evaporation of brine. Brine is obtained in several ways. Natural brine springs occur from the natural solution of rock salt by groundwater. Brine can also be pumped up to the surface at wells, shafts, or boreholes. Artificial brine is obtained through solution mining of rock salt with fresh water, known as 'controlled brine pumping'.

Salt lakes represent 23% of the area of all lakes on Earth and are among the most important natural resources globally. However, human activities such as salt harvesting can damage these lakes and their surrounding ecosystems. For example, the construction of causeways, evaporation ponds, and equipment and storage sites for tailings materials can cause environmental discomforts in the region and destroy the aesthetic appearance of the lake.

To avoid environmental degradation, an environmental impact assessment (EIA) is necessary to predict, assess, and reduce adverse environmental and social consequences of mining projects in the ecosystem of saline lakes.

The process of harvesting salt from inland salt lakes involves the following steps:

• Road construction to reach the site and transport trucks and trailers
• Digging salt from the lake bed, which can be over 1.5 m deep, using excavators
• Depositing the extracted salt as surface piles
• Evaporating water using solar energy
• Loading the trailers and trucks with harvested salt
• Transporting the salt away from the site

The environmental impacts of salt harvesting from inland salt lakes include:

• Changing the land use of the area
• Interference with the lake topography, hydrology, and water quality
• Increased traffic in the area
• Emission of toxic pollutants and substances into the air
• Social and cultural development
• Environmental arrangements

Extracting salt from plant ashes

Salt is an important nutrient that the body needs to function. While it is easy to extract salt from seawater, this is only practical if you live near the coast.

Salt can also be obtained from inland salt pans, which use brine from natural brine streams flowing over buried salt deposits that are pumped from the ground and evaporated using the open-pan technique.

However, if you do not have access to the sea or salt pans, it is possible to extract salt from plants, particularly those that are salt-tolerant and can bioaccumulate salt in their tissues.

Identify and Harvest the Plants:

Coltsfoot plants (Tussilago farfara) are easily identifiable by their yellow flowers, which resemble dandelions, and their hoof-shaped leaves with a smooth, waxy surface. They are commonly found in clusters along roadsides and ditches, especially in damaged, depleted soil.

Pick as many coltsfoot leaves as you can carry. You will need a large quantity since each leaf will only produce a small amount of salt.

Dry the Leaves:

Spread the coltsfoot leaves out in a sunny area and leave them to dry. They should feel brittle and turn a dull color when they are ready, which can take up to 3 days.

Roll the Leaves:

Take the dried leaves and roll them into tight cylinders without using any string or twine, as this will end up in your salt. Be careful as the leaves will be brittle, and you don't want to lose big chunks.

Burn the Leaves:

Hold the bundle of leaves horizontally and light one end with a match or lighter. Allow the flame to slowly progress down the leaves. You may need to blow on the flame gently to keep it lit.

Collect the Ashes:

As the leaves burn, tap the ashes that form into a container. Be careful to shield yourself from the wind, as a gust could scatter your ashes.

Use the Ashes as a Salt Substitute:

Once you have burned all the leaves, you will be left with a pile of sodium-rich ashes. These ashes can be added to your food as a source of salt. Note that they may not taste especially salty but are meant to provide sodium in survival situations.

This method of extracting salt from plant ashes is a traditional practice with a long history of use by indigenous people. While it may not be the most efficient way to obtain salt, it can be a valuable skill for survival in the wilderness.

Using salt in animal blood

Salt is an essential mineral for human survival, and while it is most easily extracted from seawater, this is only a practical method for those living near the coast.

Salt can also be obtained from inland salt pans, which use brine from natural brine streams flowing over buried salt deposits that are pumped from the ground and evaporated using the open-pan technique.

Salt is also present in the blood of animals, and historically, humans would obtain salt by consuming animal blood. However, this is no longer a common practice. Today, humans consume far more salt than is required, with an average intake of 9.5g per day, which is 2-200 times the estimated requirement.

There are several theories as to why humans have such a high salt intake, but no clear answer has been found. One theory suggests that salt may have stress-reducing properties, while another speculates that it may be due to genetic factors. Additionally, it has been observed that physical exertion and climate can influence salt intake, with athletes, soldiers, and workers in hot climates tending to have a higher salt intake.

While the benefits of salt are well-known, excessive salt consumption has been linked to various health issues, including hypertension, which is a major risk factor for cardiovascular disease. As such, it is important to regulate salt intake and maintain a balanced diet.

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