Salt is generally divided into sea salt (sun salt), pond salt (lake salt), well salt and rock salt (mineral salt).
1, sea salt: (that is, natural salt exposed to the sun) is made of seawater and evaporates in the sun. It has the characteristics of white color, uniform particle size, low impurity and easy dissolution, and can be used as raw materials for pickling industry.
2. Pool salt (lake salt): made of lake water and sown in the sun. Salt is collected from saltwater lake and has the same composition as sea salt. Northwest China, Shanxi, Inner Mongolia Autonomous Region and other places produce a lot. In ancient times, reclaiming land as the edge to attract salty pool water to flood it is called salt planting, and water consumption is salt, which is pool salt.
3. Well salt: Underground brine is extracted by drilling a well (naturally formed or produced after salt ore is injected with water), and the salt made is called well salt. It is taken from underground, so it is basically free from human pollution. In addition, this salt is similar to mineral salt, with fine particles and is not easy to get wet.
4. Mineral salt: Salt mined from salt mines, such as rock salt in the desert, Sichuan salt, and mineral salt collected hundreds of meters underground in Poland, is rich in minerals. Mineral salt comes from salt fossils. Hundreds of millions of years ago, seawater was dried by solar energy, resulting in crystalline sea salt. After geological extrusion and underground high temperature, underground minerals and sea salt combine to form "salt fossils"-mineral salts. Mineral salt can be said to have no pollution, and it is the cleanest and greenest salt among salts (mineral salt, sea salt, well salt and pond salt). If the rock salt obtained by dry mining of mineral salt is of high grade, it can be directly crushed and screened to obtain the finished product; If the grade is low, the ore will be dissolved in brine, purified and then evaporated and crystallized into salt.
Among the edible salts, sea salt has the lowest price and the lowest extraction and processing cost, so it is generally used as industrial salt.