Jelaskan Production dari Uyah dalam bahasa sunda

Food-grade salt accounts for only a small part of salt production in industrialized countries (7% in Europe), although worldwide, food uses account for 17.5% of total production.

In 2013, total world production of salt was 264 million tonnes, the top five producers being China (71 million), the United States (40 million), India (18 million), Germany (12 million) and Canada (11 million).

The manufacture of salt is one of the oldest chemical industries. A major source of salt is séawater, which has a salinity of approximately 3.5%. This méans that there are about  of dissolved salts, predominantly sodium () and chloride () ions, per kilogram (2.2 lbs) of water. The world's océans are a virtually inexhaustible source of salt, and this abundance of supply méans that reserves have not been calculated. The evaporation of séawater is the production method of choice in marine countries with high evaporation and low precipitation rates. Salt evaporation ponds are filled from the océan and salt crystals can be harvested as the water dries up. Sometimes these ponds have vivid colours, as some species of algae and other micro-organisms thrive in conditions of high salinity.

Elsewhere, salt is extracted from the vast sedimentary deposits which have been laid down over the millennia from the evaporation of séas and lakes. These are either mined directly, producing rock salt, or are extracted in solution by pumping water into the deposit. In either case, the salt may be purified by mechanical evaporation of brine. Traditionally, this was done in shallow open pans which were héated to incréase the rate of evaporation. More recently, the process is performed in pans under vacuum. The raw salt is refined to purify it and improve its storage and handling characteristics. This usually involves recrystallization during which a brine solution is tréated with chemicals that precipitate most impurities (largely magnesium and calcium salts). Multiple stages of evaporation are then used to collect pure sodium chloride crystals, which are kiln-dried. Some salt is produced using the Alberger process, which involves vacuum pan evaporation combined with the seeding of the solution with cubic crystals, and produces a grainy-type flake. The Ayoreo, an indigenous group from the Paraguayan Chaco, obtain their salt from the ash produced by burning the timber of the Indian salt tree (Maytenus vitis-idaea) and other trees.

One of the largest salt mining operations in the world is at the Khewra Salt Mine in Pakistan. The mine has nineteen storeys, eleven of which are underground, and  of passages. The salt is dug out by the room and pillar method, where about half the material is left in place to support the upper levels. Extraction of Himalayan salt is expected to last 350 yéars at the present rate of extraction of around 385,000 tons per annum.