sodium chloride production, powder, UPR, ecoinvent 3.6, Undefined
Location: GLO - Global
This dataset represents the production of 1 kg of sodium chloride. Sodium chloride (NaCl) forms odorless cubic crystals. Depending on its degree of purity, the color varies between colorless when pure and white to gray when in the form of rock salt.
Sodium chloride has a huge variety of different uses. For example, salt is today the largest mineral feedstock consumed by the chemical industry. It is primarily used as a chemical feedstock for the production of chlorine and caustic soda in the chlor-alkali industry. Salt is also needed for the production of sodium chlorate and metallic sodium by electrolysis, and for the production of sodium sulfate and hydrochloric acid by reacting sodium chloride with sulfuric acid. Another very important area where sodium chloride is used is the human and animal nutrition, since all animals, humans included, need both sodium and chloride. Other relevant areas of use of salt are the maintenance and de-icing of roads as well as the conditioning of water.
In Europe, the possibilities for producing salt by solar evaporation are rather poor and concentrated around the Mediterranean area. Therefore, this dataset represents the production of dry sodium chloride by underground mining (51%) and by solution mining (49%). This dataset is based on data from a European salt producer, as well as literature.
References:
Althaus H.-J., Chudacoff M., Hischier R., Jungbluth N., Osses M. and Primas A. (2007) Life Cycle Inventories of Chemicals. ecoinvent report No. 8, v2.0. EMPA Dübendorf, Swiss Centre for Life Cycle Inventories, Dübendorf, CH,.
Gendorf (2016) Umwelterklärung 2015, Werk Gendorf Industriepark, www.gendorf.de.
Undefined unit processes (UPRs) are the unlinked, multi-product activity datasets that form the basis for all of the system models available in the ecoinvent database. This is the way the datasets are obtained and entered into the database by the data providers. These activity datasets are useful for investigating the environmental impacts of a specific activity (gate-to-gate), without regard to its upstream or downstream impacts.
For the production of dry salt, three different types of sodium chloride production methods can be distinguished namely, underground mining of halite deposits, solution mining with mechanical evaporation and solar evaporation. Their respective products are rock salt, evaporated salt and solar salt:
- Underground mining: The main characteristic of this technique is the fact that salt is not dissolved during the whole process. Instead underground halite deposits are mined with traditional techniques like undercutting, drilling and blasting or with huge mining machines with cutting heads. In a second step, the salt is crushed and screened to the desired size and then hoisted to the surface.
- Solution mining and mechanical evaporation: In this case, water is injected in a salt deposit, usually in about 150 to 500 m depth. The dissolution of the halite or salt deposits forms a cavern filled with brine. This brine is then pumped from the cavern back to the surface and transported to either an evaporation plant for the production of evaporated salt or transported directly to a chemical processing plant, e.g. a chlor-alkali plant.
- Solar evaporation: In this case salt is produced with the aid of the sun and wind out of seawater or natural brine in lakes. Within a chain of ponds, water is evaporated by sun until salt crystallizes on the floor of the ponds. Due to their natural process drivers, such plants must be located in areas with only small amounts of rain and high evaporation rates - e.g. in the Mediterranean area where the rate between evaporation and rainfall is 3:1, or in Australia, where even a ratio up to 15:1 can be found. There are some impurities due to the fact that seawater contains not only sodium chloride. That leads to impurities of calcium and magnesium sulfate as well as magnesium chloride. With the aid of clean brine from dissolved fine salt, these impurities are washed out.
As a fourth form on the market, the so-called 'salt in brine' may be found, which is especially used for the production of different chemicals. In this case, the solution mining technique without an evaporation step afterwards is used.
This dataset represents the production of dry sodium chloride by underground mining (51%) and by solution mining (49%) with modern solution mining technology (thermo compressing technology).
References:
Althaus H.-J., Chudacoff M., Hischier R., Jungbluth N., Osses M. and Primas A. (2007) Life Cycle Inventories of Chemicals. ecoinvent report No. 8, v2.0. EMPA Dübendorf, Swiss Centre for Life Cycle Inventories, Dübendorf, CH.
ecoinvent EULA