Table 1 Advantages and Disadvantages of the process
SODIUM SULFATE (SALT CAKE OR GLAUBER’S SALT)
Sodium sulfate decahydrate or commonly called as Glauber‟s salt is a white or colorless monoclinic crystals. It effloresces upon exposure to dry air, forming powdery anhydrous sodium sulfate. It is named in honor to the first person to produce the salt from Hungarian spring waters. The naturally occurring salt is called mirabilite. Glauber‟s salt is highly soluble in water. It has a salty and bitter taste. it is used medically as a component of laxative drugs. It is also used in producing dyes.
Production of Sodium Sulfate
The production of the salt is carried out by placing about half a ton of table salt in a hemispherical pan. It is heated by direct firing. An equal weight of concentrated sulfuric acid is then added and the following reaction takes place: NaCl + H2SO4 -> NaHSO4 + HCl
The hydrochloric acid that is produced is absorbed by water. The remaining products is raked into a muffle furnace, where the following reaction is taken place at a much higher temperature:
Process
Advantages
Disadvantages
1. Solar evaporation
- Thermal storage is incorporated into the collector and is of very low cost
- Very large surfaces can be built thus large scale energy generation is possible
2. Rock salt mining (Deep-Shaft Mining)
- melting thick layers of ice and snow
-It is impure and contains clay which cannot be removed easily. - can create large underground caverns
3.well brine mining (solution mining)
- The demand of manpower is low - The investment costs are low
- can create large underground caverns - If the geological and tectonical conditions are very difficult, the solution mining is not usable