Production: Salt can be extracted from seawater by drying salt.

Purification of crude salt:

Firstly, crude salt is dissolved in water,

Re-filtering (pay attention to one post, two lows and three inclinations),

Then excessive BaCl2 solution is added to remove Na2SO4: bacl2+Na2SO4 = = baso4 ↓+2 NaCl.

Then add excess NaOH solution to remove MgCl2: MgCl2+2 NaOH = = mg (OH) 2 ↓+2 NaCl.

Then add excessive Na2CO3 solution to remove CaCl2 and BaCl2 (two reaction equations): Na2CO3+CaCl2 = = CaCO3 ↓+2 NaCl Na2CO3+Bacl2 = = BacO3 ↓+2 NaCl.

filter

Finally, a proper amount of hydrochloric acid is added dropwise until no gas is generated, and PH can be detected by removing NaOH and Na2CO3 test paper. There are also two reaction equations: HCl+NaOH==NaCl+H2O.

2HCl+Na2CO3==2NaCl+H2O+CO2

Evaporating the solution to precipitate NaCl crystals.