Objective: To prepare sodium chloride, magnesium chloride, calcium chloride and sodium sulfate. Soluble in water.

2 filtration: pour the crude brine into the filter along the glass rod.

Objective: To remove insoluble impurities from crude salt.

3. Evaporation: pour the clarified filtrate into an evaporating dish, put the evaporating dish on the iron ring of the iron frame, heat it with an alcohol lamp, and constantly stir the filtrate with a glass rod.

Objective: To obtain solid salt from solution.

Purification of crude salt

1. Experimental steps: dissolution, filtration and evaporation.

Second, the role of glass rod:

(1) Stir during dissolution to accelerate dissolution.

(2) Drainage during filtration.

(3) When evaporating, stir and heat evenly.

Third, filter attention points: one post, two low, three rely on.

4. Precautions for evaporation: glass rod is stirred, and the filtrate is evaporated by waste heat.

Put a small amount of raw salt into a beaker, add a proper amount of water and stir with a glass rod. After the original salt is completely dissolved, pour the turbid brine into the installed filter along the glass rod, and then heat the obtained filtrate in an evaporating dish until a large number of solids appear in the filtrate, and stop heating.