Question/Answer session about water purification

Hard water treatment

Hard water treatment

by Sakib Shovon -
Number of replies: 0

Basically, a salt based water softener works to remove high concentrations of calcium and magnesium from water through a process called “ion exchange.” This process “softens” hard water by substituting the hardness minerals (calcium and magnesium) with sodium chloride (salt).                                                                       

Temporary hardness: 

1. Ca(HCO3)2 + Ca(OH)2 → 2CaCO3 ↓ +2H2O

2. Mg(HCO3)2 + 2Ca(OH)2 → 2MgCO3 +2H2O

3. MgCO3 + Ca(OH)2 → Mg(OH)2 + CaCO3       

                                                                                    

Permanent Hardness:   

  1. CaSO4 + Na2CO3 → CaCO3+ Na2SO4    
  2. MgSO4 + Na2CO3 → MgCO3+ Na2SO4   
  3. MgCO3 + Ca(OH)2 → Mg(OH)2 +  CaCO3 
To remove temporary hardness we need to boil the hard water but permanent hardness cannot be removed by boiling but can often be removed by chemical treatment