Liquid-liquid extraction

Question 1

Stream products

Answer 1

• Extract- solvent rich solution containing the extracted solute ( S+A+c)
• Raffinate - residual feed solution containing little solvent and mainly carrier (C+a+s)

Question 2

Extraction over distillation

Answer 2

• Dissolved or complexed inorganic substances in organic or aqueous solutions
• Removal of a contaminant present in small concentrations
• A high-boiling component present in relatively small quantities in an aqueous waste stream
• Recovery of heat-sensitive materials, where extraction may be less expensive than vacuum distillation
• Separation of mixtures according to chemical type (related to solubility) rather than relative volatility
• Separation of close-melting or close-boiling liquids, where solubility differences can be exploited
• Separation of mixtures that form azeotropes
• Extraction of salts from polymer solutions
• Extraction of metal salts from low-grade ores
• Extraction of metal salts from wastewater
Recovery of nuclear fuels

Question 3

Lever arm rule

Answer 3

F/S = line(SM)/line(FM)

OR

F/M= line (SM)/line(FS)

• line= length

Question 4

Hunter-Nash method

Answer 4

1. Calculation of mixing point
   - plot F, S and M on tertiary diagram
2. Product mass balance
   - Find E1 and Rn ( line of E1 and Rn must go through M)
3. Calculation of operating lines