Hydrometallurgical Extraction Processes

The video tutorial explains the recycling of E-Waste using the hydrometallurgy method. It covers the three main stages of hydrometallurgical extraction: pre-treatment, chemical treatment, and metal recovery. Various leeching agents like cyanide, acids, and ammonium thiosulfate are discussed, along with their properties and applications. The video also details methods for metal recovery, such as solvent extraction, electroplating, and ion exchange. Finally, it highlights the environmental benefits of hydrometallurgy, emphasizing its reduced hazardous waste generation and easier regulation.

What is the first stage in the hydrometallurgical extraction process?

• Metal recovery

• Chemical treatment

• Pre-treatment

• Leaching

What is the main purpose of the pre-treatment stage in hydrometallurgical extraction?

• To recover metals

• To form anionic complexes

• To physically separate metals from e-waste

• To dissolve metals

Which reagent is commonly used for dissolving precious metals like gold and copper?

• Citric acid

• Ammonium sulfate

• Potassium cyanide

• Nitric acid

Which of the following acids is NOT mentioned as a leaching agent?

• Nitric acid

• Sulfuric acid

• Phosphoric acid

• Hydrochloric acid

Which leaching agent is considered safe, non-corrosive, and non-toxic?

• Ammonium thiosulfate

• Acid

• Halide solutions

• Cyanide

Which leaching agent is noted for forming stable anionic complexes with metals like gold and silver?

• Cyanide

• Ammonium thiosulfate

• Halide solutions

• Thiosulfate

In the solvent extraction method, what is used to separate the metal from the leached solution?

• Absorbents

• Ion exchange resins

• An organic solvent

• An electrolytic cell

What is the role of an electrolytic cell in the electroplating method?

• To separate phases

• To bind metal ions

• To dissolve metals

• To electroplate pure metal on the cathode

Which method involves using ion exchange resins to recover metals?

• Solvent extraction

• Electroplating

• Ion exchange method

• Absorption method

What is a key environmental benefit of hydrometallurgical extraction?

• It is faster than pyrometallurgy

• It generates less hazardous waste

• It is more cost-effective

• It requires less energy