Given below are some statements contrasting Hydrometallurgy and pyrometallurgy. Which of the following are the advantages of Hydrometallurgy (leaching)?
Given below are some statements contrasting Hydrometallurgy and pyrometallurgy. Which of the following are the advantages of Hydrometallurgy (leaching)?
The correct options are
A As compared to pyrometallurgy, hydrometallurgy offers excellent chemical selectivity and flexibility.
B Hydrometallurgy predominantly involves much lower temperatures than pyrometallurgy.
D Unlike pyrometallurgy, leaching doesn't produce huge volumes of corrosive gases that pollute the environment.
First let us look at the significant downsides to pyrometallurgy:
It requires very high temperatures, refractory materials and reducing agents (mostly coke). Intermediate steps like roasting and smelting require different setups (furnaces) with distinctly different conditions. Further, a lot of corrosive and toxic gases are evolved throughout the process. These gases cause enormous damage to the environment.
On the other hand, Hydrometallurgy largely involves aqueous chemistry at temperatures not exceeding 150 degrees Celsius. Also known as leaching, it involves the selective dissolution of metals from their ores. It offers excellent control (chemical selectivity) through each step of the process and happens at a much slower rate (disadvantage). Hydrometallurgy requires specific chemical reagents to leach dilute solutions of lean ores (where the concentration of the metal is less). Although it does produce effluents, hydrometallurgy doesn't produce high-temperature gaseous effluents. Since we deal with different types of reagents and aqueous chemistry, this method does require extensive plumbing and much larger floor space (as compared to pyrometallurgy).
A
As compared to pyrometallurgy, hydrometallurgy offers excellent chemical selectivity and flexibility.
B
Hydrometallurgy predominantly involves much lower temperatures than pyrometallurgy.
D
Unlike pyrometallurgy, leaching doesn't produce huge volumes of corrosive gases that pollute the environment.
First let us look at the significant downsides to pyrometallurgy:
It requires very high temperatures, refractory materials and reducing agents (mostly coke). Intermediate steps like roasting and smelting require different setups (furnaces) with distinctly different conditions. Further, a lot of corrosive and toxic gases are evolved throughout the process. These gases cause enormous damage to the environment.
On the other hand, Hydrometallurgy largely involves aqueous chemistry at temperatures not exceeding 150 degrees Celsius. Also known as leaching, it involves the selective dissolution of metals from their ores. It offers excellent control (chemical selectivity) through each step of the process and happens at a much slower rate (disadvantage). Hydrometallurgy requires specific chemical reagents to leach dilute solutions of lean ores (where the concentration of the metal is less). Although it does produce effluents, hydrometallurgy doesn't produce high-temperature gaseous effluents. Since we deal with different types of reagents and aqueous chemistry, this method does require extensive plumbing and much larger floor space (as compared to pyrometallurgy).
