Chemistry 3.4.3 Extracting Metals

Study Notes

Extracting Metals Low in the Activity Series

Metals low in the activity series, such as mercury and copper, exhibit very low reactivity.
Oxides of these metals can be reduced to their elemental form through heating alone.
Cinnabar (HgS) is an important ore of mercury:
- Heating in air converts HgS to mercuric oxide (HgO).
- Further heating reduces HgO to mercury.
Chemical reactions for mercury extraction:
- (2 HgS(s) + 3 O_2(g) \xrightarrow{Heat} 2 HgO(s) + 2SO_2(g))
- (2HgO(s) \xrightarrow{Heat} 2Hg + O_2(g))
Copper is found in nature primarily as Cu₂S:
- Heating in air allows conversion of Cu₂S to Cu₂O.
- Further heating with Cu₂O yields elemental copper.
Chemical reactions for copper extraction:
- (2Cu_2S + 3O_2(g) \xrightarrow{Heat} 2Cu_2O(s) + 2SO_2(g))
- (2CuO + Cu_2S \xrightarrow{Heat} 6Cu(s) + SO_2(g))

Extracting Metals in the Middle of the Activity Series

Metals such as iron, zinc, lead, and copper are more reactive than those in the low activity series, falling in the middle range.
These metals often occur as sulfides or carbonates in nature.
Extraction processes generally favor using metal oxides over sulfides and carbonates due to ease of reduction.
Sulfide ores undergo roasting to convert them into oxides:
- This process involves heating strongly with excess air.
Carbonate ores require calcination to become oxides:
- Calcination involves heating strongly in limited air.
Example of zinc extraction:
- Roasting of zinc sulfide (ZnS):
  - (ZnS(s) + 3O_2(g) \xrightarrow{Heat} 2ZnO(s) + 2SO_2(g))
Carbon serves as a reducing agent in various metal extraction processes.

Description

This quiz covers the extraction of metals low in the activity series, focusing on their reactivity and reduction processes. Explore concepts using cinnabar and mercuric oxide as examples. Test your knowledge of the heating methods used to convert ores to metals.