The Treasures of Tutankhamun and the Science of Metal Extraction

Discovery of the Tomb of Tutankhamun

• In February 1923, Howard Carter opened the tomb of Tutankhamun.

• Upon opening the door, Howard Carter revealed approximately 5000 amazing objects.

• Notable items found within the tomb include:

  • A spectacular gold mask.

  • A silver trumpet.

  • An iron dagger.

• The Discovery of King Tut is documented in resources such as "Tutankhamun His Tomb His Treasures" and "The Discovery of King Tut: The Burial Chamber & Treasury."

Materials and Metallurgy in the Tomb

• A great number of the belongings of Tutankhamun were constructed from solid gold.

• Other items were decorated with thin sheets of gold leaf.

• Many items were made of bronze, which is a metal alloy consisting of a mixture of two metals:

  • Copper.

  • Tin.

• Only a very few objects were made from iron, including a specific dagger and a set of chisels.

• Context of Iron in Tutankhamun’s time:

  • Iron was extremely rare during this period.

  • Iron objects were highly treasured as a result of this rarity.

Properties and Processing of Gold

• Panning for Gold:

  • Ancient Egyptians could have used the technique of panning for gold as they possessed all the necessary equipment.

  • Gold sinks to the bottom of a mixture during panning because the density of gold is much higher than that of the other materials present.

• Shaping Metal:

  • The Egyptians may have hammered the metal into a desired shape.

  • Alternatively, they could have melted the metal and poured it into moulds.

Principles of Metal Extraction and the Reactivity Series

• Utility of Metals:

  • Metals are used widely for a variety of different purposes.

  • The suitability of a metal for a specific use depends on its unique properties.

• Natural Occurrence:

  • Very few metals exist naturally in the Earth as a single element.

  • Most metals are found as ores within the Earth's crust.

  • A metal ore is defined as a rock containing the compound of the metal that is to be extracted.

• Native State Metals:

  • Metals that exist in their native state are very unreactive.

  • These metals appear at the bottom of the reactivity series.

  • Examples include Platinum, Silver, and Gold.

• Ore Grading:

  • High-grade ores contain a high percentage of the metal.

  • Low-grade ores contain a low percentage of the metal.

  • Extraction of metals from low-grade ores is considered less profitable.

Methods of Metal Extraction

• The choice of extraction method is dependent upon the reactivity of the metal relative to Carbon.

• Reduction by Carbon:

  • Used if the metal is less reactive than Carbon.

  • Carbon acts as a reducing agent.

  • Reduction is defined in this context as the loss of oxygen from a compound.

  • The Carbon reacts with the metal compound (usually a metal oxide) in the ore and displaces the metal.

  • This method only functions when Carbon is higher in the reactivity series than the target metal.

  • Example: Zinc                  $\text{Zinc Oxide} + \text{Carbon} \rightarrow \text{Zinc} + \text{Carbon Dioxide}$                  $2ZnO + C \rightarrow Zn + CO_2$         

  • Example: Iron                  $\text{Iron oxide} + \text{Carbon} \rightarrow \text{Iron} + \text{carbon monoxide}$                  $Fe_2O_3 + 3C \rightarrow 2Fe + 3CO$         

• Electrolysis:

  • An alternative method used if the metal is more reactive than Carbon.

Plenary Questions: True or False

• 1. Gold is near the top of the reactivity series.

• 2. The ancient Egyptians found gold in stream beds only.

• 3. Copper is above gold in the reactivity series, and below iron.

• 4. Extracting copper from its compounds involves heating substances to temperatures above $1000\,^{\circ}\text{C}$.

• 5. Iron is almost always found naturally in compounds.

• 6. Iron atoms are joined strongly to atoms of other elements in compounds.

• 7. Higher temperatures are needed to extract iron from its compounds than are needed to extract copper from its compounds.

• 8. Iron compounds are rare.

• 9. In the times of the ancient Egyptians, iron was precious partly because it was rare.

10. The properties of iron make it suitable for making weapons and tools.

Discussion and Extraction Analysis

• Extraction Feasibility:

  • Copper: Historically, every group managed to extract this metal.

  • The technology required for copper extraction is simple and was likely available to ancient civilizations.

• Comparative Melting Points:

  • It would have been easier for ancient people to melt copper than to melt iron.

  • This is because copper has a lower melting point than iron.

• Historical Value of Iron:

  • Iron was precious in ancient Egypt because it was rare and its extraction required more advanced technological conditions (higher temperatures) compared to metals like copper.