Economic importance of scandium and titanium
Each use has a reason
1. Economic importance of the first transition series
2. Why titanium?
A dentist fixes a metal post into a jawbone, and it stays for years. Why titanium, and not just any hard metal?
Pick the right answer
Predict: why is titanium used in dental implants?
- A. It is the hardest metal
- B. It is inert, so the body does not reject it
- C. It is the cheapest metal
Explanation
Titanium is an inert substance: it does not react, so the body does not reject it and it causes no poisoning. That, not hardness or price, is the book's reason for using it in dental implants.
3. Small amounts, big value
Most transition elements are found in small amounts in the earth's crust. But they have high economic importance.
| Element | % wt in the earth's crust |
|---|---|
| Sc | 0.0026 |
| Ti | 0.66 |
| V | 0.02 |
| Cr | 0.014 |
| Mn | 0.11 |
| Fe | 5 |
| Co | 0.003 |
| Ni | 0.0089 |
| Cu | 0.0068 |
| Zn | 0.0078 |
Scandium is found in very small amount spread on a large area in the earth's crust.
4. 1- Scandium
Adding a little amount of scandium to aluminum gives a light and very hard alloy. An alloy is a metal mixed with other elements; you'll study alloys later. This alloy is used in MiG fighter jets.
- Aluminum + a little scandium → Light and very hard alloy
- Light and very hard alloy → MiG fighter jets (used in)
True or false?
MiG fighter jets are made of pure scandium.
Explanation
MiG fighter jets use an alloy: a little amount of scandium is added to aluminum, which gives a light and very hard alloy.
Scandium's second use
Scandium is also added to mercury vapour lamps. They give high-quality light that looks like sunlight.
- Mercury vapour lamp + scandium → High-quality light, like sunlight
- High-quality light, like sunlight → TV photography at night (used in)
5. 2- Titanium in aircraft
Titanium is as rigid as steel, but less dense than steel. Its alloys with aluminum are used in aircraft and space shuttles. Reason: it maintains its durability at high temperatures, while the hardness of aluminum decreases.
| Rigidity | Density | At high temperatures | |
|---|---|---|---|
| Steel | rigid | denser than titanium | — |
| Titanium | as rigid as steel | less dense than steel | maintains its durability |
| Aluminum | — | light | its hardness decreases |
A shuttle must be strong, light and heat-proof. Titanium covers aluminum's weak point: heat.
6. Titanium inside the body
Inert substance
A substance that does not react. The body does not reject titanium, and it causes no poisoning.
So titanium is used in dental implants and artificial joints.
True or false?
Titanium is used in dental implants and artificial joints because it is hard.
Explanation
The book's reason is that titanium is inert: the body does not reject it and it causes no poisoning. Many metals are hard, but inside the body the metal must not react.
7. Match the reason
Pick the right answer
A surgeon fixes a broken arm bone with a metal plate that stays inside for years. Which property makes titanium safe for this?
- A. It is inert
- B. It is as rigid as steel
- C. It is less dense than steel
- D. It maintains its durability at high temperatures
Explanation
A plate that stays inside the body must not react with it. Titanium is inert, so the body does not reject it and it causes no poisoning; rigidity, low density and durability at high temperatures are its reasons for other uses.
Pick the right answer
Give a reason: titanium-aluminum alloys are used in space shuttles.
- A. Titanium maintains its durability at high temperatures, while the hardness of aluminum decreases.
- B. Titanium is inert, so the body does not reject it.
- C. Titanium is denser than steel, so it is stronger.
- D. A little scandium is added to make the alloy light.
Explanation
A space shuttle faces high temperatures. Titanium maintains its durability at high temperatures, while the hardness of aluminum decreases, so titanium-aluminum alloys are used in space shuttles.
8. Titanium dioxide and UV
Remember: UV rays carry more energy than visible light. They can damage the skin.
TiO2
Titanium dioxide (TiO2) is used in sun protection cosmetics, where minute nanoparticles prevent the effect of UV on the skin.
True or false?
Sun protection cosmetics contain titanium metal.
Explanation
Sun protection cosmetics contain the compound titanium dioxide (TiO2) as minute nanoparticles that prevent the effect of UV on the skin, not titanium metal.
9. Who does what?
Sort into groups
Sort each use: scandium, titanium, or titanium dioxide?
Added to mercury vapour lamps for TV photography at nightA little amount added to aluminum for MiG fighter jetsAlloys with aluminum for space shuttlesArtificial jointsSun protection cosmetics
Fill in the blanks
Titanium is used in artificial joints because it is an _____ substance, so the body does not reject it.
Explanation
Inert: it does not react, so the body does not reject it and there is no poisoning.
10. Summary
Back to the dentist: titanium is chosen because it is inert, not just because it is hard.
| Substance | Property / reason | Use |
|---|---|---|
| Scandium | a little added to aluminum gives a light and very hard alloy | MiG fighter jets |
| Scandium | added to mercury vapour lamps: high-quality light that looks like sunlight | TV photography at night |
| Titanium-aluminum alloys | titanium maintains its durability at high temperatures, while the hardness of aluminum decreases | aircraft and space shuttles |
| Titanium | inert: the body does not reject it; no poisoning | dental implants, artificial joints |
| Titanium dioxide | minute nanoparticles prevent the effect of UV on the skin | sun protection cosmetics |
Can you explain why titanium, and not just any hard metal, is used in artificial joints?