# Iron: abundance and suitability of iron ore

> Where iron is found, and which ore is worth using


## Objectives

- State that iron is the fourth most abundant element in Earth's crust (5% by mass), after oxygen, silicon and aluminum.
- State that pure iron metal (90%) is found only in meteorites; in the crust, iron is found as ores.
- List the three factors that decide whether an iron ore is suitable for extracting iron.

## 1. Iron ores and extraction of iron




## 2. Important, but how common?

Predict: is iron also the most abundant element in Earth's crust?

- No: three elements are more abundant than iron ✓
- No: iron is rare, under 1% of the crust
- Yes: we use so much iron, it must be the most common

Iron is not the most abundant element in the crust: it is the fourth most abundant, after oxygen, silicon and aluminum, and forms about 5% of the crust by mass. Being the most used metal does not make it the most common.

[ar-EG] الـ iron مش أكتر عنصر موجود في القشرة الأرضية: هو الرابع في الوفرة بعد الـ oxygen والـ silicon والـ aluminum، وبيكوّن حوالي 5% من القشرة الأرضية بالكتلة. وإنه أكتر metal بنستخدمه مش معناه إنه الأكتر انتشارًا.
## 3. Fourth in the crust

Iron is the **fourth** most abundant element in Earth's crust, after oxygen, silicon and aluminum. Iron in Earth's crust The mass of iron increases gradually as we come close to Earth's core.


## 4. Pure metal? Only from space

Meteorites (rocks from space) Iron is found as pure metal (90%) only in meteorites. Earth's crust Iron is found in natural ores, not as metal. Iron ore A natural material in the earth's crust that contains iron compounds, mostly iron oxides, mixed with impurities (unwanted substances). In the crust, iron comes as ore, not as metal Iron is mined as pure metal.


## 5. Rank the crust's elements

Quick recall before we move on. Order these elements from most to least abundant in Earth's crust.


## 6. Is this ore worth using?

Not every iron ore is worth extracting. The first factor in its **suitability**: **1)** The iron percentage in the ore. Is the iron percentage enough? **2)** The composition of the impurities in the ore. **3)** The type of harmful elements mixed with the ore, such as sulphur, phosphorus and arsenic. Only the iron percentage matters when choosing an ore.


## 7. Meteorite or mine?

A lump of metal that is 90% iron is found lying on the ground. Where did it most likely come from?

- From space: it is a meteorite ✓
- From deep in the crust, where iron is more abundant
- From an iron ore deposit in the Western Desert

The lump most likely came from space as a meteorite: iron is found as pure metal (90%) in meteorites. In the crust, iron is found in ores, iron compounds (mostly oxides) mixed with impurities, not as lumps of metal.

[ar-EG] الحتة دي غالبًا جاية من الفضاء، يعني meteorite: الـ iron بيتلاقى على هيئة metal نقي (90%) في الـ meteorites. أما في القشرة الأرضية فالـ iron موجود في ores، يعني iron compounds (أغلبها oxides) مخلوطة بشوائب، مش حتت metal.
## 8. Pick the better ore

A student says: "Ore X is surely more suitable, because it has more iron." What is the best reply?

- Not so fast: the harmful elements and the impurities also decide suitability ✓
- Correct: the iron percentage is the only factor
- Wrong: an ore with less iron is always easier to use

The best reply is that the iron percentage is not the only factor: the suitability of an ore also depends on the composition of its impurities and on the harmful elements mixed with it. Ore X has more iron, but it carries a lot of sulphur, phosphorus and arsenic.

[ar-EG] أحسن رد إن نسبة الـ iron مش العامل الوحيد: صلاحية الـ ore بتعتمد كمان على تركيب الشوائب اللي فيه وعلى العناصر الضارة المخلوطة بيه. الـ Ore X فيه iron أكتر، لكن فيه sulphur و phosphorus و arsenic كتير.
## 9. Summary

Iron: 4th most abundant in the crust, after O, Si and Al. It forms 5% by mass. Pure iron metal (90%): only in meteorites. In the crust: ores, iron compounds (mostly oxides) mixed with impurities. Ore suitability: iron %, composition of impurities, harmful elements (S, P, As). Can you explain why an ore rich in iron might still be a poor choice? Suitability is decided by three factors, not by the iron percentage alone: the composition of the impurities and the harmful elements mixed with the ore (sulphur, phosphorus, arsenic) count too. Common exam item: the three factors that decide the suitability of an iron ore.



Chapter: Transition Elements (https://yaani.ai/en/learn/chemistry/chem-s3-en.ch1)
Source: https://yaani.ai/en/lesson/chem-s3-en.lesson-fe.occurrence