Lesson Notes: METALS AND NON-METALS
1. Introduction to Minerals and Ores
1.1 Minerals
Minerals are naturally occurring chemical substances found in the Earth’s crust.
They are inorganic, solid, and have a definite chemical composition.
Examples: Quartz (SiO₂), Calcite (CaCO₃), Hematite (Fe₂O₃).
1.2 Ores
An ore is a mineral from which a metal can be extracted profitably.
Not all minerals are ores, but all ores are minerals.
Example:
Bauxite → an ore of aluminium
Haematite → an ore of iron
Difference Between Minerals and Ores
| Minerals | Ores |
|---|---|
| Naturally occurring compounds of metals. | Minerals from which metals can be extracted economically. |
| May or may not contain enough metal. | Always contain sufficient metal for extraction. |
| Example: Mica, feldspar. | Example: Bauxite, galena. |
2. Main Ores of Important Metals
2.1 Ores of Iron
Haematite (Fe₂O₃) – main ore
Magnetite (Fe₃O₄)
Limonite (Fe₂O₃·3H₂O)
2.2 Ores of Copper
Copper pyrite (CuFeS₂) – most important
Malachite (CuCO₃·Cu(OH)₂)
Cuprite (Cu₂O)
2.3 Ores of Silver
Argentite (Ag₂S) – main ore
Horn silver (AgCl)
Silver glance (Ag₂S)
2.4 Ores of Aluminium
Bauxite (Al₂O₃·2H₂O) – main ore
Cryolite (Na₃AlF₆)
Corundum (Al₂O₃)
3. Extraction of Metals from Their Ores (Brief Explanation)
The general process of extracting metals from ores is called metallurgy. It involves several steps:
3.1 Step 1: Mining
Ores are dug out from the earth through mining.
3.2 Step 2: Concentration of Ore (Ore Dressing)
The unwanted impurities (sand, soil, rocks) are called gangue.
Concentration means removing impurities to get pure ore.
Common methods:
Gravity separation
Froth flotation (for sulphide ores)
Magnetic separation (for magnetic ores like magnetite)
3.3 Step 3: Extraction of Metal from Concentrated Ore
Metal extraction depends on the reactivity of the metal.
A. Extraction of Moderately Reactive Metals
(E.g., iron, zinc, lead)
Method: Reduction of metal oxides using carbon, CO, or other reducing agents.
Example: Extraction of Iron from Haematite
Iron ore is mixed with coke and limestone and heated in a blast furnace.
Coke reduces iron oxide to iron.
Molten iron collects at the bottom and is tapped out.
B. Extraction of Highly Reactive Metals
(E.g., aluminium, sodium, magnesium)
Method: Electrolysis of molten compounds.
Example: Extraction of Aluminium
- Manufacturers dissolve aluminium oxide ($Al_{2}O_{3}$) in cryolite.
A high-voltage power source passes electricity through the molten mixture.
Aluminium metal collects at the cathode.
C. Extraction of Less Reactive Metals
(E.g., copper, silver, gold)
Method:
Roasting of sulphide ores
Reduction
Sometimes found in a native (free) state
Example: Extraction of Copper
Roasting of copper pyrite produces copper oxide.
Copper oxide is reduced to copper using carbon.
3.4 Step 4: Purification of Metals
Extracted metals may still contain impurities.
Purification is done by:
Electrolytic refining
Distillation
Liquation
Example: Pure copper obtained through electrolytic refining.
Conclusion (SEO-Friendly)
Metals and non-metals play a vital role in our daily lives. Understanding minerals, ores, and the main sources of important metals like iron, copper, silver, and aluminium builds a strong foundation in chemistry. A clear idea of the extraction steps helps students succeed in SEE/NEB exams and supports higher-level studies in science.
Practice : 📌 SEE MCQ Quiz – Metal and Non-metal