Tin, its Ores and Extraction | Chemistry for JAMB PDF Download

Properties and Uses of Tin

Properties

1. Physical Properties:

• Tin is a soft, silvery-white metal with a low melting point of 231.9°C.
• It is malleable, ductile, and exhibits a crystalline structure.
• Tin has a relatively low density of 7.3 grams per cubic centimeter.
• It is a good conductor of electricity and heat.

2. Chemical Properties:

• Tin has a stable oxidation state of +2 in most of its compounds.
• It is resistant to corrosion by air and water at ordinary temperatures.
• Tin reacts slowly with acids but dissolves rapidly in concentrated acids and alkalis.
• It can form various compounds, including tin dioxide (SnO₂) and stannous chloride (SnCl₂).

Uses

• Tin is commonly used as a protective coating for other metals to prevent corrosion, known as tin plating.
• It is an essential component in the production of solder, which is used for joining metals together.
• Tin is used in the manufacturing of various alloys, such as bronze (tin and copper) and pewter (tin and lead).
• Tin is a crucial ingredient in the production of tin cans and food packaging.
• It is used in the production of electronic devices, including circuit boards and semiconductors.
• Tin compounds, such as stannous fluoride, are utilized in toothpaste to prevent tooth decay.

Extraction of Tin from Its Ores

Ores

• The main tin ore is cassiterite (SnO₂), which is often found in association with other minerals, such as quartz and feldspar.
• Other tin ores include stannite (Cu₂FeSnS₄) and teallite (PbSnS₂).

Extraction Methods

1. Concentration of Ore:

• The ore is first crushed and ground to a fine powder.
• Gravity separation techniques, such as jigging or shaking tables, are employed to separate cassiterite from the gangue minerals.

2. Smelting:

• The concentrated ore is then subjected to smelting in a reverberatory furnace or a blast furnace.
• The smelting process involves heating the ore with carbon (usually in the form of coal) to reduce the tin oxide (SnO₂) to metallic tin.
• The carbon reduces the tin oxide, forming carbon dioxide (CO₂) and leaving behind molten tin.
• Impurities, such as iron, are removed as slag during the smelting process.

3. Refining:

• The obtained crude tin is further refined to remove any remaining impurities.
• One common refining method is called liquation, where the tin is heated and allowed to cool slowly, causing impurities to separate.
• Electrolytic refining may also be employed, where the tin is purified using an electrolytic cell.

4. Casting and Alloying:

• The refined tin is cast into ingots or other desired shapes for further use.
• Tin can be alloyed with other metals, such as copper or lead, to produce alloys with specific properties.

Conclusion

In conclusion, tin is a valuable metal with various properties and uses. It possesses physical properties such as being soft, malleable, and a good conductor of electricity. It also exhibits chemical properties like resistance to corrosion and the ability to form different compounds. Tin finds application in industries such as plating, soldering, alloy production, packaging, electronics, and dental care.
The extraction of tin from its ores involves several steps. The primary ore, cassiterite, is concentrated through gravity separation techniques. The concentrated ore is then smelted with carbon to reduce tin oxide to metallic tin. The resulting crude tin is further refined to remove impurities using methods such as liquation or electrolytic refining. Finally, the refined tin can be cast into desired shapes and alloyed with other metals.