Zinc

Zinc is a bluish-white, lustrous metal. It is brittle at most temperatures but becomes malleable between 100 °C and 150 °C. It is a moderately reactive metal that combines with oxygen and other non-metals, and reacts with dilute acids to release hydrogen.

Description of what it is like

It has a silvery-grey appearance when oxidation is removed. It tarnishes in moist air to form a protective layer of basic zinc carbonate.

Origin and where to find it

• Environments: Zinc is rarely found in its native form. It is mostly found in ores, the most common being sphalerite (zinc sulfide).
• Signs: Sphalerite is often found in association with galena (lead ore), chalcopyrite (copper ore), and pyrite (iron sulfide).
• Requires transformation: It requires extraction from its ore.

Minimum processing required

1. Roasting: The ore is roasted (heated in air) to convert zinc sulfide to zinc oxide.
2. Reduction: The zinc oxide is then reduced with carbon (coal/charcoal) at high temperatures to produce zinc metal. The zinc boils off as a gas and is condensed.

Tools needed to work on it

• Furnace: Capable of reaching temperatures around 1000°C for reduction.
• Retorts/Condensers: To collect the zinc vapor.
• Molds: To cast the zinc into ingots.

Common forms of use

• Sheet: Rolled zinc for roofing or battery cases (anodes).
• Coating: Dipping iron/steel in molten zinc (galvanization) to prevent rust.
• Alloy: Mixed with copper to make brass.

Possible substitutes

• Tin: For coating steel (tinplate), though less effective as a sacrificial anode.
• Magnesium/Aluminum: As sacrificial anodes.
• Plastic/Composite: For non-structural corrosion resistance.

Limitations and common failures

• Zinc Pest: At low temperatures, tin-zinc alloys can degrade.
• Fumes: Breathing zinc oxide fumes during melting/welding can cause “metal fume fever”.

Risks and safety

• Fume exposure: Melting or welding zinc and galvanized steel can release zinc oxide fumes. Use strong ventilation and avoid breathing the smoke.
• Dust ignition: Fine zinc powder can ignite; keep sparks away and store it dry.

Related materials

• Brass: Zinc alloyed with copper.
• Copper: Brass partner and common companion metal.
• Lead: Often associated in the same ores as zinc.
• Steel: Commonly galvanized with zinc for corrosion protection.