How do you make zinc ingot?

Zinc ingots are typically made through the process of smelting, which involves extracting zinc from its ore and casting it into ingots. Here's an overview of the industrial process:

1. Ore Processing: Zinc ores usually contain zinc sulfide (ZnS), zinc oxide (ZnO), or zinc carbonate (ZnCO3). The first step is to crush and grind the ore into a fine powder.

2. Roasting: The powdered ore is then roasted in a furnace at high temperatures to convert the zinc compounds into zinc oxide (ZnO) by driving off sulfur dioxide (SO2) or carbon dioxide (CO2).

3. Leaching: If the zinc is still not in a pure form, it may undergo leaching where the zinc oxide is mixed with sulfuric acid to form zinc sulfate solution, leaving behind impurities.

4. Purification: The zinc sulfate solution is purified by a series of chemical processes such as solvent extraction or electrolysis to separate zinc from other metals like iron, cadmium, and others.

5. Electrolysis: In this stage, known as electrowinning, the purified zinc sulfate solution is subjected to an electric current, causing zinc to deposit onto cathodes as pure zinc metal.

6. Casting: Once enough zinc has been deposited on the cathodes, it is removed and melted in a furnace. The molten zinc is then poured into molds to cool and solidify, forming zinc ingots.

7. Finishing: The ingots are allowed to cool completely and are often inspected for quality before being packaged and shipped for further use in manufacturing.

This is a simplified explanation of the complex process that occurs in modern zinc smelting plants. The exact steps can vary depending on the type of ore and the technology used by the processing plant.