Earth's Crust as the Source of Most Metals

Earth’s Crust as the Source of Most Metals

• The Earth’s crust is naturally rich in various metals. These metals are found in rocks known as ores.
• Most metals are found in the Earth’s crust as compounds, not as pure metals.
• An ore is a naturally occurring rock or mineral from which a specified metal can be profitably extracted.
• The most common ores we use are hematite (for iron), bauxite (for aluminium), chalcopyrite (for copper), cinnabar (for mercury), sphalerite (for zinc) and galena (for lead).
• The type and quantity of metal in an ore can greatly vary. Some ores have huge amounts of metals, while others have only tiny traces.
• For metal to be useful, it needs to be extracted from its ore. This process often requires a lot of energy and can be expensive.
• Metals at the top of the reactivity series, such as aluminium, are extracted using electrolysis.
• Metals found below carbon in the reactivity series, such as iron and zinc, are extracted through reduction using carbon.
• Extraction of metals contributes to environmental issues. Mining causes landscape damage, the use of large amounts of energy can lead to global warming, and waste from the mining process can lead to water and soil pollution.
• Ways to reduce impacts of metal extraction include recycling metals, improving efficiency of extraction processes, and using biological methods to extract metals.
• Rare metals, or those with low abundance in the Earth’s crust, are often more difficult and expensive to extract, but they may have unique properties that make them valuable in specific applications.
• Over time, as supplies of more common metals become depleted and technology for extracting rare metals improves, the extraction of these rare metals may become more common.