CopperCopper can be described today and historically as one of the most important metals. It is found among the transition metals of the periodic table and is element 29, with the acronym Cu. Copper has been and continues to be an important metal because it contains a remarkable variation of desirable characteristics due to which it can be used in many fields, as seen throughout history. If copper is not completely suitable for the purpose it can be transformed into alloys such as bronze, cupronickel and brass which, depending on the ratios, different characteristics from the combined metals can be introduced/used. These three alloys all contain a majority of copper, but the ratios in which the metals are combined can be different. Copper is believed to be the first metal mined and used by man, with a copper pendant dating to 8700 BC found in the Middle East. Copper was a likely choice for early civilizations because it was a "soft" metal. This meant that, even without technology, tools, and knowledge, humans had the ability to shape copper into tools, armor, weapons, ornaments, and cooking utensils. However, as mentioned, copper is a relatively soft metal, so because of this it was not really ideal for armour, tools or weapons, so the discovery of the technique behind combining two or more metallic substances, i.e. an alloy, was a important innovation. Processes to extract copper from compounds were not developed until around 5000 BC, so the pure copper used came directly from what they found otherwise they might have used copper-containing ores. As time passed it was discovered that under the right conditions copper and tin could be combined into bronze by heating the metal... in the middle of paper... the concentration can cause asthma. Sulfur dioxide can also cause acid rain when it accumulates in the atmosphere. Resources like copper are limited throughout the earth. To date, approximately 12-13% of all known copper reserves have been mined. By recycling copper we reduce the demand for copper, this safeguards the environment by reducing the necessary mining and therefore saving the ecosystems that live on copper ore. Copper is an ideal recyclable metal because it is 100% recyclable, meaning it is not damaged or loses properties (e.g. strength, malleability, etc.) during the recycling process. The copper recycling process uses less energy than the extraction process; therefore toxins and other emissions, such as sulfur dioxide, are not released into the atmosphere. Recycling also means less waste, reducing landfills and waste dumping, therefore helping ecosystems.