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Copper objects (3 C, 17 P) G. Gold objects (11 C, 108 P) I. Iron objects (2 C, 8 P) L. Lead objects (1 C, 8 P) M. Metal rings (5 P) ... Metal bellows; Metal foam ...
There is evidence that iron was known from before 5000 BC. [15] The oldest known iron objects used by humans are some beads of meteoric iron, made in Egypt in about 4000 BC. The discovery of smelting around 3000 BC led to the start of the Iron Age around 1200 BC [16] and the prominent use of iron for tools and weapons. [17]
The base metal iron of the iron-carbon alloy known as steel, undergoes a change in the arrangement of the atoms of its crystal matrix at a certain temperature (usually between 820 °C (1,500 °F) and 870 °C (1,600 °F), depending on carbon content). This allows the smaller carbon atoms to enter the interstices of the iron crystal.
These pits may have been in use as far back as 8,000 years ago. This copper was mined and then made into objects such as heavy spear points and tools of all kinds. It was also made into crescent objects simular to bannerstones that some archaeologists believe were for religious or ceremonial purposes. The crescents were too delicate for ...
Carbon, tin, and lead are a few of the elements well known in the ancient world, together with sulfur, iron, copper, mercury, silver, and gold. [ 20 ] Silicon as silica in the form of rock crystal was familiar to the predynastic Egyptians, who used it for beads and small vases; to the early Chinese; and probably to many others of the ancients.
The earliest iron artifacts made from bloomeries in China date to end of the 9th century BC. [39] Cast iron was used in ancient China for warfare, agriculture and architecture. [9] Around 500 BC, metalworkers in the southern state of Wu achieved a temperature of 1130 °C. At this temperature, iron combines with 4.3% carbon and melts.
In volume, copper is the third most recycled metal after iron and aluminium. [47] As of 2023, recycled copper supplies about one-third of global demand. [48] The process of recycling copper is roughly the same as is used to extract copper but requires fewer steps.
Iron-carbon phase diagram. α-Iron is a fairly soft metal that can dissolve only a small concentration of carbon (no more than 0.021% by mass at 910 °C). [133] Austenite (γ-iron) is similarly soft and metallic but can dissolve considerably more carbon (as much as 2.04% by mass at 1146 °C).