Problem description:
What is the composition of copper ore?
Analysis:
The largest natural copper obtained in nature weighs 420 tons. In ancient times, people found natural copper, cut it down with a stone axe and hammered it into objects. So bronzes squeezed into the ranks of stone tools and gradually replaced them, ending the Neolithic Age in human history.
In China, the Xia Dynasty began to use red copper, that is, natural copper, 4000 years ago. It is characterized by a forging hammer. 1957 and 1959, nearly 20 bronzes were unearthed at Huangniangtai site in Wuwei, Gansu. Through analysis, the copper content in bronzes is as high as 99.63% ~ 99.87%, which belongs to pure copper.
Of course, the output of natural copper is scarce after all. The development of production urges people to find ways to obtain copper from copper mines. The total content of copper in the earth's crust is not large, not exceeding 0.0 1%, but copper-bearing minerals are common, and most of them have various bright colors, which attract people's attention. For example, bright green malachite CuCO3. Cu(OH)2, dark blue cerulete 2CuCO3. Cu(OH)2, etc. These minerals are burned in air to obtain copper oxide, and then reduced with carbon to obtain metallic copper.
1933, malachite weighing 1 8.8kg, charcoal block with diameter exceeding1inch, general helmet for smelting copper with pottery and cinder weighing 210.8kg were found in the excavation of Yin Ruins in Anyang County, Henan Province, showing the process of China ancient working people obtaining copper from copper mines more than 3,000 years ago.
But things made of copper smelting are too soft, easy to bend and soon dull. Then it was found that tin and copper were mixed to make copper-tin alloy bronze. The melting and manufacturing of bronze devices are much easier and more difficult than pure copper (if the hardness of tin is set at 5, the hardness of copper is 30, while the hardness of bronze is 100 ~ 150). Historically, this period was called the Bronze Age.
China's book Zhou Li Kao Gong Ji during the Warring States Period summarized the experience of smelting bronze and described the different proportions of copper and tin used in bronze casting of different objects: "Gold has six qi (prescription). Its gold (copper) and tin are six points in one, that is, the gas of Zhong Ding; Its gold and tin are divided into one, that is, the axe Jin Qi; Its gold and tin are divided into one, that is, the gas of Geji; Two-thirds of its gold and tin are in one place, which is called the gas of the big blade; Its gold and tin are in the second place, that is, cutting and killing arrows (arrows) together; Suk Kim is half, called a mirror (mirror) (using a mirror to gather light to make a fire). " This shows that more than 3000 years ago, the working people in our country have realized that different bronzes have different requirements for performance, and the proportion of metal components used to cast bronzes should also be different.
Because bronze is hard and easy to melt, it can be well cast and formed, and it is stable in the air, even in the Iron Age after the Bronze Age, it has not lost its use value. For example, around 280 BC, the bronze sun god stood in Rhodes Harbor on Rhodes Island in the Aegean Sea of Europe, with a height of 46 meters, which was higher than an adult's finger.
The working people in ancient China first used natural copper compounds to smelt copper by wet method, which is the origin of wet technology and an invention in the history of world chemistry. This method is expressed by modern chemical formula:
Copper sulfate+iron = ferrous sulfate+copper