Development history of copper hydrometallurgy

    Copper hydrometallurgical Ancient China
About 10,000 years ago, humans began to use natural copper to make needles, beads, cones and so on. The earliest refining bronzes discovered so far are scrapers, cones, chisels, etc. unearthed in Iran. The age may be 3800 BC. The refining time of the bronze knives found in Gansu, China was about 2750 BC. In Cypress in 3000 BC, humans have used smelting methods to smelt copper.
The world of metallurgy has recognized that the process of wet copper smelting begins in China. The discovery of iron replacement copper reaction is far from the Western Han Dynasty. In the Han Dynasty, "Huainan Wan Bi Shu" was recorded under the volume: " Bai Qing got iron and turned into copper " . Bai Qing is a water scorpion. The replacement and extraction of metallic copper from natural copper-bearing water streams with iron began in the Tang Dynasty, and the industrial scale was formed during the Song Dynasty, when it was called the “ immersion copper method ” . Since the blue-green copper-containing water is called “ biliary water ” , the resulting copper is called “ cholesteric copper ” . According to the Song Dynasty history book "Song Hui to be drafted" recorded at the time of the southeast of the road to produce copper at the same time, only the Luzhou Water Field (now the north of Wengyuan County, Guangdong Province) an annual production of bile copper that reaches 800,000 kg, everywhere The sum is as much as 187: 442.7 thousand kilograms.
During the Northern Song Dynasty Yuanfeng and Yuanyou ( 1086~1094 ), an experienced copper smelter master also summed up the book "The Copper Dip", but unfortunately it has been lost. However, the "Organic Outline of Copper Immersion" written by later generations is still alive today. In the Southern Song Dynasty during the Jin Dynasty's invasion of the South, with the decline of the country, the biliary copper industry also declined ^[1] .
The development process of western copper hydrometallurgy
In Hungary the West's first wet copper plant in Europe near西莫尔尼兹(Schmollnitz) of a mine, the 15th century began to recover copper from the replacement of the water with iron ore. But Western Hydrometallurgical Tongchang recognized originator of Spain's Roe Tinto (Rio Tinto) mine, their first since 1752 for copper pyrite oxidation roasting and leaching, and then displaced from the leach solution Recover copper ^{[ 2 ]} .
According to records, a Spanish patent in 1854 was the production of copper by roasting, leaching and replacement. Possibly due to excessive contamination of the sulphur dioxide produced by roasting, they began to develop and use heap leaching techniques in the early 20th century, and the resulting leaching liquid flows through a series of wooden vats in which cast iron blocks are stacked.
In the 20th century, with the increasing demand for copper, people began to pay attention to the development and utilization of copper ore surface oxidized ore. The wet method has gradually become the main metallurgical method for treating oxidized ore, and has made great progress in leaching technology. However, even in the 1960s , major wet copper plants still used chutes as replacement reactors. Although there are improvements, if the bottom of the trough is a grid-like structure, the generated copper powder falls off the bottom of the iron. However, the mode of production still does not deviate from the labor-intensive mode that was formed hundreds of years ago. In particular, in the open chute, the solution and the scrap steel for replacement have a large contact surface with air, resulting in oxidation loss of iron, and the replacement iron consumption is 2.3 t/t of copper, and the production cost is still high. [next]
A cone-shaped displacement device (shown below) invented by Kennecott in the United States is a great advancement, resulting in a significant increase in mechanization. And because the contact between the solution and iron filings and air is reduced, the consumption of scrap iron per ton of copper is reduced to 1.6 t/t of copper. The iron dissolved in the solution during the replacement process is returned to the leaching pile, and the ferrous iron is gradually oxidized to high iron, which is precipitated on the surface of the ore after hydrolysis, and often has an adverse effect on the leaching. When the high-iron ions remaining in the solution are returned to the replacement process, the consumption of iron filings is increased. These are the disadvantages of the iron replacement method. The advantage is that the technology is simple and easy to grasp, so it is still used in small production so far.

    references
    1 Zhao Kuang Hua metallurgical chemical Ancient Chinese History of Science and Technology of China, chemistry volumes, Lugano tin chief editor Beijing: Science Press, 1998.179 ~ 183
2 Malouf , EE , in Internation Conference on Hydrometallurgy 1973 , Evans , DGL and Shoemaker , RSEd. , AIME , New York , 615~620 .

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