Up to now, the earliest copper products discovered in the world are mainly found in western Asia, such as in Iraq's zawy qomi region, with bronze ornaments, dating from about 10,000 B.C. to 9,000 B.C. Bronze ornaments have also been found in ali kashgar area in western Iran, dating from 9000bc to 7000bc. In southern Turkey, copper needles and cones were unearthed at the chayoni site, dating to around 8,000 BC. These copper products are made from natural copper, not from smelting ore.

From the use of pure copper, to the extraction of copper ore to the extraction of bronze alloy, mankind has experienced a rather long time of exploration, like the magic world of copper bit by bit to create a shimmering space-time tunnel.

China's shaanxi province is the world's first discovery of copper smelting. In 1973, a semicircular brass plate and a brass tube were found in the cultural site of jiangzhai, lintong, shaanxi province, dating to around 4700 BC. Worth pointing out that light source in Shanghai recently, using X-ray fluorescence scanning analysis, found that the zinc content in different areas of the village of brass slices ginger significant difference, and the distribution is scattered point lead element, its characteristics and solid state reduction method of brass are exactly the same, thus proving ancestors in the use of natural between metal and metal casting invention, have hot calcined method or solid reduction method smelting metal.

China's first use of the yellow cast money started in the Ming jiajing years.

The word "brass" was first used in the "shen yi jing · zhong huang jing" written by dongfang shuo in the western han dynasty.

This "brass" refers to what copper alloy is to be tested. "New tang book · food and goods record" also has the title of "bronze", "brass", respectively refers to the ore color and the smelting product, the pit has special name, the mountain many primitive simplicity ", refers to the fire refining pure copper.

The word brass refers specifically to copper and zinc alloy, which began in Ming dynasty, and is recorded in the Ming dynasty conference book: "in jiajing, there are six million words of tongbao money, and a total of forty-seven thousand two hundred and seventy-two jin of brass... ." Based on the analysis of the composition of the copper COINS in Ming dynasty, it was found that the brass in the sense of casting was much later than the other copper alloys.

Zinc oxide under the high temperature of 950 ℃ 1000 ℃ can quickly be back into the metal zinc, and zinc liquid at 906 ℃ has been boiling, so the reduction of metal zinc to vapor exists. During cooling, the reaction is reversed. Steam zinc is carbon dioxide in the furnace and oxidized to zinc oxide. This is the reason that the use of metallic zinc is much later than that of copper, lead, tin, and iron, and is one of the reasons that brass COINS appear late.

During the shang and zhou dynasties, the amount of zinc in copper is very low, generally in the order of 10-z. In the western han dynasty and xinmang's money, there were some individual copper, zinc and sweet COINS, some of which contained 7% zinc, but this did not indicate that the copper COINS originated in the xinmang period of the western han dynasty. Because these copper-zinc alloys are extremely rare, they generally contain much less zinc than the true brass, about 15% to 40%. Therefore, we believe that these copper COINS containing zinc were produced during the use of copper-zinc ore in the han dynasty. According to the investigation of related mines, it is found that there are abundant copolymers of copper and zinc in changwei, yantai, linyi and hubei in shandong, which makes the copper after smelting contain a small amount of zinc. In the tang dynasty, due to the standardization of the casting materials, the contents of zinc in the COINS were constant.