White copper wiping
When the content exceeds 16%, the color of the alloy becomes as white as silver, and the higher the nickel content, the whiter the color. The content of nickel in white copper is generally 25%.
In 2008, the market price of white copper was 65,500 yuan/ton. 65.5 yuan/kg 0.065 yuan/g
merits and demerits
Adding nickel to pure copper can significantly improve the strength, corrosion resistance, hardness, resistance and pyroelectricity, and reduce the temperature coefficient of resistivity. Therefore, compared with other copper alloys, white copper has excellent mechanical and physical properties, good ductility, high hardness, beautiful color and corrosion resistance.
White copper landscape ink cartridge
With rich deep drawing properties, it is widely used in shipbuilding, petrochemical industry, electrical appliances, instruments, medical devices, daily necessities, handicrafts and other fields, and is also an important alloy of resistors and thermocouples. The disadvantage of white copper is that the main added element-nickel is a scarce strategic material, and its price is relatively expensive.
Nickel white copper (copper-nickel-zinc alloy), uses: crystal oscillator shell, crystal shell, potentiometer slider, medical machinery, building materials, etc.
classify
A, complex white copper:
White copper alloys containing elements such as manganese, iron, zinc and aluminum are called composite white copper (that is, white copper containing more than three elements), including iron white copper, manganese white copper, zinc white copper and aluminum white copper. In complex white copper, the symbol of the second principal element and the number group of components other than copper content indicate the content of various elements. For example, BMn3- 12 indicates that the nickel content is about 3% and the manganese content is about 12%. There are four types of complex white copper:
① white iron and copper: the models are BFe5- 1.5(Fe)-0.5(Mn), bfe10-1(Fe)-1(Mn), bfe30-1(Mn) The addition of iron in white iron copper does not exceed 2%, which prevents corrosion and cracking. It is characterized by high strength and can obviously improve the corrosion resistance, especially the corrosion resistance of flowing seawater.
White copper hand stove
② Manganese white copper: the models are BMn3- 12, BMn4.0- 1.5 and BMn43-0.5. Manganese white copper has a low temperature coefficient of resistance, can be used in a wide temperature range, and has good corrosion resistance and good processability.
③ Zinc white copper: models are BZn 18- 18, BZn 18-26, BZN18-15-12 (Zn)-65438+. Zinc-white copper has excellent comprehensive mechanical properties, excellent corrosion resistance, good cold and hot formability and machinability. It can be made into wires, rods and plates, and used to manufacture precision parts in the fields of instruments, meters, medical instruments, daily necessities, communications and so on.
④ Aluminium white copper: models are Bal 13-3 and Bal 16- 1.5. It is an alloy formed by adding aluminum on the basis of copper-nickel alloy, and its density is 8.54-0.3. The properties of the alloy are related to the ratio of nickel content to aluminum content in the alloy. When Ni:Al= 10: 1, the properties of the alloy are the best. Commonly used aluminum-white copper is Cu6Ni 1.5Al, Cul3Ni3Al and so on. , mainly used in shipbuilding, electric power, chemical industry and other industrial sectors of various high-strength corrosion-resistant parts.
Second, ordinary copper:
Copper-nickel binary alloy (namely binary white copper) is called ordinary white copper. In ordinary white copper, the letter B indicates the nickel content, for example, B5 indicates that the nickel content is about 5%, and the rest is about copper content. The models are B0.6, B 19, B25 and B30.
Three, industrial white copper:
Industrial white copper can be divided into structural white copper and precision resistance alloy white copper (electrical white copper).
(1), structure white copper:
Structural white copper is characterized by good mechanical properties, corrosion resistance and beautiful color. Among structural white copper, B30, B 10 and zinc white copper are most commonly used. In addition, there are aluminum white copper, iron white copper and niobium white copper. B30 has the strongest corrosion resistance among white copper, but it is more expensive. Aluminum white copper is close to B30 in performance and low in price, so it can be used as a substitute for B30. Zinc-white copper was produced and used in China in the15th century, and was called "China Silver". The so-called nickel silver or German silver also belongs to this kind of zinc white copper. Zinc can be dissolved in copper and nickel in large quantities, resulting in solid solution strengthening and corrosion resistance. Zinc-white copper can be successfully cut into various precision parts after adding lead, so it is widely used in instruments and medical devices. This alloy has high strength.
White copper hand stove 2
Degree and corrosion resistance, good elasticity, beautiful appearance and low price. Aluminum in aluminum white copper can significantly improve the strength and corrosion resistance of the alloy, and its precipitates can also produce precipitation hardening.
Structural white copper is widely used in manufacturing precision machinery, chemical machinery and ship parts.
(2), precision resistance alloy with white copper (electrician white copper):
White copper (electric white copper) for precision resistance alloy has good thermoelectric properties. BMn 3- 12 manganese copper, BMn 40- 1.5 constantan, BMn 43-0.5 constantan and new constantan (also known as nickel-free manganese white copper, containing 10.8 ~ 12.5% manganese, 2.5 ~ 4.5) Manganese white copper is a kind of precision resistance alloy. This alloy has high resistivity and low temperature coefficient of resistivity, and is suitable for making standard resistance elements and precision resistance elements. It is a material for manufacturing precision electrical instruments, rheostats, meters, precision resistors and strain gauges. Kangtong and Kaotong have high thermoelectric potential and can also be used as thermocouples and compensation lines.
History of mining and use
1. smelting history of Yunnan white copper (zinc white copper) and nickel white copper;
The invention of white copper is an outstanding achievement of ancient metallurgical technology in China. In ancient China, white copper was called "thunder". Old Tang book? "Yu Fu Zhi" contains: "I took the white copper ox cart with the surplus." In other words, the Tang Dynasty stipulated that white copper could only be used as an ornament for cattle pulled by courtiers, indicating that white copper was still quite valuable in the Tang Dynasty. The white copper mentioned here should be nickel white copper instead of arsenic white copper, because nickel white copper is corrosion-resistant and suitable for decorating ox carts, while arsenic white copper is unstable in nature and will gradually turn yellow because of arsenic volatilization after a long time.
In the ancient literature of China, white copper alloy was collectively called white copper; This includes three kinds of copper alloys: one is a copper-tin alloy with high tin content, such as "Daxia Zhenxing" copper coin (4 19 ~ 424) and Suiwu coin, all of which are high tin bronze and do not contain nickel. Another example is a collection of China white bronze mirrors from Nara era (7th-8th century) collected by Japanese Zhengzang, which are also high-tin-blue bronzes, containing about 25% tin and 5% lead. The second is copper-arsenic alloy with arsenic content above 10%, that is, arsenic white copper; The third is copper-nickel alloy, that is, nickel white copper. Among the three kinds of cupronickel, nickel cupronickel is the most important, followed by arsenic cupronickel.
The invention and production of white copper by Yunnan people are recognized by academic circles at home and abroad, not only in China, but also in the world.
White copper and five poisons cost money.
In ancient times, the white copper produced in Yunnan was also the most famous, and it was called "Bai Yun Copper".
At the latest in the 4th century, there were a lot of copper mines and production in Yunnan. In Huili, Yunnan, there are still * * * copper-nickel raw ore, which provides raw materials for smelting white copper. Hanshu records: "Qian Wei gave silver to the mountains in the southwest of the county", and there is a saying that "all the mountains raised silver first class (two ounces of silver ordered by Wang Mang)". However, according to modern investigation, Zhuti Mountain (now southwest of Yibin, Sichuan) produces copper and nickel instead of silver, so "Zhuti Silver" may be nickel-white copper.
At present, it is recognized that the earliest record of white copper in China (also in the world) can be found in Huayang National Records in Changqu of the Eastern Jin Dynasty in the 4th century. Annals of South China, Volume IV. The article records: "Because of the name of the mountain, Mantis County produces silver, lead, copper and miscellaneous medicines." Mantis County is now Huize, Qiaojia and Dongchuan in Yunnan. There are abundant copper mines here, while the neighboring Sichuan Huili produces nickel mines, and there is a post road between the two places. From the perspective of resources, it is certain that the copper produced in Mantis County is nickel copper. This is the earliest reliable record of nickel white copper.
These historical records show that Yunnan Province in China produced white copper very early, but at that time it was directly extracted from ores containing copper and nickel. Although China has a long history of smelting white copper, it has not produced pure nickel. The arsenic ore produced in Yunnan is now called "arsenic nickel ore" in mineralogy. 1929, Wang Xian analyzed the chemical composition of an ancient white copper stationery in China. It is proved that it contains 6. 14% nickel, 62.5% copper and a small amount of tin, zinc, iron and lead.
The white copper utensils made in ancient China are not only sold all over the country, but also exported to foreign countries. According to research, as early as the Qin and Han dynasties, there was a coin made of white copper in Daxia country in western Xinjiang, which contained 20% nickel. Judging from its shape, composition and historical conditions at that time, it was probably shipped from China. During the Tang and Song Dynasties, China nickel-white copper was exported to Arabia, and Persians called it "China Stone" at that time. About16th century later, China white copper was sold all over the world and won wide acclaim. It is exported through Guangzhou and sold to Europe by the British East India Company. The English word "Paktong" or "Petong" is a transliteration of the Cantonese word "white copper", which means white copper from China, that is, copper-nickel alloy produced in Yunnan.
There are more and more records about nickel-white copper in Ming dynasty, which shows that the origin of nickel-white copper is concentrated in Yunnan and Sichuan provinces.
Nickel-white copper has been recorded in more and more detail in the literature of Qing Dynasty. In the Qing Dynasty, there were factories and mines specializing in smelting white copper and workshops for producing white bronzes in Yunnan. Si Lifei's Yunnan Series and Yunnan Tongzhi Draft, which was continued in Guangxu period, both claimed that Dingyuan County (now Mouding County) had Damaoling White Copper Factory and Matai White Copper Factory. There is a dense copper factory in Dayao County. Its production situation. According to the relevant records in Continued Yunnan Tongzhi Draft, Dayaoling White Copper Factory in Dingyuan produces about 20,000 to 30,000 kilograms of white copper a year.
In addition, Huili, Sichuan Province was also an important producer of nickel copper in the Qing Dynasty, with white copper factories such as Lima River, Jiudaogou, Qingshuihe and Li Xi, among which Li Xi White Copper Factory has the longest history and the largest scale. During the Qianlong period, there were 2 16 smelters with an annual output of about 37 tons of white copper.
During the Jiaqing period of the Qing Dynasty, Tan Cui talked about the production of Yunnan white copper workshops in Zhi Heng, Yuhai, Yunnan: "White copper pots are the best in Yunnan, and their shops are all above the Sipailou (now the middle section of Zhengyi Road in Kunming). My husband's copper is from Yunnan. Yunnan craftsmen can't be big gongs and small gongs, but they must buy it from Jiangning. Jiangning artisans brought white copper from Yunnan, not a basin like Yunnan, because of water and soil. There are many white bronze vessels, although they are good, they are not unique, and the unique ones are only pots, so they are expensive in the sea. " The Yunnan white copper basin mentioned here can't afford to be dirty, and it will be new as soon as you try it.
A Qing Dynasty White Copper Pot
Call China a must.
About the smelting technology of nickel copper, the literature records are very vague. The research on the ancient nickel-copper smelting sites in Lima River, Xiaoguan River, Li Xi and Qinggangshan in Huili, Sichuan shows that the smelting temperature of ancient nickel-copper is 1300℃ ~ 1400℃, and the process is very complicated, which requires repeated calcination and smelting. The white copper produced by Huili is actually a binary alloy of copper and nickel, while Yunnan white copper is a ternary alloy of copper, nickel and zinc, which is made of Huili white copper, copper, zinc and brass. Nickel white copper is called "Yunnan white copper" because it is generally mixed and colored in Kunming, Huize and other places in Yunnan, and then exported to other provinces or export.
Second, the imitation of western countries:
17 ~ 18 century, nickel-white copper was introduced to Europe in large quantities and was regarded as a treasure. It is called "China Silver" or "China White Copper", which has a great influence on modern western chemical technology. /kloc-after the 6th century, some European chemists and metallurgists began to study and imitate China white copper. French Jesuit priest Duholde wrote in "Quan Zhi of the Chinese Empire" published in 1735: "The most outstanding copper is white copper, which is the same color as silver and is only found in China and Yunnan provinces."
1775, Time, published in Britain, recorded the strange research and valuable discovery of Burley, a freight passenger of the British East India Company in Guangzhou, which mentioned that Britain would try to copy the China copper purchased from Guangzhou by the East India Company. The article said: "Last summer, a ship arrived in Britain from China, and he (Berry) attached the white copper he got from Yunnan ... The purpose was to experiment and imitate this China white copper under the guidance of Moore, secretary of the British Handicraft Manufacturing and Business Promotion Association." Then in 1776, Engistrum, a chemist in charge of the Ministry of Mining of the Swedish government, published a paper on Yunnan white copper. The results of sample analysis show that the ratio of nickel content to copper content is 5 or 6 13 or 14, and it is found that China white copper is a ternary alloy of copper, nickel and zinc. He claims that it is very expensive to buy this alloy from China, and thinks that some mining areas in Sweden also have the same mineral, so it should not be difficult to copy it.
1822, Fife, a chemist from the University of Edinburgh in England, published his analysis results of Yunnan white copper. The alloy ratio is 40.4% copper, 3 1.6% nickel, 25.4% zinc and 2.6% iron. And said that at that time, no one in Britain knew how to copy this China white copper.
The following year, British Thomson Company first produced an alloy similar to China Yunnan white copper. In the same year, the German Haining Geer brothers copied Yunnan white copper successfully. Immediately, large-scale industrial production began in the west, and this alloy was renamed as "Deyin" or "Nickel Silver", while the veritable Yunnan white copper was actually forgotten.
When western countries copied Yunnan white copper successfully, the export volume of China white copper decreased greatly. By the end of19th century, Deutsche Bank had replaced China Baitong to occupy the international market, and China Baitong mining and metallurgy industry declined. However, Yunnan white copper is still very popular throughout the country. Until the 1920s and 1930s, there were still many white copper shops in Kunming, whose products were bright and clean, moderate in hardness, durable and free of scum. Among them, "Jiangnan Bao" Baitong Store is the most famous, and its products include hookahs, pipes, ink cartridges and basins. In particular, the basin enjoys the highest reputation and is exported to Jiangnan, Beijing and Tianjin. Before liberation, it was very glorious for Yunnan folks to marry women and have a white copper basin in their dowry. If the product is made in "Jiangnan Bao" store, the buyer will feel more glorious. The used price is still three or four times higher than other products.
Third, the history of arsenopyrite smelting:
In addition to nickel-white copper, there is also a kind of arsenic-white copper in ancient China, that is, arsenic-copper alloy. This arsenic copper is an outstanding contribution of ancient alchemists in China. However, they call it "medicinal silver", which means silver made by alchemy. This "medicinal silver" is more difficult than smelting nickel and copper, and it is easy to be poisoned by arsenic. Therefore, the alchemist paid a huge price for this achievement.
Arsenopyrite is made from arsenite (arsenite, realgar, etc.). ) or arsenic (As2O3) to some red copper. When the arsenic content in copper is less than 10%, it is golden yellow, which alchemists call "medicinal gold" (that is, arsenic brass); When the arsenic content is equal to or greater than 10% (arsenic copper), it becomes as white as snow and as bright as silver, which is called "medicinal silver".
The history of smelting arsenopyrite can be traced back to the early Western Han Dynasty, and it rose at the same time as alchemy. According to Song Dynasty's Rotten Mat Talk, three alchemists, Sanmaojun, who practiced in Maoshan during Han Jing's reign, suffered natural disasters in Danyang (now Xuancheng, Anhui Province), so they used calcined arsenic powder to refine the copper produced in Danyang into silver to save the hungry people. So later, the alchemist called this "medicine silver" Danyang silver.
Yinsheng carved white copper ink cartridge
Early arsenic copper smelting in China was made of realgar or orpiment spots. Around the Eastern Jin Dynasty, China began to refine arsenic copper, which was called "mottling". Ge Hong, a famous alchemist in Jin Dynasty, wrote in Bao Puzi? It is clearly recorded in the "Zezhang" that the realgar used for copper becomes "gold". Tao Hongjing, a medical master in the Qi and Liang Dynasties in the Southern Dynasties, also mentioned in his Records of Famous Doctors that "realgar can be used as gold" and that "the method of refining clothes is all in the immortal scriptures."
Ge Hong and Tao Hongjing probably got arsenic brass with very low arsenic content, which the alchemist might mean by "Xiongjin". During this period, the works such as "Secrets of Immortal Health Care" also mentioned the formula of Dan medicine with copper as "white", but the medication was more complicated.
When the Emperor of Sui Dynasty was in power, there was an alchemist named Su Yuanlang and Qing Xiazi, who once studied aisles in Juqu (Maoshan) and claimed to be the true sutra of Commander Da Maojun. He once wrote "On Treasure", which recorded that arsenic can "turn copper into silver". It is the first time that arsenic is used to point out white copper, which is a great progress in arsenic white copper smelting technology.
In the first year of Tang Suzong (AD 758-760), there was an alchemist named Jin Lingzi. He wrote a book "Dragon and Tiger Return to Dan" and an article "Diandanyang Fang", which introduced in detail the method of melting arsenic and white copper: "Take the paste from the upper piece, and every two or two kilograms ... Danyang can be divided into two pots, each pot can only be touched. Each medicine is divided into six pills, and three pills are taken continuously each time. When the golden juice is like water, poke it directly into the bottom of the pot. When you are exhausted, stir it with charcoal and drum it for thirty or twenty times. And adding medicine, so repeatedly similar, is to pour into the huachi, make beads, and stir them with willow branches to break them, instead of making beads. According to the first three pills, also put them into the pool. See if the color is white. The medicine is burned without use, and the contents are not white. To refocus, take white as the degree. "
Therefore, Jinling Zi first made arsenic from realgar, and then made the latter into pellets, which were put into molten copper juice one by one and stirred with charcoal until the copper juice turned white. In this process, As2O3 is first reduced to elemental arsenic by carbon, and then immediately dissolved in copper, thus gradually generating copper arsenite (Cu3As). According to this record, a simulation experiment was carried out, and arsenic copper ore containing 9.92% arsenic was successfully extracted. This record shows that the technology of smelting arsenic and copper by China alchemists in the middle Tang Dynasty has reached a quite mature stage. But this has long been the real secret of an alchemist, handed down from master to apprentice, top secret. Recently, an arsenic white bronze ware from the middle and late Tang Dynasty was found in the Tubo tomb in Dulan, Qinghai Province, which is a copper arrow with arsenic 15.8%. This shows that poisonous sand has been applied to a certain extent in the Tang Dynasty.
There is a story of "Danyang becomes silver" in Volume 10 of Spring Moon Hee in Song Dynasty: "Xue Tuo, a native of Lanling, is a famous Danyang. I tried to visit him only from Jane's because I knew his medicine. I copied two coins with a medicine paste and said,' This is my January grain, which can turn copper into rotten silver …' The medicine is white and polished, and the jujube meat is round. Once the copper juice melts, put it into the crucible, and the copper such as iron excrement will stick to the surface of the pot for a while, then remove the stone and stir it, and pour it into the pot. Although it is really rotten silver, it is obvious that what is described here is the refining process of arsenic copper. The medicine used is arsenic trioxide (arsenic trioxide), which reduces arsenic to arsenic by using the charcoal produced by jujube meat at high temperature, and makes it react with copper to form white copper, which is called "rotten silver"; Nitrite and mirabilite are added as slagging agents to remove deoxygenated products produced by chemical reaction. When this record talks about the alchemist making silver from calcined copper, it is also said that this is an anecdote stunt. It shows that until the Song Dynasty, refining poisonous sand was still an alchemist's "skill".
After the Yuan and Ming Dynasties, this kind of "medicinal silver" was gradually known to ordinary people, and the refining method of arsenic and copper gradually spread. There is a record of smelting arsenic and copper in Wu Ge's Random Talk written by Yuan people. Li Shizhen's Compendium of Materia Medica in the Ming Dynasty said: "White copper comes from Yunnan, and red copper is used to refine arsenic." Song Ying Xing's Heavenly Creations? The hardware also said: "copper is white copper made of arsenic and other drugs ... red copper rises to yellow and then melts to make a device. If it rises with arsenic, it is white copper." Double the difficulty of the work, and wasteful people will do it. "The smelting of arsenic and copper is recorded. Because arsenic copper and nickel copper are similar in appearance, they are often confused in Ming literature.
But so far, no arsenic copper made by ancient alchemists has been found. This is probably because this "medicinal silver" smelting technology is only mastered by a few people, and the output is very small and has been lost for a long time; Second, it is easy to deteriorate (arsenic will gradually evaporate and become reddish brown) and toxic; Third, arsenic copper is often used as silver in the market, which is forbidden and can only be refined in a small amount in the dark; Fourth, refining is difficult, costly and expensive.
China has had two independent copper systems since ancient times. Poisonous sand is unique to China. This smelting technology is a valuable cultural heritage of China.
Use white copper
Among copper alloys, white copper is widely used as corrosion-resistant structural parts in shipbuilding, petroleum, chemical industry, construction, electric power, precision instruments, medical instruments, musical instrument manufacturing and other departments because of its excellent corrosion resistance and easy molding, processing and welding. Some white copper also has special electrical properties, which can be used to make resistance elements, thermocouple materials and compensation wires. Non-industrial white copper is mainly used to make decorative handicrafts.
How to distinguish between white copper and sterling silver ornaments
Because white copper jewelry is similar to pure silver jewelry in color and workmanship. Some unscrupulous merchants take advantage of consumers' ignorance of silver jewelry and sell white copper jewelry as pure silver jewelry, thus making huge profits. So, how to tell whether it is pure silver jewelry or white copper jewelry?
It is understood that general sterling silver jewelry will be marked with the words S925, S990, XX foot silver and so on. , while white copper jewelry is not clearly marked or marked; Silver ornaments can be held by hand and traced on the surface of silver with a needle; Moreover, copper is tough and not easy to scratch; The color of silver is slightly yellow and silvery white, because silver is easily oxidized. After oxidation, it is dark yellow, while the color of copper is pure white, and green spots will appear after a period of time.
In addition, if a drop of concentrated hydrochloric acid is dropped on the inside of silver jewelry, white moss-like silver chloride precipitate will be formed immediately, while white copper will not. [ 1]