Method for detecting the purity of gold precious metals(Part 1)

In order to ensure the hardness, gloss and beauty of jewelry, the raw material of gold jewelry is not a single pure metal, but an alloy body with gold as the main material.At present, China's jewelry industry compulsory standard 08 11887-2008 stipulates that gold jewelry can be roughly divided into 9K, 14K, 18K, 22K, pure gold and thousands of pure gold according to the purity of gold.For the analysis and testing of gold and other constituent elements in various types of jewelry, there are currently corresponding standard analysis methods in China, mainly including national standards, industry standards, and local standards.These analytical methods provide the necessary technical support for the fair trade of gold jewelry and the quality supervision of relevant departments. According to the principle and nature of analytical testing methods, these methods can be roughly divided into density method, X-ray method, fire assay method, gravimetric method, inductively coupled plasma atomic emission spectrometry, etc.


Today we mainly introduce the determination method of precious metals in gold jewelry, Fire Assay .




The fire assay method is mainly used for the determination of the amount of gold in gold jewelry and is a classic detection method. The principle of this method is to preliminarily analyze or estimate the content of gold, add a certain proportion (generally 2 to 5 times the amount of gold) of pure silver, wrap it in a certain amount of lead foil, put it in an ash dish, and put it in a high-temperature furnace Gray blow, so that the metal impurity elements in the gold are separated out with the lead molten liquid, and finally only the combined particles of gold and silver are left, crushed, placed in a gold basket, and the silver is separated with nitric acid, and finally the remaining gold tablets Weighing can calculate the gold content.


The fire assay method has high precision and accuracy, and has a wide range of application. It can be applied to 333 ‰-999.5‰ gold jewelry. Therefore, it is considered an ideal arbitration method.

Next time we will talk other way . See you !!


 



Post time: Jul-07-2020

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