2. Weighing method. The specific gravity of platinum iron is 2 1.4, and that of silver is 10.49. Compared with the same volume of materials, the weight of platinum is almost twice that of silver.
3. Appearance comparison method. Platinum is gray and hard; And silver is white, delicate and smooth, softer than platinum.
4. Fire method. After high temperature firing and cooling, the color of platinum remains unchanged, and it is still gray; Silver becomes moist red or black red.
5. Chemical identification method. Grinding platinum on the touchstone, dropping nitric acid and hydrochloric acid on the touchstone, and if there is a substance, it is platinum; Grind silver on the touchstone, drop a few drops of nitric acid and rinse with water. If this substance disappears, it is silver.
Extended data
App application
Of the 245 tons of platinum sold by 20 10,13 tons (46%) are used for automotive catalytic converters, 76 tons (3 1%) are used for jewelry, and the remaining 35.5 tons are used for investment, electrodes, anticancer drugs, oxygen sensors, spark plugs and turbine engines.
catalyst
The biggest use of platinum is as a catalyst for chemical reactions, usually platinum black. /kloc-at the beginning of the 0 th century, chemists began to use platinum powder to catalyze the ignition reaction of hydrogen. At present, platinum is widely used in catalytic converters of automobiles, so that unburned hydrocarbons with low concentration in exhaust gas are completely burned, and carbon dioxide and water vapor are produced. In petroleum industry, platinum can be used to catalyze several different reactions, especially the catalytic reforming of naphtha to produce high octane gasoline. Platinum dioxide (or Adams catalyst) is a catalyst for hydrogenation, especially for the production of vegetable oil. Platinum metal can catalyze the decomposition of hydrogen peroxide into water and oxygen.
Standard of weights and measures
During the period from 1889 to 1960, the definition of rice was based on the length of a special platinum-iridium alloy rod (90: 10), which was called international rice source. The original of 1799 is platinum. The original international kilogram device is a cylinder made of the same batch of platinum-iridium alloy of 1879, and it is also the standard weight of kilograms.
The standard hydrogen electrode is made of platinum, which is also because platinum has high corrosion resistance.
precious metal
Platinum is a precious metal trading commodity. The ISO currency code of platinum ingot is "XPT". Platinum coins, platinum bars and platinum ingots can be traded or collected. Because platinum is not easy to corrode and has a shiny appearance, it is also used as jewelry, usually 90% to 95% alloy. Publications on jewelry trading generally advise jewelers to scrape some scratches on the surface of platinum.
In the watchmaking industry, many companies will use platinum to make limited edition watches. Platinum will neither lose its luster nor be scratched (compared with gold), so it is very suitable for clocks and watches.
Like other industrial commodities, the price of platinum fluctuates more than that of gold. In 2008, the price of platinum dropped from $2,252 to $774 per troy ounce, and its market value shrank by nearly two-thirds. Compared with the same period, the price of gold dropped from about $0/000 per ounce to about $700, and the market value only dropped by one third.
In the sustained and steady growth economy, the price of platinum is often twice that of gold; In unstable times, due to the reduction of industrial demand, platinum prices generally fall below the gold price level. When the economy is depressed, the price of gold is more stable because its demand is not driven by industrial use. /kloc-in the 0/8th century, Louis XV of France announced that platinum was the only metal worthy of the king in view of its rarity.
Other uses
Platinum wire can be used as an electrode in the laboratory. Thermogravimetric analysis will use platinum plate and support, because it must be strictly chemically inert at high temperature (about1000 C). Platinum is an alloy additive for various metal appliances, such as metal wires, corrosion-resistant experimental containers, medical equipment, dentures, electrical contacts and thermocouples. Platinum-cobalt alloy and iron-platinum alloy can be made into strong permanent magnets. It is also the main material of hard disk recording layer. Platinum-containing anodes are used in ships, pipelines and steel docks.
A symbol of dignity
Platinum is extremely rare and is usually regarded as a symbol of nobility. The platinum card service level of credit cards, debit cards and some membership cards is generally higher than that of gold cards. For records, the "White Gold Award" is the second highest honor, lower than diamonds and higher than gold, silver and bronze. For example, in the United States, records that sell more than one million copies will be called "platinum records" and records that sell more than ten million copies will be called "diamond records". Other commodities will also be called "platinum" if the surface is silvery white. Queen Elizabeth's crown was specially made for the coronation of George VI, and its frame was made of platinum. This is the first British crown to use platinum.
Refer to Baidu Encyclopedia-Platinum