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Platinum is a chemical element, which is commonly called Platinum and belongs to the platinum group. Its chemical symbol Pt is one of the precious metals. Platinum alloy

The atomic weight is 195.078, which is slightly smaller than the atomic weight of gold, and the atomic number is 78, which belongs to the transition metal.

Platinum

The Platinum melting point of 1772 °C, the Platinum boiling point of 3827 ± 100 °C, the Platinum density of 21.45g / cm3 (20 °C), soft, good ductility, thermal conductivity, and electrical conductivity. Sponge platinum is a gray sponge-like substance with a large specific surface area and strong absorption capacity for gases.

Powdered platinum black can absorb a large amount of hydrogen. Platinum chemically inert, stable in air and moist environment, is lower than 450 deg/C heating, the surface form two platinum oxide film, can react with sulfur, phosphorus, a halogen at a high temperature.

Platinum is insoluble in hydrochloric acid, sulfuric acid, nitric acid, and alkaline solutions, but soluble in aqua regia and molten alkali. The oxidation state of platinum is +2, +3, +4, +5, +6. It is easy to form a coordination compound such as [Pt(NH3)2]Cl2, K[Pt(NH3)Cl5].

Physical Properties

Platinum is a silvery-white shiny metal, melting point 1772 °C, boiling point 3827 ± 100 °C, density 21.45g / cm3 (20 °C), soft, good ductility, thermal conductivity, and electrical conductivity. Platinum is insoluble in hydrochloric acid, sulfuric acid, nitric acid, and alkaline solutions, but soluble in aqua regia and molten alkali.

Platinum is a transition metal with high density, ductility, silver color, metallic luster, the hardness of 4-4.5 and relative density of 21.45. The melting point is 1773 ° C. Rich in ductility, it can be drawn into a very fine platinum wire and rolled into a very thin platinum foil.

Chemical Properties

Chemically stable It is insoluble in strong acid and alkali solution and does not oxidize in air. The first ionization energy is 9.0 eV. The valence is +2, +4 and +6. The temperature of 1772 °C, the boiling point of 3827 °C. The density is 21.46 g/cm3. Silver-white metal, soft and malleable.

The crystal structure is a face-centered cube. Platinum has high chemical stability. In addition to being dissolved in aqua regia and molten alkali, it is also soluble in a mixture of hydrochloric acid and hydrogen peroxide, hydrochloric acid and perchloric acid. In addition, platinum does not react with ordinary strong acid at normal temperature.

Platinum alloys || What Platinum is Used for || Platinum Chemical Properties

However, platinum is susceptible to corrosion at high temperatures. For example, for a variety of oxidants, strong bases, heavy metals that are easily reduced, and sulfur, phosphorus, arsenic, etc. platinum is destroyed by it, or alloyed with it, because of this, Do not heat or melt alkali metal oxides, sodium thiosulfate, phosphorus and large amounts of sulfur, and samples containing heavy metals (such as lead, tin, antimony, arsenic, mercury, copper, etc.) in platinum vessels. Do not use a large amount of peroxidizing or sodium hydroxide (potassium) as a flux at high temperatures. Halogen or halogen-decomposing substances are not allowed in platinum vessels. But the following substances can dissolve platinum:

  • Aqueous water (a mixture of nitric acid and hydrochloric acid in a ratio of 1:3 (by volume))

Although aqua regia can dissolve platinum, it is related to the state of platinum. The dense platinum has a very slow dissolution rate of aqua regia at room temperature, and the platinum wire with a diameter of 1 mm takes 4-5 hours to completely dissolve. Platinum black (platinum powder) reacts with concentrated sulfuric acid upon heating to form Pt(SO4)2 , SO2 and water. Chloroplatinic acid is prepared by dissolving platinum metal in aqua regia. The product of this reaction is H2PtCl6, rather than the previously considered nitrogen-containing platinum compound. Chloroplatinic acid is a reddish-brown solid which can be obtained by evaporating its solution.

Pt + 4 HNO 3 + 6 HCl → H 2 PtCl 6 + 4 NO 2 + 4 H 2 O

  • Alkali metal cyanide

Alkali metal cyanide also dissolves platinum, which reacts with halogen at high temperatures, but selenium, tellurium and phosphorus react more readily with platinum. The dense metal platinum is not oxidized in the air at any temperature.

  • a mixture of hydrochloric acid and hydrogen peroxide
  • Molten alkali
  • a mixture of hydrochloric acid and perchloric acid

Reaction with aqua regia:

3Pt+4HNO3+18HCl=3H2[PtCl6]+4NO↑+8H2O

Aromatic water is used to dissolve the treated platinum concentrate or the anode mud produced by electrolytic copper and nickel. After a series of chemical treatments, ammonium chloroplatinate can be obtained, which is slowly burned at 1000 °C to decompose to obtain spongy platinum.

Platinum in the hydrogenation, dehydrogenation, isomerization, cyclization, dehydration, dehalogenation, oxidation, cracking and other chemical reactions and contact method to produce sulfuric acid, ammonia oxidation method to prepare nitric acid, ammonia and methane to prepare hydrocyanic acid, to prepare cyclohexane It is used as a catalyst when producing vitamins.

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The octane number of gasoline products can be improved by reforming naphtha with a platinum catalyst. Platinum and its alloys are resistant to oxidation and corrosion at high temperatures and are used in the manufacture of crucibles, evaporating vessels, electrodes, nozzles, reactors, and the like.

Platinum alloy

Platinum and platinum-rhodium alloys are used as furnace wires and thermocouples in high-temperature furnaces in the metallurgy, glass and ceramic industries. Platinum is also used to make jewelry.

Classification

Platinum is a platinum group element of Group VIII in the periodic table, tin white metal, atomic number 78, relative atomic mass of 195.09, density of 21.45 g/cm3, melting point of 1769 ° C, and boiling point of 3800 ° C. Pure platinum has good high-temperature oxidation resistance and chemical stability, and is easy to process. Platinum compounds are used as catalysts in the fields of chemical, pharmaceutical, refining, and automotive exhaust gas purification.

Natural platinum

Platinum minerals containing impurities such as iron, antimony, and palladium are silvery-white or dark gray. They are equiaxed crystal systems and are irregular granular or scaly aggregates with a density of 13.35~19g/cm3 and are ductile. Chemical composition: Pt crystal is a natural elemental mineral of the equiaxed crystal system.

In addition to Pt, natural platinum often contains iron, which is called crude platinum ore when it reaches 9-11%; it is called iron-platinum ore, up to 28%. Also often contains nickel, gold, copper, palladium, rhodium, and ruthenium, etc., the highest content of palladium can reach 21.8~30.0%.

Sponge platinum

Gray spongy metal-containing platinum mass fraction ≥99.9%, divided into three grades according to platinum content: SM-Pt99.99, SM-Pt99.95, and SM-Pt99.9, generally fired and tempered by fire method Made.

High purity sponge

The gray spongy metal-containing platinum mass fraction ≥99.995% is divided into two grades according to the platinum content: SM-Pt99.995 and SM-Pt99.999, which are generally prepared by separating and purifying from various platinum-containing materials. For chemical industry, electrical instruments, precision alloys, and temperature measuring materials.

Ultrafine platinum powder

Containing platinum ≥99.95%, average particle size of 7.0m/g, bulk density of 0.4-0.7g/cm, tap density of 0.7-1.1g/cm-3.

Platinum rhodium alloy

The platinum-based binary alloy containing ruthenium is a continuous solid solution at high temperature, and solid-phase decomposition occurs when it is slowly cooled to 975-700 °C, but the phase equilibrium process proceeds slowly.

The oxime is volatile and oxidized, which can significantly improve the corrosion resistance of platinum. The alloy has high hardness, high melting point, high corrosion resistance, and low contact resistance.

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Platinum silver alloy

A binary alloy containing platinum as a base, a peritectic reaction occurs at 1185 °C and 45% Ag. The alloy has high strength, good elasticity and low elastic aftereffect, small resistivity, low thermoelectric potential, heat resistance, corrosion resistance, no magnetism and stable performance.

Platinum silver alloy is difficult to smelt and process. Generally, a high-frequency induction heating furnace is used. Hydrogen protection smelting, the ingot must be homogenized and processed into sheets and wires.

Platinum Molybdate

A platinum-based binary alloy containing molybdenum, the platinum-rich solid solution is a face-centered cubic structure, and the electrical resistivity increases linearly with increasing molybdenum content.

The platinum-molybdenum alloy has a tensile strength of 922 N/mm-2, a resistivity of 0.64 Ω.mm-2/m, and a temperature coefficient of resistance of 2.4×10−4/°C. The high-frequency induction heating furnace is used to protect the smelting hydrogen, condensing the exhaust gas several times, casting the hot forging and cold working into wires and sheets.

Platinum alloy

Platinum-molybdenum alloy is mainly used as a thermocouple material with high thermoelectric potential and good stability. It can work in the nuclear field and the temperature is 1500~1600°C. In addition, platinum-molybdenum alloys can also be used as potentiometer windings and high-temperature strain materials.

Platinum Rhodium Alloy

A platinum-based binary alloy containing ruthenium undergoes a simple peritectic reaction at a temperature of 2450 °C, is protected by smelting with hydrogen gas in a high-frequency furnace, and is cold worked into a material after hot billet opening. Platinum-rhodium alloys are available in PtRe8 and PtRe14 alloys. PtRe8 is a high-temperature thermocouple material.

Platinum Cobalt Alloy

A platinum-based binary alloy containing cobalt, at high temperature, platinum and cobalt can be infinitely miscible, the solid solution is a face-centered cubic lattice, slowly cooled to 833 ° C, the order begins to appear in the alloy.

Platinum and cobalt alloys are extremely magnetic, have high magnetic stability, and are chemically resistant. Both potassium hydroxide and hot concentrated sulfuric acid cannot corrode them. The alloy is mainly used in aerospace, marine, aviation instruments, measuring instruments, electronic clocks, magnetrons, etc.

Platinum Copper Alloy

A binary alloy containing copper as a base, which is a continuous solid solution at high temperature. At low temperature, there is an orderly transformation in the range of 3% to 93% copper composition, and the phase structure changes from a cubic lattice to a rhombohedral lattice, resulting in an alloy. Significantly strengthened. Products are PtCu2.5, PtCu5,

Alloys such as PtCu8.5, PtCu15, and PtCu25 are smelted by high-frequency induction heating furnace or medium-frequency induction heating furnace. The ingot must be processed into a material after homogenization, and is mainly used for manufacturing electrical contact and resistance materials.

Platinum Nickel Alloy

A platinum-based binary alloy containing nickel, which is a continuous solid solution at a high temperature, forms two super structured compounds below about 645 °C. Platinum-nickel alloys include PtNi2, PtNi5, PtNi10 and PtNi20. When heated in an oxidizing atmosphere, nickel is selectively oxidized and argon-protected by high-frequency induction heating furnace to be processed into wires and sheets.

Platinum Rhodium Alloy

A platinum-based binary alloy containing ruthenium, such as PtRu4, PtRu5, PtRu10, and PtRu14. 钌 Improves corrosion resistance and has a strong anti-tarnishing ability. It selectively oxidizes and volatilizes above 900 °C. The argon gas is used to protect the smelting in a high-frequency induction heating furnace.

A binary alloy containing ruthenium based on platinum. Niobium has the effect of increasing the hardness and electrical resistivity of the alloy. The platinum-rhodium alloy is smelted by argon gas in a high-frequency furnace and cold-rolled into a material after hot rolling.

Identification features: metallic luster, silver-to-steel gray, large ratio, not oxidized in the air, in addition to aqua regia, not dissolved in common acids; high in specific gravity and hardness is distinguished from natural silver.

Genesis: Natural platinum is mainly found in magmatic deposits, which are related to basic rocks and ultrabasic rocks, in addition, they are often enriched in sand mines.

Famous places of origin: World famous places are Merensky Reef in South Africa, Ural in Russia, Sudbury in Canada, and the United States. Natural platinum is also produced in some ultrabasic rocks in China.

Name source: Platinum, Platina from Spanish, meaning silver;

Crystal morphology: hexahedral crystals; granular or grape-like, occasionally cubic crystal;

Crystal structure: crystal system and space group: equiaxed crystal system, Fm3m;

Unit cell parameters: a0=3.924?

Platinum Resistance

Powder crystal data: 2.265(1) 1.962(0.53) 1.1826(0.33)

Mohs hardness: 4~4.5

Specific gravity: generally between 14 and 19, depending on the type and content of other elements contained; the theoretical proportion of pure platinum is 21.45. Magnetic when rich in iron.

Melting point: 1772 ° C.

Other properties: Extremely resistant to corrosion. Strong anti-oxidation. The coefficient of thermal expansion is small. Thermoelectric stability is strong. Good ductility. High catalytic activity.

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Uses: Natural platinum is almost the only source of metallic platinum. In addition to jewelry, platinum is used extensively in automotive catalytic converters and as a catalyst in the refining industry for the manufacture of electronic devices, platinum enamel, dental materials and spinnerets of rayon.

Platinum alloy mixed with other metals such as alloy made of platinum, such as with palladium, rhodium, yttrium , ruthenium, cobalt, osmium , copper or the like. Although platinum hardness is higher than gold, it is not enough as enamel, and it must be alloyed with other metals to make jewelry. The jewelry industry uses more platinum, rhodium alloys, and platinum and rhodium alloys. Platinum and cobalt alloys are used for casting in Europe and Hong Kong.

Platinum

In Japan, a chain of platinum (85%) and palladium alloy is used. International platinum ornaments stamp the word is Pt, Plat or Platinum and with purity per thousand figures represent the sum, expressed as Pt900 purity is 900 ‰. The specifications of Japanese platinum jewelry are marked Pt1000, Pt950, Pt900, Pt850.

Cisplatin

The English name Cisplatin, a commonly used chemical for cancer treatment , has a high therapeutic effect. Alias: cisplatin, cis-dichlorodiamine ligose, dichlorodiammine platinum, cisplatin. English name: Cisplatin (CDDP) Function and use: This product is a cell cycle non-specific drug, has cytotoxicity, can inhibit the DNA replication process of cancer cells, and damage its cell membrane structure, has a strong broad-spectrum anti-cancer effect.

Clinically used in ovarian cancer, prostate cancer, testicular cancer, lung cancer, nasopharyngeal cancer, esophageal cancer, malignant lymphoma, breast cancer, head and neck squamous cell carcinoma, thyroid cancer and osteosarcoma and other solid tumors can show efficacy.

Side effects: 1 There is myelosuppression, platelet and leukopenia. Have gastrointestinal reactions, nausea, vomiting. Nephrotoxicity, excessive drinking or infusion, forced diuresis can reduce nephrotoxicity. Renal dysfunction should be used with caution. Western dose: adult dose 10mg~20mg/day, dissolved in 200ml~300ml normal saline, intravenous drip, in the dark within 2 hours, each treatment is 200mg~400mg, after the dosage reaches 100mg~200mg, interval 1~2 weeks. When the total dose reached 200 mg, most patients showed subjective and objective relief.

Chloroplatin [alias] cisplatin; cisplatin; cis-dichlorobisammonium platinum, bischlorobisammonium platinum, cisplatin, cisplatin, ammonia chloroplatinum, tin platinum, cisplatin

[foreign name] Cisplatin, Cis-Platinum, DDP, PDD, NSC-119875, Randa, Neoplatin, Platinol

[Indications] The anti-tumor spectrum is widely used, and it is clinically used to treat testicular tumors. It has good effects on both embryonal tumors and seminoma and has no cross-resistance with commonly used drugs. Good effect on ovarian cancer, breast cancer and bladder cancer. It also has a certain effect on head and neck cancer, lung cancer, esophageal cancer, malignant melanoma, malignant lymphoma, soft tissue sarcoma and cancerous ascites. It works better with other anticancer drugs.

Description of use

Platinum is widely used due to its high chemical stability (insoluble in any acid and base except aqua regia) and catalytic activity. Strong magnets can be combined with cobalt.

It is often used to make corrosion-resistant chemical instruments, such as various reaction vessels, evaporating dishes, crucibles, electrodes, platinum mesh, etc.

Platinum and platinum rhodium alloys are often used as thermocouples to measure temperatures from 1200 to 1750 °C. It can also be used to make jewelry. Platinum can be used as a catalyst in chemical reactions such as hydrogenation, dehydrogenation, isomerization, cyclization, dehydration, dehalogenation, oxidation, and cracking.

In medicine, do anticancer drugs, platinum compounds such as cis-platinum (Cisplatin) is used for cancer chemotherapy purposes.

Electronic materials, surfactants.

Storage and transportation

Store at room temperature and dry.

Hazard statement

Platinum is one of the rarest elements in the earth’s crust. Platinum is almost completely dispersed in alluvial deposits and ore deposits, such as magnetite, ore, chromite, ilmenite, nickel sulphide ore, platinum-bearing chalcopyrite, platinum-bearing pyrrhotite, nickel pyrite, etc.

In addition, platinum is also alloyed with other platinum-based elements such as natural platinum, palladium-platinum ore, antimony ore, and the like.

The main platinum mines include arsenic platinum ore, sulphur platinum ore, iridium-platinum ore, sulphur-platinum-palladium ore, sulphur-nickel-palladium-platinum ore, etc, as well as bismuth platinum ore, tin-lead platinum-palladium ore, ruthenium platinum ore, arsenic platinum bismuth ore, arsenic bismuth platinum palladium ore, platinum-containing gold ore.

The world’s most abundant platinum resource is South Africa, followed by Russia, Canada and the United States.

Platinum has six stable isotopes: platinum-190, platinum-192, platinum-194, platinum-195, platinum-196, and platinum-198.

In nature, it often exists in the state of natural minerals and is extremely dispersed. It is obtained by enriching and extracting the original platinum ore.

Upstream raw materials: ammonia, sulfur dioxide, sulfuric acid, ammonium chloride, chlorine, sodium chlorate

Downstream products: nitric acid, chloroplatinic acid, carbon monoxide combustion improver