Crucibles are laboratory containers designed to withstand extremely high temperatures for heating chemical compounds. They come in various sizes and usually include a matching lid. During heating, crucibles are often supported by a pipeclay triangle placed on a tripod. Materials used include porcelain, alumina, or inert metals. Platinum was historically one of the first materials used for crucibles. Ceramics like alumina, zirconia, and especially magnesia tolerate the highest temperatures. More recently, metals such as nickel and zirconium have also been used. The lids are typically loose-fitting to allow gases to escape during heating. Small porcelain crucibles (10–15 ml) are commonly used in gravimetric chemical analysis and often disposed of after use, especially when sold to laboratories in bulk.

Platinum possesses valuable properties such as high density—nearly twice that of lead—and exceptional corrosion resistance. It is malleable and ductile, allowing it to be shaped without breaking or losing strength. Additionally, platinum is biologically compatible, being non-toxic and stable, which means it does not react adversely with body tissues. Recent studies also indicate platinum may inhibit the growth of certain cancer cells.

Platinum is typically found alongside other platinum group metals (PGMs). In regions like South Africa’s Bushveld complex, PGMs are abundant enough for exclusive extraction, while in places like Russia’s Norilsk and Canada’s Sudbury deposits, platinum is recovered as a by-product of nickel and copper mining. Extracting pure platinum is capital- and labor-intensive; producing one troy ounce (31.135g) can require up to six months and 7–12 tons of ore. The initial step involves crushing the ore and mixing it with reagents in water—a process called froth flotation—where air bubbles cause platinum particles to attach to oxygen and rise to the surface as froth, which is skimmed off for further refining.

Thanks to its corrosion resistance and stability at high temperatures, platinum is ideal as a catalyst in chemical reactions. It accelerates reactions without being consumed. Around 37% of platinum demand comes from automotive catalytic converters that transform over 90% of harmful exhaust hydrocarbons into less damaging substances. Platinum also catalyzes nitric acid production and enhances gasoline octane levels. In electronics, platinum crucibles are used for semiconductor crystal growth in lasers, and platinum alloys serve in magnetic disks for hard drives and automotive switch contacts.

Platinum is often extracted from placer deposits and ores like sperrylite and cooperite, usually alongside other PGMs. Its extraction is resource- and labor-intensive. After ore crushing, the froth flotation process separates platinum for refining. Due to its natural white luster, durability, and hypoallergenic qualities, platinum is favored in jewelry and decoration, often alloyed to improve workability while retaining purity.

Platinum group metals include six elements: platinum, palladium, rhodium, iridium, ruthenium, and osmium. Minerals containing PGMs often have varying proportions of these elements. Many PGMs are extracted as minor constituents of copper and nickel ores in parts per million. Their smelting requires higher temperatures and specialized equipment compared to gold and silver. Major producers are South Africa, Russia, and North America.

Medium frequency induction casting machines are preferred for platinum due to their ability to control atmosphere and provide rapid, safe melting. However, smaller shops often rely on vertical centrifugal casting machines for torch casting, which are safer and more efficient than horizontal centrifuges. Vertical machines produce high torque and strong centrifugal force, minimizing spill risks. These machines are typically mounted securely for two-person operation: one loading the flask, the other melting the metal.

Commonly used platinum casting alloys include platinum 900/iridium 100 (90/10 iridium), known for good casting and welding properties without oxidation and sufficient hardness (~120 HV). Recently, platinum 950/iridium 50 (95/5 iridium) alloys comply with purity standards but have lower hardness (~80 HV), leading to wear issues. Platinum 950/cobalt 50 alloy offers fine grain structure, high fluidity, hardness (~135 HV), and ease of polishing but oxidizes easily, requiring hydrogen/oxygen fuel or induction heating. Platinum 950/copper/cobalt alloys are non-magnetic alternatives but similarly require controlled atmospheres to prevent oxidation.