坩埚Crucible

瓷坩埚最常用，可耐约 1100 °C，用于灼烧沉淀和灰化，但不能用于碱熔（NaOH、Na₂CO₃ 会腐蚀瓷釉）；铂坩埚耐高温、耐大多数化学试剂，用于重量分析和碳酸盐熔融，但怕王水、硫化物、易还原金属和含磷含碳物质；镍和铁坩埚用于过氧化钠或氢氧化钠碱熔；石墨坩埚用于金属冶炼；石英坩埚用于拉制单晶硅。

Porcelain crucibles are the most common, good to about 1100 °C for igniting precipitates and ashing, but not for alkaline fusions, since NaOH and Na₂CO₃ attack the glaze; platinum crucibles tolerate high temperatures and most reagents for gravimetric work and carbonate fusions, but are damaged by aqua regia, sulfides, easily reduced metals and phosphorus- or carbon-rich materials; nickel and iron crucibles serve sodium peroxide and hydroxide fusions; graphite crucibles serve metal smelting; and quartz crucibles are used to grow single-crystal silicon.

坩埚放在泥三角上用本生灯加热，或放入马弗炉中高温灼烧；用坩埚钳夹取，热坩埚放在石棉网上或干燥器中冷却，不能骤冷；重量分析中坩埚需灼烧至恒重（两次称量相差不超过 0.2–0.3 mg）。

Heat the crucible on a pipe-clay triangle over a Bunsen burner or ignite it in a muffle furnace; handle it with tongs, cool it on a gauze or in a desiccator and never quench it; in gravimetric analysis ignite to constant mass, with successive weighings agreeing within 0.2–0.3 mg.

坩埚是冶金和炼金术最古老的器具之一，青铜时代已用黏土坩埚熔炼金属。英文 crucible 源自拉丁语，引申为“严峻考验”。18 世纪亨茨曼发明坩埚炼钢法，生产出高质量的工具钢。

Crucibles are among the oldest tools of metallurgy and alchemy; clay crucibles melted metal in the Bronze Age. The English word, from Latin, also came to mean a severe test. In the eighteenth century Huntsman's crucible-steel process produced high-quality tool steel.