Credit: NILERED/SCIENCE PHOTO LIBRARY

Caption: Melting and cleaning potassium in mineral oil. This footage shows part of a series of steps in a process used to clean and purify potassium that had acquired a layer of oxides. Before the stage shown here, the oxides were removed from the potassium by chemical treatment. Then the partially-cleaned potassium was placed in this beaker of mineral oil to be melted down. Here, the potassium is being stirred as the mineral oil is heated. Eventually, the pieces of potassium melt and merge into a spherical mass, allowing remaining solid impurities to be scraped off its surface after it solidifies, followed by further cleaning stages.

Release details: Model release not required. Property release not required.

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