Tony Withers: Lab: Cleaning Crucibles

Instructions for cleaning Pt crucibles

Note that web-based summaries of standard operating procedures are not exhaustive.
Not all of the relevant safety information is included in this document.
Further training is required for safe operation and will be provided in person.

To remove contaminants such as Fe and Mn from platinum labware, we bring the platinum into contact with a silicate or borate liquid. The aim is that at high temperatures the contaminants will partition into the liquid, which can then be quenched to form glass and removed from the crucible. Repeated fusions may be required to reduce contamination to an acceptable level. Liquid compositions with low melting points that can be used for this include lithium metaborate and sodium metasilicate. Transition metal contaminants will tend to color the glass, so a clear glass is usually a good indicator of a clean crucible.

The standard operating procedure for the cleaning process was provided by Lora Armstrong:

LSA 2012.

 

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