Mixed glue to secure charged particle (7)

I believe the answer is:

granule

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'particle' is the definition.
(I know that granule is a type of grain)

I don't understand the remainder of the clue.

(Other definitions for granule that I've seen before include "Tiny bit of instant coffee or sugar?" , "Small particle (of e.g. sugar)" , "Fine particle" , "Piece of sugar or salt" , "Small compact particle" .)

I've seen this clue in The Sun and The Times.

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