Characteristics
Purple-K powder has an acrid taste and odor, is free-flowing, floating on most liquids, non-abrasive, does not wet with water and is compatible with most foam concentrates. It has violet color, to distinguish it from other dry agents. Its principal component is potassium bicarbonate (78–82% by weight), with addition of sodium bicarbonate (12–15%), mica (1–3%), Fuller's earth (1–3%), amorphous silica (0.2–%), and is made hydrophobic by methyl hydrogen polysiloxane (0.2–1%).
Purple-K is normally non-toxic, but ingestion of large amount can cause alkalosis. In high temperatures it decomposes to carbon dioxide and potassium oxide, which is toxic and highly corrosive.
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