To make caustic; to treat with caustic chemicals or to render something chemically corrosive or verbally harsh.
From caustic plus the suffix -ize (to make or cause to be). This is a productive English pattern for creating verbs from adjectives, especially in scientific and technical contexts.
In the paper industry, causticization is literally done: caustic soda is recovered and reused in cooking liquor. The verb shows how technical jargon often abstracts physical processes into sleek linguistic packages.
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