Caustic soda (tseem hu ua sodium hydroxide) yog ib yam tshuaj lom neeg siv tau ntau yam thiab siv dav hauv ntau yam lag luam xws li textiles, pulp thiab ntawv, alumina, xab npum thiab tshuaj ntxuav tes, roj av refining thiab dej kho. Feem ntau nws muag ua ob lub xeev: kua (alkali) thiab khoom (flakes). Caustic soda flakes yooj yim dua rau kev thauj mus los deb thiab yog cov khoom nyiam rau kev xa tawm. Lub tuam txhab yog tus tsim caustic soda thib ob loj tshaj plaws hauv Is Nrias teb nrog lub peev xwm tsim khoom txhua xyoo ntawm 1 lab tonnes.