Caustic soda (leyi tivekaka tani hi sodium hydroxide) i khemikhali ya ti indasitiri leyi tirhisiwaka ngopfu naswona yitirhisiwa ngopfu leyi tirhisiwaka eka ti indasitiri to hambana hambana kukatsa na swiambalo, pulp na maphepha, alumina, xisibi na swibasisi, ku basisiwa ka petroleum xikan’we naku basisiwa ka mati. Hi ntolovelo yi xavisiwa hi swiyimo swimbirhi swa physical: liquid (alkali) na solid (flakes). Ti caustic soda flakes ta olova ku ti fambisa eka mpfhuka woleha naswona i xitirhisiwa lexi tsakeriwaka ku xaviseriwa matiko yale handle. Khamphani leyi i ya vumbirhi hi vukulu eka muhumelerisi wa caustic soda e India laha yingana vuswikoti bya vuhumelerisi bya lembe na lembe bya 1 million tonnes.