Question: the three main raw materials for portland cement are
Answer: iron; 26Fe; Fe; Eisen; Ferrum metallicum; Ferrum; Hierro; element 26; fer; silicon; element 14; Si; silicon dioxide; Silicon dioxide, colloidal; Siliziumdioxid; Siliceous earth, purified; SiO₂; silica; Silicon dioxide (amorphous); Silicon dioxide; Diatomaceous silica; (SiO2)n; Silica, amorphous; Silicon dioxide, fumed; Silica, colloidal; Colloidal silicon dioxide; Silica gel; Colloidal silica; Diatomaceous earth; SiO2; Diatomite; Kieselsäureanhydrid; Siliceous earth; [SiO2]; silicic anhydride; Infusorial earth; Silica; Silicon oxide; aluminum oxide; Abramax; Alcoa F 1; Ketjen B; Hypalox II; Aluminum trioxide; Abrasit; Dotment 358; Diadur; Exolon XW 60; Jubenon R; Catapal S; Abrarex; Dispal alumina; Abramant; Aloxite; Almite; alpha-Alumina; alpha-Aluminum oxide; Martoxin; Cab-O-grip; Aluminium oxide; Compalox; Alon C; Alumina; Dispal M; Fasertonerde; Faserton; Lucalox; Poraminar; Dialuminum trioxide; Conopal; Aluminum oxide; Dotment 324; Dural; calcium; element 20; Ca