To make pure caesium, ores of caesium and rubidium are crushed and heated to 650 °C with sodium metal, generating an alloy that can then be separated via a fractional distillation technique.
tə mˌeɪk pjˈʊɹ sˈiːsiəm, ˈoːɹz ʌv sˈiːsiəm ænd ɹuːbˈɪdiəm ɑːɹ kɹˈʌʃt ænd hˈiːɾᵻd tə sˈɪkshˈʌndɹɪd fˈɪfti dᵻɡɹˈiːz sˈiː wɪð sˈoʊdiəm mˈɛɾəl, dʒˈɛnɚɹˌeɪɾɪŋ ɐn ˈælɔɪ ðæt kæn ðˈɛn biː sˈɛpɚɹˌeɪɾᵻd vˈaɪəɹ ɐ fɹˈækʃənəl dɪstɪlˈeɪʃən tɛknˈiːk.