Impuphu yezinki (uthuli lwezinki): impuphu ecolekile empunga yensimbi yezinki, imvamisa inenani elincane le-oxide. Yenziwa ekucutshungulweni kwezinki noma ngokugaya insimbi emcengeni ngaphansi kancane kwephoyinti layo lokuncibilika elingu-420 °C (Thorpe 1913). Isetshenziswa njenge-reducing agent nokwenza i-sherardizing.