Ore is sorted after crushing, by process in which lumps of ore are fed past a source of electromagnetic radiation to obtain the emission of X-ray fluorescence with a wavelength characteristic of one constituent (I) of the ore, and a wavelength characteristic of one constituent (I) of the ore, and a wavelength characteristic of a second constituent (II), so a signal is produced which represents the ratio of the intensities of the two radiations; the signal is compared with a threshold value and the material is sepd. into lumps giving high signal and lumps with a low signal. The process is pref. used for the enrichment of iron ores where (I) is Fe and (II) is Ca, the Fe providing the low signal. The process is pref. used for the enrichment of iron ores where (Ie is Fe and (II) is Ca, the Fe providing the low signal. The X-ray fluorescence radiation used is pref. K alpha for Fe and K alpha for Ca. Method is applicable to lumps with average size 50-150 mm at a speed of 10 lumps/second.
展开▼
