Abstract: The grade of a low-grade sedimentary sepiolite ore from Hunan Province is 28.90%,and the main gangue minerals are quartz,talc and calcite.In order to improve the grade of sepiolite as much as possible and simplify the beneficiation process,the flowsheet of water leaching,sieving,dispersion and sedimentation was carried out according to the properties of the raw ore.After water leaching,the raw ore was sieving with a 74 μm sieve,and the fine grained products were screened for dispersion test.After optimization of dispersion conditions,the proper dispersant was determined as sodium pyrophosphate,and the proper addition amount was 0.8 g/L.The grade of sepiolite was 92.77% and the enrichment ratio was 3.21 with the dispersion solid-liquid ratio of 1∶10 mg/L,the dispersion time of 20 min,the dispersant speed of 2 000 r/min and the slurry pH of 9,which realized the efficient purification of sepiolite resource.

Key words: low grade, sepiolite, particle size screening analysis, dispersion, sedimentation height