The Knelson concentrator，a commonly utilized centrifugal gravity separation device in gold ore processing，is esteemed for its superior recovery efficacy with respect to fine gold.The separation performance of the Knelson concentrator is intricately linked to both material characteristics and operational parameters，with heavy mineral concentration mechanisms varying depending on specific conditions.Consequently，investigating the impact of heavy mineral concentration mechanisms on separation efficiency can be instrumental in enhancing the effectiveness of gold ore separation processes.This study utilized a quartz vein gold ore from Gansu Province as the primary material to investigate the correlation between the concentration criterion （X） of individual enrichment rings of the MD3 Knelson concentrator and the mechanisms of concentration and separation.The findings indicate that heavy minerals were predominantly enriched through plating on the concentrate bed surface when X exceeded 9.In cases where X ranged from 5 to 9，heavy minerals were enriched through the continuous replacement of gangue minerals.Correspondingly，when X was less than 5，heavy minerals were enriched through elutriation.At a rotational speed of 1 465 r/min and a water flow rate of 3.0 L/min，coarse and medium-grained gold were concentrated in the lower rings through substitution，while micro and fine-grained gold were accumulated in the upper rings through surface plating and percolation or migration.The resulting concentrate grade was 124.4×10^-6 with a gold recovery rate of 70.36%，indicating optimal beneficiation effectiveness.Excessive X values led to material bed compaction and premature onset of overload phenomena.If the X value is insufficiently large，the high water flow results in the depletion of micro and fine gold particles，which are detrimental to the gold recovery process and should be minimized in industrial applications.