Abstract: Due to the changes in the composition of Jinchuan nickel raw materials,the copper content of high-nickel matte is elevated,which changes the equilibrium state of the milling and flotation system,resulting in higher metal intercontainment in the secondary copper and nickel concentrates. The quality of flotation products depends on the size and mosaic relationship between nickel and copper mineral crystals,while the crystals size and mosaic relationship is affected by heat preservation and slow cooling conditions. Therefore,it is urgent to investigate the influence of heat preservation and slow cooling conditions on the flotation behavior of minerals in high nickel matte. The results showed that under the appropriate slow cooling and temperature control conditions,a copper concentrate with 53. 9% Cu grade and 86. 1% Cu recovery and a nickel concentrate with 66. 2% Ni grade and 81. 5% Ni recovery can be obtained by 1 roughing test. Compared with the test results of the field samples, the flotation effect of high nickel matte was improved. The mechanism study showed that the flotation effect was better than that of the original sample because of the increase in the grain size and monomer dissociation of pyrochlore in the sample after controlled temperature and slow cooling.