Abstract: The fixed carbon content of a crystalline graphite ore from Tanzania is 3.74%, among of which the +147 µm size flake graphite accounts for 97.18%. In this paper, the different rough concentrates and further regrinding and reflotation tests between high pressure roller mill and ball mill were compared.The results showed that the effect of the new process of "particles bed comminution (high pressure roller mill)−grading and grading separation" was better. The regrinding of coarse−grained low−carbon products avoided the damage of gangue to large−scale graphite with high dissociation degree in coarse concentrate, and the carbon grade increased rapidly. Its recleaning concentrate and medium−grained medium−carbon were combined into one product, and fine−grained high−carbon products were regrinding and re−concentration in two stages respectively. The fixed carbon content of both concentrates were greater than 96%. Compared with the conventional process, "five times regrinding and six times flotation" were reduced. The final carbon grade of the concentrate was higher than 95% and the +0.15 mm particle size was about 65% in both processes. The +0.30 mm content in the new process was 3.37% higher.