Study on the effect of plasticizer agent on the fluidity of superfine full tailings filling slurry based on diffusivity test

Aiming at the problem of poor fluidity of superfine full tailings cement cemented filling slurry,through the contrast experiments of slurry diffusivity with different concentration,different cement-sand ratio and different plasticizer content,and the diffusivity curve zone named gravity transport zone,pressurized pumping zone and transport difficulty zone,the influence law of the fluidity of superfine full tailings filling slurry is investigated by taking the superfine full tailings of a gold mine in China as the research object.The results show that without additives,the critical transport concentration of the slurry is 64%,and there is a critical liquid-solid conversion concentration of 70%.When the concentration is not more than 64%,the slurry can be pumped under pressure,and when the concentration is more than 70%,the slurry will undergo liquid-solid conversion.The external cause of self flow and pressure pumping is that the superfine full tailings filling slurry can bleed water and form a stable water film.The polycarboxylate-based superplasticizer can obviously improve the fluidity of the slurry.When the plasticizer content is 0.50%-1.00%,the fluidity of the slurry with high concentration (68%-72%) and medium to high cement-sand ratio (1∶6、1∶4) can be greatly improved to meet the transportation conditions.For the slurry with high concentration (68%-72%) and low cement-sand ratio (1∶8),the plasticizer content needs to be increased to more than 1% to make it have better transportation.