The retarding phenomenon appeared in the paste filling of a lead-zinc mine and it was ameliorated after adding coagulants. To optimize the paste material ratio under addition of coagulants, we carried out a uniform design experiment. The effects of paste concentration and sand-cement ratio on bleeding rate, fluidity, backfill gradient and paste strength were investigated. The results show that the paste bleeding rate, fluidity and backfill gradient were mainly influenced by concentration, and they were negatively correlated with the concentration. The sand-cement radio had a small impact on fluidity but a major impact on paste concentration. The smaller the sandcement ratio was, the larger the intensity of paste was. Based on the ratio ranges corresponding to the four indices of bleeding rate, fluidity, backfill gradient, and paste strength, the recommended ratio is 75% to 76% and the sand-cement ratio is 7:1 to 8:1.

uniform design  /  optimization of mix proportion  /  paste backfill