Abstract: The hydration condensation of unclassified-tailings paste filling slurry of a lead-zine mine is slow,which seriously affect the process of filling operation,the aggregate sinking phenomenon of the aggregate filling slurry is prone to exist,which lead to the slurry segregation phenomenon is appeared,so,the quality of filling slurry is affected seriously.The mechanical model of paste in filling slurry is established to analyze the influence of sodium sulfide to hydration condensing properties of the paste in a lead-zine mine.The zinc nitrate is mixed with unclassified-tailings paste filling mixture slurry with different proportion,the test result show that the slurry condensation is slowed by zinc ions in unclassified-tailings.Based on the above analysis results,the sodium sulfide with different proportion is mixed with the mixture slurry to obtain the new paste slurry,the test results show that the coagulation effects of sodium sulfide to paste slurry is existed,with the increasing of additive amounts of sodium sulfide,the initial condensation time of paste slurry with the linear decreasing regularity approximately,with the addition of sodium sulfide,the strength of the paste test blocks with condensation 7,14,28 d,the ideal additive amounts of sodium sulfide of the corresponding maximum strength of the paste block is 1%～1.5%.The above test results further show that the zinc sulfide sediment is formed by combing with sulfur ions and zinc ions of paste slurry,the hydration and condensation process of paste slurry are promoted by alkaline slurry environment formed by sulfur ions hydrolysis.

Key words: Paste filling, Sodium sulfide, Hydration, Condensation time, Strength