Study On Solidified Agent Of Tailings Soil And Strength Of Solidified Tailings Soil

In this paper,the problems of land occupation and environmental pollution caused by the stacking of tail residue are solved,and the solidification and recycling of the tail residue is taken as the background.Using slag powder,sodium sulfate,cement,reinforcing powder and fly ash as basic components,the optimal mix proportion of solidified agent was obtained through mix design,and a kind of solidified agent for tailings soil was prepared.At the same time,the paper studies the curing reaction mechanism between the tailings and the curing agent,and the influence of different amount of activator,admixture and fiber on the curing strength of the tailings.The experimental results are helpful to solidify the tailings to produce building materials for engineering application.The results show that:(1)The optimum mix proportion of solidifying agent is 58% of slag powder,13% of sodium sulfate,16% of cement,8% of reinforcement powder and 5% of fly ash.The analysis shows that with the increase of slag powder and fly ash content,the compressive strength of solidified tailings gradually decreases,and with the increase of sodium sulfate,cement and reinforcement powder content,the compressive strength of solidified tailings increases.Sodium sulfate and cement can improve the early curing strength,but not the late strength.By comparing the curing agent with other cementitious materials,it can be found that the curing strength of the curing agent in this paper is significantly better than that of cement,and the economic cost of the curing agent is also significantly lower than that of ordinary cement.(2)The increase of strength of tailings by curing agent is mainly due to the formation of ettringite and hydrated calcium silicate by pozzolanic reaction after the mixing of tailings and curing agent.A large number of ettringite crystals and amorphous calcium silicate hydrate formed the skeleton that is filled in the middle of tailings particles,the macroscopic reaction is that the compressive strength of tailings increases with the age.(3)Sodium silicate activator can improve the compressive strength of solidified tailing soil,and it has obvious effect on improving the early 7d compressive strength,and the optimum dosage is 9%.With the increase of Na OH activator content,the compressive strength of tailing soil increases continuously.When sodium silicate and sodium hydroxide are mixed together,it is found that the effect of increasing the curing strength is better than that of single activator.Both polypropylene fiber and basalt fiber can improve the compressive strength of solidified tailings,but there is an optimal content.The two kinds of fibers can improve the flexural strength of solidified tailings,and the longer the fiber length,the better the effect.The failure toughness of polypropylene fiber solidified tailings is significantly stronger than that of basalt fiber.