Application Research Of Slag-based Curing Agent

Currently, most of the mine tailings have been filled with cement as stabilizer, but the cement performs poorly during cementing partial small, partial acid tailings, and there is a small water-cement ratio adjustable range, high energy consumption and environmental pollution. However, the slag is a kind of large industrial waste which is produced in blast furnace process and it has high potential activity. Replacement of cement with slag can reduce the heat of hydration, improve workability and durability of filling, and can be effective use of resources, energy saving, lower costs. Therefore, the study of slag as the main raw material for the stabilizer has an important strategic significance greatly.Slag-based stabilizer KL is prepared by selecting pyrite full-tailings as the research objectbased on the analysis of the raw materials' basic performance and choosing the appropriate materials. Through experimental study on its performance and it has been applied in actual engineering. On this basis, X-ray diffraction(XRD) and scanning electron microscope(SEM) are adopted to reveal the cementing mechanism of tailings filling with KL, which will provide theory evidence and technical support for the further study and application strongly.KL is a low-alkali excitation stabilizer used slag as main raw materials, which can effectively improve the residual sulfur in the tailings damages the filling in later period. When used KL cementing mine tailings, in the conditions of cement sand ratio(ratio of dry material) is 1:4~1:8, the mass concentration of filling slurry is 60%~68%, the compressive strength of filling can meet the requirements of mine tailings filling,and the largest mass concentration of filling slurry can reach 68% to meet the pipeline gravity transportation. In the same conditions, the performance of KL is better than the cement and “cement +fly ash”, and the strengths of filling are higher in early period and more stable in later period, its compressive strength can respectively reach 6.0 times and 3.6 times of cement and “cement +fly ash” at 90 days, which can also result in superior durability and less pollution to the environment. The micro-test results show that KL cementing the tailings as the main hydration product is ettringite(AFt) and calcium silicate hydrate(C-S-H) gel. AFt mainly concentrated in early generation, in later period the main product is the C-S-H gel. AFt can't generate or generate very little in the late, it won't destroy the formed C-S-H gel structure and ensure the durability of the filling. Pilot field application shows that KL filling the pyrite full-tailings has good flow properties and mechanical properties, which achieved the ideal filling effect and can realize large-scale application.Meanwhile, studying on the feasibility of KL applied to hydraulic groutingoffers a new way to develop a new hydraulic grouting material. Studies have shown that KL can meet the requirements of the standard on the material, and has a certain groutability. Compared with the cement slurry, KL slurry has better bleeding ratio and stone rate, high calculus strength but needs longer setting time. Improving the fineness of materials is adopted to solve this problem, but it will against slurry fluidity and increase energy consumption and costs.Slag is a kind of large industrial waste, it can be regarded as main raw materials of cementing material applied in the mine tailings failing and hydraulic grouting, which has a good performance and can effectively utilize industrial waste, conserve resources and energy, protect the environment in line with national sustainable development and has a very broad prospects.