Preparation Technology And Activation Mechanism Of Tungsten Tailing Based Composite Admixture

The long-term hoarding of a large number of tungsten tailings not only causes a waste of resources but also pollutes the surrounding environment.In order to solve the above problems and realize the reduction,resource recovery and large-scale utilization of tungsten tailings,a black and white tungsten gravity separation tailings was selected as the research object,and tungsten tailings were activated as admixtures to replace part of cement.In this paper,two processes of mechanical activation and mechanical-chemical compound activation are used to activate tailings,and the effects of the type and amount of activators on the physical properties and structure of tungsten tailings concrete admixture are studied.the optimum activation process of slag-tungsten tailings admixture is explored,and the activation mechanism of activator is expounded.The main conclusions are as follows:（1）Mechanical activation and mechanical-chemical composite activation processes can significantly stimulate the potential activity of tungsten tailings.The activity of tungsten tailings increases gradually with the increase of grinding time and then tends to smooth.When the grinding time is 60min,the compressive strength of 28d reaches 31.22MPa and the activity index is 63.48%.Mechanical-chemical composite activation can further improve the activity of tungsten tailings.The activation effect is the best when the dosage of H2 in the single activator is 0.03%,when the mass ratio of H2 to H6 in the composite activator is 1:1 and the total dosage is 0.03%,the activation effect of tungsten tailings can be significant.The activity index of 3d,7d and 28d of the test block is more than 70%,the compressive strength of 28d is increased by8.67%,and the activity index is 71.96%.（2）The later strength of test block can be significantly improved by adding slag.When the ratio of slag to slag is less than 20%,the compressive strength of the mortar test block increases greatly.The activity of mixed admixtures can be significantly improved by 0.03%H2,the 28d compressive strength reaches 44.04MPa,the activity index is 80.94%,and the cement strength index reaches 42.5.The response surface method that the order of the three factors affecting the early strength of mortar test block is grinding time>H1≥H2,and the interaction is not significant.The order of influence on the strength of mortar test block is H1>grinding time>H2,H1 and H2 interaction had significant effects.The optimal activation conditions were as follows:milling time was 104.42min,the dosage of H1 and H2 was 0.022%,the activity index of the predicted value is 81.59%,the actual value is close to the predicted value,and the result is reliable.（3）The incorporation of H1 and H2 compound agent has a certain activation effect on tungsten tailings,which accelerates the hydration of tailings test blocks,increases the compactness of slurry,and increases the compressive properties.The activity index at 7d and28d increased by 13.54%and 3.92%,respectively.The agent can accelerate the hydration of the slag test block in the early stage,but slow down in the late stage.The compressive strength of the test block increases at 3d and 7d,and the activity index increases by 8.71%and 12.14%,respectively,while the strength activity index decreases by 6.95%in the late stage.The activation effect of the reagent and the synergistic effect of the slag and tungsten tailings greatly increased the activity index at 3d and 7d,but the early hydration of the test block consumes a large amount of slag to generate Ca（OH）₂ to inhibit the hydration of C₃S and C₂S,resulting in a small strength increase in the later stage.