| As a kind of new green cementing material, geological polymer has become the research hot spot and been paid for much attention because it has high strength, harden fast, better corrosion, high temperature resistant and many other features and a variety of solid wastes which rich in active silicon alμminμm component such as slag, fly ash and coal gangue can be used as the main raw material and realize "grey" cement to "green" change. This paper is a subproject of the national natural science foundation of China coal joint project 《research of gangue in cement and concrete resource utilization of key scientific problems》. All the research results are funded by this foundation.At first, this paper adopts the method of thermal activation and mechanical activation, stimulate the potential activity of coal gangue. Next use activated coal-gangue, slag and fly ash as the main material, under the action of an alkali silicate (chemical activation), to prepare coal gangue, slag-fly ash geopolymer, emphasis is on the composite activation technology of coal gangue. First step select activators aging time, potassiμm hydroxide dosage and activator varieties three factors, according to the orthogonal table L16(45), the experimental study on flexural and compressive strength of mortar as objective function, and determine the optimal mixing proportion of geological polymer ligand; The second step on activation of coal gangue to thermal, mechanical and chemical, choosing the dosage of calcination temperature, grinding time and stimulating agent as the impact factor, through univariate comparison tests, determine the best dosage interval factor; The third step using quadratic response surface central composite design to do the experiment research, and establish coal gangue-slag-fly ash geopolymer activated coal gangue and its activity corresponds to the corresponding parameter in quantitative relationship between erode. Specific research contents and results are as follows:(1) Coal-slag-fly ash geopolymer ligand optimal solution is:activator varieties of sodiμm silicate and potassiμm hydroxide, potassium hydroxide content is 25% (representing activator), the ligand aging time 48h. The effect factors on strength of mortar in order of size:Excitation agent type> potassiμm hydroxide dosage> aging time.(2) Fuxin Qinghemen mine gangue:①when calcining temperature at 650℃～750℃ the activity is the best. The XRD and SEM analyze that the kaolinite, mica in coal gangue happened dehydration reaction with increasing of temperature, the Si ions and A1 ions in the calcined coal gangue had a largest elution amount at 700℃. Slag makes the overall structure of the hydrated slurry denser, fly ash and calcined gangue contain large amounts of aluminum, generate hydrated aluminum silicates which have a framework structure.② the optimal area of the grinding time is 1 min-3 min. Gray correlation analysis shows, particle size of coal gangue is less than 11.11μm showed a positive correlation with the mortar 3d and 28d flexural, compressive strength, otherwise showed a negative correlation,③ when the activator ligand dosage is 20%～22.5%, the strength can be prepared to meet 62.5R grade.(3) Establishment the regression equation with a good fitting degree between calcined coal gangue with temperature, grinding time, Ligand content and the strength of mortar... |
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