| Anhui huainan and huaibei mining area are the important coal production base in China,coal gangue is produced with the development of coal resource.Large amounts of coal gangue stockpiling not only take up a lot of land,and cause some contamination of environment around the mining areas.Currently clay is the most normal silicon aluminum material in cement industry in our country,with the increase of the state environmental protection strength,find suitable silicon aluminum resources is very important.The mainly chemical composition of coal gangue is SiO2 and Al2O3,the usage of coal gangue in cement industry not only can save a lot amount of land resources,coal gangue can also be fully utilized,conform to the sustainable development views in the cement industry.A coal gangue from huainan mining area is chosen to be silicon aluminum material,the reasonable formula and thermal process in the preparation of cement clinker is explored,the burnability of raw meal with different formula and thermal process is analyzed,the chemical composition and mineral composition of clinkers are analyzed.The clinker and gypsum are mixd by a ratio of 96:4 to prepare the cement,a variety of means of the analysis of hydration heat,chemical combination water,compressive strength and XRD are combined to summarize the influence rule and the mechanism of the hydration process and macroscopic properties of cement.Based on the reasonable formula of coal as silicon aluminum material gangue using in raw meal is verified,fluorite and phosphorous slag are chosen to be mineralizer,the influence rule and mechanism of mineralizer on calcining process are researched.The main conclusions are as follows:(1)Using coal gangue as silicon aluminum material to prepare cement clinker,when the KH was in a range of 0.89 to 0.95,IM was in a range of 1.2 to 1.6,SM was in a range of 2.1 to 2.6,the calcinations temperature is 1400?,soaking time is 30 min,the cement raw meals can been transformed into clinker,and the f-CaO contents are all below 2%;when the content of limestone in raw meal is high,appropriated extend the soaking time can obviously reduce the content of f-CaO in clinker.(2)The mineral composition of clinker prepared by coal gangue is similar to clinkers prepared by clay,mainly C3S?C2S?C3A and C4 AF,the ratio of each mineral composition in clinker is reasonable.The content of C3 S increases with the value of KH.(3)3d compressive strength for pure paste of the cement prepared by coal gangue is substantial increased compared with P?42.5 cement,28 d compressive strength for pure paste of the cement can achieve the same level.(4)In the scope of the setting modulus,with increase of KH,the hydration heat quantity of the cement is increased in 72h;with decrease of IM,the hydration heat quantity of the cement shows a trend of increases first and then decreases;with decrease of SM,the hydration heat quantity of the cement decreases.(5)The hydration products of cement prepared by coal gangue is similar to cement prepared by clay,mainly ettringite,calcium hydroxid,unhydrated C3 S andC2S.With increase of KH and calcining temperature,the content of chemical combination water of cement is increased,indicate that the hydration degree increases.(6)Phosphorous slag composite mineralizer is effective in improving burnability of raw meal,and phosphorous slag can provide CaO,a certain amount of limestone is saved.When sintering temperature from 1300? to 1400?,the effect of phosphorous slag composite mineralizer is still obvious.Phosphorous slag composite mineralizer increase the amount of liquid and decrease viscosity,accelerate the solid phase reaction. |
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