| Environmental and safety issues resulting from iron tailings has become serious asiron tailings piled up got more and more during the development of mining industry,thus it has been social wildly focused. Contemporarily, the increasing demand forcement as economy advances has brought about a series of environmental problems.Preparation of cemented filling materials through iron tailings can not only solveproblems brought by iron tailings, but also relieve ones by cement industry. To explorethe feasibility of preparation of cemented filling materials through iron tailings, thispaper took iron tailings from Heishan(in Hebei province) as research objects andmotivated its activity by varied kinds of methods. Basic characteristics of iron tailingswas studied systematically by XRF、XRD、SEM methods and so on. Stimulating effectsof aluminum activity in iron tailings was researched by different stimulating ways andcemented filling materials meeting the requirements produced. Final conclusions areshown below:Silicon and aluminum content in iron tailings are11.82%and6.44%respectivelythrough basic characteristics researches. This kind of iron tailing belongs to low-siliconiron tailings for low silicon and aluminum content. Its main phases include clinochlore、chlorite and nepouite in which silicon and aluminum exist. Through the microstructureanalysis, original iron tailings has irregular lamellar structure possessing rough surface,large porosity, loosen texture, bad gelling property and uneven particle size sdistribution to the disadvantage of hydration reaction.Through the alkali solution leaching test on the iron tailings，the leaching solubilityof the silicon is282ug/mL and the aluminium is29.4ug/mL; The activity of silicon andaluminum cannot be enhanced by the thermodynamics activation way. Under differentcalcining temperature and time, leaching solubility of silicon and aluminum changesslightly, also the activation level is very low; The activity of silicon can be effectivelylifted by Alkali fusion way which can improve the activity of silicon、aluminum, andwith the increase of the amount of NaOH added.Through single factor experiment on the mass ratio of NaOH and iron tailingswhich can influence the activity of silicon, aluminum in the alkali solution leaching test,the result shows that with increasing of the mass ratio of NaOH and iron tailings,leaching solubility of silicon and aluminum is also increased; When the mass ratio of NaOH and iron tailings reached to1.1, leaching solubility of silicon and aluminumreached to the maximum.The alkali solution orthogonal experiment research shows that the importance ofthe factors influence the activity of silicon and aluminum is C (the mass ratio ofNaOH/iron tailings)> B (calcining time)> A (calcining temperature);The influence offactor A and factor B is not significant; Factor C can influence significantly on theactivity of silicon and aluminum; In the alkali solution test of iron tailings,thecombination of the calcining temperature which is350℃, the calcining time which is60min, the mass ratio of NaOH/iron tailings is1.1is the best.The study of the effectabout the mass ratio of NaOH/iron tailing and NaNO3/iron tailings to improve theactivity in the iron tailings has been done, by the two factor analysis of varianceexperiment. The result shows that the activity of the silicon and aluminum in the irontailings cannot be improved by salt melt test. Through change the mass ratio ofNaOH/iron tailing and NaNO3/iron tailings, the impaction of improving silicon activityis not significant. But changing the mass ratio of NaNO3/iron tailings to impactaluminum activity is significant.The result shows that the test pieces, which was prepared by iron tailings and thethermodynamic activated iron tailings, has no strength, by mortar strength test. Averagestrength of the test pieces is1.18MPa, which was prepared by the salt melt iron tailings,and average strength of the test pieces is high to8.14MPa, which was prepared by alkalifuse iron tailings. |
PDF Full Text Request