Study On Application Of Ferronickel Slag In Cement And Concrete

As the growing shortage of resources and energy and the introduction of national environmental policy in China, the comprehensive utilization of ferronickel slag has attracted more and more attention. On the other hand, China cement and concrete industry is facing severe problems, including energy shortages, environmental damage and other serious problems. the adoption of ferronickel slag as cement and concrete could not only consume a large number of ferronickel slag and solve the environmental problems of the metallurgical industry, but also can find a large amount of raw material sources for the production of cement and concrete.This hesis makes a comprehensive analysis on the characters of ferronickel slag from Shandong Xinhai Technology Co., Ltd, focuses on the study of ferronickel slag in cement and concrete application and the chemical activation of ferronickel slag-cement composite cementitious material. The main research works and results are listed as follows:The comprehensive analysis of the ferronickel slag features found that the ferronickel slag, containing C2 S, C3 S, a lot of vitreous and other mineral phase, has the potential to be used as cementitious materials, but CaO content in ferronickel slag is low and MgO content is high; Through studying the influence of grinding time on ferronickel slag fineness, specific surface area and activity, we chose specific surface area of 461m2/kg, 45μm sieve 7.03%ferronickel slag as subsequent trials raw material; In addition to low alkalinity, ferronickel slag physical properties meet the two grade steel slag powder of GB/T 20491-2006;Ferronickel slag are mostly irregular angular particles and its surface structure is compact and smooth; Reasonable distribution of ferronickel slag particles have the effect of filling and compaction.The study of ferronickel slag application in cement shows that, when ferronickel slag used as cement admixture, the best content is 15%; ferronickel slag can significantly reduce the hydration heat release rate and hydration heat of cement system; the appropriate proportion is 1:2 when ferronickel slag and mineral powder used as cement admixture; When ferronickel slag, mineral powder and fly ash used as cement admixture, the appropriate proportion is 1:2:1; With the increase of ferronickel slag, ferronickel slag- mineral powder,ferronickel slag-mineral powder-fly ash admixture dosage, cement standard consistency water demand is gradually increasing, the setting time is prolonged, the strength is gradually decreased, and the stability is qualified. Under the same dosage, the composite admixture is helpful to improve the strength of the cement system.The study of ferronickel slag-cement composite cementitous material chemical activation shows that: The optimum content of calcium oxide is 3%, the optimum content of water glass is 1.5%, the optimum content of sodium sulfate is 1.0%, the optimum content of compound activator is 1.5%; The activation effect of compound activator-HY is the most significant which can make the activity of ferronickel slag achieve the level of steel slag requirements; Activator can accelerate the hydration rate of ferronickel slag, make ferronickel slag-cement composite cementitious material system hydration hardening structure more compact and the strength could be greatly enhance.The study of ferronickel slag application in concrete shows that: When ferronickel slag replace cement, with the increase of ferronickel slag to replace cement, the slump of concrete increases gradually and ferronickel slag to replace the best cement content is 15%; When ferronickel slag instead of fly ash, with the increase of ferronickel slag to replace fly ash, the concrete slump is first decreased and then increased. When the ferronickel slag replaces 40%fly ash, concrete slump is the worst; When the ferronickel slag instead of fly ash is 60%, the highest compressive strength of concrete, the compressive strength of concrete is the best.When ferronickel slag, mineral powder, fly ash used as concrete admixture, the appropriate proportion is 1:2:1, and the concrete admixture’s appropriate proportion is 30%.