Study On Active Excitation Of Steel Slag And Application Of Building Materials

Steel slag is the industrial waste generated from steelmaking.Compared with the comprehensive utilization rate of nearly 100%in developed countries such as Europe,the United States,Japan,and other countries,the comprehensive utilization rate in China is only 30%.The main mineral components of the steel slag are RO phase,olivine,magnesium rhodomes,C₂S,C₃S,C₄AF,C₂F and so on.The steel slag has similar substances as the cement cement composition:C₂S,C₃S,C₄AF,and C₂F,which lays the potential for steel slag as a cementitious material.However,due to its low hydration activity and difficulty in grinding because of its hard texture,its use as a building material has been limited.In this paper,the combination of physical excitation and chemical excitation fully stimulates its performance as a cementitious material,and a series of microscopic characterization methods are used to elucidate the relationship between its macroscopic strength and microscopic properties.In this paper,molasses,triethanolamine and its esterification products were used to compound active grinding aids for steel slag.The efficiency of grinding aids was studied,and the mechanism of its action was analyzed.The results show that triethanolamine and octanoic esterification products and molasses compounded into the grinding aid for the best effect,when the blend ratio of 0.04%,the specific surface area of 545m²·kg-¹,compared to the blank sample to improve 87%.The 45μm sieve residue is 5.03%,and the remaining 80μm sieve is 0.54%,which is 13.17%and 5.69%lower than the blank group respectively.The 3 to 32μm ratio of C34 reached 68.92%.The content of 32-60μm is reduced by 30percentage points compared with the blank group,the content greater than 60μm is reduced by 20 percentage points,and the grinding effect is significantly improved.The effects of four different single-doped activators,such as sodium sulfate,sodium silicate,sodium aluminate,and silica fume,on the activity of steel slag were studied.The strength and microscopic properties were compared and analyzed.The results showed that the early strength of the sodium sulfate was better.When the blend ratio was 1%,the compressive strength at 3 days was 22.3 MPa and the compressive strength at 7 days reached 32.9 MPa.The score is characterized by weak early strength and high late strength.The 28 d compressive strength at a blend ratio of 46.7 MPa was 46%higher than that of the blank group.By XRD,FTIR,SEM and TG-DTG analysis,the amount of Ca（OH）₂ in the hydration product is relatively small,and the number of AFt crystals and C-S-H is more,indicating that the structure is compact and the intensity is good.In this paper,the compound activator was also studied based on the single-doped activator.Four different compound activators were analyzed.The results showed that the optimal compound activator was:silica fume:sodium silicate=1:1,the amount was 2%,and its 28d strength reached 47.3 MPa.Through microscopic analysis,the cement test block is filled with C-S-H gel and needle-like AFT ettringite,filling the pores between the cement test blocks,and promoting its strength.