Study On Synergistic Preparation Of Glass-ceramics From Iron Tailings,Fly Ash And Nickel-iron Slag

With the increasing demand for iron and steel materials and coal-fired energy supply,The discharged iron tailings,fly ash and nickel-iron slag are increasing.However,the recovery efficiency of iron tailings,fly ash and nickel-iron slag is low in China.Most of them are stored in the open air,and dust will be brought into the air in windy weather to form haze,which seriously affects human living environment.Therefore,it is very important to study the synergistic preparation of glass-ceramics from iron tailings,fly ash and nickel-iron slag for improving the recovery and utilization of iron tailings,fly ash and nickel-iron slag and solving their environmental protection problems.According to the composition of iron tailings,fly ash and nickel-iron slag and the ratio requirement of CaO-MgO-Al₂O₃-SiO₂ glass-ceramics,the total content of iron tailings and fly ash is fixed at 70%.Among them,the iron tailings are 45%,50%,55%,60%and 65%,respectively.The proportion of nickel-iron slag and carbide slag is fixed at 20%,of which the amount of nickel-iron slag is 0%,5%,10%,15%and 20%respectively.The additive content is10%.And the corresponding glass-ceramics were prepared by melting method.XRD and SEM were used to test the crystalline phase and morphology of samples with different raw material ratios,and the optimum ratio was determined by combining the mechanical properties and other data.The experimental results show that:there is synergistic effect among iron tailings,fly ash and nickel-iron slag.With the increase of iron tailings and nickel-iron slag content,the bending strength of microcrystalline samples first increases and then decreases.The mass loss rate increases slowly in acidic solution and decreases slowly in alkaline solution.The optimum ratio of raw materials is 50%iron tailings,20%fly ash and 5%nickel-iron slag?The test number is 2#?.The bending strength of the sample is as high as 183.90 MPa.The crystalline phase of the sample is anorthite and ordinary pyroxene,and the crystallization degree is high.Based on previous experiments,the effects of nucleation and crystallization on the properties of 2#were further studied by orthogonal design experiments.The results show that:the optimum heat treatment methods of 2#raw material ratio are nucleation temperature755?,nucleation time 90 min,crystallization temperature 970?and crystallization time120 min.The order of influence degree of four heat treatment factors on the properties of glass-ceramics is:crystallization temperature>crystallization time>nucleation temperature>nucleation time.The crystallinity of glass-ceramics increases gradually with the increase of crystallization temperature,but too high crystallization temperature will lead to the decline of the properties of the samples.Crystallization time determines the process of grain growth,and too short time will lead to the grain grow incompletely,and too long time will lead to the grain grow excessively.The results of flexural strength test and corrosion resistance test show that,the maximum flexural strength of microcrystalline samples obtained by optimum heat treatment process can reach 223.31 MPa,the corrosion proportion in H₂SO₄ solution is 0.302%,and the corrosion proportion in NaOH solution is 0.31%.The microcrystalline samples obtained by optimum heat treatment process are excellent green building materials.