Effect Of Different Activators On Properties Of Copper Slag Powder-based Cementitious Materials

With the increase of copper output year by year,more and more copper slag are piled up.The task of copper slag resource utilization is more difficult.Copper slag powder-based cementitious material is a composite cementitious material made up of copper slag powder and cement and other raw materials.The copper slag composite cementitious material made from copper slag and cement not only has small production energy consumption,but also can use a large number of industrial by-products copper slag.However,the cementitious materials made of copper slag can not be widely used because of its poor mechanical properties in the early stage.Therefore,Ca（OH）₂,anhydrite and Na₂SO₄ were selected as the activators to study the effect of three different activators on the mechanical properties of copper slag powder-based cementitious materials.First of all,the particle size distribution of copper slag is studied by grinding,and the influence of grinding time on the particle size distribution of copper slag is analyzed;secondly,the excitation degree of different activators with different content on the activity of copper slag is studied by measuring the compressive strength and flexural strength of copper slag powder-based cementitious materials;finally,the excitation degree of different activators on copper slag is discussed by SEM analysis The function and influence mechanism of slag activity.Through the experimental study,the following conclusions are obtained:1.Through the study of copper slag particles in different grinding time,the results show that:the grinding efficiency of copper slag almost tends to zero after grinding time more than 60 minutes;the particle size distribution of copper slag particles can better obey RRB distribution model.Through the analysis of coMParison of surface area and characteristic particle size,it is found that the particle size of copper slag particles tends to be concentrated and stable with the increase of grinding time.Considering the economic and test results,60min is the best grinding time for copper slag particles,and the grinding time has the greatest contribution to the grinding of copper slag particles.2.The excitation effect of Ca（OH）₂,anhydrite and Na₂SO₄ on compressive strength is the highest in the test group with 45%copper slag.The results showed that Na₂SO₄ had the best stimulating effect at 7d,Ca（OH）₂ and anhydrite had the best enhancing effect on the compressive strength of copper slag powder-based cementitious system at 28d,and the activating degree of Ca（OH）₂ was the highest among the three activators,while for the flexural strength,anhydrite and Na₂SO₄ had the best stimulating effect at 28d.3.by means of scanning electron microscopy（SEM）analysis,it is shown that when Ca（OH）₂ is used as an activator,the microstructure of copper slag based cementitious materials shows the highest content of ettringite（AFt）and C-S-H gel,and the bonding degree and filling rate are obviously higher than those of the control group without doping.4.Considering the compressive strength and flexural strength of copper slag powder-based cementitious materials,Ca（OH）₂ as an activator has the best excitation effect on the system in the experimental research age range,which can better reflect the superiority of its mechanical properties.