Development And Proportioning Optimization Of Alkali Activated Mineral Admixture Copper Slag Based Cementitious Material

Copper slag as a large amount of industrial solid waste,because of its low activity,difficult to develop,low degree of resource utilization,a large number of copper slag accumulated on the surface,occupy land and lead to environmental pollution.The vitreous content of waterquenched copper slag is high,which can be developed and used as cementing material.The vitreous content of slow-cooling copper slag is low,and it is mainly used as mineral admixture because of its low activity.In this study,a method combining laboratory test,detection analysis and theoretical research was adopted to prepare a new type of copper slag-based cementing material with water-quenched copper slag(later referred to as copper slag)as the main raw material,along with alkali activator and mineral admixture.The main research contents and conclusions are as follows:(1)Exploring experiment of single alkali-doped activatorThe effect of sodium hydroxide,sodium silicate and sodium silicate on the compressive strength of copper slag paste was studied.The results show that the copper slag paste has almost no strength without alkali activator.When different alkali activators are used to stimulate the copper slag,the compressive strength of copper slag first increases and then decreases with the content of alkali activator,Compared with several different alkali activators,sodium silicate has the most significant effect on the activation of copper slag.(2)Exploration of single mineral admixturesThe results show that there are significant differences in the mechanical properties of copper slag modified by three kinds of mineral admixtors.The modification effect of L on the mechanical properties of copper slag is the most significant,while the modification effect of silica fume and fly ash on the mechanical properties of copper slag is not obvious.(3)Optimization of the ratio of copper slag-based cementitious materialsThe orthogonal experiment with three factors and four levels was carried out to determine the optimal ratio scheme(modulus(1.3),alkali equivalent(10%)and mineral admixture(30%)).The alkali equivalent factor has the most significant effect on the compressive strength of copper slag at various ages.(4)Microstructure analysis of copper slag-based cementification test blockScanning electron microscopy(SEM)experiments were carried out on copper slag powder and copper slag-based cementing test block.According to the observation and analysis,the hydration reaction of copper slag excited by alkali activator is obvious,and the hydration degree of copper slag modified by mineral admixture is obviously better than that of single alkali admixture.(5)Analysis of hydration products of copper slag-based cementitious test blocksComparative analysis of the hydration products of copper slag powder and copper slag-based cemented test blocks was carried out.It was found that the hydration products increased significantly and the strength increased significantly after the alkali excitation and mineral admixture modification of copper slag.(6)Toxicity leaching test analysis of copper slag and copper slagbased cementification test blockToxic leaching tests of copper slag and copper slag-based cementification test blocks were carried out.The results showed that the concentration of heavy metals in copper slag,copper slag-based cementification test blocks for 3d and 28 d were all lower than the limit of the toxicity identification standard of solid waste leaching,and the concentration of heavy metals in copper slag leaching solution was higher than the limit of the concentration of heavy metals in the tertiary water quality standard.