| Green high-performance is today’s development direction of cement-based materials, and the technology of adding admixtures to the traditional cement is one of the main methods to attain high performance. The study about lithium-slag used as the cement admixture has attracted more and more attention in recent years, and the procoagulant application of microwave to concrete as an efficient and clean energy has also been studied. However, the current research and development works in this area are lack of reference for the process parameters and related basis of engineering application because of being still in its infancy. Therefore, the further research on procoagulant performance of lithium-slag and microwave to sulphoaluminate cement (SAC) will be conducted in this paper, so as to obtain the experimental results with reference value.Firstly, the rapid determination method of lithium-ion in lithium slag was studied. The suitable conditions of the spectrophotometric determination of trace amounts lithium-ion under the normal temperature were obtained through the conditions test and the investigation of lithium-ion linear measurement range. The results show that the absorbance curve of lithium-ion fits well the Lambert-Beer law over the concentration ranges of0.1-0.5mg/L and0.5-2mg/L. The absorption coefficients are0.223L/(mg·cm) and0.031L/(mg·cm) respectively.Secondly, the method and effect for microwave to activate lithium slag was explored. By measuring the effects of microwave power, action time and pH on the precipitation amount of lithium salts, the suitable conditions of microwave activating lithium slag were obtained as pH=2,50%of microwave power,0.4of mass ratio of slag to water, and3minutes of reaction time. The maximum lithium-ion precipitation per70g lithium-slag is about7mg in this condition, being17times more than the amount of free lithium-ion in unactivated lithium-slag.Subsequently, the effects of different admixtures amounts on the condensation strength of SAC slurry were studied and compared, using original lithium-slag and lithium-slag activated by microwave as the admixtures. The results show that the initial and final condensation time of SAC slurry can be shortened when the addition amounts of original lithium-slag are5%and10%. The Id and7d compressive strength of SAC slurry with5%original lithium-slag are all higher than the pure test block, but its28d compressive strength is slightly lower than the pure test block. The addition of microwave-activated lithium-slag can further reduce the initial and final condensation time, and enhance the early compressive strength.Finally, the procoagulant performance of microwave on SAC slurry was researched by comparing the influence of different microwave power, action time and procoagulant methods on the compressive strength of test block of SAC. The procoagulant conditions of microwave optimized in this study are10%of microwave power,5min of action time,5min of curing time and1h circulation procoagulant, respectively. Under these conditions, the integrity of test block can be guaranteed, and its1h compressive strength can be up to3.8times more than that of natural curing conditions.The research results indicate that the activity of lithium-slag activated by microwave can be enhanced; the use of microwave can further shorten the condensation time of SAC slurry and improve its condensation strength. These measures can greatly improve the production efficiency and the utilization rate of mould, provide the guidance for actual preparation of cement products, it has potential industrial application value. |
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