Study On Magnesium Aluminum Silicate Prepared By Blast Furnace Slag And Its Modification

Recently the main utilization mode of metallurgical solid waste blast furnace slag is still the field with low added value such as building materials,resulting in the failure to fully utilize many valuable components in blast furnace slag and causing resource waste.Blast furnace slag contains silicon,magnesium,aluminum and other valuable elements,which can be used for preparing magnesium aluminum silicate.Based on this,this paper studies the preparation of magnesium aluminum silicate by solution precipitation method and hydrothermal method.XRF,XRD,infrared spectrum,scanning electron microscope,analysis of whiteness and other modern detection and analysis methods were used to detect and analyze the samples,and compared with magnesium aluminum silicate extracted from minerals and prepared with chemical reagents.Finally,the samples were modified by surfactant and reductant methods.The main conclusions are as follows:?1?In the process of preparing magnesium aluminum silicate from blast furnace slag,the residual sulfate ion has obvious influence on its dispersion performance.When the residual SO₃ content is more than 3.62%,it has no dispersing ability.When the residual SO₃ content was lower than 1.26%,the product dispersion is significantly improved.Solution precipitation samples preparation as the amorphous,the best reaction temperature is 75?;After increasing the SiO₂ content,the sample dispersion is improved to a certain extent,but the SiO₂ content did not change after increasing to53%.The sample is amorphous without sodium silicate in hydrothermal method,and the sample have good dispersion.The sample is crystalline with sodium silicate added,and the dispersion and whiteness are reduced.?2?The content of SiO₂ in samples prepared by blast furnace slag is as low as45.47%,followed by samples prepared by chemical reagents by 61.18%,and the content of SiO₂ in mineral extract samples is as high as 72.99%.Mineral extraction samples were crystalline,chemical reagents and bf slag samples were amorphous,and bf slag samples were crystalline after adding sodium silicate by hydrothermal method.The mineral extraction samples have obvious intergranular boundaries,and the chemical reagent and bf slag samples have fuzzy particle boundaries,loose structure and small particle size.The whiteness of the samples prepared with chemical reagents was 97.4%.The mineral extraction samples were followed by 65.6%.The whiteness of samples prepared by bf slag is the lowest 55.1%.Mineral extraction samples and chemical reagent hydrothermal samples have better dispersion,chemical reagent solution precipitation samples have worse dispersion,bf slag hydrothermal samples without sodium silicate have better dispersion,and other samples have worse dispersion.?3?After the modification with sodium hexametaphosphonate and triethanolamine,the particle size of the sample did not change significantly,but the particle morphology changed into a fluffy ball and a floccus structure,and became a large particle composed of many fine particles.The specific surface area of the sample increased from 409.59m²/g to 481.73m²/g and 509.12m²/g,respectively.In comparison,triethanolamine had a better effect on improving the dispersion of the sample,with the optimal dosage of 4%.After the reduction treatment with hydroxylamine hydrochloride,the sample whiteness was improved to a certain extent.The optimal amount of hydroxylamine hydrochloride was 1:2,and the sample whiteness was the highest at 62.7%.Continue to increase hydroxylamine hydrochloride dosage,No new infrared absorption peaks appeared in the samples.