Optimization of process parameters for preparation of nanoscale calcined kaolinite from coal gangue
Coal gangue is rich in kaolinite resources.To address the challenges in the nanoscale preparation processes of kaolinite from coal gangue,including complex procedures,high costs,and low yield,this study employed the supergravity method to prepare nanoscale calcined kaolinite from coal gangue.The effects of rotational speed(A),reaction time(B),and material flow(C)on the particle size distribution of the calcined kaolinite were investigated through single-factor experiments.Based on these experiments,the response surface methodology(RSM)was used to fur-ther optimize the preparation parameters,with the D90 of calcined kaolinite as the response indicator.The results indicate that the regression equation for the preparation of nanoscale calcined kaolinite via the supergravity method is Y=90.60-48.50A+17.62B+3.87C-11.50AB-3.50AC+25.25BC+25.33A2+29.58B2+28.58C2.Analysis of variance shows that the quadratic terms A2,B2,and C2 have P-values less than 0.000 1,indicating that these factors significantly influence the average particle size of kaolinite.The factors affecting the D90 of calcined kaolinite are in the order from large to small:A,B,C,with the interaction terms affecting D90 in the order from large to small:BC,AB,AC.The optimal process parameters are determined to be a ratational speed of 1 900 r/min,a reaction time of 16 min,and a material flow of 1 600 mL/min.Under these condi-tions,the D90 of calcined kaolinite(N-K)is found to be 78 nm.Scanning electron microscopy(SEM)and transmission electron microscopy(TEM)analyses reveal that the calcined kaolinite prepared under optimal conditions exhibits a dispersed state with layer thicknesses within 2 nm-8 nm,charac-teristic of two-dimensional nanomaterials.
万方数据
维普
