Research on drawing three-dimensional washability surface of coal

In order to reflect the situation of coal washability and mass distribution more fully,this paper based on traditional washability curve,served the size fraction and size consist as the third shaft,using MATLAB software,by cubic interpolation（cubic） of the two-dimensional interpolation（graddata） method,the three-dimension cumulative float surface,densimetric surface and near-density surface were drawn.By the two-dimensional interpolation,it can inquire theory separation index under any size fraction by float ash and float production.It has certain reference significance for evaluating the coal’s washability.