A novel data fusion technique is presented that combines X-ray computed tomography (CT) and electron probe microanalysis to investigate fly ash particles. The technique is called Tomography Assisted Chemical Correlation (TACCo). This technique fuses 2D compositional data with 3D X-ray CT data. The method produces 3D constituent and microstructure maps. Results and observations are presented that show the power of the technique for data visualization as well as quantitative analysis. Published by Elsevier Ltd.