To recombine is to mix or merge two or more things again. If you lose track of how much baking soda you've added to your cake batter, you might decide to start over and recombine the ingredients more carefully.
A collage artist who explores similar themes in different works might tend to recombine the same images again and again. And a scientist studying chemical reactions might recombine chemicals dozens of times before reaching a conclusion. When you combine things, you merge them together. The Latin roots are com-, "together," and bini, "two by two." The re- prefix adds the sense of "again."