Thank you @craigastewart ! ^^)
Well, for the matching of tiles, I delete all the voxels of my scene excepted the line of voxels of a border that I move to the opposite border, and I draw my new tile from this line.
For the emissive effect on sketchfab, I create a new texture in black and white that I add to the emission settings of the material. But this method is mainly for adding a bloom effect in the right place. In fact to set my work on Sketchfab, my workflow is the following :
After I've finished my scene to re-built my scenery in blender, I create a new uvmap for each tile in addition to the colors uvmap generated by magicavoxel. Now each tile have got two uvmappings. This new uvmapping serves me either to bake the ambient occlusion and ligths on a new texture that I add to the lightmap in the material settings on Sketchfab, either to bake the AO, lights and colors on the same texture.
After that I add my emissive texture and I play with The bloom effect on Sketchfab.
The result is the following :
With this method I have almost the same result like in my render. I hope I answered your questions and sorry for my english. ><'