If you really want to use the deezer://
scheme, you can use the following uri :
uri = "deezer://www.deezer.com/track/"+track_id;
Edit :
You can also use some query parameters to add behavior to your link, for instance the following uri : deezer://www.deezer.com/album/10596327?autoplay=true&start_index=13
will open the deezer app on the album's page immediately and will start playing with the 14th track (0 based index).