Ranking system?

I really enjoy the new update and the new DLC, but I still dont get the ranking system in this game.. I played the 10 matches that you have to play in order to acquire a rank. I ended up winning 8 out of the 10 matches with a K/D of at least 2 each game, several of matches with even higher, despite this I was put in Silver II! Can someone explain to me how this ranking system works?