I think that just lasts while you have morning sickness i had the same problem and after getting into 2md trimester currently 14 weeks the taste is gone thank God! :)
I am a couple of days from being 16 weeks and I still have morning sickness. I know the taste of metal very well. It was I til recently that I was able to regain my taste back. What helped me was brushing me teeth after every meal and drinking plenty of cold water.