Belgium took the lead in the 22nd minute when Alexander Hendrickx scored from a penalty corner in the seventh minute before Sebastian Dockier (27th minute) made it 2-0 in the second quarter.
Argentina fought hard in the second half and pulled one back in the 42nd minute through Agustin Mazzilli's field strike.
Thereafter, the Argentines tried hard and kept putting pressure on the opponents in search of the equaliser but failed to break the resolute Belgian defence.
Argentina will play Great Britain in the fifth to eight place classification matches tomorrow, while Germany will face Canada in the play-off game on Saturday.