It said it wants to restart operations as soon as possible, following the refinery's closure in early February.
Gunvor said the deal was expected to be completed formally within 6 to 8 weeks, and had support from the local and Belgium state authorities.
The Antwerp plant has a processing capability of more than 100,000 barrels per day (bpd), and storage capacity of more than 1.2 million cubic metres, Gunvor said.