Thamesteel will resume production after the firm was bought by a new company owned by Al-Tuwairqi Group.
Thamesteel - at Sheerness on the Isle of Sheppey, Kent – went into administration earlier this year with the loss of more than 350 jobs.
"The sale will mean that steel production on the site can recommence with, hopefully, the recreation of a large number of the jobs lost when the company entered administration on 25 January this year," said a statement announcing the news.
Joint administrator Rod Weston, of accountancy firm Mazars, said: "This sale is very good news for Sheerness. It concludes what has been a long and painful process for all involved.
"At many points we feared the eventual outcome might be very bleak for the future of steel production on the island. However, after several false dawns, we have secured a sale to the only bidder to come forward with the intention of restarting production at the plant."
Around 350 workers lost their jobs when Thamesteel went into administration and a further 20 were made redundant at a later date, leaving fewer than 30 on the site.
Michael Leahy, general secretary of steel union Community, said: "This is fantastic news for our members who have been campaigning since the closure in January.
"We fought a long, hard campaign taking our Save our Steel message right to the heart of government and winning the backing of the local community on the Isle of Sheppey.
"It is a moment for our members to feel proud of their efforts and overcoming the challenges they have faced in recent months before we look forward to a renewed partnership with the new owners so we can bring steelmaking and jobs back to Sheerness."