The refinery is located adjacent to Jubilee's large stockpiles of zinc, lead and vanadium contracted from BMR Group.
Jubilee said the refinery would save it from having to build another, reducing the waiting period before first metal was delivered by around 18 months to within a year of the acquisition.
It would also reduce the project capital to produce first metal by around £18.32 million.
Jubilee said it had already secured Zambian ministerial approval for the deal.
The company will finance the deal through a combination of debt and equity, having secured £11.07 million in equity and a convertible loan note of £6.11 million.
The funding will also go towards delivering its nearby Kabwe project.
Jubilee will pay US$6 million within five business days after the closing date of the deal, then make two $3 million instalments, the first either 30 days after the refinery is converted to a zinc processing plant or within six months from the closing date, whichever comes first.
The third and final payment will take place either 30 days after commercial production begins, or six months after the second payment.
The refinery will ramp up over two years from an initial processing rate of 20 tonnes per hour producing zinc concentrate and vanadium pentoxide to 40tph of zinc metal, vanadium pentoxide and lead concentrate.
As Sable Zinc ramps up to full capacity, Jubilee aims to produce over 8,000t per annum of zinc, 1,500tpa of vanadium and 15,000tpa of lead as it ramps up to full capacity.