Dangote Group, the company owned by Africa's richest man Aliko Dangote, said on Monday it planned to buy phosphate from Morocco and potash from Congo-Brazzaville to feed a planned fertilizer plant.
Dangote has raised a $3.3 billion loan to develop a $9 billion oil refinery and petrochemical complex in Nigeria, Africa's biggest economy and top oil producer. The group has invested $3.5 billion of its own equity.
Dangote told a business forum in Lagos his firm was close to signing a deal with a Moroccan firm to supply phosphate, without giving details.
He also said his planned oil refinery would have a capacity of 650,000 barrels per day (bpd), up from an initial plan of 400,000 bpd.
"We can actually build ... 30 percent cheaper than previously," Dangote said, referring to lower construction cost as a result of cheap global steel prices.
The refinery and petrochemical complex will go online around 2018, company officials have said.
He said Dangote Group was also constructing a gas pipeline beneath the sea to link Nigeria's oil-producing Delta region to West Africa.
The pipeline will be able to transport 1.5 billion standard cubic feet of gas per day, he said, without giving more details.
Dangote Group, which is active in cement, oil, food and sugar business, is also expanding into farming.
Dangote said his firm planned to produce one million tonnes of rice within five years. Nigeria imports annually 2.8 million tonnes of rice, the majority of which is smuggled into the country, he said.
"Our projects are mainly import substitution." he said. "We are working to be self-sufficient."