The biggest cement factory in sub-Saharan Africa has been opened in Nigeria by Africa's richest man, Aliko Dangote.

非洲撒哈拉以南地区最大的水泥厂在尼日利亚由首富阿里科·丹格投资建成。

Aliko Dangote was last year named Africas richest man by Forbes magazine
The Obajana plant in the central Kogi State is expected to produce about 10 million tonnes of cement a year.

It is one of the country's biggest investments outside the oil sector¹ in recent years.

BBC Nigeria correspondent Will Ross says there is reason to be optimistic about Africa's economic prospects².

Nigeria's economy is expected to grow by about 6% this year.

However, analysts³ warn that the growth is not reaching all sectors⁴ of society and the gap between the rich and poor is growing ever wider.

Our correspondent says the ceremony was a glitzy affair, with plenty of personal wealth on display as Nigeria's elite⁵ came together to celebrate industrial success.

President Goodluck Jonathan called the plant a "quantum leap（巨大突破） " for Nigeria's cement sector.

The Dangote group has invested some $6.5bn (£4.2bn) in the sector in recent years.

There are also plans to expand the Obajana plant to make it the world's biggest.