Can Africa trade with Africa?

Obiageli Ezekwesili writes:

Today, there is strong consensus among African leaders that regional integration is indispensable to unlock economies of scale and sharpen competitiveness. And promoting intra-African trade has emerged as a top priority, in recognition that the African market of one billion consumers can be a powerful engine for growth and employment.
Yet despite the introduction of free trade areas, customs unions, and common markets within the Region, the level of intra-African trade remains among the lowest in the world -- only about 10% of African trade is within the continent, compared to about 40% in North America and about 60% in Western Europe.