Is it tenable to argue that European capital was invested in Africa where exploitable resources promised attractive returns?

Answer 1

The Natural Resources of Africa, including human resources, provided wealth for the colonial powers of Europe. Their military forces defeated the relatively primitive tribal forces to set up both public and private empires within Africa.

Many private companies continued the practice throughout the 20th century, in what is called "economic Imperialism" which is markedly similar to the 19th century mercantilism.

The lure of vast wealth even influenced Belgium, which had practically no army or navy, to engage in colonial activities in central southern Africa. Using various diplomatic schemes, King Leopold II managed to control a vast region of the Congo. Quasi-military expeditions under Henry Morton Stanley (British) and William Grant Stairs (Canadian) acquired the Katanga region, known to be rich in copper and later in cobalt.