Egypt was neither black or white, it was just Egypt. Every culture must be judged in its own right, not just lumped together in broad categories.
And if one likes to name people after their colour the egyptians could be called brown since most of them had/has a skin-colour in some brown shade.
The notions of Black and White is just modern political categories that can not be applied on ancient cultures.
As for the matter if Egypt was an african civilisation: yes it was, Egypt lies in Africa and they received and gave influences to its other african neighbours. It also received and gave influences to their neighbours in southern Europe and the middle east.
As a matter of fact: most culures (if they are not completely isolated) is an amalgam of their own indigenious traits and of influences from other cultures. In the end the differnt traits melts together and forms a unique culture.