Israel tried, but African politicians prefer bribes.
There is little trade because there is little Africa and Israel can offer each other. China's huge industries need African minerals so they invest in Africa. Israel did provide much technical assistance to the new west African states back in the early 60s, but after '67 their politicians preferred Arab petrodollars. That has mostly dried up but there is little that Israel produces that African can pay for, and little that Africa produces that Israel needs. Except perhaps diamonds. So while Africa is growing, thanks in part to Chinese investments, there is little basis for ISrael-African trade right now. But only time will tell.