The Arab slave trade in Africa existed far longer than the West African. Saudi Arabia only outlawed slavery in 1962 and still continues in some forms even today.
Osama bin Laden was reported saying 'African women are only good for a man's lower pleasures.' Not too surprising given bin Laden grew up as a young man of privilege in Sudan (his father had business ventures there). Even now Northern Sudanese (more Arab) would refer to Southern Sudanese as slaves. There was always a sexual component to the Arab slave trade (caucasian women were especially prized and were routinely targeted in Eastern Europe) for markets in the Ottoman Empire.
Slavery in the Middle East was more of the Roman model: Any conquered people (provided they weren't Muslim) could be enslaved. Converting to Islam after the fact did not result in freedom for the slave. Muslims Turks and Barbary Pirates routinely took slaves from Europe.
Slavery was not restricted to mostly to hard manual labor (with some limited domestic work) as in much of the New World--although slaves did that too in the Muslim world. Slaves in the Middle East could work in a variety of trades and jobs, many were educated and could read (making them move valuable economically), some were enslaved to be military units such as the Janissaries. Because of lack of education in sub-Saharan Africa and general racism in the Arab world, white slaves generally did better than black slaves. That was all relative though--slaves had a hard existence everywhere.
Rascism in the Arab world continues today. The Arab world's dirty secret is open racism against sub-Saharan Africans. Racism is alive and well on Arab TV shows.
AoSHQ: Morning Report 09.17.19.