It was narrated from Ibn 'Urnar that the Messenger of Allah (ﷺ), said:
"The divorce of a slave woman is twice, and her waiting period is two menstrual cycles. " (JA)
English reference (JA): Vol. 3, Book 10, Hadith 2079 (JA)
Arabic reference (JA): Book 10, Hadith 2157 (JA)