The Shaykh (Al-Mufid), may Allah سبحانه وتعالى have mercy on him, said: “If the Muslim does not find a believer who is entitled to zakat, while zakat has become obligatory upon him, and he finds a believing owned slave (mamluk) being sold, he buys him with the wealth of zakat and frees him. Likewise, if he finds one who is entitled to zakat, but he sees a believing owned slave (mamluk) in necessity, so he buys him with his zakat and frees him, it suffices him.” What indicates that is what was narrated (in the following hadith):
Commentary #6