A mathematical model of the technology of extraction of copper from industrial slags Kamolkhon Karimov, Nodir Turakhodjaev, Azamat Akhmedov and Sherzod Tashbulatov E3S Web Conf., 264 (2021) 04077 Published online: 02 June 2021 DOI: 10.1051/e3sconf/202126404077