The bulk of the global gold reserves concentrate in mining and processing waste. This gold represents very fine and scattered particles, which complicates recovery. Implementation of a new method for dispersed micro-size gold in a patent-protected machine, including heating, melting, post-cooling milling and gravity separation, in the tests of rebellious silicate–carbonate ore has proved dissociation of gold and coarsening of gold particles. As a consequence, gold recovery in gravity separation can be largely improved, especially in case of reduced number of particle sizes and when close-cut fractions are processed separately. Cyanation after thermal treatment allows all gold to be extracted. On the other hand, melting of waste produces slag to be recycled as well. Recycling alternatives of any manmade products, and, in particular, slag, should base, for the first turn, on the environmental impact analysis, especially, regarding soil. The chemical composition of slag is compared with reference allowable concentrations of toxic substances in soil and with governmental standards set for feed for different process flows. The environmentally safe flow chart is proposed for integrated processing of gold-bearing silicate–carbonate mill tailings by thermal treatment which recovers disperse micro-size gold while slag is usable as an aggregate in backfill mixtures and as a corrective ingredient in the cement industry. The proposed flowchart is applicable to recycling of mining waste in different processing scenarios of goldbearing silicate–carbonate ore. The study was carried out under agreement with the Ural Mining University, State Contract No. 0833-2020-0008 Development and Ecological Feasibility Study of Mining and Metallurgy Disturbed Land Reclamation Using New-Type Improvers and Fertilizers, in association with and using the equipment of the Shared Use Canter at the Federal Research Center for Biological Systems and Agrotechnologies of the Russian Academy of Sciences, Accreditation Certificate No. Ross RU.0001.21 PF59, Unified Russian Shared Use Center Register, http://www.ckp-rf.ru/ckp/77384.
Mineralogical study and enhanced gravity separation of gold-bearing mineral, South Eastern Desert, Egypt
