Leaching of gold from a mechanically and mechanochemically activated waste (original) (raw)

Mechanical activation and electrolysis of gold from goldsmith's waste

Acta Montanistica Slovaca, 2012

The intensification of the thiourea leaching of gold from goldsmith's waste (Košice, Slovakia) using mechanical activation as the pretreatment step. The leaching of “as-received“ sample in an acid thiourea solution resulted in 77 % Au dissolution, after mechanical activation 98 % of the gold was leached during 120 min. The activation was performed in an attritor using variable milling times. The physico-chemical changes in the waste as a consequence of mechanical activation had a pronounced influence on the subsequent gold extraction. Maximum recovery of gold was reached behind 60 minutes at optimum conditions of electrolysis.

Electrolysis of Gold from Filtration Waste by Means of Mechanical Activation

2012

The intensification of the gold thiourea leaching from a filtration waste (Kosice, Slovakia) using mechanical activation as the pretreatment step has been studied. The leaching of “as-received“ sample in an acid thiourea solution resulted in 65 % Au dissolution. However, after mechanical activation in a planetary mill 99 % of the gold was leached. The optimum redox potential for electrolysis is in the range 500-523 mV for the gold extraction 99.79 % from the mechanically activated sample. The mechanical activation resulted in an increase of the specific surface area of the waste from 0.7 m 2 g -1 to a maximum value of 13.5 m 2 g -1 . The physicochemical changes in the filtration waste as a consequence of mechanical activation had a pronounced influence on the subsequent gold extraction.

Hydrometallurgical Recovery of Gold from Mining Wastes

2020

Gold is a highly required material for a wide range of personal and industrial applications. The high demand for gold, together with the shortage of natural resources and high pollution potential of wastes generated during mining and ore processing activities led to search for alternative sources of gold. A possible source is represented by mine wastes resulting from the processing of polymetallic or sulfidic ores. The reprocessing of wastes and old tailings with moderate to low content of gold offers not only a business opportunity, but also enhances the quality of the surrounding environment, changes the land use and offers a wide range of socio-economic benefits. Cyanidation, the most widespread Au leaching option, is progressively abandoned due to the high risk associated with its use and to the low public acceptance. Therefore, alternative methods such as thiocyanate, thiourea, thiosulphate and halide leaching gained more and more interest. This chapter presents the most import...

APPLICATION OF INNOVATIVE PROCESSES FOR GOLD RECOVERY FROM ROMANIAN MINING WASTES

Chemistry Journal of Moldova, 2020

The application of a new hydrometallurgical process for gold extraction by thiosulphate leaching from Romanian mining wastes, coming from Balan and Deva deposits, was studied. Another objective of this work was to develop an integrated flow-sheet including the recycling of process solutions and of the coconut activated carbon used for gold purification. There was obtained 85% of Au extraction after leaching; moreover, an integrated flow-sheet, including recycling of process solution and carbon, was outlined, based on results obtained at a laboratory scale, using a schematic chemical circuit of treatment. Global recovery of the process (leaching-adsorption-desorption-electrodeposition) of about 75-80% of Au was achieved. The developed integrated flow-sheet, allows to recycle the reagents during the process, with a loss of only 5-10%, in particular thiosulphate and alcohol, for each complete circuit of treatment.

A Review on Studies and Research on Gold Recovery from Industrial Solid Waste

http://ijshr.com/IJSHR\_Vol.1\_Issue.2\_April2016/IJSHR008.pdf, 2016

Solid waste treatment is becoming more important in industrial waste treatment. The electronic circuits and components contain various hazardous as well as precious materials. The use of heavy metals in the various components of mobiles, computers, remote, chips and other components calls for effective solid waste management. The electronic waste includes used components and electronic goods. These electronic materials and goods contain various valuable metals like gold, silver, platinum etc. These wastes are normally treated unscientifically. These methods are inefficient and at times hazardous. There is need to explore methods which are systematic and efficient. The current review summarizes research and studies for recovery of gold from waste.

An innovative thiourea gold leaching process

Hydrometallurgy, 1998

The aim of this experimental work was devoted to the preliminary evaluation of the feasibility of thiourea leaching for the extraction of gold from a domestic gold-bearing ore 4 g/t Au, at laboratory scale. The study has permitted identification of the influence of temperature, leaching agent concentration, pulp density and leaching time on the gold dissolution. Gold has been recovered