The gold recovery from secondary resources is in the spotlight due to its high economic value and as the circular economy's main objective. As a valuable secondary source, the slag resulted from the gold-bearing electrolytic mud smelting contains up to 0.8-15 k g t −1 Au and 9-13 kg t −1 Ag, respectively. The gravity separation's use to concentrate gold contained by the slag causes significantly reduced reagents and energy consumptions. The diminished reacting time and the increased recovery yield due to the augmentation of contact surface between the solid phase and the leaching reagent are other important advantages. The present contribution aims to point out that a new different type of waste such as the slag resulted from the gold-bearing electrolytic mud smelting may be capitalized using gravity separation on Gemini table and Knelson concentrator, respectively. Metal recoveries up to 90-92% Au and 46-60% Ag, respectively, were obtained on Gemini table . The contributing editor for this article was Brajendra Mishra.

Recently, the application of microwaves as a source of energy to the extractive industry has received particular attention from a large number of researchers. During the mid-1960s to 1988 most researches focused on the behavior of microwave radiant materials. These research activities continue to be important as long as the fundamental data on microwave interaction with materials is important for the successful application of technologies. This article presents the comparative cyanide tests of unprocessed and non-fired pyrite as well as the technical indicators obtained in these tests. After performing comparative cyanidation tests on unroasted and roasted pyrites at 400 and 700oC it was found that there was no significant reduction in lime and cyanide consumption for roasted pyrite at 400oC but for the roasted pyrite at 700oC the consumption of lime is reduced from 110 kg�t-1to 10 kg�t-1, cyanide is reduced from 2.8 kg�t-1 to 1.76 kg�t-1, and yields of leaching increase from 50 % for unroasted pyrite at 81 % for roasted pyrite.

The paper presents the main thermodynamic aspects related to the gold dissolution with thiosulphate, thiourea and thiocyanate. The thermodynamic stability of the gold complexes and the reaction mechanisms that ensure the gold dissolution in the most representative lixiviants with potential for use in the gold industry are analyzed. The performances of the lixiviants are analyzed in several ways in antithesis with those of the cyanide: ecological, technological and economic.

The paper presents the main thermodynamic aspects related to gold dissolution in different lixiviants. We analyzedthe thermodynamic stability of the gold complexes with the most representative lixiviants with potential for use in the gold industry. Based on the stability constants we determined the electrode potentials of the gold dissolution reactions in variouslixiviants and we presented the electrochemical mechanism of gold dissolution is alkaline cyanide solutions.