Fast and Effective Gold Leaching from a Desulfurized Gold Ore Using Acidic Sodium Chlorate Solution at Low Temperature

Abstract

The effects of various leaching conditions for gold extraction from sulfur-containing gold ore using acidic sodium chlorate solution were investigated. The contents of gold and sulfur from the ore were 55.7 g/ton and 11.67 wt %, respectively. It was found that the presence of sulfur greatly inhibited gold extraction. The optimal desulfurization temperature, desulfurization time, leaching temperature, leaching time, adding rate of NaClO 3 , HCl concentration, weight ratio of NaCl to sample, agitation speed, and ratio of liquid lixiviant volume to solid sample weight were 650 °C, 2 h, 40 °C, 45 min, 0.25 mL/min, 3 M HCl, 0.2, 250 rpm, and 10, respectively. The gold extraction percentage and the weight loss percentage of the sample were 97% and 8.8%, respectively, under these optimal conditions. Gold leaching by this method was very fast and effective, and the temperature was low. These characteristics made it possible to apply this method in continuous operation mode in industry.

Water-Soluble Phosphine Capable of Dissolving Elemental Gold: The Missing Link between 1,3,5-Triaza-7-phosphaadamantane (PTA) and Verkade’s Ephemeral Ligand

“…On the basis of the available observations, one can conclude that CAP exhibits the capability toward complexation-promoted oxidative dissolution of elemental Au to Au­(I). Gold is the noble metal, and aside from the several strong oxidizers such as aqua regia, hot H 2 SeO 4 , halogens, Me 3 PI 2 , hypochlorite (ClO – ) and chlorate (ClO 3 – ), there are very few classes of compounds capable of promoting oxidative dissolution of Au(0) under the mild conditions. The mechanisms underlying those reactions always imply complexation of Au with the ligands having strong affinity for gold, thereby shifting the redox potential of Au(0)/Au­(I,III) pair toward negative values with the formation of Au­(I) or Au­(III) species.…”

A Novel, Solvent-Free Mechanochemistry Approach for Gold Extraction from Anode Slime

“…On the basis of the result, the reagent cost to treat 1 t of anode slime was 16.8 $/t; as a comparison, the reagent cost of gold extraction using a hydrometallurgy process was usually higher. The reagent cost for thiosulfate leaching, thiourea leaching, and chlorate leaching to process 1 t of anode slime was 331 $/t, 1120 $/t, and 146 $/t, respectively (Table ). The result demonstrated that our method was highly competitive in reagent cost.…”

“…Gold conversion was about 70.38% at 15 min and then slightly increased to 92.9% as the reaction time extended from 15 to 60 min. For the hydrometallurgical process, it usually took hours or even dozens of hours to achieve optimal gold yield. − The outstanding reaction efficiency of the approach was likely to ensure low energy consumption.…”

Selective and Effective Reduction of Gold Ions from Acidic HCl–NaClO3 Leachate with Oxalic Acid

“…1 An acidic goldcontaining chloride filtrate collected from the leaching experiments was thus obtained. The concentrations of gold and hydrochloric acid from the leachate were 3.43 ppm and ∼3.33 M, respectively.…”

“…The concentrations of gold and hydrochloric acid from the leachate were 3.43 ppm and ∼3.33 M, respectively. The gold ions existed mainly in the form of chloroauric ([AuCl 4 – ]) ions . The reduction of Au­(III) to nanoparticles of metallic Au has been reported using reducing agents such as ascorbic acid, Sn­(II), glycerol, hydrogen peroxide, glucose, trisodium citrate, and dimethylamine borane .…”