Abstract:

Gold cyanide leaching for a arsenic and sulfur-bearing gold concentrate at Tianmashan，Tongling，was difficult due to the fine disseminated grain sizes and large amounts of the gold mineral wrapped by sulfides.In order to improve the efficiency of cyanide leaching，some of tests regarding acidic oxidation pretreatment in the systems of HCl-H₂O₂-addictive were carried out under the conditions that the proportion of grinding fineness at -0.048 mm was 90%，pulp density at 40 g/L，stirring speed at 400 r/min，reaction temperature at 60 ℃，reaction time at 4 h，dosage of HCl at 0.7 mol/L，dosage of H₂O₂ at 0.5 mol/L and dosage of ethylene glycol at 9 mL/L.As a result，the dissolution rates of iron，arsenic and copper were 48.1%，99.3% and 89.76%，respectively.What’s more，the leaching rate of cyanide leached gold increased 33.6% than that of cyanide leached directly after oxidation pretreatment to gold concentrate.It was evident that the crystal structure of sulfide was destructed after oxidation pretreatment，meanwhile，the As，Cu and other ingredients were dissolved.Thus，the gold cyanide leaching rate increased.Finally，some guidance for other similar arsenic and sulfur-bearing refractory gold concentrate processing is provided，which is expected to be meaningful for applicability and development of the oxidation pretreatment with the HCl-H₂O₂-ethylene glycol.

Key words: arsenic and sulfur-bearing gold concentrate, oxidation pretreatment, HCl-H₂O₂, dissolution rate, ethylene glycol