Roasting and chlorine leaching of gold-bearing refractory concentrate:Experimental and process analy

• 作 者: Ida De Michelis Agostino Olivieri Stefano Ubaldini Francesco Ferella Francesca Beolchini Francesco Vegliò
• 机 构: Department of Chemistry,Chemical Engineering and Materials,University of L’Aquila,Institute of Envir
• 出 处: International Journal of Mining Science and Technology
• 发表日期: 2013年05期

This paper deals with gold extraction from a refractory concentrate by chlorine leaching.The process considers a pre-treatment of refractory materials by low temperature oxidation carried out with low oxygen concentration.The oxidized material is treated by leaching with brine.After gold adsorption/reduction onto activated carbon,iron and base metals can be precipitated by NaOH.Roasting tests show the necessity to carry out a thermal pre-treatment at least at 550°C to obtain a reduction of sulfur and mercury in the material(50%and 90%,respectively).Highest gold extraction yield(around 93%)is obtained in the leaching test performed with material sample treated at 650°C.This result confrms the necessity to optimize the thermal pre-treatment to improve Au recovery and to reduce chlorine consumption.A comparison with conventional cyanidation confrms that chlorination could be an useful alternative:in fact,gold extraction yield is quite low:57%in non-pre-treated material and 25%in pre-treatment material.

This paper deals with gold extraction from a refractory concentrate by chlorine leaching. The process considers a pre-treatment of refractory materials by low temperature oxidation carried out with low oxygen concentration. The oxidized material is treated by leaching with brine. After gold adsorption / reduction onto activated carbon, iron and base metals can be precipitated by NaOH. Roasting tests show the necessity to carry out a thermal pre-treatment at least at 550 ° C to obtain a reduction of sulfur and mercury in the material (50% and 90% , respectively) .Highest gold extraction yield (around 93%) is obtained in the leaching test performed with material sample treated at 650 ° C. This result confrms the necessity to optimize the thermal pre-treatment to improve Au recovery and to reduce the chlorine consumption .A comparison with conventional cyanidation confrms that chlorination could be an useful alternative: in fact, gold extraction yield is quite low: 57% in non-pre-treated material and 25% in pre-tre atment material.