Leaching of Silver and Gold Contained in a Sedimentary Ore, Using Sodium Thiosulfate; A Preliminary Kinetic Study

Metals

Norman Toro¹  Ricardo I. Jeldres²  Eduardo Cerecedo-Sáenz³  Juan Hernández-Ávila³  Eleazar Salinas-Rodríguez³  Edmundo Roldán-Contreras³  Ventura Rodríguez-Lugo³ 

[1] Departamento de Ingeniería Metalúrgica y Minas, Universidad Católica del Norte, Antofagasta 1270709, Chile;Departamento de Ingeniería Química y Procesos de Minerales, Facultad de Ingeniería, Universidad de Antofagasta, Antofagasta 1240000, Chile;Área Académica de Ciencias de la Tierra y Materiales, Universidad Autónoma del Estado de Hidalgo, Carretera Pachuca-Tulancingo km 4.5, Mineral de la Reforma, Hidalgo 42184, Mexico;

关键词: thiosulfate;    gold leaching;    silver leaching;    kinetic analysis;    sedimentary ore;    diffusion control;    mixed control;   

DOI  :  10.3390/met10020159

来源: DOAJ

【 摘 要 】

Some sedimentary minerals have attractive contents of gold and silver, like a sedimentary exhalative ore available in the eastern of Hidalgo in Mexico. The gold and silver contained represent an interesting opportunity for processing by non-toxic and aggressive leaching reagents like thiosulfate. The preliminary kinetic study indicated that the leaching process was poorly affected by temperature and thiosulfate concentration. The reaction order was −0.61 for Ag, considering a thiosulfate concentration between 200−500 mol·m⁻³, while, for Au, it was −0.09 for a concentration range between 32−320 mol·m⁻³. By varying the pH 7−10, it was found that the reaction order was n = 5.03 for Ag, while, for Au, the value was n = 0.94, considering pH 9.5−11. The activation energy obtained during the silver leaching process was 3.15 kJ·mol⁻¹ (298−328 K), which was indicative of a diffusive control of the process. On the other hand, during gold leaching, the activation energy obtained was of 36.44 kJ·mol⁻¹, which was indicative that this process was mixed controlled process, first at low temperatures by diffusive control (298−313 K) and then by chemical control (318−323 K).

【 授权许可】

Unknown