Abstract When gold was leached using copper ammonia thiosulfate solution, the dissolution rate of gold decreased as the leaching time increased. The dissolution of gold powder with 44 and 77 μm particles was studied，and the results indicated that the dissolution rate was not decreased by surface passivation or the decrease in copper concentration but by the changes of the electronic structure of the gold surface caused by the change in the exposed crystal surface. The transmission electron microscopy images of the gold powder revealed that the high-index (220) and (311) crystal surfaces almost disappeared during leaching. Furthermore, the surface of gold consisted mainly of the low-index (111) crystal surface during the later stages of leaching. Owing to the changes in crystal surface, the work function of the gold surface increased from 6.56 to 6.95 eV, and the increase in work function hindered the loss of electrons from the gold surface. When cobalt was used to modify the gold surface, the work function decreased from 6.56 to 5.99 eV. The leaching results indicated that the cobalt modification increased gold dissolution, and the gold leaching percentage was increased by 40% within 8 h. the tendency of gold to dissolve more easily after it underwent surface modification was confirmed by the apparent activation energy of the surface-modified being lower than that of the fresh gold powder, the formation of intermediate products of Co3O4 with high oxidation ability and the galvanic interaction between cobalt and gold electrodes. Dry-grind was applied for gold concentrate calcine and different contents of cobalt powder to study the possibility of industrial application of this effect. The results showed that only adding 50 mg cobalt to 100 g gold ores was beneficial to gold leaching

中文翻译：

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通过钴表面改性增加金在硫代硫酸铜氨溶液中的溶解

摘要 硫代硫酸铜氨溶液浸出金时，随着浸出时间的增加，金的溶解速度下降。对44和77 μm颗粒金粉的溶解进行了研究，结果表明溶解速率的降低不是由于表面钝化或铜浓度的降低，而是由于变化引起的金表面电子结构的变化。在暴露的晶体表面。金粉的透射电子显微镜图像显示，在浸出过程中，高指数 (220) 和 (311) 晶体表面几乎消失。此外，在浸出后期，金的表面主要由低指数（111）晶体表面组成。由于晶体表面的变化，金表面的功函数从6.56增加到6。95 eV，并且功函数的增加阻碍了电子从金表面的损失。当使用钴修饰金表面时，功函数从 6.56 eV 降低到 5.99 eV。浸出结果表明，钴改性提高了金的溶解度，8h内金浸出率提高了40%。通过表面改性的表观活化能低于新鲜金粉的表观活化能，形成具有高氧化能力的 Co3O4 中间产物和电偶相互作用，证实了经过表面改性后金更容易溶解的趋势在钴电极和金电极之间。将干磨应用于金精矿煅烧和不同含量的钴粉，以研究这种效果在工业应用中的可能性。