The oxidation roasting pretreatment process, which is a mature and dominant industrial practice for treating complex polymetallic gold deposits, has a low recovery of associated silver and exhibits an unclear reaction sequence. This study takes a silver-containing gold ore as the research object and investigates the effect of (i) sodium sulfite as an additive, (ii) main gold-bearing mineral pyrite, and (iii) gangue mineral quartz, on silver during the roasting process in roasting and leaching tests. Characterization techniques included scanning electron microscopy–energy dispersive spectroscopy analysis, and thermogravimetry–differential scanning calorimetry analysis. The results based on thermodynamic calculations and characterization show that the main reason for the low extraction of silver is that the calcined product (i.e., iron silicate) formed by the reaction between pyrite and quartz during the roasting process is mutually absorbed and wrapped with silver oxide. In addition, silver minerals decompose some iron sulfides and iron oxides under high-temperature conditions, promoting the reaction of iron and quartz to form iron silicate while strengthening the secondary encapsulation of silver by products of roasting, thus deteriorating the extraction of silver. The addition of sodium sulfite reduces the formation of iron silicate and increases the extraction of silver by directly promoting the conversion of pyrite to iron oxide. This study provides a theoretical basis for further improving the roasting and leaching of silver.

中文翻译：

---

黄铁矿、石英和亚硫酸钠对难熔硫化物精矿焙烧及氰化浸出金、银、铜的影响


氧化焙烧预处理工艺是处理复杂多金属金矿的成熟且占主导地位的工业实践，其伴生银回收率低且反应顺序不明确。本研究以含银金矿石为研究对象，研究了（i）作为添加剂的亚硫酸钠、（ii）主要含金矿物黄铁矿和（iii）脉石矿物石英在焙烧过程中对银的影响焙烧和浸出测试过程。表征技术包括扫描电子显微镜-能量色散光谱分析和热重分析-差示扫描量热分析。热力学计算和表征结果表明，银提取率低的主要原因是在焙烧过程中黄铁矿与石英反应形成的煅烧产物（即硅酸铁）与氧化银相互吸附包裹。 。另外，银矿物在高温条件下分解出部分硫化铁和氧化铁，促进铁与石英反应生成硅酸铁，同时强化了焙烧副产物银的二次包封，从而恶化了银的提取。亚硫酸钠的添加减少了硅酸铁的形成，并通过直接促进黄铁矿转化为氧化铁来增加银的提取。该研究为进一步改进银的焙烧浸出工艺提供了理论依据。