高硫高砷金精矿生物预氧化条件优化

Condition optimization for bio-oxidation of high-S and high-As gold concentrate

摘要:

摘要:【目的】研究温度以及返回液添加量对体系中氧化效果以及金(Au)氰化浸出率的影响。【方法】针对某高硫高砷金精矿建立了一套连续生物预氧化体系(氧化时间6 d)，比较不同的温度(40℃和45℃)和返回液添加量(0和600mL)对生物预氧化效果的影响:间隔8 h连续测定氧化体系中的氧化液、氧化渣以及氰化渣中的总Fe、总S、总As以及SO4 2－和Au含量;并用16S rRNA基因克隆文库的方法对体系中的浸矿菌群结构进行分析。【结果】结果显示，提高温度和添加氧化返回液都会改变体系:升高温度在一定程度上提高了体系的氧化程度，主要表现为显著降低了尾渣中总铁、总硫含量，显著提高了尾渣中的S6 + 比例，并且降低前三槽氧化体系的耗碱量;投加返回液则会降低体系的氧化程度，主要表现为显著提高了尾渣金品位和铁含量，显著降低了尾渣中的S6 + 以及Au 浸出率;Dissimilarity和DCA结果表明温度变化对体系的影响更为显著;氧化过程中的Au 浸出率、硫氧化率以及As 去除率，三者互为显著正相关;克隆文库结果显示，该浸矿菌群主要包括3类细菌: Acidithiocacillus caldu (71%)、Leptospirillum ferriphilum (23%)和Sulfobacillus thermosulfidooxidans(6%)，基于97%相似性的OTU覆盖率达93.67%。【结论】研究结果表明，相对于添加返回液，温度变化会更显著的改变体系反应效率。提高体系温度有利于矿物的氧化，而添加返回液会降低Au浸出率。本文首次研究了连续生物预氧化过程中温度梯度和返回液添加对体系的影响，本研究结果对中温生物预氧化工业生产的工艺优化、降低工业运行成本具有重要的指导意义。

Abstract:

Abstract:［Objective］To study the effects of temperature and lixivium return on the concentrate bio-oxidation and rate of gold cyanide leaching.［Methods］ The bioleaching of a high-sulphur (S) and high-arsenic (As) refractory gold concentrate was conducted，and we studied the effects of different temperature (40 ℃ and 45 ℃) and lixivium return (0 and 600 mL) on the bio-oxidation efficiency．The bacterial community structure also was investigated by 16S rRNA gene clone library.［Results］ The results showed that both the temperature and lixivium return significantly influenced the oxidation system． The temperature rising elevated the oxidation level，while the addition of lixivium depressed the oxidation． Dissimilarity and DCA (detrended correspondence analysis) indicated the effect of temperature on oxidation system was much greater than lixivium． The bacterial community was comprised by Acidithiocacillus caldu (71%)，Leptospirillum ferriphilum (23%) and Sulfobacillus thermosulfidooxidans (6%) indicated by the clone library，and the OTU coverage based on 97% sequence similarity was as high as 93.67%.［Conclusion］Temperature rising to 45 ℃ would improve the oxidation efficiency while lixivium return would decrease it．This study is helpful to provide an important guiding value for the industry cost optimization of mesophile bacterial oxidation and reduction process.