Abstract In this study, the effect of using strong oxidants with alkaline glycine solutions on the leach rate and recovery of gold was studied in the absence of cyanide. Prior research indicated that when using only alkaline glycine and air at ambient temperature in the absence of catalysts, leaching times would be too long for conventional agitated tank leaching of ores. The ores used in this study were from oxidised geological domains, which would not be expected to excessively consume oxidant. Ores with reactive sulfides or other reducing minerals would be expected to rapidly consume an oxidant, making the process ineffective. The influence of the oxidants such as potassium permanganate, hydrogen peroxide, sodium chlorate, potassium iodide, and potassium ferricyanide were initially evaluated in a screening test. The highest gold extractions were observed with potassium permanganate, where a recovery of 85.1% was achieved at 1.5 kg/t glycine and 3 kg/t permanganate at 30% solids, pH 10.5 and ambient temperature using a bottle roll process. This compared to a 87.4% recovery against a conventional cyanidation benchmark with 30% solids, pH 10.5 and ambient temperature using the bottle roll. Other oxidants only achieved a recovery of 11% at best, so permanganate was the focus of the optimisation work. The solution pH had very little effect on gold recovery between 9.5 and 11.5. The ratio of glycine to permanganate concentration is significant, if potassium permanganate is in a molar excess, the recovery is greatly reduced due to oxidation of the glycine. The main products of this reaction, when lime was used as pH modifier, were determined to be calcium carbonate, calcium oxalate, trace amounts of ammonia and manganese dioxide. Gold is recoverable from leach solutions by conventional adsorption onto activated carbon.

中文翻译：

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在高锰酸盐存在下从碱性甘氨酸溶液中从氧化矿石中浸出金

摘要 在这项研究中，研究了在没有氰化物的情况下使用强氧化剂和碱性甘氨酸溶液对金浸出率和回收率的影响。先前的研究表明，在没有催化剂的情况下，在环境温度下仅使用碱性甘氨酸和空气时，对于传统的搅拌槽浸出矿石来说，浸出时间会太长。本研究中使用的矿石来自氧化地质区域，预计不会过度消耗氧化剂。预计含有活性硫化物或其他还原性矿物的矿石会迅速消耗氧化剂，使该过程无效。高锰酸钾、过氧化氢、氯酸钠、碘化钾和铁氰化钾等氧化剂的影响最初在筛选试验中进行了评估。使用高锰酸钾观察到最高的金提取率，其中在 1.5 kg/t 甘氨酸和 3 kg/t 高锰酸盐下，在 30% 固体、pH 10.5 和环境温度下，使用滚瓶工艺实现了 85.1% 的回收率。相比之下，使用瓶辊，在 30% 固体、pH 10.5 和环境温度下，传统氰化基准的回收率为 87.4%。其他氧化剂最多只能达到 11% 的回收率，因此高锰酸盐是优化工作的重点。溶液 pH 在 9.5 和 11.5 之间对金回收率的影响很小。甘氨酸与高锰酸盐浓度的比例是显着的，如果高锰酸钾摩尔过量，由于甘氨酸氧化，回收率大大降低。该反应的主要产物，当石灰用作 pH 调节剂时，被确定为碳酸钙、草酸钙、痕量氨和二氧化锰。金可以通过传统的活性炭吸附从浸出液中回收。