Development of gold flotation depressants for refractory gold ores

大多数难处理金矿需要经过处理，破坏包裹的硫化矿物，释放出金进行氰化回收。压力浸出或生物浸出（氧化）通常用于破坏硫化物矿物，然后是氰化物浸出。难选金矿石中碳酸盐矿物的存在，在压力浸出和生物浸出过程中产生单质硫等部分氧化产物，造成酸和氰化物消耗的浪费，不利于金的回收过程。我们建议用反浮选法去除这些碳酸盐矿物和单质硫。为此，需要适当的金浮选抑制剂，但目前还没有。在难熔金矿中，金通常与毒砂伴生。通常需要对毒砂进行浓缩，以富集金品位，供后续处理。这通常需要从黄铁矿中选择性分离毒砂。目前的做法是用强氧化剂抑制毒砂，同时漂走黄铁矿。如果矿石中含有天然金块，则需要合适的金抑制剂。在本研究中，我们将利用巯基试剂在金表面的自组装现象来指导金浮选抑制剂的开发。微浮选和批量浮选以及原子力微观（AFM）力和感应测量将在金粉，难熔金矿石和硅晶片上溅射金进行。浮选和力/诱导时间将相互关联，因此**原子力显微镜将成为评估试剂对金的影响的主要工具。研究不仅可以开发出合适的金抑制剂，还可以开发出合适的评价技术，用于评价难以获得或价格昂贵的高纯矿物和贵金属粉末的浮选行为。

Most refractory gold ores need to be treated to destroy the encapsulating sulfide minerals to release the gold for**cyanidation recovery. Pressure leaching or bioleaching (oxidation) are typically used to destroy the sulfide**minerals, followed by cyanide leaching. The presence of carbonate minerals in the refractory gold ore, the**generation of partial oxidation product such as elemental sulfur during pressure leaching and bioleaching, are**detrimental to the gold recovery process due to wasteful acid and cyanide consumption. We propose to remove**these carbonate minerals and elemental sulfur by reverse flotation. For that purpose, appropriate flotation**depressants for gold are required, which are not currently available.**In refractory gold ores the gold is typically associated with arsenopyrite. Often it is required that the**arsenopyrite be concentrated to enrich the gold grade for subsequent processing. This usually entails the**selective separation of arsenopyrite from pyrite. Current practice is to use strong oxidation reagents to depress**arsenopyrite while floating away pyrite. Again suitable gold depressants are required if the ore contains native**gold nuggets.**In the proposed research we will utilize the phenomena of self-assembling of thiol reagents on gold surface to**guide the development of gold flotation depressants. Microflotation and batch flotation as well as atomic force**microscopic (AFM) force and induction measurements will be performed on gold powders, refractory gold**ores, and silicon wafers sputtered with gold. The flotation and force/induction time will be correlated so that**the AFM will be the primary tool to assess the effect of reagents on gold. The research will not only develop**suitable gold depressants but also suitable evaluation techniques to assess the flotation behaviors of hard-to-get**or expensive high purity minerals and precious metal powders.