Development of gold flotation depressants for refractory gold ores

大多数难处理金矿需要破坏包裹的硫化物矿物，才能将金释放出来进行氰化回收。加压浸出或生物浸出(氧化)通常用于破坏硫化矿物，然后是氰化物浸出。难浸金矿石中碳酸盐矿物的存在，加压浸出和生物浸出过程中生成元素硫等部分氧化产物，由于废酸和氰化物的消耗，不利于金的回收过程。我们建议通过反浮选脱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。在难处理的金矿中，金通常与毒砂共生。通常需要对毒砂进行浓缩，以富集金品位以供后续加工。这通常需要选择性地分离毒砂和黄铁矿。目前的做法是使用强氧化剂来抑制毒砂，同时漂移黄铁矿。同样，如果矿石中含有天然矿物，则需要合适的金抑制剂。在拟议的研究中，我们将利用硫醇试剂在金表面自组装的现象来指导金浮选抑制剂的发展。微浮选和间歇浮选以及原子力显微镜(AFM)力和感应测量将在金粉、难熔金矿和溅射金的硅片上进行。浮选和作用力/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。这项研究不仅将开发合适的黄金抑制剂，而且还将开发合适的评价技术来评估难以获得或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 forcyanidation recovery. Pressure leaching or bioleaching (oxidation) are typically used to destroy the sulfideminerals, followed by cyanide leaching. The presence of carbonate minerals in the refractory gold ore, thegeneration of partial oxidation product such as elemental sulfur during pressure leaching and bioleaching, aredetrimental to the gold recovery process due to wasteful acid and cyanide consumption. We propose to removethese carbonate minerals and elemental sulfur by reverse flotation. For that purpose, appropriate flotationdepressants 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 thearsenopyrite be concentrated to enrich the gold grade for subsequent processing. This usually entails theselective separation of arsenopyrite from pyrite. Current practice is to use strong oxidation reagents to depressarsenopyrite while floating away pyrite. Again suitable gold depressants are required if the ore contains nativegold nuggets.In the proposed research we will utilize the phenomena of self-assembling of thiol reagents on gold surface toguide the development of gold flotation depressants. Microflotation and batch flotation as well as atomic forcemicroscopic (AFM) force and induction measurements will be performed on gold powders, refractory goldores, and silicon wafers sputtered with gold. The flotation and force/induction time will be correlated so thatthe AFM will be the primary tool to assess the effect of reagents on gold. The research will not only developsuitable gold depressants but also suitable evaluation techniques to assess the flotation behaviors of hard-to-getor expensive high purity minerals and precious metal powders.