Sustainable System for Mineral Beneficiation

矿石是岩石或沉积物，是贵重金属和矿物的来源。矿石必须经过加工才能回收金属和矿物，许多金属首先以矿物形式浓缩，然后再通过化学方法转化为金属形式。从矿石中提取和浓缩矿物质需要消耗大量的水。例如，2017年美国矿山生产了127万吨铜，这需要大约5亿吨的水。虽然金属回收正在上升，但它并没有抵消随着时间的推移金属使用量的持续增加。大多数国内矿藏位于该国干旱地区（犹他州、亚利桑那州、新墨西哥州和内华达州），矿物开采的高用水需求加剧了城市中心的供水问题。为了解决高用水需求，该项目将开发具有表面化学成分的工程微球，以粘附在干燥的矿物颗粒上，以减少矿物提取的水消耗。该研究将集中于开发化学改性玻璃微球之间相对于聚苯乙烯控制的粘附强度。玻璃是硅酸盐矿物的代表，硅酸盐矿物是矿体中最普遍存在的矿物类型。玻璃微球将经过化学修饰，形成附着在小矿物颗粒上的超疏水或超亲水表面。矿物粘附在模型玻璃微球上，作为粒度的函数，将通过跌落测试、光谱和图像分析的组合进行测试和建模。使用van Oss-Good-Chaudhury和Hansen溶解度参数方法对黏合剂表面能进行量化。粘附结果将用于开发和验证预测计算模型，以实现工艺设计和优化相关工艺参数。该项目的成功完成将使矿物的回收更加可持续，用水量更少，对环境的影响也更小。该研究将被纳入本科设计项目和研究生建模课程，并将支持两名研究生的实践研究训练。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Ores are rocks or sediments that are the source of valuable metals and minerals. Ores must be processed to recover metals and minerals, and many metals are first concentrated in mineral form, before being chemically converted to metallic form. Extraction and concentration of minerals from ores consumes an immense amount of water. For instance, 1.27 million tons of copper were produced from US mines in 2017, and this required roughly half a billion tons of water. Although metal recycling is on the rise, it has not offset the continued increase of metal use with time. Most domestic ore deposits are found in arid regions of the country (Utah, Arizona, New Mexico and Nevada), and high water demand for mineral extraction exacerbates water supply concerns for urban centers. To address the high water demand, this project will develop engineered microspheres with surface chemistry tailored to adhere to dry mineral particles in order to reduce the water consumption of mineral extraction. The research will focus on exploiting the strength of adhesion between chemically modified glass microspheres relative to polystyrene controls. Glass is representative of silicate minerals, which are the most ubiquitous type of minerals found in ore bodies. The glass microspheres will be chemically modified to create superhydrophobic or superhydrophilic surfaces that adhere to small mineral particles. Mineral adherence to the model glass microspheres, as a function of particle size, will be tested and modeled via a combination of drop tests, spectroscopy, and image analysis. Adhesive surface energy will be quantified using van Oss-Good-Chaudhury and Hansen solubility parameter approaches. The adhesion results will be used to develop and validate a predictive, computational model to enable process design and optimize relevant process parameters. Successful completion of the project will enable more sustainable recovery of minerals with less water consumption and reduced environmental impact. The research will be incorporated into undergraduate design projects, and graduate courses on modeling, and will support the hands-on research training of two graduate students.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.