Sustainable System for Mineral Beneficiation

矿石是岩石或沉积物，是有价值的金属和矿物的来源。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，然后才被化学转化为金属形式。从矿石中提炼和浓缩矿物要消耗大量的水。例如，2017年美国矿山生产了127万吨铜，这需要大约5亿吨水。尽管金属回收利用呈上升趋势，但这并没有抵消金属使用量随着时间的推移而不断增加的影响。大多数国内矿藏都位于美国的干旱地区(犹他州、亚利桑那州、新墨西哥州和内华达州)，对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的工程微球，以附着在干燥的矿物颗粒上，以减少矿物提取的用水量。这项研究将集中在利用化学修饰的玻璃微球与聚苯乙烯对照之间的粘合强度。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。玻璃微球将被化学修饰，以创建附着在小矿物颗粒上的超疏水或超亲水表面。作为颗粒大小的函数，模型玻璃微球上的矿物粘附性将通过落差测试、光谱分析和图像分析相结合的方式进行测试和建模。粘合剂表面能将使用van Oss-Good-Chaudhury和Hansen溶解度参数方法进行量化。粘合结果将用于开发和验证预测性计算模型，以便进行工艺设计和优化相关工艺参数。该项目的成功完成将能够以更少的用水量和减少对环境的影响实现更可持续的矿物回收。这项研究将被纳入本科设计项目和建模方面的研究生课程，并将支持两名研究生的动手研究培训。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.