Fundamental study of in-situ gas nucleation by hydrodynamic cavitation for fine particle flotation

加拿大是世界上主要的矿业国家之一，生产着60多种重要的矿物和金属，供全球使用。矿业是加拿大经济的支柱，几乎占全国GDP的3%。然而，加拿大矿业公司在满足全球对大宗商品的需求方面面临着许多挑战。面对不断下降的矿石品位和更加严格的环境法规，创新至关重要。高品位矿石资源的迅速枯竭促使采矿和选矿行业探索加工低品位矿石的新技术。要有效地从低品位矿石中回收有价值的矿物，需要高耗能的细磨来解放矿物，并需要一种新的细粒浮选技术。小于5微米的细小颗粒的浮选极具挑战性，因为气泡-颗粒的碰撞和附着效率低下，再加上煤泥涂层，导致回收率低和选择性差。由于金属氢氧化物物种和细脉石矿物颗粒在目标矿物表面的非选择性沉淀或沉积，目标矿物颗粒表面的煤泥涂层更难浮选细粒。这反过来又会导致尾矿中有价值的矿物流失。 为强化细粒浮选，提出了常规尺寸气泡与水力空化产生的微气泡或纳米气泡潜伏颗粒之间的两步附着法。该项目的成功将加强加拿大在自然资源可持续开发和利用方面的领导作用，并使加拿大保持在新技术开发的前沿。

Canada is one of the leading mining nations in the world, producing more than 60 vital minerals and metals that are used globally. Mining is a pillar of the Canadian economy, generating almost 3% of the national GDP. However, Canadian mining companies face a number of challenges in meeting the global demand for commodities. Innovation is critical in the face of declining ore grades and more stringent environmental regulations. The rapid depletion of high-grade mineral ore resources has driven the mining and mineral processing industry to explore new technologies to process lower grade ores. The effective recovery of valuable minerals from low grade ores requires energy-intensive fine grinding for mineral liberation and a new technology for fine particle flotation. The flotation of fine particles of sizes less than 5 micron is extremely challenging due to inefficient bubble - particle collision and attachment, compounded by slime coatings, leading to a low recovery and a poor selectivity. The slime coatings on target mineral particles are more problematic for fine particle flotation due to non-selective precipitation or deposition of metal hydroxide species and fine gangue mineral particles on the surface of target minerals. This in turn results in a loss of valuable minerals in tailings. A two-step attachment between conventional size bubble and microbubble or nanobubble-laten particles generated by hydrodynamic cavitation is proposed for enhancing fine particle flotation. The success of this project will strengthen Canada's leadership role in sustainable development and utilization of natural resources and keep Canada in the forefront of new technology development.