In the search for more sustainable alternatives to the chemical reagents currently used in froth flotation, the present work offers further insights into the behavior of functionalized cellulose nanocrystals as mineral hydrophobization agents. The study corroborates that hexylamine cellulose nanocrystals (HACs) are an efficient collector for the flotation of quartz and also identifies some particular characteristics as a result of their colloidal nature, as opposed to the water-soluble reagents conventionally used. To investigate the individual and collective effects of the frother and HACs on the attachment of particles and air bubbles, an automated contact timer apparatus was used. This induction timer measures particle-bubble attachment probabilities (P_att) without the influence of macroscopic factors present in typical flotation experiments. This allowed the study of the combined influence of nanocellulose and frother concentration on P_att for the first time. While HACs readily adsorb on quartz modifying its wettability, the presence of a frother leads to a drastic reduction in P_att up to 70%. The improved recovery of quartz in flotation cells might thus be attributed to froth stabilization by HACs, perhaps acting as a Pickering foam stabilizer. Among the main findings, a tendency of HACs to form mineral agglomerates was identified and further explained using the extended DLVO theory in combination with measured adsorption rates in a quartz crystal microbalance. Therefore, this study distinguishes for the first time the antagonistic effect of frothers on P_att and their synergies with HACs on the stabilization of orthokinetic froths through the hydrophobization mechanism unlike those of typical water-soluble collectors.

中文翻译：

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纤维素纳米晶体作为矿物颗粒的疏水化剂的胶体行为

在寻找目前泡沫浮选中使用的化学试剂的更具可持续性的替代方案时，本工作为功能化纤维素纳米晶体作为矿物疏水剂的行为提供了进一步的见识。这项研究证实了己胺纤维素纳米晶体（HAC）是一种用于浮选石英的有效捕收剂，并且由于其胶体性质，与常规使用的水溶性试剂相反，它们还可以识别某些特殊特征。为了研究起泡剂和HAC对颗粒和气泡附着的个体和集体影响，使用了自动接触计时器设备。该感应计时器测量粒子气泡的附着概率（P _att），而不受典型浮选实验中存在的宏观因素的影响。这使得纳米纤维素和起泡剂浓度对组合影响的研究P _ATT首次。虽然HACS容易吸附在石英修改其润湿性，起泡剂引线的存在，以大幅减少P _ATT高达70％。因此，浮选池中石英回收率的提高可能归因于HAC可能起到Pickering泡沫稳定剂的作用，使泡沫稳定。在主要发现中，鉴定了HACs形成矿物团聚体的趋势，并使用扩展的DLVO理论结合在石英晶体微量天平中测得的吸附速率进一步进行了解释。因此，本研究区分首次上起泡剂的拮抗作用P _ATT和它们的协同作用与上同向气得口吐白沫的通过不像那些典型的水溶性收集器的疏水化机构稳定HACS。