ABSTRACT

Bubble–particle interactions are crucial in the flotation process, and the influence of adsorbed chemicals on bubble-surface collisions/attachment is important to fully understand the role of mixed collector in low-rank coal (LRC) flotation. In this paper, the process of rising bubble attachment to LRC surface in the presence of adsorbed dodecane (D)-oleic acid (OA) collector mixture was studied using high-speed video camera and molecular-kinetic (MK) model. The results showed that collector adsorbed on LRC surface reduced the collision times, the time for stopping collision and reaching standstill. Mixed collector showed more obvious advantages than single collectors in accelerating bubble-surface collisions/attachment and increasing contact line length. Only when OA and OA-D were adsorbed, the wetting film between bubble and LRC surface broke and a stable three-phase contact was formed. The molecular displacement length of D-OA was smaller than that of single collectors, indicating the adsorption sites of bubbles on LRC surface treated with D-OA were more dense, and the higher displacement frequency of D-OA meant that the molecular displacement rate and TPCL expansion velocity was faster. D-OA enhanced the hydrophobicity of LRC surface through the synergistic effect between OA and D, which promoted the kinetics of bubble interaction with LRC surface.

摘要

气泡-颗粒相互作用在浮选过程中至关重要，吸附化学物质对气泡表面碰撞/附着的影响对于充分了解混合捕收剂在低阶煤 (LRC) 浮选中的作用非常重要。在本文中，使用高速摄像机和分子动力学（MK）模型研究了在吸附的十二烷（D）-油酸（OA）捕集剂混合物存在下气泡上升到LRC表面的过程。结果表明，吸附在LRC表面的捕收剂减少了碰撞次数、停止碰撞和达到静止的时间。混合收集器比单一收集器在加速气泡表面碰撞/附着和增加接触线长度方面表现出更明显的优势。只有当 OA 和 OA-D 被吸附时，气泡与LRC表面之间的润湿膜破裂，形成稳定的三相接触。D-OA 的分子位移长度小于单个捕集剂，说明 D-OA 处理的 LRC 表面上气泡的吸附位点更密集，D-OA 的位移频率越高，意味着分子位移速率和TPCL 扩张速度较快。D-OA通过OA和D的协同作用增强了LRC表面的疏水性，从而促进了气泡与LRC表面相互作用的动力学。D-OA的位移频率越高，意味着分子位移速率和TPCL膨胀速度越快。D-OA通过OA和D的协同作用增强了LRC表面的疏水性，从而促进了气泡与LRC表面相互作用的动力学。D-OA的位移频率越高，意味着分子位移速率和TPCL膨胀速度越快。D-OA通过OA和D的协同作用增强了LRC表面的疏水性，从而促进了气泡与LRC表面相互作用的动力学。