754 Figure 6 – Froth Surface Area as a function of Flotation Tank Volume. It has been also recognized that center launders significantly enhance the recovery of coarser particles (Liu et al. 2022) Higher recoveries can be achieved, particularly in cells with the potential to recover more floatable material. The primary reason for less efficient recovery of coarser particles is that froth containing coarser particles tends to be less stable. Unstable bubbles are more prone to bursting, causing valuable minerals to fall back to the bottom of the flotation cell, (Vallejos et al. 2022). Another reason is that feed containing more coarser particles, and therefore low residual of floatable minerals, causes the lack of froth mobility (Bermudez et al. 2022). The limited mobility of the froth results in lower froth recovery compared to froth with high mobility, which easily overflows the launder lip, thereby enhancing the recovery of valuable metals (Corona-Arroyo et al. 2021). Poor recovery of these coarser particles can sometimes create a bottleneck in production. For instance, an increase in grinding circuit throughput has affected metal recovery due to the coarser grind size. Coarser grind sizes lead to longer froth transport times and reduce froth mobility, as coarser particles have a lower ability to float compared to finer particles. In these cases, the installation of center launder upgrades has proven very efficient way to enhance the process performance and recovery of valuable metals. (Bermudez et al. 2022) The shorter transport distance (FTD) provided by center launders helps mitigate this issue by reducing the likelihood of bubble breakage and improving overall recovery rates for coarser particles, (Liu et al. 2022). The impact of center launder upgrade on operating parameters, like airflow rates and froth bed depths has also been investigated. Measurements showed that after the retrofit, similar gas velocities (Jg) were achieved with reduced airflow rates. The reduction in airflow rates is expected to lower the energy consumption of the blower, thereby promoting more sustainable metals processing. On the other hand, the froth bed thickness in upgraded cells is considered to be higher due to smaller froth surface areas, which has been enhanced process control. (Bermudez et al. 2022) 3. EVALUATION OF CENTER LAUNDER UPGRADE INSTALLATIONS Center launder installations have been successfully implemented in various operations, including Hudbay Constancia, Kennecott Copperton, Bagdad, Red Chris, and New Afton Mine, to address current
RkJQdWJsaXNoZXIy MTM0Mzk2