On-stream analysis of iron ore slurry using laser-induced breakdown spectroscopy

On-stream analysis of the element content in ore slurry has important significance in the control of the flotation process and full use of raw materials. Therefore, techniques that can monitor the chemistry in slurries online are required. Laser-induced breakdown spectroscopy (LIBS) is one of the potential approaches to online measurements due to its capability of in situ and real-time analysis. However, using LIBS for on-stream analysis of slurries is challenging due to the issues such as surface ripples, sample splashing, sedimentation, etc. To address these problems, we developed a slurry circulation system. The effects of slurry flow rate on LIBS spectra were investigated to achieve the optimal detecting surface for better repeatability of LIBS. The coefficient of determination R² of the calibration curve for Fe element is 0.982, and the limit of detection of Fe element was estimated to be 0.075 wt. % under the optimized experimental parameters. The results show that this slurry circulation system is applicable to the on-stream slurry analysis.