Flotation performance and kinetics study of low-grade limestone with fatty acids-rich oilseed residue as green collector

With the depletion of mineral resources and increasing environmental protection requirements, researching and developing efficient and environmentally friendly flotation agents is crucial for the comprehensive utilization of mineral resources. Low-grade limestone deposits with high impurities pose a challenge for efficient processing and direct industrial applications. This study explores a novel and sustainable approach to address this challenge by evaluating the prospective use of a fatty-acid-rich oilseed residue as a bio-collector (referred to as collector SSFA) to recover carbonates from a low-grade limestone, characterized by high acid insolubles content and its influence on the kinetics of the flotation process. The bio-collector (SSFA) outperformed the conventional collector sodium oleate (referred to as SSO) by significantly increasing the recovery of total carbonates (TC) while simultaneously reducing acid insolubles (AI). A low-grade limestone feed containing 78.40 % TC and 20.90 % AI was upgraded through both mechanical and column flotation techniques. Mechanical flotation yielded a product with 92.9 % TC, 93.48 % TC recovery, 4.0 % AI, and 77.58 % yield at SSFA dosage of 0.87 kg/t. Column flotation, at the same dosage, yielded a product with slightly higher TC content (94.20 %), lower TC recovery (91.02 %), similar AI content (4.07 %), and slightly lower yield (74.68 %). The kinetics of the flotation process indicated that the limestone sample exhibited fast-floating behaviour, attributed to the enhanced selectivity of the SSFA collector. The bio-collector SSFA stands out as a promising and sustainable alternative to conventional collectors for large-scale low-grade limestone flotation due to its remarkable ability to selectively recover total carbonates while minimizing acid insolubles.