The role of some special ions in the flotation separation of pentlandite from lizardite

• Constitution ions were found to significantly improve pentlandite recovery efficiency.
• Improved recovery was due to the zeta potential changes of the mineral surfaces and the aggregation of lizardite particles.
• Constitution ions dispersed lizardite particles from pentlandite surfaces by making the surfaces of pentlandite and lizardite particles homocharged.
• The bimodal distribution of lizardite particles was observed in constitution ion solutions.
• The formation of spongy lizardite fibers was a novel factor interfering with the flotation of pentlandite, which was repressed efficiently in constitution ion solutions.

In this work, the flotation of pentlandite/lizardite system was studied in deionized water, brine and solutions containing some special “constitution ions” with different ionic strengths, respectively. The flotation results show that the “constitution ions” significantly improve the recovery efficiency of pentlandite compared with deionized water or brine. The possible mechanisms responsible for the improved flotation separation in these special solutions are investigated by electrokinetic studies, scanning electronic microscopy (SEM) analysis and size distribution tests. Experimental results demonstrate that the reconstitution of electrical double layer mitigates the coating of lizardite particles on pentlandite surfaces and induces the aggregation of lizardite particles for the enhanced recovery of pentlandite.

Model for the changes of pentlandite–lizardite system in deionized water (A) and high concentration NiCl2 solution (B).Figure optionsDownload as PowerPoint slide