Exploration study of nickel slag/modified slag in the ultra-precision polishing of magnetic compound fluid

Nickel slag is the solid waste obtained from the nickel smelting process. Based on the magnetic elements in nickel slag, it is a potential ingredient that could be used in magnetic compound fluid (MCF) polishing. This work discusses polishing in MCF using nickel slag and modified slag. Investigations are conducted into how MCF is affected by the amount of modified slag and nickel slag present during polishing. The connections between shear force, position, material removal rate, morphological characteristics, and polishing quality are covered. Nickel slag is mixed with CaO, the alkalinity is adjusted, and the mixture is heated to 1500 °C to fully melt and oxidize it. The resulting product is modified slag. The morphological changes in MCF slurry before and after polishing were examined using an industrial camera, and the effect of different MCF slurry components on polishing performance was analyzed throughout the polishing process. In addition, the positioning of modified slag within the magnetic cluster formed during the polishing process was determined through a scanning electron microscope and by energy dispersive x-ray spectroscopy mapping of MCF slurry. The aforementioned research establishes the polishing mechanism for nickel slag and modified slag. The experimental results indicate that the polishing effect of the experimental group with added modified slag is better than that of added nickel slag. Under the same conditions, the surface roughness was reduced by 60% when modified slag was used instead of nickel slag. It was found that the optimal process is where the modified slag content is 10%, where the material removal rate is 1.207 × 108 µm3/min and the surface roughness decrease rate is 95.482%. The polishing shear force is around 2.7N, which is twice as much as that of nickel slag.