Predicting the effect of operating and design variables in grinding in a vertical stirred mill using a mechanistic mill model

• Published in: Powder technology 2021-07, Vol.387, p.560-574
• Main Authors: de Oliveira, Alessandro L.R., de Carvalho, Rodrigo M., Tavares, Luís Marcelo
• Format: Article
• Language: English
• Subjects: Breakage function; Breakage rates; Condoms; Copper ores; Discrete element method; Distribution functions; End of life; Grinding; Grinding mills; Linings; Modeling; Reduction; Stirred ball mill
• ISSN: 0032-5910; 1873-328X
• DOI: 10.1016/j.powtec.2021.04.057

The work uses the UFRJ mechanistic mill model and DEM to analyze the effect of several design and operating variables on the apparent breakage rates and breakage distribution function of a batch gravity-induced stirred mill grinding copper ore. It shows that breakage rates increase significantly with stirrer speed; that increase in percent solids decreased breakage rates, whereas the increase in grinding media size resulted in increase in breakage rates of coarser and reduction for finer particles. Reduction in mill diameter resulted in higher breakage rates, while smooth liners were responsible for higher breakage rates of coarse particles, but at a much higher mill power. The work also shows that increasing the mill filling to match the power demanded when the screw is new allows reaching approximately the same mill performance when the screw is worn and in its end of life. [Display omitted] •Sensitivity analysis using a mechanistic model of gravity-induced stirred mill•Stirrer speed has significant effect on breakage rates and breakage function•Smooth liners increased breakage rates, but at much higher powers•Ball size resulted in significant effects on both breakage rates and breakage function•Stirrer wear reduced significantly breakage rates and could be compensated with ball addition