Population Balance Model Approach to Ball Mill Optimization in Iron Ore Grinding

Abstract

The process of particle size reduction by grinding is inherently inefficient and involves high capital and operating costs. In particular, ball milling is one of the important unit operations in the iron ore pelletizing process. The mill product, due to its physical properties, determines the efficiency of subsequent stages of classification, filtration and pelletizing, thus impacting the quality of iron ore pellets. The work demonstrates the application of the population balance model in the optimization of a full-scale ball mil circuit grinding pellet fines with the aim to evaluate the optimal solids concentration to improve iron ore pellet quality. Initially, detailed experimentation was carried out in a 25.4 cm diameter batch mill and a relationship for mill scale-up using a linear population balance model in wet grinding systems was established. The selection and breakage parameters and the specific selection functions were determined for pellet feed iron ore. It was possible to identify the non-normalizable nature of the breakage functions of the ore studied, which were modeled properly. Afterwards, as a result of incorporating the specific selection functions and breakage functions into the linear population balance model, it was possible to predict product size distributions in the pilot and plant scale mills (0.416 and 5.18 m diameter, respectively) from data obtained in the 25.4 cm diameter mill. Finally, with this scaleup procedure it was possible to appraise the plant scale optimization via laboratory scale grinding mill tests. The effects of changing percent solids were assessed in order to improve the industrial mill performance and the optimal value should be in the range from 76 to 80%.

Coal Sampe Preparation Strategy using the TENCAN GQM series Ball Milling device.

“…The Volatility recorded across all coal materials reflected an inverse relationship with respect to the overall coal material hardness thus due to structural compactness of the coal sample volatile substances are intrinsically blended within the coal maceral making it difficult for them to escape into the environment hence dominating other embedded compounds containing water of crystallization thus adding to the strength of the material and increasing the resilience to fracture during milling. Additionally, the coal ash relative composition is a desirable quality especially for civil and construction industries (bricks), cement and textile manufacturing sectors (tiles), the agriculture fertilizer institutions (soil pH stabilizers) [51], [58] etc., hence, due to ball milling configuration of the TENCAN [GQM] series Roll Ball Mill utilization, special device setting can be conditioned to fracture coal of varied composition into desirable product output such that through optimization, modelling and simulation of experimental data, predictable outcome routes can be fashioned [14], [15], [59].…”

“…Nonetheless most customized cylindrical mill designs are constructed with liners of tungsten carbide high-grade matrix alloys or other exceptional composite rubber liners capable of withstanding accelerated wear rates and highly scratch resistant. Liners are waved in structure while others are grid shape manufactured to aid industrial milling cylinders comminute various material at minimum effort because they prolonged the lifespan of mill equipment while affording maximum grinding efficacy achieved through liner grids and an added hard surface [12], [13], [14], [15].…”

Coal Sample Preparation Strategy using the TENCAN GQM series Ball Milling device.

“…Additionally, the coal ash relative composition is a desirable quality especially for civil and construction industries (bricks), cement and textile manufacturing sectors (tiles), the agriculture fertilizer institutions (soil pH stabilizers) [53], [59], [54], [51], [58], etc., hence, due to ball milling configuration of the TENCAN [GQM] series Roll Ball Mill utilization, special device setting can be conditioned to fracture coal of varied composition into desirable product output such that through optimization, modelling and simulation of experimental data, predictable outcome routes can be fashioned [14], [15], [60], [59].…”

“…Nonetheless most customized cylindrical mill designs are constructed with liners of tungsten carbide high-grade matrix alloys or other exceptional composite rubber liners capable of withstanding accelerated wear rates and highly scratch resistant. Liners are waved in structure while others are grid shape manufactured to aid industrial milling cylinders comminute various material at minimum effort because they prolonged the lifespan of mill equipment while affording maximum grinding efficacy achieved through liner grids and an added firm surface [12], [13], [14], [15].…”