Nailing The Granulometry With Geometry

Tumbling mills are a primary determinant of the operating costs of cement production and mining operations. Over recent decades there have been many efforts to improve the energy efficiency of tumbling mills, including alternative technologies such as HPGR systems and vertical roller mills. To help cement producers and mining companies address this challenge, Relo-B Ltd has developed the Relo grinding media (RGM) which has increased mill operating capacities without incurring any further capital costs, thus reducing overall operating costs. This grinding solution was designed to increase throughput, minimise energy consumption, and extend the lifetimes of the components.

The new grinding media was named Relo grinding media in honour of the German engineer Franz Reuleaux, a mechanical engineer, who gave his name to this geometrical shape in the nineteenth century. Although these grinding bodies come in slightly different shapes, they are all derived from Reuleaux geometry, i.e. the Reuleaux triangle and the Reuleaux tetrahedron, which are the key structural shapes of the RGM. The new grinding media are made of steel, encompassing all types commonly used for making balls. Moreover, due to their shape, steel Relo grinding bodies have better quench hardening compared to steel balls at equal tempering conditions. This results in a higher overall hardness as the distance from the surface to the centre of Relo grinding body is smaller than the same for a sphere. These recent developments in grinding media design, such as RGM, have the potential to offer significant efficiency improvements in tumbling mill grinding circuits. RGM can be easily applied to existing mining operations or cement plants without the need to retrofit mills or undertake expensive reengineering exercises.

Because of their Reuleaux geometry, RGM have a greater surface area and higher bulk density compared to balls of the same mass and size. Ideally, RGM have a surface area approximately 10% larger than balls of the same mass (volume) and have approximately 10% higher bulk density than steel balls. As a result, for a given charge volume, an increased grinding media surface area is available for size reduction when charged with RGM, but the mill would also draw more power.

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Read the article online at: https://www.worldcement.com/special-reports/12062023/nailing-the-granulometry-with-geometry/