In mineral processing, the selection of a secondary grinding process requires a comprehensive consideration of ore characteristics and production requirements. When the ore has a fine interpenetration and requires a high fineness of at least 60% of the -200 mesh, a single ball mill cannot achieve efficient crushing. In such cases, secondary grinding can significantly improve product uniformity. For example, when processing precious metal ores such as gold, a grate ball mill for coarse grinding in the first stage (increasing production capacity by 20%-30%) and an overflow ball mill for fine grinding in the second stage effectively avoid over-grinding and improve the degree of monomer dissociation.

For complex ores with uneven interpenetration or high-density minerals, secondary grinding combined with intermediate separation offers unique advantages. Inserting magnetic separation or gravity separation equipment into the grinding cycle can promptly separate dissociated minerals, reduce the accumulation of heavy metal minerals in the return sand, and thus improve overall recovery. Furthermore, when the processing capacity of the primary ball mill is insufficient, adding a secondary grinding system (such as a PCZ series hammer mill for pre-crushing) can increase the raw ore processing capacity from 80 tons/hour to 150 tons/hour while reducing specific energy consumption.

Notably, secondary grinding requires balanced loads and optimized ball ratios: the coarse grinding stage utilizes large-diameter balls at high speeds, while the fine grinding stage uses small-diameter balls at low speeds. While this process increases equipment configuration complexity, modular design (such as the use of a unified grate ball mill) simplifies maintenance and management, making it particularly suitable for large-scale mineral processing plants and deep processing applications with stringent product particle size requirements.