Application Practice of Producing High Quality Aggregate with Thin-layer Limestone

CHEN Jun; LI Cong; SONG Liuqing; WANG Tao; LIU Yang

doi:10.19698/j.cnki.1001-6171.20251050

Abstract：This study analyzed the issues existing in traditional manufactured aggregate production lines,such as suboptimal particle morphology of the products,cumbersome processes,high investment costs,and significant losses of fine sand and mud powder in the wet sand-making process.Taking a project of thin-bedded limestone and dolomite mine as an example,a dry-process aggregate production line with an annual output of 5 million tons was constructed using low-grade limestone and high-magnesium dolomite,achieving efficient utilization of mineral resources.The dry process is introduced,which acquires different particle sizes of soil-containing stone chips,crushed stones for sand-making,and 10～20mm high-quality aggregates through two-stage crushing and multi-level screening.Among them,the 0～15mm crushed stones for sand-making are further processed by a vertical roller mill grinding system to yield high-quality manufactured sand,while the 0～5 mm soil-containing stone chips are processed by a dry washing and column crushing sand-making system to produce ordinary manufactured sand.The comparison reveals that the vertical roller mill grinding products outperform the column crushing making products in terms of quality stability,particle size distribution,and morphology.The performance of concrete is comparable to that of natural sand,with lower costs,meeting the green development requirements of the sand and gravel industry and having broad application prospects.