Secondary sand-gravel separation system

The utility model relates to the field of concrete recycling, in particular to a secondary sand-gravel separation system, which is characterized in that a sand-gravel separator is arranged to carry out primary sand-gravel separation on residual concrete after construction is finished, the separated sand-gravel is conveyed to a stirrer, and meanwhile, a sludge separator is additionally arranged; sludge generated by the sand and stone separator is subjected to secondary screening, so that sand and stones with small particle sizes are screened out, and the cost of raw materials is reduced; wastewater generated by two times of separation is subjected to different treatments, clear water obtained by sedimentation of wastewater generated by a sand-gravel separator can be used for cleaning the sand-gravel separator next time, wastewater generated by a sludge separator is subjected to stirring fermentation treatment, obtained clear water can be used as a raw material for concrete production, and due to the fact that