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    A breakthrough in the recycling technology for foundry waste sand, achieving a comprehensive utilization rate of 95%.


    Release time:

    2025/11/18

    In recent years, technology for the recycling and reuse of casting sand waste has achieved significant breakthroughs, with a comprehensive utilization rate reaching 95%, making it a key driving force behind the industry's green transformation.

    In recent years, the technology for the recycling and reuse of casting waste sand has achieved remarkable breakthroughs, with a comprehensive utilization rate reaching as high as 95%. This technology has become a key driving force behind the industry’s green transformation. By employing multi-stage purification, particle-size control, and performance reconstruction, the technology enables nearly “non-destructive” regeneration of old sand. The regenerated sand’s performance indicators now fully match or even surpass those of new sand, allowing it to directly replace new sand in the production of high-end castings such as automotive components and aerospace parts.

    The technological breakthroughs are primarily reflected in three key areas: First, optimization of the thermal regeneration process—adopting a secondary roasting technique and using a heat exchanger to raise the air temperature inside the furnace, thereby ensuring complete combustion of residual carbon materials in the spent sand and enabling the recycling of thermal energy to reduce energy consumption. Second, combined dry-and-thermal regeneration—targeting mixed-type spent sand by first subjecting it to low-temperature roasting to brittle the binder film, followed by mechanical friction to remove the film, thus balancing efficiency and cost. Third, upgrading the intelligent sorting system—integrating modules such as magnetic separation, screening, and air classification to precisely separate ferrous impurities from fine powders, ensuring uniform particle size distribution of the regenerated sand and keeping the loss on ignition below 1.5%.

    At the application level, companies such as Chongqing Changjiang Materials have already established 27 recycling production lines, with an annual capacity to process over 5 million tons of waste sand. The recycled sand is widely used by more than 500 automotive and rail transit enterprises. The separated dust, after proper treatment, is converted into construction auxiliary materials and soil conditioners, achieving full-process resource utilization. This technology not only reduces the amount of newly mined sand and lowers carbon emissions but also, through a closed-loop industrial chain model, promotes the casting industry’s transition toward a development path characterized by “low extraction, high utilization, and low emissions.”