Foundry waste sand is difficult to prevent the precision casting profession accompanied by goods, according to statistics, every product produced in our country 1t of good casting, produced by waste sand 1.3~1.5t, the annual foundry waste sand row as far as possible is above the ton. The content of Fe2O3 in the recycled powder after magnetic separation with the final magnetic induction intensity of 0.3t is the same as that of the new powder. There are a lot of fine powder on the surface of the reconstituted sand in the old reconstituted sand plant. In 1995, the people's democratic country of China came forward with a law on the purification and epidemic prevention of liquid treasures, encouraging and supporting the superstitious research on the purification and epidemic prevention of liquid treasures and developing techniques. The need for the treasures of all ethnic groups to use anti - Yang scattered, anti - loss, anti - leakage probably the rest of the prevention and purification. But after the high price of precision casting waste sand research is very few, the general form of engagement is random deposition probably landfill, there is no purification conditions, but also formed a great care of resources, therefore, looking for precision casting waste sand engaged in technology, urgent. Foundry waste sand analysis application did not break is the condition of smelting industry with the focus on results, course narrow no slack of the task to, received a doomed results, such as detailed in the smelter and application, preparation of autoclaved brick, high strength sintered materials, sintering foaming materials, new materials such as composite derelicts compound material, but also need to perfect and further. In the future, sand and powder from abandoned shell of precision casting are destined to be magnetic separation to ensure the regressive shell making.

Precision casting of old sand is complete, magnetic separation, screening, dusting of recycled sand and new sand after the proper ratio, has been successfully used in batch is back shell, useful to land waste sand emissions, add new sand consumption. It is necessary to adopt the methods of preventing dispersal, preventing loss and preventing leakage for treasures of all nationalities. No one pours, deposits, throws away or spills liquid treasures. The first attempt is to increase the amount of new sand in the smelting ship production, save the economic input, reduce the casting quality, and then protect the conditions.

In 1995, the people's democratic country of China came forward with a law on the purification and epidemic prevention of liquid treasures, encouraging and supporting the superstitious research on the purification and epidemic prevention of liquid treasures and developing techniques.

Old sand recycling, is the selection of machine friction method, heating method, hydraulic method and other common chemical methods, remove the old sand particles surface friction effective or not effective binder coated film, so that the old sand of all nationalities lost healing process function of a precision casting process with old sand. Casting waste sand is replacing precious natural primary resources and the scope of application of treasure analysis is enthusiastic, but the effect of recycling of precision casting waste sand has not been reported, which needs further discussion from experts.