Method for recycling cast waste sand

Abstract

The invention provides a method for recycling cast waste sand, which is characterized in that: adding calcium chloride or ferrous chloride into the waste sand in a molar ratio of sodium in waste sand to the calcium chloride or ferrous chloride of 2:0.8-1.5 and uniformly mixing the materials to recycle the waste sand. The method can be used for harmless treatment of cast waste sand, namely water-glass sand, to make the cast waste sand a stable and reliable building material that can be used in a large amount. Thus, not only the serious pollution caused by the burying and discarding of the conventional cast waste sand to the ecological environment and great waste of finite resources are prevented, but also the elimination of finite land occupation and the change of the cast waste sand into the building material are realized. The sodium oxide (Na2O) content of recycled waste sand provided by the invention is lower than 1 percent; the recycling cost is low; the selling price is 2 to 3 times the recycling cost; and real 'zero' discharge is realized.

Description

technical field [0001] The invention relates to a method for regenerating foundry waste sand, which belongs to the technical field of comprehensive recycling and utilization of waste resources. Background technique [0002] Usually the solid waste in foundry enterprises is mainly waste sand, accounting for more than 70% of the total. In 2006, the annual output of castings in my country has reached more than 28 million tons. For every ton of qualified castings produced, about 1.5 tons of waste sand will be produced, and the total amount of waste sand is nearly 42 million tons. However, the recycling rate of waste sand is only 20-30%, and most of them are disposed of by landfill or random disposal, which will undoubtedly cause serious pollution to the ecological environment and is also a great waste of limited resources. , but also occupy limited land, and also spend transportation costs, land acquisition costs, etc. for the discharge of these waste residues, which is unfavor...

AI Technical Summary

Problems solved by technology

Sodium carbonate (Na 2 CO 3 ) will absorb moisture and carbon dioxide (CO2) in the air for a long time 2 ), generating 1, 3 and 10 sodium carbonate (Na 2 CO 3 ), and form a hard block, the result is that the structure of the waste sand is changed and the performance is unstable, so that the possibility of using the waste sand as a building material fails