Precoated sand and preparation process thereof

Abstract

The invention particularly discloses precoated sand. The precoated sand comprises the following ingredients of quartz sand, a binder and calcium stearate, and the binder comprises the following ingredients of starch, cane sugar, dolomite powder, quartz powder, epoxidized vegetable oil and arginine. A preparation process for the precoated sand comprises the following steps that S1, the quartz sand is weighed and roasted for 4-6 h at the temperature of 870-900 DEG C; S2, the quartz sand obtained in the stepS1 is placed at the temperature of (-10)-(-30) DEG C to be cooled, and cooled sand is obtained; S3, the binder and the calcium stearate are added in the cooled sand to be stirred, uniformly mixed and cooled, and a mixture is obtained; and S4, the mixture is crushed and sieved to obtain the precoated sand. According to the precoated sand and the preparation process thereof, the binder is prepared from raw materials which do not generate harmful gas in the using process, and the precoated sand has the advantages of being high in strength and small in gas forming amount; zeolite powder is added, and the air permeability and the strength of the precoated sand are both improved; and by means of the manner that zinc oxide is adopted to modify the zeolite powder, the strength of the precoated sand can be further improved.

Description

Technical field [0001] The present application relates to a coated sand and its preparation process. Background technique [0002] Grit coated sand surface that is covered with a layer of sand or a core sand binder before molding. The sand is typically preheated to a certain temperature, stirring add the binder, the binder coated sand surface, cooling, crushing and screening to obtain coated sand. Coated sand is mainly used in steel, cast iron. [0003] In the related art, usually a phenolic resin as a binder, and then by making the addition of hexamethylenetetramine in the phenolic resin is cured coated sand surface, to obtain coated sand. However, this method of coated sand prepared by harmful gases generated, in use, is not conducive to the health of staff. Inventive content [0004] In order to improve the problem of preparing a phenol resin obtained using the coated sand of harmful gases, in use, the present application provides a coated sand and its preparation process. ...

AI Technical Summary

Problems solved by technology

[0004] In order to improve the problem that the coated sand prepared by phenolic resin produces harmful gas during use, this application provides a coated sand and its preparation process