Inorganic precoated sand and preparation method thereof

Abstract

The invention discloses inorganic precoated sand. The inorganic precoated sand is prepared from raw materials in parts by weight as follows: 80-90 parts of crude sand, 0.3-3 parts of a curing agent, 0.01-0.1 parts of a polyacrylamide modifying agent, 2-10 parts of a binder and 0.04-0.6 parts of calcium stearate. The invention further discloses a preparation method of the inorganic precoated sand. The method comprises steps as follows: (1) the crude sand and the curing agent are mixed; (2) the polyacrylamide modifying agent is added for a reaction; (3) the binder is added and mixed for a reaction; (4) the calcium stearate is added and mixed for a reaction. The prepared inorganic precoated sand is high in strength and good in collapsibility, according to the preparation method, inorganic phosphate of a basic metal replaces organic resin of traditional precoated sand to be used as the binder, intake of organic compounds is avoided, discharge of toxic and hazardous gases is reduced, and the production environment of workers is greatly improved.

Description

technical field [0001] The invention relates to the technical field of molding sand, and belongs to an inorganic coated sand and a preparation method thereof. Background technique [0002] Dr. Kronin of Germany invented the coated sand during World War II. The powdery thermosetting phenolic resin was mechanically mixed with the original sand, and solidified when heated. Later, it was developed into a thermoplastic phenolic resin plus a latent curing agent (urol). Tropin) and lubricants are formulated into coated sand through a certain coating process. When the coated sand is heated, the resin wrapped on the surface of the sand particles melts. Under the action of the methylene decomposed from urotropine, the molten resin The linear structure is rapidly transformed into a non-melting body structure, so that the coated sand is solidified and formed. This processing technology requires high ambient temperature, and harmful gases are likely to be generated during processing. C...

AI Technical Summary

Problems solved by technology

However, the application of organic binders is harmful to environmental pollution and workers' health. Engineers re-evaluated the problem of using inorganic materials as core sand binders, and began to look for practical technical methods to solve their problems in engineering. Insufficient performance, insufficient efficiency, and insufficient reliability in the application process

[0004] Due to the limitations of the current process conditions and materials, most casting core (shell) materials are mainly resin sand, water glass sand, ordinary coated sand, etc. as foundry sand, but these materials have encountered many problems in the process of use, resin sand When in use, a large amount of toxic gases such as benzene, aldehyde, sulfur, etc. will be released, polluting the environment and damaging human health. When making sand cores, the core box is prone to fouling, and a release agent is required. At the same time, cleaning of the core box also requires special cleaning agent, and the old sand cannot be recycled, which not only destroys the natural environment but also wastes resources; the water glass sand has low strength, poor moisture resistance, poor collapse performance, poor surface quality of castings, and prone to sticky sand defects. Sand is difficult, and old sand is also difficult to recycle; ordinary coated sand has a complicated preparation process, more energy consumption, higher cost, and poor cost performance

Now inorganic coated sand is also gradually developed, which solves the pollution phenomenon of organic matter, but the existing inorganic coated sand production process requires high temperature conditions, and the requirements for the production process of inorganic coated sand are relatively high