Molding sand for non-ferrous castings and preparation method thereof

Abstract

The invention provides molding sand for non-ferrous castings. The molding sand is prepared from the following raw materials in parts by weight: 40-45 parts of alunite, 13-15 parts of plant ash, 20-30 parts of bentonite, 50-55 parts of mineral waste residue, 40-45 parts of medical stone powder, 12-15 parts of gypsum, 3-4 parts of zinc oxide, 3-5 parts of calcium lignosulphonate, 2-3 parts of diffusing agent MF2, 2-3 parts of polyvinyl alcohol, 1-2 parts of sodium carbonate, 2-3 parts of calcium oxide, 5-8 parts of magnesium oxide, 10-16 parts of aluminum sulfate slag, 5-8 parts of sodium metasilicate, 2-3 parts of glycerol triacetate, 1-2 parts of diethylene glycol benzoate and a proper amount of water. The molding sand prepared by calcining, smashing and carrying out high-temperature calcination on the alunite, the bentonite, the mineral waste residue, the gypsum and the like in combination with the dispersion and grinding of additives such as the calcium lignosulphonate has excellent smoothness, air permeability, caking property, toughness and plasticity. Meanwhile, the collapsibility of the molding sand is improved by using the powder such as the plant ash, the medical stone powder and the aluminum sulfate slag, so that the brightness of non-ferrous metals can be improved.

Description

Technical field [0001] The invention relates to the field of casting, in particular to a molding sand used for non-ferrous metal castings and a preparation method thereof. Background technique [0002] Molding sand is a material used for molding in casting. Molding sand is generally made by mixing molding materials such as raw sand for foundry, molding sand binder, and auxiliary additives in a certain proportion. Natural clay-containing silica sand can also be used. The usual molding sand formulations for aluminum casting have too large a particle size or Too small, the sand diameter is too large, although the air permeability is good, the surface of the aluminum sand part is relatively rough, the smoothness is not good, and the sand diameter is too small, resulting in poor air permeability of the sand mold and pores in the aluminum casting. The pulverized clay green sand, which is widely used at home and abroad, is generally made by mixing raw sand, binders, pulverized coal add...

AI Technical Summary

Problems solved by technology

Molding sand is generally made by mixing molding materials such as raw sand for casting, molding sand binder and auxiliary additives in a certain proportion. Natural silica sand containing clay can also be used. In the usual molding sand formula for aluminum casting, the particle size of the molding sand is too large or If it is too small, the diameter of the sand material is too large. Although the air permeability is good, the surface of the aluminum sand parts is rough and the finish is not good. The diameter of the sand material is too small, resulting in poor air permeability of the sand mold and air holes in the aluminum casting

Coal powder clay green sand, which is widely used at home and abroad, is generally made of raw sand, binders, coal powder additives, etc. and water. It has a certain anti-sticking sand effect, low material cost, and high production efficiency. However, its consumption is large, the emission is serious, and the coal powder is burned and decomposed in the casting process to produce toxic gas pollution.