CN103570367A - High fire-resistant molding sand for casting and preparation method thereof - Google Patents

Abstract

The invention discloses high fire-resistant molding sand for casting and a preparation method thereof. The high fire-resistant molding sand for casting comprises the following raw materials in parts by weight: 60-80 parts of fused ceramsite, 20-30 parts of mullite, 10-15 parts of corundum powder, 5-10 parts of nanometer boron nitride, 3-6 parts of light magnesium oxide, 4-8 parts of kaolin, 2-4 parts of illite, 3-5 parts of modified water glass, 1.5-2.5 parts of asphalt, 1-2 parts of polytetrafluoroethylene micro powder, 2-3 parts of polyvinylpyrrolidone and 4-8 parts of water. The high fire-resistant molding sand for casting has high degree of fire resistance, good air permeability, good filling ability and good collapsibility, is difficult to break and high in repeated utilization rate, does not generate dust and cause siliceous dust damage and belongs to the green and environment-friendly molding sand for casting. Castings produced by using the molding sand are high in size precision and have few cracks and surface detects, and the rate of finished products of the castings is high.

Description

High refractory cast moulding sand and preparation method thereof

Technical field

The present invention relates to a kind of high refractory cast moulding sand and preparation method thereof, belong to molding sand technical field.

Background technology

Produce in the past big-and-middle-sized foundry goods and all adopt clay-beaded sand, made and will deliver to stoving oven after type and dry, the production cycle is long, and casting accuracy is poor, and labor condition is poor, can not meet the needs of production development far away.Sodium silicate sand is because mobility is high, and compact rate of molding is high, and sclerosis is fast, and casting accuracy is high, originates wider, cheap, and the features such as environmental protection, have become in recent decades one of molding sand kind with fastest developing speed.Most steel casting and large-sized iron casting adopt sodium silicate sand explained hereafter, the phenomenons such as although sodium silicate sand advantage is a lot, under the condition of high temperature, molding sand easily expands, fragmentation, thus affect the casting of foundry goods.

Summary of the invention

The object of the invention is to for the deficiencies in the prior art, improve that a kind of refractoriness is high, the high refractory cast moulding sand of good permeability, environmental protection and preparation method thereof.

The technical solution used in the present invention is as follows:

A refractory cast moulding sand, is made by the raw material of following weight part: mound sand 60-80, mullite 20-30, lapis amiridis 10-15, nm-class boron nitride 5-10, light magnesium oxide 3-6, kaolin 4-8, illite 2-4, modified water glass 3-5, pitch 1.5-2.5, ptfe micropowder 1-2, polyvinylpyrrolidone 2-3, water 4-8;

The preparation method of described modified water glass is as follows:

(1) take the raw material of following weight part: water glass 25-35, water soluble starch 4-8, dextrin 3-6, urea 3-4, S-WAT 2-3, sodium polyacrylate 4-6, potassium primary phosphate 2-4, Xylitol 1-2, polyisobutene 2-3, calcium lignin sulphonate 3-5, sylvic acid polyoxyethylene ester 1.5-2.5, Xylo-Mucine 1-2, vermiculite 4-6, sepiolite 3-5, nano aluminium oxide 2-3, jade powder 1.5-2.5, plant ash 2-3, calcium chloride 1-2, sodium-chlor 0.5-1, Di(dioctylpyrophosphato) ethylene titanate 0.5-1,

(2) by vermiculite, sepiolite mixes, pulverized 100-150 mesh sieve, then in the powder after sieving, add calcium chloride and sodium-chlor, stir, 880-940 ℃ of calcining 2-3h, shrend, then be placed in the hydrochloric acid soln that concentration is 10-15%, be heated to boiling speed lapping 15-20min, the sodium hydroxide solution regulator solution PH that is 15-20% by concentration is again to neutral, stir 10-15min, filter, with distilled water, clean filter residue, filter residue after cleaning adds water making beating and makes the slurry that solid content is 50-60%, add again polyisobutene, calcium lignin sulphonate, sylvic acid polyoxyethylene ester and Xylo-Mucine, under 60-80 ℃ of bath temperature below speed lapping slurry particle diameter to 15 μ m, be spray dried to powder, with nano aluminium oxide, jade powder, plant ash and Di(dioctylpyrophosphato) ethylene titanate, high-speed mixing 5-10min, dry, pulverize porphyrize, cross 300-400 mesh sieve, stand-by,

(3) powder step (2) being made mixes with water glass, water soluble starch, dextrin, urea, S-WAT, sodium polyacrylate, potassium primary phosphate and Xylitol, stirs 1-2h, obtains modified water glass.

A preparation method for high refractory cast moulding sand, comprises the following steps:

(1), by mound sand, mullite, illite co-grinding, excessively after 200-250 mesh sieve, be dry mixed 3-4min with lapis amiridis, nm-class boron nitride, light magnesium oxide, kaolin;

(2) add pitch, ptfe micropowder, polyvinylpyrrolidone, water, wet mixing 2-3min;

(3) finally add modified water glass, mix 1-2min, shake out.

Beneficial effect of the present invention:

Molding sand refractoriness of the present invention is high, is difficult for fragmentation, and repeat usage is high, without dust, and good permeability, fillibility is good, and collapsibility is good, without silicious dust harm, belongs to environmental type moulding sand for casting; The dimensional precision that this molding sand is produced foundry goods is high, breaks and few surface defects, and casting yield is high.

Embodiment

A refractory cast moulding sand, is made by the raw material of following weight (kg): mound sand 65, mullite 25, lapis amiridis 10, nm-class boron nitride 7, light magnesium oxide 4, kaolin 6, illite 3, modified water glass 4, pitch 2, ptfe micropowder 1.5, polyvinylpyrrolidone 2, water 6;

The preparation method of described modified water glass is as follows:

(1) take the raw material of following weight part: water glass 30, water soluble starch 6, dextrin 4, urea 3, S-WAT 2.5, sodium polyacrylate 5, potassium primary phosphate 3, Xylitol 1.5, polyisobutene 2, calcium lignin sulphonate 4, sylvic acid polyoxyethylene ester 2, Xylo-Mucine 1.5, vermiculite 5, sepiolite 4, nano aluminium oxide 2, jade powder 2, plant ash 2.5, calcium chloride 1.5, sodium-chlor 0.6, Di(dioctylpyrophosphato) ethylene titanate 0.5;

(2) by vermiculite, sepiolite mixes, pulverized 100 mesh sieves, then in the powder after sieving, add calcium chloride and sodium-chlor, stir, 910 ℃ of calcining 3h, shrend, then be placed in concentration and be 12% hydrochloric acid soln, be heated to boiling speed lapping 15min, the sodium hydroxide solution regulator solution PH that is 16% by concentration is again to neutral, stir 10min, filter, with distilled water, clean filter residue, filter residue after cleaning adds water making beating, and to make solid content be 60% slurry, add again polyisobutene, calcium lignin sulphonate, sylvic acid polyoxyethylene ester and Xylo-Mucine, under 80 ℃ of bath temperatures below speed lapping slurry particle diameter to 15 μ m, be spray dried to powder, with nano aluminium oxide, jade powder, plant ash and Di(dioctylpyrophosphato) ethylene titanate, high-speed mixing 8min, dry, pulverize porphyrize, cross 300 mesh sieves, stand-by,

(3) powder step (2) being made mixes with water glass, water soluble starch, dextrin, urea, S-WAT, sodium polyacrylate, potassium primary phosphate and Xylitol, stirs 1h, obtains modified water glass.

A preparation method for high refractory cast moulding sand, comprises the following steps:

(1), by mound sand, mullite, illite co-grinding, excessively after 250 mesh sieves, be dry mixed 3min with lapis amiridis, nm-class boron nitride, light magnesium oxide, kaolin;

(2) add pitch, ptfe micropowder, polyvinylpyrrolidone, water, wet mixing 2min;

(3) finally add modified water glass, mix 2min, shake out.

The performance test of the present embodiment molding sand is as follows:

Green compression strength (kPa): 51

24h tensile strength (MPa): 0.48

Ventilation property: 129

Compact rate of molding (%): 44

Shatter index (%): 87.

Claims (2)

1. one kind high refractory cast moulding sand, it is characterized in that, by the raw material of following weight part, made: mound sand 60-80, mullite 20-30, lapis amiridis 10-15, nm-class boron nitride 5-10, light magnesium oxide 3-6, kaolin 4-8, illite 2-4, modified water glass 3-5, pitch 1.5-2.5, ptfe micropowder 1-2, polyvinylpyrrolidone 2-3, water 4-8;

The preparation method of described modified water glass is as follows:

Take the raw material of following weight part: water glass 25-35, water soluble starch 4-8, dextrin 3-6, urea 3-4, S-WAT 2-3, sodium polyacrylate 4-6, potassium primary phosphate 2-4, Xylitol 1-2, polyisobutene 2-3, calcium lignin sulphonate 3-5, sylvic acid polyoxyethylene ester 1.5-2.5, Xylo-Mucine 1-2, vermiculite 4-6, sepiolite 3-5, nano aluminium oxide 2-3, jade powder 1.5-2.5, plant ash 2-3, calcium chloride 1-2, sodium-chlor 0.5-1, Di(dioctylpyrophosphato) ethylene titanate 0.5-1,

By vermiculite, sepiolite mixes, pulverized 100-150 mesh sieve, then in the powder after sieving, add calcium chloride and sodium-chlor, stir, 880-940 ℃ of calcining 2-3h, shrend, then be placed in the hydrochloric acid soln that concentration is 10-15%, be heated to boiling speed lapping 15-20min, the sodium hydroxide solution regulator solution PH that is 15-20% by concentration is again to neutral, stir 10-15min, filter, with distilled water, clean filter residue, filter residue after cleaning adds water making beating and makes the slurry that solid content is 50-60%, add again polyisobutene, calcium lignin sulphonate, sylvic acid polyoxyethylene ester and Xylo-Mucine, under 60-80 ℃ of bath temperature below speed lapping slurry particle diameter to 15 μ m, be spray dried to powder, with nano aluminium oxide, jade powder, plant ash and Di(dioctylpyrophosphato) ethylene titanate, high-speed mixing 5-10min, dry, pulverize porphyrize, cross 300-400 mesh sieve, stand-by,

The powder that step (2) is made mixes with water glass, water soluble starch, dextrin, urea, S-WAT, sodium polyacrylate, potassium primary phosphate and Xylitol, stirs 1-2h, obtains modified water glass.

2. the preparation method of high refractory cast moulding sand according to claim 1, is characterized in that comprising the following steps:

(1), by mound sand, mullite, illite co-grinding, excessively after 200-250 mesh sieve, be dry mixed 3-4min with lapis amiridis, nm-class boron nitride, light magnesium oxide, kaolin;

(2) add pitch, ptfe micropowder, polyvinylpyrrolidone, water, wet mixing 2-3min;

(3) finally add modified water glass, mix 1-2min, shake out.