SU1680434A1 - Composition of anti-sintering compound used in foundry shops - Google Patents

Abstract

The invention relates to foundry and relates to non-stick materials used as additives for molding and core sands. The purpose of the invention is to reduce the cost and accelerate the formation of a reducing medium at the metal-form interface while maintaining a high yield of pyrocarbon and low gas emissions. The introduction of a nonstick coating based on a liquid material of an amyclic or aromatic class of anhydrous sodium carbonate in an amount of 2-10 wt.% Allows to increase the yield of pyrocarbon by 25-35% and reduce the gas-content of these materials by 20-30% during destruction. 2 tab. SP g

Description

FIELD OF THE INVENTION The invention relates to a foundry industry and relates to non-stick materials used in foundries as additives for molding and core sands.

The purpose of the invention is to reduce the cost and accelerate the formation of a reducing medium at the metal-form interface while maintaining a high yield of pyrocarbon and low gas-creation.

The main component of the composition is a liquid material of an alicyclic or aromatic hydrocarbon series (tars of various origins, pure or used mineral oils of various purposes, coolant).

These materials are representative of the alicyclic hydrocarbon series. Potassium repellent (for example, GFK-1) is a representative of substances characterized by an aromatic hydrocarbon ring. A mixture of hydrocarbons of an alicyclic and aromatic series, such as fuel oil, can also be used.

The amount of sodium carbonate in the composition of the nonstick composition is due to the effectiveness of its effect on hydrocarbon liquid materials. It was established experimentally that the content of sodium carbonate should be in the range of 2 to 10 wt.%, Since it is within these limits that

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maximum positive effect. When the content of sodium carbonate is less than 2 wt.%, Its effect is clearly not enough, since there is practically no increase in the yield of pyrocarbon and a decrease in the gas-creation ability during the destruction of hydrocarbon materials. Entering sodium carbonate in excess of 10 wt.% Is not economically feasible, since it does not increase positive effect, and in addition, the amount of coke residue after destruction increases. At the same time, sodium carbonate must be crushed to fractions less than 50 µm, since larger particles do not ensure its uniform distribution in the bulk of the hydrocarbon material (sodium carbonate precipitates, especially in low viscosity systems), therefore, it is necessary to increase its amount and continuously mix get the desired positive effect. The minimum particle size of sodium carbonate is not limited down to the molecular level.

The introduction of sodium carbonate has a positive effect on the direct decomposition reaction of the molecules of the hydrocarbons of the epicyclic and aromatic series in the temperature range of 600–1000 ° C, as a result of which the effectiveness of the non-stick material increases.

Example. The liquid hydrocarbon nonstick material was mixed with anhydrous sodium carbonate sieved through a 005 sieve. The resulting composition was used to determine the yield of decomposition products at 875 ° C pyrolytic carbon and the mineral coke residue,

The results of the definitions are presented in table 1,

Similar results were obtained when anhydrous sodium carbonate was introduced into other liquid hydrocarbon materials of alicyclic or aromatic structure: various mineral oils, waste of cooling fluids, oil tars, plasticizer oil PN-6.

From the presented experimental data it follows that the introduction of finely ground anhydrous sodium carbonate into the composition of the liquid hydrocarbon antistick

additives allows a 25-35% increase in the yield of pyrocarbon and reduce gassing by 20-30%,

Using the developed formulations of anti-burn compositions,

prepared a single molding mixture. The preparation of the mixtures was carried out by feeding the components to the mixing runners in the conventional manner. The resulting mixtures were subjected to technological tests according to GOST and generally accepted methods. The basic composition of the mixture is as follows: quartz sand 1K02A 2.5; water-bentonite suspension at 1200 kg / m3 3.0; anti-burn composition 0.3; turnaround mixture

up to 100. The compositions of non-stick compositions and the property of molding compounds are presented in table. 2

Thus, the proposed foundry composition for foundry

The production has high technical and economic indicators and allows to increase the efficiency of using carbon-containing materials as antiburning materials.

Claims (1)

Claims of the Invention The composition of the non-stick composition for foundry production of predominantly casting molds and cores, comprising a liquid material of an alicyclic or aromatic class, is an inorganic antioxidant, characterized in that 0 the metal – form interface, while maintaining a high yield of pyrocarbon and low gas content, the composition contains anhydrous sodium carbonate as an antioxidant in the following ratio of components, 5% by weight: liquid material of alicyclic or aromatic class 90-98; anhydrous sodium carbonate 2-10. table 2 100 0.09 1 / i5 95 0.095 140 5 6-7,5 95 4-5 85 0.3 0.43