EXOTHERMIC FEEDER PRODUCTION METHOD

Field of the Invention

The present invention relates to the exothermic feeder production method used in the casting sector since during casting, there must be enough liquid metal in the system to fill the gaps that may occur as a result of the shrinkage or volumetric shrinkage of the metals and alloys during cooling and solidification, that is, by the volumetric shrinkage of the solidified metal, at this point, in order to prevent the formation of cavities, used to create a liquid metal reservoir according to the type and geometry of the part to be cast.

The present invention provides secondary use by re-evaluating waste materials in the production process. Thus, it offers an environmentally friendly, low cost and ergonomic production and usage opportunity.

Prior Art

Feeding in the casting process is a very important issue in foundries so as to obtain a defect-free and high quality casting product and to create an economical production process.

Today, feeders can be produced with different methods according to their types. Iron oxide material is used in addition to silica sand, aluminum material, resin and acid type binders among the standard components mentioned in the literature for the production of exothermic feeders.

The value of the limited resources in the world is increasing day by day in today's conditions. Labor and energy-related costs for ore extraction are increasing day by day due to increasing prices globally and metal ore resources, which are limited with the increase of the total population, are decreasing day by day. The market price increases as the declining ore resources cannot adequately meet the current demand.

The costs of exothermic feeders, which contain two basic metal components, both iron oxide and aluminum, are increasing day by day and foundries are adversely affected by this increase.

In the document numbered CN112496279, which is related to the subject in the state of the art, casting ingot feeding method that is obtained by firing the ingot mold and door brick at 300-500°C for 3-6 hours and the heat-producing heatinsulating riser brick at 100-300°C for 2-4 hours, wherein Al content >20% by weight, Si content >20% by weight, aluminum silicate content 20-40% by weight, MgO content of 10, -20% by weight and water content <1% by weight in the exothermic insulating feeder brick. It differs from our invention in that it is mentioned that the casting process is completed by taking it out of the mold after the casting is completed and the cooling process is done by scientifically controlling the casting rate.

In the document numbered CN208825479, which is related to the subject in the state of the art, an exothermic feeding unit is disclosed which comprises of first and second mold halves meeting in a vertical parting line and together forming a casting cavity and a feeder cavity and an exothermic feed unit located in the feed cavity, an inlet, a cavity and an outlet in fluid communication with the casting cavity but here the outlet is separate from the inlet. Vertically split casting system, a casting system and exothermic feeding unit which defines the flow of molten metal into the casting cavity from the inlet of the exothermic feed unit through the chamber and the exit of the exothermic feed unit, is disclosed. It relates to the structural improvement of the feeder and differs from our invention in that it is not an invention regarding its chemical content. In the document numbered CN103551515, which is related to the subject in the state of the art, an invention regarding an exothermic heat preservation feeder for casting and a method of preparation of the feeder, is disclosed. It belongs to the casting field and solves the problems that an existing feeder has a poor thermal insulation effect and insufficient heat to shorten the solidification. The duration of molten metal in the feeder reduces casting defects such as casting shrinkage voids and shrinkage porosity and increases product yield. The feeder is prepared from expanded vermiculite, magnesite powder, quartz sand, aluminite powder, graphite powder, magnesium powder, iron oxide powder, sodium nitrate, fluorite powder, sodium silicate, red mud and lignin. Preparation method comprises of the following process steps; placing expanded vermiculite, magnesite powder, 40% sodium nitrate, adding 40% of red mud and 40% of lignin into a runner wheel sand mixer and mixing, then adding quartz sand, aluminite powder, graphite powder, magnesium powder, iron oxide powder, sodium nitrate and fluorite powder, mixing the same, adding and mixing the remaining red mud, lignin and sodium silicate; and compressing, drying and demoulding after filling into a mold and hardening. Iron oxide material is used as the oxidizing material in the abovementioned invention and it is different from our invention.

The document numbered MX2011005223, which is related to the subject in the state of the art relates to an exothermic molding material mixture for producing feeders for casting aluminum, comprising at least: - a fireproof base molding material; - a binder; - a proportion of an oxidizable metal of from 5 to 18 % by weight relative to the molding material mixture; - an oxidizing agent at a proportion of 10 to 50 % by weight relative to the quantity of oxidizing agent required for completely oxidizing the oxidizable metal; and an igniter for oxidizing the oxidizable metal at a proportion of 15 to 50 % by weight relative to the quantity of the oxidizable metal. A feeder made of the exothermic molding material mixture ignites reliably, even at low temperatures, and is characterized by low heat emission and it is different from our present invention since the use of filter waste dust instead of iron oxide material as an oxidizing agent is not mentioned. In the document numbered US4665968, which is related to the subject in the state of the art, a casting mold with a feeder, particularly for producing cast iron, includes an exothermically heated feeder mass. The casting material in the cylindrical or slightly conical feeder volume of the feeder mass is kept in a liquid state until termination of the drawing in of casting material by suction into the casting cavity. The feeder volume has dimensions corresponding to the quantity of casting material drawn into the mold cavity to compensate for casting shrinkage, plus a maximum security allowance of 30 percent of the quantity of casting material drawn in. To obtain a feeder mass which is less costly than conventional feeder masses, from the point of view of simpler and more propitious temperature measurements, the feeder mass has an outside shape of a flattened sphere, a flattened ellipsoid or a flattened pear. The smallest diameter is far from the casting produced. It is mentioned that the flattening is provided adjacent to the casting. There is a structural invention in said document. It differs from our invention in that it is not an invention regarding its chemical content.

In the document numbered US6972059, which is related to the subject in the state of the art, an essentially fluoride-free exothermic feeder is referred to as a reagent containing aluminum oxide, the oxidizing agent iron oxide, and an alkali nitrate, SiO2-containing filler having a specific surface area of about 1 to about 10 m2/g and it is different form our invention since it contains iron oxide as an oxidising agent.

In the document numbered US6972059, which is related to the subject in the state of the art, a heat generating apparatus for casting is disclosed, comprising a molded body obtained by molding and curing a mixture of a basic component consisting of an oxidisable metal, an oxidizing agent and a refractory aggregate, glass hollow microspheres, and an inorganic or organic binder, characterized in that; exothermic assembly is mentioned for casting obtained by dispersing hollow glass microspheres and embedding in the molding matrix and it is different from our present invention that the use of filter waste dust instead of iron oxide material as an oxidizing agent is not mentioned.

In current applications, as mentioned in the documents referred to above, the exothermic feeders currently used do not provide solutions to all these problems and they are and high-cost, non-environmentally friendly, non-ergonomic exothermic feeders during use and production.

Description of the Invention

The inventive exothermic feeder production method comprises of the following process steps;

- Adding 50-70% silica sand, which has both wet and dry strength, is resistant to high temperatures, provides a smoother surface on the cast part, and allows gas transfer,

- Adding 5-20% aluminum powder, which is resistant to high temperatures for a long time,

- Adding 10-20% cold box hardening resin, which provides a great reduction in harmful odor emissions such as benzene, toluene and xylene, and reduces catalyst consumption,

- Adding 10-20% cold box activator acid, which enables the activation of materials,

- Adding 10-20% foundry filter waste dust, which is an industrial waste for foundries, which cannot be recovered in the foundry process and used as an oxidizing agent

Filter waste dust is an industrial waste for foundries and cannot be recovered in the foundry process. For this reason, waste is sent to disposal. While the feeder is produced in cold box core machines in order to be affected by the cost increases at the minimum level, studies are carried out on the reuse of chemical components by providing industrial waste recovery with the help of the inventive exothermic feeder production method. The use of silica sand and aluminum powder is kept constant for the production of exothermic feeders, instead of supplying iron oxide as oxidizing material, fdter waste dust from the grinding and cleaning workshops of foundries is used.

It is clarified after experimentation that filter waste dust is the output of the grinding process, it has 80-95% metal content in the burr belts, in the drying ovens with a temperature of 100 degrees, the weight does not increase after 8 hours and 16 hours of drying, and it has the iron oxide property in its chemically present state.

When the filter waste dust is sent to waste disposal companies for certain costs, gains due to waste disposal costs are achieved with the help of the inventive exothermic feeder production method.

The filter waste dust is re-evaluated within the production processes and its secondary use is provided with the help of the inventive exothermic feeder production method. In this way, waste recycling is experienced.

While the filter waste dust is collected or stocked at the same, it creates dust and causes environmental pollution, but it is eliminated with the help of the inventive exothermic feeder production method. Since the waste filter dust in the feeder is used and evaluated in the casting process, the possibility of dusting and polluting the environment during storage is minimized with the help of its use in the production of exothermic feeders.

The iron oxide material, which is used as the oxidizing material in the production of exothermic feeders, has limited resources and the market price is increasing day by day because it is a metal material. Additional iron oxide material purchase for exothermic feeder production is completely eliminated by using process waste as an oxidizer instead of iron oxide material. Exothermic feeder production cost is reduced.

The risk of wastage increases in parts, in the case that the feeders that are not used in cost-based casting processes and whose use is not determined to be cost-effective are not included in the casting, it is also eliminated with the reduction of exothermic feeder production costs with our invention. Quality improvements are achieved in parts by reducing costs and expanding their use.