JP7358450B2 - Compositions containing oxidized materials for sand casting and methods of preparation and use thereof - Google Patents

Description

[Priority claim]
This PCT International Application claims the benefit of priority from U.S. Provisional Patent Application No. 62/650,698, filed March 30, 2018, the subject matter of which is incorporated herein by reference in its entirety. form part of

Embodiments of the present disclosure generally relate to compositions useful for reducing emissions during casting, and methods of preparing and using such compositions.

Casting is a casting process in which an article is prepared by pouring a heated liquid material, such as metal, into a mold and allowing it to cool. The cast metal article is then released or "knocked out." Foundry produces a variety of emissions, including hazardous air pollutants, such as volatile organic compounds (VOCs) released during the casting, cooling, and beating phases of the casting. Safety and environmental concerns are associated with VOCs, including benzene, toluene, ethylbenzene, and xylene (commonly referred to as "BTEX"), carbon monoxide (CO) and methane ( _CH4 ) released during casting. It will be done. These emissions create certain safety and environmental concerns.

Emissions from the casting process are associated with green molding compositions formed from the compounds used to make the molds, such as binder compositions. It is therefore desirable that green molding compositions be made from materials that reduce the amount of harmful emissions during casting while maintaining mold performance and casting quality of the casting.

The present disclosure includes compositions useful in sand casting, including green casting, the preparation of such compositions, and methods of their use.

For example, the present disclosure includes a binder composition that includes a carbonaceous material and an inorganic binder, wherein at least one of the carbonaceous material and the inorganic binder is oxidized. According to some aspects of the present disclosure, the binder composition may include from about 0.1% to about 20.0% by weight carbonaceous material. For example, from about 2% to about 22%, from about 5% to about 20%, from about 7.5% to about 17.5%, or about 10% by weight, based on the total weight of the binder composition. % to about 15% by weight of carbonaceous material. In some examples, the carbonaceous material includes coal, lignite, lignite coal, leonardite, graphite, anthracite, cellulose, or combinations thereof. In some embodiments of the present disclosure, the binder composition comprises about 70% to about 90% by weight of an inorganic binder, such as about 75% to about 88% by weight, or about 80% to about 85% by weight. % may be included. Exemplary inorganic binders include sodium bentonite, calcium bentonite, or mixtures thereof. In some embodiments of the present disclosure, the Fe ²⁺ /Fe ³⁺ ratio of the inorganic binder is less than 1.2, such as less than 1.0, less than 1, less than 0.9, less than 0.8. It may be oxidized as such.

According to some aspects of the present disclosure, the binder composition may include a high aspect ratio silicate. In some embodiments of the present disclosure, the binder composition comprises, for example, from about 0.5% to about 4.0%, from about 1% to about 3.5%, based on the total weight of the composition. or about 3.5% to about 5.0% by weight, such as about 0.3% to about 4.5% high aspect ratio silicates, based on the total weight of the binder composition. It may contain from 0.1% to about 5.0% by weight high aspect ratio silicates. In some embodiments of the present disclosure, the high aspect ratio silicate may include mica or talc. Additionally or alternatively, the high aspect ratio silicates include muscovite, paragonite, lepidolite, phlogopite, biotite, or combinations thereof. good.

The present disclosure further includes green molding compositions comprising binder compositions and aggregates as described above or elsewhere herein. The aggregate may include silica sand, zircon sand, aluminosilicate, or mixtures thereof.

The disclosure further includes a method of preparing a foundry composition. For example, the method includes oxidizing a carbonaceous material and preparing a binder composition by combining the oxidized carbonaceous material with an inorganic binder. The method further includes combining the oxidized carbonaceous material and the high aspect ratio silicate before, after, or simultaneously with combining the oxidized carbonaceous material and the inorganic binder. According to some aspects of the present disclosure, oxidizing the carbonaceous material includes treating the carbonaceous material with an oxidizing agent, such as, for example, soda ash, hydrogen peroxide, ozone, or a combination thereof. In some embodiments of the present disclosure, the ratio of Fe ²⁺ to Fe ³⁺ of the inorganic binder is, for example, less than 0.9, less than 0.8, less than 0.7, less than 0.6, or less than 0.5. It may be less than 1, such as. The method may further include adding aggregate and water to the binder composition to form a green molding composition. According to some aspects of the present disclosure, the green molding composition has a yield of, for example, from about 22.5 N/m ² to about 30.0 N/m ² , or from about 24.0 N/m ² to about 27.5 N/m 2 . The green compression strength may range from about 21.5 N/m ² to about 30.5 N/m ² , such as ² . Additionally or alternatively ^, the ^green molding composition ^{may e.g.} or having a green shear strength in the range of about 2.5 N/m ² to about 3.7 N/m ² , such as about 3.1 N/m ² to about 3.4 N/m ² . good.

The disclosure further includes a method of molding an article. For example, the method includes introducing the heated material into a mold, the mold containing any of the binder compositions and/or green molding compositions described above or elsewhere herein. and cooling the heated material. The method includes, for example, less than 0.12 mg/g, less than 0.10 mg/g, less than 0.08 mg/g, less than 0.06 mg/g, less than 0.05 mg/g, after introducing the heated material into the mold. It may further include forms that release less than 0.15 mg/g BTEX, such as.

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate various illustrative aspects of the disclosure and, together with the description, serve to explain the principles of the disclosure.

2 is a graph of BTEX emissions measured from the green molding composition in Example 2.

Certain aspects of the disclosure are described in more detail below. In the event of any conflict with terms and/or definitions that are incorporated by reference into this application, the terms and definitions set forth herein will control.

As used herein, the term "comprises," "comprising," or any other variation thereof shall be construed to include non-exclusive inclusion. , a process, method, composition, article, or device that includes a listing of elements does not include only those elements and is not expressly enumerated in such process, method, composition, article, or device. Other or unique elements may also be included. The term "exemplary" is used in the sense of "example" rather than "ideal."

As used herein, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. The terms "approximately" and "about" refer to about the same as the referenced number or value. As used herein, the terms "approximately" and "about" are to be understood to include ±5% of a particular amount or value.

Aspects of the present disclosure provide binder compositions, and their preparation, comprising an inorganic binder, such as a clay mineral, and a carbonaceous material, wherein the inorganic binder and/or the carbonaceous material is at least partially oxidized. Including methods and uses. For example, the binder composition may be used in a green mold process in combination with an aggregate, such as sand.

Compositions according to the present disclosure may include one or more inorganic binders. Exemplary binders include, but are not limited to, natural and synthetic clays, such as bentonite. Bentonite is a phyllosilicate clay that primarily contains smectite minerals, such as montmorillonite. Different types of bentonite are generally named according to the predominant compositional element, such as potassium bentonite, sodium bentonite, calcium bentonite, and aluminum bentonite. For example, the composition (eg, binder composition) may include at least one selected from sodium bentonite, calcium bentonite, potassium bentonite, lithium bentonite, aluminum bentonite, and mixtures thereof. Bentonite may impart plasticity to the binder composition. In some embodiments, the inorganic binder may include a mixture of bentonite and other inorganic binders.

Inorganic binders may be obtained at any geographic point or region on Earth. For example, the inorganic binders of the present disclosure may be used in the western, midwestern, and/or southern regions of the United States, including, but not limited to, Wyoming, Montana, South Dakota, Indiana, Michigan, Wisconsin, Ohio, and Mississippi. , and Alabama), Greece, Germany, Turkey, Italy, Bulgaria, China, India, Russia, or Brazil, and other countries and geographic regions around the world. Clays from different geographical regions may have different chemical compositions. For example, clay obtained in India may have higher levels of oxidation than clay obtained in the United States.

According to some aspects of the present disclosure, the inorganic binder may include at least 75% by weight bentonite, such as from 75% to 100% by weight bentonite. For example, the inorganic binder may contain at least 80%, at least 85%, at least 90%, or at least 95% by weight of bentonite, such as from about 85% to about 95%, or from about 90% to about It may contain 98% by weight bentonite.

In some exemplary binder compositions of the present disclosure, the sum of the inorganic binders relative to the total weight of the composition is from about 75% to about 88%, or from about 80% to about 85%, by weight. , may range from about 70% to about 90% by weight. For example, the binder composition may include about 75%, about 80%, about 83%, about 85%, or about 88% by weight of an inorganic binder based on the total weight of the binder composition.

According to some aspects of the present disclosure, the inorganic binder may be at least partially oxidized. For example, the inorganic binder may include one or more oxidizing agents, including, but not limited to, hydrogen peroxide (H ₂ O ₂ ), oxygen (O ₂ ), ozone (O ₃ ), or soda ash ( Sodium carbonate) (Na ₂ CO ₃ ) may be combined with or exposed to. In some examples, the oxidizing agent may be an aqueous solution. The inorganic binder may be combined with the oxidizing agent by any suitable method that enables the reaction. For example, the oxidizing agent may be mixed with the inorganic binder in a ratio of 1:100 to 10:1, such as from about 1:75 to about 1:15, or from about 1:50 to about 1:25. ) may be mixed within a range of weight ratios. In some embodiments, the oxidizing agent is mixed with the inorganic binder for a period of time, such as from about 5 minutes to about 48 hours, such as about 30 minutes, about 1 hour, about 2 hours, about 4 hours, about 8 hours. It may be left undisturbed for about 12 hours, about 24 hours, or about 48 hours.

Additionally or alternatively, the inorganic binder may be selected according to its level of natural oxidation (eg, exposure to environmental oxidants over a period of time). For example, inorganic binders may have different oxidation levels depending on the geographic location from which the binder was obtained (eg, natural clay deposits). Furthermore, the depth of the inorganic binder below the surface may also affect the degree of oxidation of the inorganic binder. For example, surface-level or near-surface clay minerals are typically more sensitive to atmospheric conditions such as oxygen, ozone, and/or environmental radicals (e.g., OH, _NO2, etc.) compared to clay minerals deep underground. is expected to be more oxidized due to higher exposure to oxidizing agents.

The inorganic binder may undergo oxidation through heat treatment, for example during a casting process. Thus, for example, partially oxidized inorganic binder due to a casting process may be recycled into a new binder composition.

The oxidation state of the various components of the inorganic binder may be used to assess their relative degree of oxidation. For example, clay minerals such as bentonite typically contain iron, which may exist in different oxidation states, specifically Fe ²⁺ (ferrous), and Fe ³⁺ (ferric). The relative concentrations of ferrous and ferric iron can be used to assess the amount of oxidation, eg, redox state, of bentonite. The concentration of Fe ²⁺ relative to Fe ³⁺ may be determined by measuring the acid soluble iron of the inorganic binder.

Acid soluble iron content (as an indication of relative degree of oxidation) can be determined by the following procedure. Mix 2 grams of clay sample with 50 ml of 0.5M H ₂ SO ₄ in a 50 ml Nelgene vial. After the bentonite particles had settled, the supernatant was pipetted to 0.25 ml into a 50 ml vial and 25 ml of deionized water was added. Then add 1 ml of FerroZine™ (sodium 3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine-4',4''-disulfonate) indicator and mix. The colored complex formed between the obtained ferrous ion (Fe ²⁺ ) and FerroZine (trademark) was measured with a spectrophotometer, and the amount of solubilized ferrous iron was calculated against the soluble iron calibration curve. Approximately 200 mg of ascorbic acid was then added to the solution (to reduce Fe ³⁺ to Fe ² ) and the resulting color was measured as the total iron content of the clay.

In some non-limiting examples, the inorganic binder comprises about 270 ppm to about 335 ppm Fe ²⁺ and about 525 ppm to about 700 ppm Fe ³⁺ (e.g., a ratio of Fe ²⁺ to Fe ³⁺ ranges about 0.4). to about 0.6). For example, the inorganic binder may include about 300 ppm to about 315 ppm Fe ²⁺ and about 575 ppm to about 635 ppm Fe ³⁺ . These ranges are merely exemplary; higher amounts of Fe ³⁺ relative to Fe ²⁺ give an indication of a more oxidized material.

According to some aspects of the present disclosure, the ratio of Fe ²⁺ to Fe ³⁺ (Fe ²⁺ /Fe ³⁺ ) of the inorganic binder is less than 1.0, less than 0.9, less than 0.8, 0.7 It may be less than 1.2, such as less than 0.6, less than 0.5. For example, the ratio of Fe ²⁺ to Fe ³⁺ of the inorganic binder may range from about 0.5 to about 1.5, about 0.75 to about 1.25, or about 0.8 to about 1.2. . In some embodiments, the ratio of Fe ²⁺ to Fe ³⁺ of the inorganic binder is about 0.5, about 0.6, about 0.7, about 0.8, about 0.9, about 1.0, or about 1.1.

In some embodiments of the present disclosure, the binder composition may include at least one carbonaceous material. Carbonaceous materials may be inorganic, organic, or mixtures thereof. Carbonaceous materials that may be useful in the compositions herein include, but are not limited to, coal (e.g., bituminous coal, such as lignite coal and sea coal). lignite, leonardite, graphite, anthracite, cellulose, and combinations thereof. In at least one embodiment, the composition includes coal, a combination of coal and graphite, or a combination of coal and lignite.

According to some aspects of the present disclosure, the total weight of carbonaceous materials in the composition (eg, binder composition) may range from about 0.1% to about 30% by weight. For example, the composition may contain about 1% to about 25%, about 2% to about 22%, about 5% to about 20%, about It may contain from 7.5% to about 17.5%, or from about 10% to about 15%.

In some embodiments of the present disclosure, the composition includes, for example, from about 7.5% to about 20.0%, from about 8.0% to about 18%, by weight of coal, based on the total weight of the composition. A range of about 5.0% to about 25.0% by weight, such as 0% by weight, about 9.0% to about 15.0% by weight, or about 10.0% to about 12.5% by weight. may be included.

In some embodiments of the present disclosure, the carbonaceous material may be at least partially oxidized. For example, the carbonaceous material may be exposed to (reacted with) one or more oxidizing agents. Thus, for example, exposing at least the outermost surface of the carbonaceous material (e.g., the surface of the particles of carbonaceous material) to one or more oxidizing agents so as to provide particles of carbonaceous material that are oxidized. It may be processed by Exemplary oxidizing agents include, but are not limited to, hydrogen peroxide ( _H2O2 ), oxygen _{( O2} ), _ozone ( _O3 ), and soda ash ( _Na2CO3 ). It will be done. In some embodiments, oxidizing agents may be used in combination, including two or more of the aforementioned oxidizing agents. In at least one embodiment, the carbonaceous material includes coal particles that have been oxidized by exposure to hydrogen peroxide, soda ash, or both hydrogen peroxide and soda ash. In at least one embodiment, the carbonaceous material includes coal particles that have been oxidized by exposure to an oxidizing agent in an aqueous solution.

The carbonaceous material may be oxidized in any suitable manner. For example, the oxidizing agent may be mixed or kneaded with the carbonaceous material and the resulting mixture may be mixed or kneaded for a period of time (e.g., at least 5 minutes, 15 minutes, 30 minutes, 1 hour, 2 hours, 3 hours, 6 hours, 12 hours, 18 hours, 24 hours, 30 hours, 36 hours, 42 hours, or 48 hours). In some embodiments, the carbonaceous material is placed in contact with the oxidizing agent for several days, such as at least 1 day, at least 3 days, at least 5 days, at least 10 days, at least 15 days. Additionally or alternatively, the oxidizing agent is applied to the carbonaceous material over a period of several days, such as from about 1 to about 12 days, from about 2 days to about 10 days, from about 3 days to about 9 days, from about 4 days to about 8 days. May come into contact with the material.

The amount of oxidizing agent is from about 0.02% to about 8%, from about 0.05 to about 5.0%, or from about 1% to about 3% by weight, based on the weight of the carbonaceous material. It may range from about 0.01% to about 10.0% by weight. For example, the ratio of the weight of the oxidizing agent to the weight of the carbonaceous material ranges from about 1:100 to about 1:10, such as from about 1:75 to about 1:15, from about 1:50 to about 1:25. It may be.

In some embodiments of the present disclosure, carbonaceous materials may be treated with a solution containing from about 0.1% to about 15% by weight oxidizing agent. For example, the solution may contain about 0.2% to about 12%, about 0.5% to about 11%, about 1% to about 10%, or about 2% to about 8% by weight. % oxidizing agent. In at least one embodiment, the solution may include about 3% hydrogen peroxide by weight. In some examples, the solution contains, for example, about 9% by weight, about 8% by weight, about 7% by weight, about 6% by weight, about 5% by weight, about 4% by weight, about 3% by weight, about 2% by weight, or less than about 10% by weight soda ash, such as about 1% by weight. Additionally or alternatively, the carbonaceous material may be treated with a solution (eg, such as an aqueous solution) containing multiple oxidizing agents.

In some embodiments, the carbonaceous material may be oxidized by heat treatment. For example, carbonaceous materials may be partially oxidized by being exposed to oxygen and elevated temperatures during sand casting, and these oxidized carbonaceous materials may be at least partially recovered for reuse. It's okay to be.

The compositions herein may further include one or more high aspect ratio silicates. The aspect ratio (ρ) of a particle may be defined as the length along the principal axis of the particle divided by the width. The term "high aspect ratio silicates" includes silica minerals having an aspect ratio of at least 10, such as an aspect ratio between 10 and 1000. For example, the compositions herein may contain about 10 to about 500, about 10 to about 250, about 10 to about 200, about 10 to about 150, about 20 to about 100, about 20 to about 80 , about 30 to about 100, about 40 to about 100, about 40 to about 80, or about 50 to about 70, such as about 20, about 25, about 30, about 35, about 40, The silicates may have aspect ratios of about 45, about 50, about 55, about 60, about 65, about 70, about 75, about 80.

Exemplary high aspect ratio silicates suitable for the compositions herein include, but are not limited to, mica and talc. Mica minerals suitable for the compositions herein include, but are not limited to, muscovite, paragonite, phlogopite, biotite, and combinations thereof.

Binder compositions according to the present disclosure may contain from about 0.1% to about 4.8%, from about 0.2% to about 4.5%, about 0.0% by weight, from about 0.2% to about 4.5%, based on the total weight of the binder composition. .5% to about 4.0%, from about 0.8% to about 3.8%, from about 1.0% to about 3.5%, from about 1.2% by weight about 3.0%, about 1.5% to about 3.0%, about 1.8% to about 2.8%, or about 2.0% to about 2.5% by weight. %, such as from about 0.1% to about 5.0% by weight, of high aspect ratio silicates. For example, the binder composition may be about 0.5%, about 1.0%, about 1.2%, about 1.5%, about 1.8% by weight based on the total weight of the binder composition. , about 2.0%, about 2.1%, about 2.2%, about 2.3%, about 2.4%, or about 2.5% by weight of a high aspect ratio silicate. may be included.

As mentioned above, the compositions herein may be binder compositions suitable for combination with aggregates, for example, to prepare green molds. In some embodiments of the present disclosure, the binder composition includes from about 70% to about 90% by weight of at least one inorganic binder, from about 0.1% to about It may include 30% by weight of at least one carbonaceous material and from about 0.1% to about 5.0% by weight of at least one high aspect ratio silicate. For example, the binder composition may include from about 75% to about 85% by weight of an inorganic binder, from about 1% to about 25%, from about 5% to about 22% by weight, based on the total weight of the binder composition. %, or about 10% to about 15% by weight carbonaceous material, and about 1% to about 4%, or about 2% to about 3%, high aspect ratio silicate material. In some examples, the inorganic binder includes bentonite, such as sodium bentonite and/or calcium bentonite, and the carbonaceous material includes coal. In some examples, the high aspect ratio silicate includes mica.

In some embodiments of the present disclosure, at least one or both of the inorganic binder and the carbonaceous material may be at least partially oxidized. In at least one embodiment, both the inorganic binder (or one of the at least two or more inorganic binders) and the carbonaceous material (or one of the at least two or more carbonaceous materials) are oxidized. The inorganic binder and carbonaceous material may be oxidized separately before being combined to prepare the binder composition, or may be oxidized simultaneously or substantially simultaneously.

In at least one embodiment, the carbonaceous material is first oxidized (eg, by exposure to one or more oxidizing agents) and then the oxidized carbonaceous material is combined with an inorganic binder. In a further embodiment, the inorganic binder and the carbonaceous material are first combined and the resulting mixture is oxidized, for example, by exposure to one or more oxidizing agents. The high aspect ratio silicate may optionally be combined with the oxidized carbonaceous material at the same time, before or after the oxidized carbon material and inorganic binder are combined.

The amount of volatile organic compounds and/or water in the binder compositions herein may be determined via VOC and loss on ignition (LOI) testing. VOC and LOI measurements may be performed according to AFS Standards and Test Procedures (AFS Mold and Core Test Handbook). VOC refers to the measurement of the amount of raw material in a composition that vaporizes at a temperature of 900°F (482°C). LOI values are determined by heating at high temperatures (“high heating” of the material), especially at temperatures during casting, e.g. 982°C (~1800°F) according to AFS5100-00-00-S, before and after heating. refers to the difference in weight of materials. The LOI value indicates the amount of flammable materials, such as organic compounds, in the green molding composition that decompose when heated to the temperatures present during casting.

In some embodiments, the binder composition comprises, for example, about 13.5% to about 18%, about 14% to about 17.5%, or about 14.5% to about 17% by weight. may have a VOC content ranging from about 13.0% to about 18.5% by weight. Additionally or alternatively, the binder compositions herein have an LOI value in the range of about 22% to about 27%, such as about 23%, about 24%, about 25%, or about 26%. You can show it.

The binder compositions herein may be combined with at least one aggregate and water to produce a green molding composition. As used herein, the term "aggregate" includes homogeneous materials, e.g. particles each containing the same or substantially the same composition, as well as materials of different compositions, e.g. agglomerated into a single particle. Contains heterogeneous or composite particles. Aggregates suitable for the compositions herein include, for example, natural and synthetic sands and sand composite materials. Examples of aggregates that may be used in the compositions herein include, but are not limited to, silica sand (SiO ₂ ), chromite sand (FeCr ₂ O ₄ ), and zircon sand (ZrSiO ₄ ). any of which may optionally contain other elements such as magnesium, aluminum, manganese, and/or carbon (eg, graphite). Other types of sand and other aggregates are likewise contemplated and may be used in the compositions herein without departing from the principles herein.

In some embodiments of the present disclosure, the green molding composition is about 72% to about 88%, about 74% to about 84%, or about 76% by weight based on the total weight of the composition. from about 70% to about 90%, such as from at least 75%, at least 80%, at least 85%, at least 90% by weight, based on the total weight of the composition The green molding composition may contain at least 70% by weight of at least one agglomerate, such as one agglomerate, based on the total weight of the green molding composition.

The green sand may further include water to provide a moisture content ranging from about 2.75% to about 6.25% by weight based on the total weight of the green molding composition. For example, the green molding composition may be about 2.94% to about 5.08%, about 3.13% to about 5.43% by weight, based on the total weight of the green molding composition. It may have a moisture content of about 4.19% to about 5.08%, about 4.33% to about 5.94% by weight. Before the green molding composition is processed in a casting procedure, the moisture content of the composition is from about 2.94% to about 3.16%, from about % to about %, or from about % by weight. It may range from about % by weight. For example, 2.90% by weight, 2.92% by weight, 2.94% by weight, 2.96% by weight, 2.98% by weight, 3.00% by weight, based on the total weight of the green mold composition, 3.02%, 3.04%, 3.06%, 3.08%, 3.10%, 3.12%, or 3.14% by weight.

Green molding compositions prepared from the binder compositions of the present disclosure (e.g., including an inorganic binder and a carbonaceous material) can contain from about 5% to about 20% by weight, based on the total weight of the green molding composition. %, about 8% to about 16%, or about 10% to about 15% by weight of the binder composition. For example, the green molding composition may include about 70% to about 90% by weight of at least one aggregate, about 5% to about 20% of a binder composition (e.g., including an inorganic binder and a carbonaceous material). and about 2.75% to about 6.25% water moisture.

The performance of a green casting composition may be analyzed according to a series of properties of the green casting composition. For example, green molds can be measured using measurements such as VOC, LOI, moisture content, compactability, permeability, wet tensile strength, green shear strength, methylene blue uptake, and/or AFS clay content, among other properties. May be characterized or evaluated. These measurements are typically performed according to AFS standards and test procedures (AFS Mold and Core Test Handbook).

Typically, green molding compositions are tested using a cylindrical specimen measuring 2 inches in diameter and 2 inches in height (i.e., a 2 inch by 2 inch cylindrical sample). Alternatively, a cylinder-shaped test piece with a diameter of 50 mm and a height of 50 mm is used. Green molding compositions prepared from the binder compositions herein may be tested by VOC and LOI measurements as described above. Green molding compositions according to the present disclosure have a VOC content ranging from about 1.8% to about 2.4% by weight, such as from about 2.0% to about 2.2% by weight. good. The LOI level of the green molding compositions herein may be from about 3.5% to about 4.5%, from about 3.7% to about 4.2%, or from about 3.8% by weight. It may range from about 4.0% by weight.

Green compressive strength refers to the pressure required to cause a sample to fail under compressive load. The composition for green mold molding according to the present disclosure is about 21.0 N/cm ² to about 32.0 N/cm ² , about 21.5 N/cm ² to about 31.0 N/cm ² , about 22.0 N/cm ² about 20.0 N/cm ² , such as from about 30.5 N/cm ² , from about 22.5 N/cm ² to about 30.0 N/cm 2 , or from about 24.0 N/cm ² to about 27.5 N/cm ² It may have a green compressive strength ranging from ² to about 35.0 N/cm ² .

Green shear strength refers to the stress required to cause a sample to fail under shear loading, such as a lateral force. The green molding composition according to the present disclosure has an energy density of about 2.6 N/cm ² to about 3.8 N/cm ² , about 2.7 N/cm ² to about 3.6 N/cm ² , about 2.9 N/cm ² to about 3.5 N/cm ² , from about 3.1 N/cm ² to about 3.4 N/cm ² , from about 2.4 N/cm ² to about 4.0 N/cm ² . may have.

Wet tensile strength is a useful criterion for determining the ability of a sand mold to resist eschar formation, or the formation of undesirable bumps or roughness in a casting. During casting, water from the sand adjacent to the molten metal is returned, creating a zone of concentration between the dry and wet sand. The strength of the sand in this layer is considered the wet tensile strength. The higher the wet tensile value, the less the tendency to crust. The green molding composition according to the present disclosure has a yield of about 0.302 N/cm ² to about 0.432 N/ ^{cm 2 , about 0.308 N/cm 2 to about 0.400 N/cm 2 at room} temperature (~25° C.), from about 0.300 N/cm ² to ^about 0.510 N/cm ² , such as from about 0.333 N/cm 2 to about 0.395 N/cm ² , or from about 0.340 N/cm ² to about 0.386 N/cm ² It may have a wet tensile strength in the range of .

Compactability (also referred to as "compressability") evaluates the change in volume of green sand during compaction. Compactability is measured as the percentage decrease in height of the sample after applying a pressure of about 140 psi to the sample for 3 seconds. Green molding compositions according to the present disclosure contain about 44.0% to about 47.0%, about 44.5% to about 46.5%, or about 45.0% to about 46.0%. The compactability may range from about 43.5% to about 47.5%.

The Methylene Blue (mL) test is a measurement of the amount of inorganic binder material, such as clay, that has the ability to absorb water remaining in the green molding composition. The ability of the inorganic binder material to absorb water affects the strength of molds prepared from green molding compositions. Exemplary binder compositions according to the present disclosure have methylene blue levels ranging from about 47 mL to about 65 mL, such as about 49 mL to about 63 mL, about 51 mL to about 61 mL, about 53 mL to about 59 mL, or about 53 mL to about 57 mL. .

The AFS clay content test indicates the amount of fine soil and water-absorbing material in the green molding composition. The test measures the amount of clay in a 50 g sample of green sand, typically by repeated agitation washing with water and dilution with caustic soda. The AFS clay content is twice the difference between the initial weight of the sample and the final dry weight of the sample. Exemplary binder compositions according to the present disclosure include about 9.0% to about 11.5%, about 9.4% to about 11%, about 9.6% to about 10.8%, about 9.8% to It has an AFS clay content measurement range of about 10.5%, about 10.0% to about 10.3%.

Casting of materials releases various emissions, such as gases and particles, including VOCs. Most of these emissions are released during the pouring, cooling, and shake out stages of the casting process. Typical emissions from the casting process include, but are not limited to, water vapor, CO, _CO2 , _CH4 , and BTEX (benzene, toluene, ethylbenzene, and xylene) gases. These emissions may be removed from the binder composition used to prepare the green molding composition (e.g., a binder composition illustratively including an inorganic binder, a carbonaceous material, and optionally a high aspect ratio silicate). The mass of the compound released relative to the mass of the compound may be measured.

In some embodiments, the release level of BTEX of the green molding compositions herein is less than 0.12 mg, less than 0.10 mg, less than 0.08 mg, less than 0.06 mg, less than 0.05 mg, etc. , less than 0.15 mg of BTEX per gram of binder composition used to prepare the green molding composition. For example, the level of BTEX emissions may be, for example, from about 0.02 mg/g to about 0.09 mg/g, from about 0.03 mg/g to about 0.07 mg/g, or from about 0.02 mg/g to about 0.06 mg The production weight (grams) of BTEX per gram of binder composition may be from about 0.01 mg/g to about 0.10 mg/g, such as from about 0.01 mg/g to about 0.10 mg/g.

The CO ₂ emissions of the green molding compositions herein may be less than about 7.2 mg per gram of binder composition used to prepare the green molding composition. For example, the green molding composition may release between 3.13 mg and about 7.20 mg, between about 3.29 mg and about 6.99 mg per gram of binder composition used to prepare the green mold composition. good.

In additional or alternative aspects of the present disclosure, the green molding compositions herein have a CO release of less than 2.15 mg/g per gram of binder composition used to prepare the green mold; It may be less than about 2.18 mg/g, such as less than 2.00 mg/g, less than 1.90 mg/g, less than 1.80 mg/g, less than 1.75 mg/g. For example, the CO release level may be about 1.65 mg/g to about 2.20 mg/g, about 1.84 mg/g to about 2.15 mg/g.

Additionally or alternatively, the green molding compositions herein emit less than 0.5 mg of methane ( _CH4 ) per gram of binder composition used to prepare the green molding composition. It's good. For example, the level of CH ₄ release may be from about 0.18 mg/g to about 0.24 mg/g, from about 0.19 mg/g to about 0.21 mg/g.

Aspects of the present disclosure are further described with reference to the following non-limiting numbered paragraphs disclosing exemplary embodiments.

1. A binder composition comprising a carbonaceous material, an inorganic binder, and a high aspect ratio silicate, wherein at least one of the carbonaceous material or the inorganic binder is oxidized.

2. A binder composition comprising a carbonaceous material and an inorganic binder, wherein the inorganic binder is oxidized such that the ratio of Fe ²⁺ to Fe ²⁺ of the inorganic binder is less than 1.2. Composition.

3. A binder composition comprising an oxidized carbonaceous material and an inorganic binder, wherein the oxidized carbonaceous material is prepared by treatment with an oxidizing agent.

4. 4. The composition of paragraph 3, wherein the oxidizing agent comprises soda ash, hydrogen peroxide, ozone, or a combination thereof.

5. The composition according to any one of paragraphs 1 to 4, wherein the inorganic binder has a Fe ²⁺ /Fe ³⁺ ratio of less than 1.

6. A composition according to any one of paragraphs 1 to 5, wherein the inorganic binder comprises sodium bentonite, calcium bentonite, or a mixture thereof.

7. The composition of any one of paragraphs 1-6, comprising from about 70% to about 90% by weight of the inorganic binder.

8. The carbonaceous material or the oxidized carbonaceous material is oxidized carbon (e.g., oxidized lignite coal, oxidized bituminous coal, or oxidized sea coal), oxidized lignite ), oxidized leonardite, oxidized graphite, oxidized anthracite, oxidized cellulose, or a combination thereof.

9. The composition of any one of paragraphs 1-8 comprising from about 0.1% to about 20.0% by weight of said carbonaceous material or said oxidized carbonaceous material.

10. A composition according to any one of paragraphs 2 to 9 further comprising a high aspect ratio silicate.

11. A composition according to any one of paragraphs 1 to 10, wherein the high aspect ratio silicate comprises mica or talc.

12. 12. The composition of any one of paragraphs 1, 10, or 11, comprising from about 0.1% to about 5.0% by weight high aspect ratio silicate.

13. according to paragraphs 1 or 10-12, wherein the high aspect ratio silicate comprises muscovite, paragonite, lepidolite, phlogopite, biotite, or combinations thereof. Composition.

14. A green molding composition comprising a binder composition according to any one of paragraphs 1 to 13 and an aggregate.

15. 15. The green molding composition of paragraph 14, wherein the aggregate comprises silica sand, zircon sand, aluminosilicate, or a mixture thereof.

16. 14. A method of preparing a foundry composition according to any one of paragraphs 1 to 13, optionally oxidizing a carbonaceous material and combining the oxidized carbonaceous material with an inorganic binder. A method comprising preparing a binder composition of.

17. 17. The method of paragraph 16, wherein oxidizing the carbonaceous material comprises treating the carbonaceous material with an oxidizing agent.

18. 18. The method of paragraph 17, wherein the oxidizing agent comprises soda ash, hydrogen peroxide, ozone, or a combination thereof.

19. Any one of paragraphs 16-18, further comprising combining the oxidized carbonaceous material and a high aspect ratio silicate before, after, or simultaneously with combining the oxidized carbonaceous material and an inorganic binder. The method described in.

20. 20. A method according to any one of paragraphs 16 to 19, wherein the ratio of Fe ²⁺ to Fe ³⁺ of the inorganic binder is less than 1.2 or less than 1.

21. further comprising adding agglomerates and water to the binder composition to form a green molding composition, optionally the green molding composition comprising about 21.5 N/m ² to about 30.0 N/m 2 . 21. A method according to any one of paragraphs 16 to 20, having a green compression strength in the range of 5 N/ ^m2 .

22. 22. The method of paragraph 21, wherein the green molding composition has a green shear strength in the range of about 2.5 N/ ^m2 to about 3.7 N/ ^m2 .

23. A method of shaping an article, the method comprising introducing a heated material into a mold, the mold comprising a mixture of a carbonaceous material, an inorganic binder, an aspect ratio silicate, water, and an aggregate. wherein at least one of the carbonaceous material or the inorganic binder is oxidized and cooling the heated material.

24. 24. The method of paragraph 23, wherein the mold releases less than 0.10 mg/g BTEX after introducing the heated material into the mold.

25. 25. The method of paragraph 23 or 24, wherein the carbonaceous material comprises oxidized carbon.

26. 26. A method according to any one of paragraphs 23-25, wherein the high aspect ratio silicate comprises mica or talc.

27. Use of a binder composition according to any one of paragraphs 1 to 13 and/or a green molding composition according to paragraphs 14 or 15 for reducing emissions during casting.

The use according to paragraph 27, wherein said emissive material comprises BTEX.

Other aspects and embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the embodiments disclosed herein.

The following examples are merely illustrative, without of course limiting the present disclosure. It will be understood that the present disclosure encompasses additional aspects and embodiments consistent with the above description and the following examples.

Example 1

Four different binder compositions were prepared to study the effect of oxidation on emissions during casting. Each binder composition contained 80% bentonite and 20% coal by weight. Compositions 1 and 4 were prepared from natural sodium bentonite (commercial product of BPM National Standard). Compositions 2 and 3 were prepared using bentonite that was more highly oxidized than the bentonite used in Compositions 1 and 4. Compositions 1 and 2 were prepared using commercially available coal. Compositions 3 and 4 were prepared using oxidized carbon, where three different variations of composition 4 were prepared. Specifically, the oxidized carbon was 25 pounds of the same type of commercially available coal used in compositions 1 and 2 and three oxidizer solutions: 10% soda ash solution, 3% hydrogen peroxide solution, or room temperature. Prepared from one of water. In each case, the coal was placed in the oxidizer solution and left for 10 days, after which the oxidized coal was washed with water. The oxidized carbon was then dried in an oven at 225°F until the moisture content was less than 3%. Compositions 1 to 4 are summarized in Table 1 below.

Example 2

Each of compositions 1-4 was combined with sand and water to prepare corresponding green mold compositions 1-4 for measuring green mold properties and emissions during sand casting. Each green molding composition combines 9% by weight bentonite based on the total weight of the green molding composition and 1.8% by weight coal based on the total weight of the green molding composition. It was prepared in Water was then added to achieve a compactability of 42-48%. Green mold properties (green compressive strength, green shear strength, wet tensile strength, permeability, methylene blue, and AFS clay) were measured before casting according to AFS standards and test procedures (AFS Mold and Core Test Handbook).

For test casting, test molds were made from each of green molding compositions 1-4, and molten metal was poured into the molds. After cooling, the metal was removed and the green mold was reused for the next test casting. Each green molding composition was heated in four test casting cycles, and the green molding properties of each green molding composition were measured following each heating cycle according to the same AFS standards and test procedures. The data are shown in Tables 2-5.

As shown in Tables 2-5, compositions 1-4 exhibited similar wet tensile strengths. Compositions 3 and 4 showed improved green compressive strength. Compositions 1 and 2 exhibited improved green shear strength. These results suggest that the use of oxidized clay and/or oxidized carbon provides equivalent or improved green mold properties.

After four heating cycles, approximately 5-10 g portions of each of green molding compositions 1-4 were dried in a speed drier to sufficiently reduce the moisture content of the compositions. Two samples weighing 1 g each were then tested for each dry sand composition to determine the release of _CO2 , CO, _CH4 , _H2O and BTEX. Each sample was placed in a quartz glass crucible and inserted into a glass rod connected to a tube furnace (Ansyco). The tube furnace and glass rod were filled with nitrogen. Before the sample was inserted into the tube furnace, an initial measurement of the gases emitted from the furnace was taken to record control measurements, i.e., the amount of emitted gas present in the tube furnace was measured prior to adding the sample. amount was measured. Control measurements were recorded only on the first sample tested or as needed to test the functionality of the tube furnace. Control measurements were recorded over periods of up to 5 minutes. The glass crucible containing the sample was then introduced into a tube furnace until the sample completely passed through the glass rod. Using a Fourier Transform Infrared Spectroscopy (FT-IR Gasmet Analyzer), the BTEX, CO, The tube furnace was maintained at a temperature of approximately 900 °C while measuring the emissions of CH4 and _CH4 . The amount of gas released from the sample was observed by a monitor connected to a tube furnace that curved the amount of gas released from the sample. Measurements of released gas were taken until all curves approached zero, at which point no further gas was released from the sample. The area under each released gas curve was calculated to determine the amount of each gas released during the measurement period. After measuring the outgassing rate of each sample, the glass crucible and sample were removed from the oven and left at room temperature to cool. Once cooled, the remaining weight of the sample was measured.

The emission data for two samples of each composition were averaged to determine the mass of specific gas emissions per gram of binder composition used to prepare the corresponding green molding composition (mg/g). g). Table 6 shows the emissions of CO ₂ , CO, CH ₄ , water (steam), and BTEX.

The BTEX release amount of each binder composition is shown in FIG. As shown in Figure 1, green molding compositions containing oxidized carbon (compositions 3 and 4) were compared to green molding compositions containing commercially available unoxidized coal (compositions 1 and 2). and released a small amount of BTEX. Additionally, compositions containing oxidized bentonite (compositions 2 and 4) exhibited less BTEX release than green molding compositions containing bentonite that had not undergone an oxidation process. These results suggest that the use of oxidized materials in the binder composition reduces the amount of certain emissions produced during casting, such as BTEX.

The specification and examples thereof are to be considered as exemplary only, with a true scope and spirit of the disclosure being indicated by the following claims.

Claims (19)

carbonaceous material;
A binder composition comprising an inorganic binder; and a high aspect ratio silicate, the binder composition comprising:
at least the inorganic binder is oxidized ,
A binder composition , wherein the inorganic binder comprises sodium bentonite, calcium bentonite, or a mixture thereof . carbonaceous material; and oxidized inorganic binder;
A binder composition comprising:
The ratio of Fe ²⁺ to Fe ³⁺ of the inorganic binder is less than 1.2,
A binder composition , wherein the inorganic binder comprises sodium bentonite, calcium bentonite, or a mixture thereof . oxidized carbonaceous material
A binder composition comprising :
The binder composition of claim 1, wherein the oxidized carbonaceous material is prepared by treatment with an oxidizing agent. 4. The binder composition of claim 3, wherein the oxidizing agent comprises soda ash, hydrogen peroxide, ozone, or a combination thereof. The binder composition according to any one of claims 1 to 3, wherein the inorganic binder has a Fe ²⁺ /Fe ³⁺ ratio of less than 1. The binder composition according to any one of claims 1 to 3, comprising 70 % to 90 % by weight of the inorganic binder. 4. The carbonaceous material comprises oxidized carbon, oxidized lignite, oxidized leonardite, oxidized graphite, oxidized anthracite, oxidized cellulose, or a combination thereof. The binder composition described in . 8. The binder composition of claim 7, wherein the oxidized carbon is oxidized lignite coal, oxidized bituminous coal, or oxidized sea coal. 0 . A binder composition according to any one of claims 1 to 3, comprising from 1% to 20.0 % by weight of said carbonaceous material. The binder composition according to claim 2 or 3, further comprising a high aspect ratio silicate. A binder composition according to claim 1 or 10, wherein the high aspect ratio silicate comprises mica or talc. 0 . 1% to 5 % by weight. A binder composition according to claim 1 or 10, comprising 0% by weight of said high aspect ratio silicate. 11. The high aspect ratio silicate of claim 1 or 10, wherein the high aspect ratio silicate comprises muscovite, paragonite, lepidolite, phlogopite, biotite, or combinations thereof. Binder composition. A green molding composition comprising a binder composition according to any one of claims 1 to 3 and an aggregate. 15. The green molding composition of claim 14, wherein the aggregate comprises silica sand, zircon sand, aluminosilicate, or a mixture thereof. A method of molding an article, the method comprising:
introducing a heated material into a mold, said mold comprising a mixture of carbonaceous material, an inorganic binder, a high aspect ratio silicate, water, and aggregates;
at least the inorganic binder is oxidized, and cooling the heated material ,
The method wherein the inorganic binder comprises sodium bentonite, calcium bentonite, or a mixture thereof . 17. The method of claim 16 , wherein the mold releases less than 0.10 mg/g BTEX after introducing the heated material into the mold. 18. A method according to claim 16 or 17 , wherein the carbonaceous material comprises oxidized carbon. A method according to any one of claims 16 to 18 , wherein the high aspect ratio silicate comprises mica or talc.

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