WO1995011787A1 - Heat-cured foundry binders and their use - Google Patents
Heat-cured foundry binders and their use Download PDFInfo
- Publication number
- WO1995011787A1 WO1995011787A1 PCT/US1994/012180 US9412180W WO9511787A1 WO 1995011787 A1 WO1995011787 A1 WO 1995011787A1 US 9412180 W US9412180 W US 9412180W WO 9511787 A1 WO9511787 A1 WO 9511787A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- silica
- source
- alumina
- foundry
- weight
- Prior art date
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
- C04B28/24—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing alkyl, ammonium or metal silicates; containing silica sols
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C1/00—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds
- B22C1/16—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents
- B22C1/18—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents of inorganic agents
- B22C1/186—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents of inorganic agents contaming ammonium or metal silicates, silica sols
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B12/00—Cements not provided for in groups C04B7/00 - C04B11/00
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
- C04B2111/0087—Uses not provided for elsewhere in C04B2111/00 for metallurgical applications
Definitions
- This invention relates to heat cured foundry binders comprising in admixture (a) a soluble source of silica, and
- a soluble source of alumina such that the source of silica, source of alumina, or both contain an alkali metal.
- the binder components form a saturated solution when they are mixed with an aggregate.
- the resulting mix is shaped and heated at an elevated temperature to form a cured foundry shape bonded together by a crystalline bonding phase.
- Heat is applied by warm air, baking in an oven, microwave, or preferably from hot-box equipment.
- the subject invention relates to heat cured foundry binders comprising in admixture:
- a soluble source of alumina such that the source of silica, source of alumina, or both contain an alkali metal.
- the binder components form a saturated solution when mixed with an aggregate.
- the resulting mix is shaped and cured by heating with warm air, baking in oven, microwave, and preferably in hot-box equipment to form a crystalline binding phase by dehydration during heating. Most of the water is removed from the binder during curing.
- the foundry mixes prepared with these binders have a benchlife of up to five hours.
- These heat cured binders differ significantly from the self-setting binders disclosed in U.S. Patent 4,357,165 (see Figure 1) which are hydrogels and are cured at ambient temperature.
- the heat cured binders which are the subject of this invention form crystalline structures with a characteristic x-ray diffraction pattern (see Figure 2) , and are formed within a prescribed molar ratio of silica source and alumina source.
- Foundry mixes are prepared by mixing the binder components with a foundry aggregate. In contrast to the foundry mixes of U.S. Patent 4,357,165 which have zero or little benchlife, the foundry mixes made with the subject binders have a benchlife of up to five hours. The foundry mixes are shaped into molds, cores, and assemblies thereof. In contrast to the foundry shapes made with the binders described in U.S.
- Patent 4,357,165 the subject binders provide cured foundry shapes which set quickly at elevated temperatures, have good tensile strengths, do not require excess free alkali (which is disadvantageous for reclamation and shakeout) , show good humidity resistance, are used in commercially acceptable binder levels (generally less than about 5 weight percent based upon the weight of the aggregate) , and do not need calcined kaolin to improve the hot strength.
- FIGURE 1 is an x-ray diffraction pattern for a binder prepared in accordance with U.S. Patent 4,357,165.
- the x-ray diffraction pattern shows the binder is a crystalline material.
- ENABLING DISCLOSURE AND BEST MODE The binder consists of two components: (1) a soluble silica source, and (2) a soluble alumina source, such that the source of silica, source of alumina, or both contain an alkali metal.
- Either component may be liquid or solid, but at least one component must be liquid. If either component is a solid component, the solid component will dissolve in the liquid component when the two components are mixed.
- the soluble silica source is preferably an alkali silicate in aqueous solution, more preferably sodium silicate, colloidal silica, or solid silica, fumed or precipitated.
- the soluble alumina source is preferably a solid alkali alu inate, or an alkali aluminate in solution, preferably where sodium aluminate is the alkali aluminate.
- Sodium aluminate can be used as a powder or as an aqueous solution without affecting curing time significantly. The powder, however, provides greater flexibility to the formulator when adding other components to the binder, but liquid components are easier to use.
- the amount of solids in the aqueous solution containing the source of silica generally ranges from 40 to 55 weight percent, based upon the weight of the aqueous solution, preferably about 50 weight percent.
- the amount of solids in the source of alumina generally ranges from 40 to 50 weight percent, based upon the weight of the aqueous solution, preferably about 45 weight percent.
- the weight composition of alkali to alumina to silica, expressed as oxides, in the binder ranges from about 20 to about 40 weight percent alkali, from about 30 to about 50 weight percent alumina, and from about 20 to about 40 weight percent silica, said weight percents being based upon the total weight of the binder composition, preferably from about 28 to about 32 weight percent alkali, from about 38 to about 42 weight percent alumina, and from about 28 to about 35 weight percent silica. All weight ratios are expressed as if the source of silica and alumina were an oxide. This is common practice in the trade. The source of silica is first applied to the aggregate when making a foundry mix. Then the source of alumina is mixed with the aggregate.
- the binder is preferably incorporated with sand at binder levels of 1 to 5 weight percent based upon the weight of the aggregate.
- the aggregate used to prepare the foundry mixes is that typically used in the foundry industry for such purposes or any aggregate that will work for such purposes.
- the aggregate will be sand which contains at least 70 percent by weight silica.
- Other suitable aggregate materials include zircon, olivine, alumina-silicate sand, chromite sand, and the like.
- Particularly preferred sand is silica sand having a fineness grade of 70 to 105 for instance. It is believed systems based on such sand will be particularly useful for high pressure die casting.
- the sand mixture is compacted into cores and/or molds to form foundry shapes and heated to 100*C to 300*C, preferably 150 * C to 250*C until the foundry shapes can be handled without breaking, typically for 30 seconds to 20 minutes. Heating time is a function of the temperature and the heating process used.
- the heat source may be from the warm air, baking in a conventional oven, microwave, or preferably from hot-box equipment. Foundry shapes prepared with the binder exhibit adequate immediate strengths for handling and show added strength development during 24 hours after curing. The heat-cured foundry shapes also exhibit excellent humidity resistance, much better than the foundry shapes made with the alumino-silicate no-bake binders shown in U.S. Patent 4,357,165.
- PI Part I (source of silica)
- PII Part II (source of alumina)
- RH room humidity
- RT room temperature
- Examples A, B, and C are controls introduced for comparative purposes.
- the foundry shapes are allowed to cure at room temperature substantially in the manner as disclosed in U.S. Patent 4,357,165.
- Examples 1-3 relate to a binder system wherein the Part II is a solid sodium aluminate while Examples 4-15 relate to a binder system using a liquid Part II. Examples 4-15 also show the effects of using different sand in binder systems where the Part I and Part II components are liquids. The conditions of use are set forth in Tables I to III which follow.
- the foundry aggregate was prepared by mixing the sand with the Part I and Part II using a paddle style mixer (Hobart N-50) and cured with hot-box equipment.
- the colloidal silica solution (Part I) contains about 50% solids and only small amount of sodium.
- the aqueous sodium aluminate solution (Part II) contained 45% solids and has a Na 2 0/Al 2 0 3 molar ratio of 1.26:1.0.
- the calculated molar ratio of Na 2 0:Al 2 0 3 :Si0 2 is 1.3:1.0:1.3.
- Mixing the solutions of the silica source and the alumina source resulted in the formation of a saturated solution on the sand mix.
- the sand mixes were made into the shape of dogbones for tensile strength measurements with a Thwing-Albert TA 500.
- the dogbone shapes were cured by heating them in hot-box equipment.
- the temperature of the heated core box, sand type, blow pressure, and the blow time are shown in the tables.
- the humidity resistance was tested by placing samples which had cured for 24 hrs into a humidity chamber at 25 C * and 99% relative humidity (RH) for 1 hr.
- RH relative humidity
- Metal castings made with the binders showed excellent resistance against erosion and veining while penetration and surface finish were good. Shakeout for aluminum castings was on the average about 45 seconds.
- Examples A, B, and C are controls introduced for comparative purposes.
- the foundry shape is allowed to cure at room temperature substantially in the manner as disclosed in U.S.* Patent 4,357,165.
- Table I indicates that tensile strengths of the foundry shapes made with binders according to U.S. Patent 4,357,165 were unacceptable for commercial use.
- Table II Examples 1-3, shows the test results using binder systems within the scope of this invention where the Part I is liquid. Part II is solid, and hot-box equipment was used for curing. Foundry shapes with acceptable tensile strengths were made from this binder.
- Examples 4-15 show test results using binder systems within the scope of this invention where both the Part I and Part II are liquid. Unless otherwise stated, the procedure used was the same as that set forth in Examples 1-
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Inorganic Chemistry (AREA)
- Mechanical Engineering (AREA)
- Mold Materials And Core Materials (AREA)
- Moulds For Moulding Plastics Or The Like (AREA)
- Heating, Cooling, Or Curing Plastics Or The Like In General (AREA)
- Molds, Cores, And Manufacturing Methods Thereof (AREA)
Abstract
Description
Claims
Priority Applications (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU80891/94A AU8089194A (en) | 1993-10-27 | 1994-10-24 | Heat-cured foundry binders and their use |
JP7512766A JP3043812B2 (en) | 1993-10-27 | 1994-10-24 | Binders for thermosetting molds and their uses |
AT94932010T ATE251533T1 (en) | 1993-10-27 | 1994-10-24 | NO METHOD FOR PRODUCING A WORKABLE MOLD |
CA002174751A CA2174751C (en) | 1993-10-27 | 1994-10-24 | Heat-cured foundry binders and their use |
DE69433227T DE69433227T2 (en) | 1993-10-27 | 1994-10-24 | NO METHOD FOR PRODUCING AN EDITABLE MOLD |
EP94932010A EP0724510B1 (en) | 1993-10-27 | 1994-10-24 | A process for preparing a workable foundry shape |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US08/144,237 | 1993-10-27 | ||
US08/144,237 US5417751A (en) | 1993-10-27 | 1993-10-27 | Heat cured foundry binders and their use |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1995011787A1 true WO1995011787A1 (en) | 1995-05-04 |
Family
ID=22507690
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1994/012180 WO1995011787A1 (en) | 1993-10-27 | 1994-10-24 | Heat-cured foundry binders and their use |
Country Status (7)
Country | Link |
---|---|
US (1) | US5417751A (en) |
EP (1) | EP0724510B1 (en) |
JP (1) | JP3043812B2 (en) |
AT (1) | ATE251533T1 (en) |
AU (1) | AU8089194A (en) |
DE (1) | DE69433227T2 (en) |
WO (1) | WO1995011787A1 (en) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE4319187A1 (en) * | 1993-06-09 | 1994-12-15 | Bayer Ag | Casting investment materials |
US5837047A (en) * | 1996-12-11 | 1998-11-17 | Ashland Inc. | Heat curable binder systems and their use |
DE102004042535B4 (en) * | 2004-09-02 | 2019-05-29 | Ask Chemicals Gmbh | Molding material mixture for the production of casting molds for metal processing, process and use |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4357165A (en) * | 1978-11-08 | 1982-11-02 | The Duriron Company | Aluminosilicate hydrogel bonded granular compositions and method of preparing same |
US4432798A (en) * | 1980-12-16 | 1984-02-21 | The Duriron Company, Inc. | Aluminosilicate hydrogel bonded aggregate articles |
US4533393A (en) * | 1982-12-16 | 1985-08-06 | Dynamit Nobel Aktiengesellschaft | Aqueous curable molding compositions based on inorganic ingredients and process for the production of molded parts |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1999382A (en) * | 1932-06-13 | 1935-04-30 | Grasselli Chemical Co | Refractory material for use in metal castings and process for making the same |
FR2464227B1 (en) * | 1979-09-04 | 1985-09-20 | Cordi Coord Dev Innovation | MINERAL POLYMER |
US5474606A (en) * | 1994-03-25 | 1995-12-12 | Ashland Inc. | Heat curable foundry binder systems |
-
1993
- 1993-10-27 US US08/144,237 patent/US5417751A/en not_active Expired - Fee Related
-
1994
- 1994-10-24 DE DE69433227T patent/DE69433227T2/en not_active Expired - Lifetime
- 1994-10-24 AU AU80891/94A patent/AU8089194A/en not_active Abandoned
- 1994-10-24 EP EP94932010A patent/EP0724510B1/en not_active Expired - Lifetime
- 1994-10-24 JP JP7512766A patent/JP3043812B2/en not_active Expired - Lifetime
- 1994-10-24 WO PCT/US1994/012180 patent/WO1995011787A1/en active IP Right Grant
- 1994-10-24 AT AT94932010T patent/ATE251533T1/en active
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4357165A (en) * | 1978-11-08 | 1982-11-02 | The Duriron Company | Aluminosilicate hydrogel bonded granular compositions and method of preparing same |
US4432798A (en) * | 1980-12-16 | 1984-02-21 | The Duriron Company, Inc. | Aluminosilicate hydrogel bonded aggregate articles |
US4533393A (en) * | 1982-12-16 | 1985-08-06 | Dynamit Nobel Aktiengesellschaft | Aqueous curable molding compositions based on inorganic ingredients and process for the production of molded parts |
Also Published As
Publication number | Publication date |
---|---|
DE69433227D1 (en) | 2003-11-13 |
US5417751A (en) | 1995-05-23 |
JP3043812B2 (en) | 2000-05-22 |
JPH09504485A (en) | 1997-05-06 |
EP0724510A1 (en) | 1996-08-07 |
EP0724510B1 (en) | 2003-10-08 |
DE69433227T2 (en) | 2004-08-19 |
ATE251533T1 (en) | 2003-10-15 |
AU8089194A (en) | 1995-05-22 |
EP0724510A4 (en) | 1996-12-04 |
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