US3445251A - Molding sand - Google Patents

Molding sand Download PDF

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Publication number
US3445251A
US3445251A US542320A US54232066A US3445251A US 3445251 A US3445251 A US 3445251A US 542320 A US542320 A US 542320A US 54232066 A US54232066 A US 54232066A US 3445251 A US3445251 A US 3445251A
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United States
Prior art keywords
sand
humate
bentonite
alkaline
sodium
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US542320A
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English (en)
Inventor
Michael J Nevins
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NL Industries Inc
Original Assignee
Nat Lead Co
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Filing date
Publication date
Application filed by Nat Lead Co filed Critical Nat Lead Co
Priority to US542320A priority Critical patent/US3445251A/en
Priority to GB15248/67A priority patent/GB1119027A/en
Priority to BE696901A priority patent/BE696901A/fr
Priority to FR102316A priority patent/FR1518433A/fr
Priority to FI671067A priority patent/FI47051C/fi
Priority to DE19671558130 priority patent/DE1558130B1/de
Priority to SE5076/67A priority patent/SE316267B/xx
Priority to NL6705234A priority patent/NL6705234A/xx
Application granted granted Critical
Publication of US3445251A publication Critical patent/US3445251A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • 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
    • B22C1/167—Mixtures of inorganic and organic binding agents

Definitions

  • a molding sand composition comprises sand as a major constituent, the binder being bentonite 'adlmxed with about one-eighth to about three times its Weight of alkaline alkali metal humate, suflicient binder being used to obtain a green compression strength of at least four pounds per square inch. Within this range of humatezbentonite ratios, the green compression strength is very much higher than would be predicted from the individual components.
  • This invention relates to molding sands such as are used in the metal casting art and more particularly to an improved molding sand in which certain humates are used with clay as a binder.
  • a mold is formed from a suitable sand which is combined with binding material which permits the sand to be molded into the desired shape, and to retain that shape during the casting process.
  • binding material which permits the sand to be molded into the desired shape, and to retain that shape during the casting process.
  • the nature of the bond between the sand particles must be such that it will give way subsequent to the pouring and solidifying of the metal, in order that the casting may be readily removed and freed of sand particles. This is particularly necessary where the shape of the casting includes re-entrant cavities.
  • the sand mold must presenta surface to the impinging uid lmetal which after cooling and shaking out leaves the metal surface as smooth as possible, so that cleanup operations on the casting may be minimized.
  • the sand after casting and shaking out should be capable of substantially indenite re-use, by reworking with additional bonding agents as needed.
  • the most Widely used and generally the most satisfactory bonding agent for ordinary sand molds is bentonite, which may be of a highly swelling type as found in Wyoming, South Dakota, and elsewhere; or it may be of a lesser swelling variety, as found in Texas and Mississippithese two varieties being often known as western bentonite and southern bentonite respectively.
  • Minor amounts of other additives are commonly used besides the sand, bentonites, and tempering water of the basic molding sand composition.
  • These generally include cereal binders, particularly those ma'de from the proteinrich fraction of the maize kernel; dextrine, powdered bituminous coal (sea coal), wood flour, rpitch, silica flour, and others.
  • Nonbentonitic clays such as tire clay may sometimes be added in addition to the bentonite to improve strength at high temperatures.
  • the sand itself is generally silica sand, that is, quartz, although other mmerals may be used for special compositions, such as olivine and Zircon.
  • An object of the present invention is to provide a molding sand composition containing bentonite and .a certain humate additive, which is easily prepared and maintained and has improved properties.
  • FIGURLE l is a graph showing the irnproved results obtainable with my invention.
  • I provide a molding sand composition, the major constitutent of which is sand, and a minor constituent of which is bentonite together with fnom about one-eighth to about three times its weight of an alkaline, alkalized humate as defined below.
  • suicient water is incorporated in the composition to provide adequate binding properties.
  • bone-dry bentonite has little or no binding eiect on the sand particles, and likewise, when a gross excess of water is used, the bentonite can no longer act -as an adhesive for the sand grains.
  • the bentonite may be any of those commonly employed in the molding sand art, and may be the highly swelling type exemplified by Wyoming bentonite or the lesser swelling types as found in Texas and elsewhere.
  • the bentonite is used in a comminuted form, such as ground to pass a 200- mesh screen, although coarser and finer grinds may be used. As far 4as the sand and the bentonite are concerned, therefore, the procedure is conventional.
  • the alkaline, alkalized humate is any alkali metal salt of humic acid, such as sodium, potassium, vor lithium humate, these being water soluble, as is well known, and is most conveniently derived from lignite, particularly weathered lignite such as occurs in great abundance in North Dakota, Texas, New Mexico, northern Europe, and elsewhere.
  • alkalized humate humic acid is reacted with an alkali-metal alkali, preferably selected from the group consisting of sodium and potassium alkalies.
  • This group includes such well-known members as caustic soda, soda ash, potash lye, and the like. It is not necessary to use a chemically pure humic acid, but indeed, I prefer to utilize a lignite rich in alkalisoluble constituents and simply grind these together with the selected alkali, preferably with enough water to bring about a rapid neutralization reaction, if indeed, the lignite is not moist enough to provide the necessary water by itself.
  • This grinding together can be carried out in any suitable apparatus and may even be done in the foundry muller during preparation of the molding sand. More complicated procedures may be used, such as dispersing the ground lignite in a solution of the alkali and water, settling out the insoluble constituents, and recovering the alkalized humate by drying and grinding, but this increases the cost and scarcely affects the nal results.
  • the humic acid will, in general, require a minimum of about one-fourteenth to about one-fourth of its dry weight of sodium hydroxide to produce a sodium humate (which is the alkalized humate in this instance) which at the same time is alkaline, viz., which has a pH in excess of 7. (Of course, if other alkalies are used, the known prnciplcs of chemical stoichiometry should be observed.)
  • Humic acids in general, and in particular those derived from lignite have equivalent weights in the neighborhood of 320 and 360.
  • a weathered lignite having 80% (by dry weight) of alkalized, soluble humic acids is utilized, admixing this with about one-tenth of its weight of sodium hydroxide will, as may be readily calculated, result in the conversion of all of the humic acid to sodium humate.
  • sodium humate will have a slightly alkaline pH, in the neighborhood of 8 to 9.
  • alkali in the form of sodium hydroxide may be employed.
  • alkali metal humate used in the invention may be termed an alkaline alkali metal humate.
  • the relative proportions of bentonite to the alkaline, alkalized humate is, in accordance with my invention, from about one-eighth to about three parts of the latter for each part of bentonite by weight.
  • the best ratio is from about 75:25 to 50:50 parts bentonite to parts humate.
  • the exact ratio preferred will depend upon the thermal characteristics and mass of metal being poured, and like factors. I have had somewhat better results using bentonite of the Wyoming type than of the so-called southern type, although both may be used, separately and indeed in admixture.
  • This material was used as a binder in making up a molding sand mix consisting of 94 parts by Weight Ottawa sand, 4 parts of this binder, and 2 parts water.
  • the ingredients without the water were dry mulled for 3 minutes in a foundry muller, the water then added, and then mulled for -an additional 10 minutes.
  • the molding sand composition-s thus produced were tested in accordance with standard methods of the American Found-rymens Association.
  • the green compressive strength and the green shear strength appear in the drawing; the dry compressive strength was 19 p.s.i., and the permeability was 1-89 by the standard test method. This produced a molding sand having excellent molding properties, good shakeout, and leaving a clean surface on the casting.
  • Example 2 The procedure of Example l was carried out, except :that Texas bentonite was used in place of the Wyoming bentonite. With the same proportions, the green compressive strength was 9.5 p.s.i., the green shear strength was 2.3 p.s.i., the dry compression strength was 22 p.s.i., and the permeability was 202.
  • EXAMPLE 3 In this example, the effect of alkaline, alkalized humate was compared with unalkalized humic material. To a foundry muller was added 94 pounds of Ottawa sand, followed by 2 pounds of Wyoming bentonite. The -muller was started, .and 2 pounds of the alkaline, alkalized humate, prepa-red as in Example l, were added and dry mulling continued vfor three minutes. Two pounds of water were .then added and mulling continued for an additional ten minutes.
  • EXAMPLE 4 A foundry test was carried out using about 18,000 pounds of a silica sand known as Manley No. 410 (fineness number of 55), made up to an eventual binder content of 4.4% by weight, the sand binder consisting of by weight of Wyoming bentonite and 25% by Weight of the product obtained by mixing lignite with sodium hydroxide in a 4ratio of 6:1. Water was .added lto an eventual moisture content of about 3.2%. This was used in making a gray iron casting in the form of a hub approximately 5 inches in diameter and 5 inches high.
  • Manley No. 410 fineness number of 55
  • the .sand unix previously used was a conventional one using the same base sand, approximately 5% Wyoming bentonite and from 3% to 5% of bituminous coal (sea coal).
  • sea coal bituminous coal
  • inventive sand composition was successfully used with about 2% less moisture than the previously used sand, and it had two 'and onetha'lf times the permeability of the latter, even though the same sand base was used.
  • EXAMPLE 5 Good resul-ts obtained Ias described in Example 4 above gave encouragement to the production of a 1,300-pound batch of sand mix using a much ner sand, Manley number 805, with the additives as previously described in Example 4.
  • the inherently vhigh permeability obtained in laccordance with the invention permitted the use of the liner sand with a consequent improvement in the finish of the castings obtained.
  • the permeability of the mix was 55, which was higher than the average permeability ot about 45 of the coarser sand ymix formerly used, and already described in Example 4 above.
  • the amount of binder -that is, the .total amount of -bentonite and the alkaline, alkalized humate used in my molding sands is subject to some variation, depending upon the personal preferences of the foundrymen, the sand grain fineness number, and the characteristics of the particular bentonite chosen.
  • suflicient binder r should be used to give a green compression strength of at least 4 p.s.i.
  • a total binder content of 2% to 3% is sucient to achieve this minimum.
  • a molding sand composition comprising as a major constituent sand, and suflcient bentonite admxed with from about one-eighth to about three times the weight of said ben-tonite of an alkaline, alkali metal humate to f impart to said composition a green compressive strength of at least four pounds per square inch.
  • composition in accordance with claim 1 wherein said alkali metal is selected from the group consisting of sodium, potassium, .and lithium.
  • composition in accord-ance with claim 1 wherein said humate is the reaction product of lignite having an alkali solubility of at least 65% by dry weight with sucient sodium hydroxide to produce an alkaline sodium humate.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Inorganic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Mold Materials And Core Materials (AREA)
US542320A 1966-04-13 1966-04-13 Molding sand Expired - Lifetime US3445251A (en)

Priority Applications (8)

Application Number Priority Date Filing Date Title
US542320A US3445251A (en) 1966-04-13 1966-04-13 Molding sand
GB15248/67A GB1119027A (en) 1966-04-13 1967-04-03 Molding sand
FR102316A FR1518433A (fr) 1966-04-13 1967-04-11 Sables de moulage
FI671067A FI47051C (fi) 1966-04-13 1967-04-11 Kaavaushiekkakokoomus.
BE696901A BE696901A (fr) 1966-04-13 1967-04-11 Sable de fonderie
DE19671558130 DE1558130B1 (de) 1966-04-13 1967-04-12 Formsandmasse, die aus sand, wasser, einem in wasser hochquellenden bentonit und einem wasserloeslichen alkalisalz besteht
SE5076/67A SE316267B (de) 1966-04-13 1967-04-12
NL6705234A NL6705234A (de) 1966-04-13 1967-04-13

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US542320A US3445251A (en) 1966-04-13 1966-04-13 Molding sand

Publications (1)

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US3445251A true US3445251A (en) 1969-05-20

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US542320A Expired - Lifetime US3445251A (en) 1966-04-13 1966-04-13 Molding sand

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Country Link
US (1) US3445251A (de)
BE (1) BE696901A (de)
DE (1) DE1558130B1 (de)
FI (1) FI47051C (de)
FR (1) FR1518433A (de)
GB (1) GB1119027A (de)
NL (1) NL6705234A (de)
SE (1) SE316267B (de)

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3549392A (en) * 1969-01-08 1970-12-22 Nalco Chemical Co Mold coating
US4034794A (en) * 1975-10-31 1977-07-12 Nalco Chemical Company Casting process with lignosulfonate-humate-graphite mold coatings
US4203771A (en) * 1976-04-08 1980-05-20 Hirofumi Matsui Green sand composition for casting
US4830673A (en) * 1986-10-03 1989-05-16 E.C.C. America Inc. Method for reducing the abrasion of calcined clay
US5275114A (en) * 1989-04-11 1994-01-04 American Colloid Company Sodium bentonite clay binder mixture for the metal casting industry
US5372636A (en) * 1993-01-22 1994-12-13 Bentonite Corporation Foundry mold composition, foundry mold made therefrom and method for producing the same
US5688313A (en) * 1996-06-21 1997-11-18 Amcol International Corporation Activated carbon foundry sand additives and method of casting metal for reduced VOC emissions
US5769933A (en) * 1996-06-21 1998-06-23 Amcol International Corporation Activated carbon foundry sand additives and method of casting metal for reduced VOC emissions
US5810918A (en) * 1996-06-21 1998-09-22 Amcol International Corporation Method of analyzing and/or treating foundry sands for reduced VOCs
US5893946A (en) * 1996-06-21 1999-04-13 Amcol International Corporation Combustible carbonaceous compositions and methods
US20110079366A1 (en) * 2009-10-06 2011-04-07 Amcol International Corp. Lignite-urethane based resins for enhanced foundry sand performance
US20110082233A1 (en) * 2009-10-06 2011-04-07 Amcol Internatinal Corp. Lignite-based urethane resins with enhanced suspension properties and foundry sand binder performance
US20110081270A1 (en) * 2009-10-06 2011-04-07 Amcol International Corp. Lignite-based urethane resins with enhanced suspension properties and foundry sand binder performance
US20110220316A1 (en) * 2009-10-06 2011-09-15 Amcol International Corporation Non-veining urethane resins for foundry sand casting
WO2013015981A1 (en) 2011-07-22 2013-01-31 Amcol International Lignite-based foundry resins
CN109158527A (zh) * 2018-10-31 2019-01-08 谷函（杭州）新材料科技有限公司 一种无煤环保铸造型砂添加剂及其在型砂中的用途

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4131476A (en) * 1977-08-05 1978-12-26 Whitehead Brothers Company Additive for green molding sand

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1420750A (en) * 1921-01-27 1922-06-27 Royal N Riblet Traffic indicator
US2237593A (en) * 1939-11-27 1941-04-08 Peerpatco Inc Foundry composition and method
CA717419A (en) * 1965-09-07 G. Henderson Sydney Moulding processes
US3210203A (en) * 1962-12-20 1965-10-05 Nat Lead Co Molding sand
US3212144A (en) * 1962-06-22 1965-10-19 Frank R Capps Sand molds for metal casting and methods therefor

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT177888B (de) * 1951-06-26 1954-03-10 Huettenbedarf Dipl Ing Rolf Zi Verfahren zur Behandlung von Bentonit für Formsande, Formmassen u. dgl. sowie mit diesem Bentonit hergestellte Formsande, Formmassen u. dgl.
BE635513A (de) * 1962-07-30

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA717419A (en) * 1965-09-07 G. Henderson Sydney Moulding processes
US1420750A (en) * 1921-01-27 1922-06-27 Royal N Riblet Traffic indicator
US2237593A (en) * 1939-11-27 1941-04-08 Peerpatco Inc Foundry composition and method
US3212144A (en) * 1962-06-22 1965-10-19 Frank R Capps Sand molds for metal casting and methods therefor
US3210203A (en) * 1962-12-20 1965-10-05 Nat Lead Co Molding sand

Cited By (27)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3549392A (en) * 1969-01-08 1970-12-22 Nalco Chemical Co Mold coating
US4034794A (en) * 1975-10-31 1977-07-12 Nalco Chemical Company Casting process with lignosulfonate-humate-graphite mold coatings
US4203771A (en) * 1976-04-08 1980-05-20 Hirofumi Matsui Green sand composition for casting
US4830673A (en) * 1986-10-03 1989-05-16 E.C.C. America Inc. Method for reducing the abrasion of calcined clay
US5275114A (en) * 1989-04-11 1994-01-04 American Colloid Company Sodium bentonite clay binder mixture for the metal casting industry
US5333673A (en) * 1989-04-11 1994-08-02 American Colloid Company Metal casting in a sand mold having a sodium bentonite clay binder mixture
US5372636A (en) * 1993-01-22 1994-12-13 Bentonite Corporation Foundry mold composition, foundry mold made therefrom and method for producing the same
US5688313A (en) * 1996-06-21 1997-11-18 Amcol International Corporation Activated carbon foundry sand additives and method of casting metal for reduced VOC emissions
US5695554A (en) * 1996-06-21 1997-12-09 Amcol International Corporation Foundry sand additives and method of casting metal, comprising a humic acid-containing ore and in-situ activated carbon or graphite for reduced VOC emissions
US5769933A (en) * 1996-06-21 1998-06-23 Amcol International Corporation Activated carbon foundry sand additives and method of casting metal for reduced VOC emissions
US5810918A (en) * 1996-06-21 1998-09-22 Amcol International Corporation Method of analyzing and/or treating foundry sands for reduced VOCs
US5893946A (en) * 1996-06-21 1999-04-13 Amcol International Corporation Combustible carbonaceous compositions and methods
US20110079366A1 (en) * 2009-10-06 2011-04-07 Amcol International Corp. Lignite-urethane based resins for enhanced foundry sand performance
US8309620B2 (en) 2009-10-06 2012-11-13 Amcol International Corp. Lignite-based urethane resins with enhanced suspension properties and foundry sand binder performance
US20110081270A1 (en) * 2009-10-06 2011-04-07 Amcol International Corp. Lignite-based urethane resins with enhanced suspension properties and foundry sand binder performance
WO2011044003A2 (en) 2009-10-06 2011-04-14 Amcol International Corp. Lignite-urethane based resins for enhanced foundry sand performance
WO2011044005A1 (en) 2009-10-06 2011-04-14 Amcol International Corp. Lignite-based urethane resins with enhanced suspension properties and foundry sand binder performance
WO2011044004A2 (en) 2009-10-06 2011-04-14 Amcol International Corp. Lignite-based urethane resins with enhanced suspension properties and foundry sand binder performance
US20110220316A1 (en) * 2009-10-06 2011-09-15 Amcol International Corporation Non-veining urethane resins for foundry sand casting
US20110082233A1 (en) * 2009-10-06 2011-04-07 Amcol Internatinal Corp. Lignite-based urethane resins with enhanced suspension properties and foundry sand binder performance
US8853299B2 (en) 2009-10-06 2014-10-07 Amcol International Corp. Lignite-based urethane resins with enhanced suspension properties and foundry sand binder performance
US8426494B2 (en) 2009-10-06 2013-04-23 Amcol International Corp. Lignite urethane based resins for enhanced foundry sand performance
US8436073B2 (en) 2009-10-06 2013-05-07 Amcol International Lignite-based foundry resins
US8623959B2 (en) 2009-10-06 2014-01-07 Joseph M. Fuqua Non-veining urethane resins for foundry sand casting
US8802749B2 (en) 2009-10-06 2014-08-12 Amcol International Corporation Lignite-based foundry resins
WO2013015981A1 (en) 2011-07-22 2013-01-31 Amcol International Lignite-based foundry resins
CN109158527A (zh) * 2018-10-31 2019-01-08 谷函（杭州）新材料科技有限公司 一种无煤环保铸造型砂添加剂及其在型砂中的用途

Also Published As

Publication number Publication date
FI47051C (fi) 1973-09-10
FI47051B (de) 1973-05-31
SE316267B (de) 1969-10-20
NL6705234A (de) 1967-10-16
DE1558130B1 (de) 1974-01-24
FR1518433A (fr) 1968-03-22
GB1119027A (en) 1968-07-03
BE696901A (fr) 1967-09-18

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