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
  • C04B24/00—Use of organic materials as active ingredients for mortars, concrete or artificial stone, e.g. plasticisers
  • C04B24/40—Compounds containing silicon, titanium or zirconium or other organo-metallic compounds; Organo-clays; Organo-inorganic complexes
  • C04B24/42—Organo-silicon compounds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
  • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
  • B02C23/00—Auxiliary methods or auxiliary devices or accessories specially adapted for crushing or disintegrating not provided for in preceding groups or not specially adapted to apparatus covered by a single preceding group
  • B02C23/06—Selection or use of additives to aid disintegrating
• • 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
  • C04B7/00—Hydraulic cements
  • C04B7/14—Cements containing slag
• • 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
  • C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
  • C04B2103/52—Grinding aids; Additives added during grinding
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P40/00—Technologies relating to the processing of minerals
  • Y02P40/10—Production of cement, e.g. improving or optimising the production methods; Cement grinding

Definitions

• the present invention is directed to a novel grinding aid for slag, and slag/clinker blends and the resulting cement products therefrom.
• Hydraulic cements are powder material which, when mixed with water, alone or with aggregate, form rock-hard products, such as paste, mortar or concrete.
• Paste is formed by mixing water with a hydraulic cement.
• Mortar is formed by mixing a hydraulic cement with small aggregate (e.g. sand) and water.
• Concrete is formed by mixing a hydraulic cement with small aggregate, large aggregate (e.g. 0.2-1 inch stone) and water.
• portland cement is a commonly used hydraulic cement material with particular standard specifications established in the various countries of the world (See “Cement Standards of the World", Cembureau, Paris, France).
• hydraulic cements are prepared by sintering a mixture of components including calcium carbonate (as limestone), aluminum silicate (as clay or shale), silicon dioxide (as sand), and miscellaneous iron oxides. It is common that the mixture to be sintered contains as a component up to 80% slag. The components lose their separate identity and are chemically transformed during the sintering process. During the sintering process, chemical reactions take place wherein hardened nodules, commonly called clinkers, are formed.
• the granulated blast furnace slag is a cementitous material made from iron blast furnace slag. It is a non-metallic by-product of the iron industry having silicates and alumino silicates of calcium and other bases developed in a molten condition simultaneously with iron in a blast furnace at about 2700°F.
• gypsum calcium sulfate
• gypsum calcium sulfate
• other materials may be ground with the clinker or blended with the clinker to provide a particular type of hydraulic cement.
• a frequently added component is ' granulated blast furnace slag, pozzolans which are substituted for a portion of the expensive clinker material: This use of slag is distinguished from its use as an an optional ingredient in the sintered clinker described above.
• Another component which may be added to the clinker is fly ash.
• the slag and the clinker may be ground together, or ground separately and then blended together.
• ground or unground slag may be added to the clinker, then the clinker/slag blend may be ground.
• the clinker may constitute up to
• Slag and fly ash are generally inert and are used in cements where economy is of prime consideration and some diminution in strength is acceptable.
• the term "blended cement” refers to hydraulic cements having between 5 and 80% (more conventionally 5- 60%) slag as part of its composition. Products include hydraulic cements such as portland blast furnace slag cement, slag modified portland cement and the like.
• One of the major classes of grinding aids used today is the oligomers of lower alkylene glycols, such as diethylene glycol. They are used because of their availability and low cost. These glycols have had their grinding effectiveness enhanced by the inclusion of polyglycerols, lower fatty acids and sulfonated lignin (U.S. Pat. No. 4,204,877); unsaturated aliphatic acid and amines (FR 2,337,699); a C3 aliphatic acid salt and an amine (U.S. Pat. No. 3,615,785); as well as alcohols and amides (U.S. Pat. No. 5,125,976). Although the time required (and thereby energy consumed) is lessened when clinkers are ground in the presence of glycol grinding aids, the resultant powder cements do not exhibit any beneficial effect over cements formed without such grinding aid.
• Silicon containing grinding aids other than those of the present invention have been disclosed in the art.
• Liquid Grinding Aids on Cement Clinker (Puvodni Prace, May 7, 1971) teach that short ' trimethyl endblocked polydimethylsiloxanes can be used as grinding aids for clinker.
• Silanes and their condensation products have also been disclosed for use as masonary additives, e.g., as in WO 81/01703 entitled "Process for the Preparation of a Mortar and the Product Thereby Obtained.”
• this patent application does not disclose the use of silanes as a grinding aid for cement clinker, slag, or clinker/slag blends.
• the present invention is directed to a novel grinding aid for slag and slag/clinker raw material blends.
• the grinding aid is any silicon containing fluid or blends thereof.
• the compositions improve grinding efficiency of the slag or slag/clinker blends by reducing energy consumption during the grinding process.
• the grinding aid of the present invention is added to the slag or slag/clinker blend to reduce the energy consumed during grinding and/or to improve the properties of the hydraulic cement product.
• the grinding aid can be a siloxane fluid, a cyclic siloxane, silane, siliconate, polydiorganosiloxanolate, or mixtures thereof. Each of these components will be described herein in detail.
• the polydiorganosiloxanes useful in the invention are preferably linear polydiorganosiloxanes, but branched polydiorganosiloxanes would work as well.
• the polyorganosiloxanes could be functional or non-functional.
• functional siloxane it is meant a polydiorganosiloxane having at least one pendant or terminal functional group, such as hydroxyl, alkoxy, vinyl, amine, etc.
• the functional polydiorganosiloxane could also be terminated with hydrogen atoms.
• Non-functional siloxane fluids are typically endblocked with methyl or ethyl groups.
• the organic groups along the backbone of the siloxane can be methyl, ethyl or phenyl, with methyl being most preferred.
• the polymers are preferably ' short chain molecules having from 1 to 50 repeating silicon units and are well known in the art.
• the functional polydiorganosiloxanes preferably have an average of at least two functional groups per molecule and the most preferred functional groups are hydroxyl groups situated at the terminal positions of the polydiorganosiloxane.
• the non-functional siloxanes are preferably endblocked with methyl groups.
• the trimethyl end blocked polydiorganosiloxanes have a viscosity in the range of 0.65 cst to 20 (mm)2/s.
• hydroxyl terminated polydiorganosiloxanes represented by the general formula
• Hydroxyl terminated polydiorganosiloxanes are well known in the art and can be prepared by conventional methods.
• the chain length of the siloxane polymer preferably has an average number of siloxane units per polymer molecule of at least 2.
• the hydroxylated siloxane can vary from thin fluids to non-flowable gums.
• Preferred R! groups are methyl, ethyl or phenyl, with methyl being most preferred. Accordingly, it is often preferred to employ a mixture of lower and higher molecular weight siloxanes in the compositions used in this invention.
• the polydiorganosiloxane can be completely hydroxyl terminated or a portion of the polymer chains can be terminated on one end by a methyl radical. It is preferred that siloxane is hydroxyl terminated and that all Y groups in the general formula are hydroxyl radicals.
• cyclic siloxanes used as grinding aids can be used alone or blended with the other components described herein.
• Cyclic siloxanes are well known in the art, and may have functional groups such as vinyl, hydroxy, alkoxy or SiH disposed thereon or may be non- functional, such as those cyclic siloxanes defined by the formula: [(CH 3 ) 2 SiO] m - where m has a value of 3 to 8 inclusive.
• cyclic siloxanes are respectively hexamethylcyclotrisiloxane, octaniethylcyclotetrasiloxane, decamethylcyclopentasiloxane and dodecamethylcyclohexasiloxane.
• the cyclic siloxanes employed according to this invention ' are relatively volatile materials having boiling points below about 250°C at 760 mm Hg.
• the cyclic siloxanes may be employed as the individual compounds or as mixtures of two or more different cyclic siloxanes.
• silicon containing additives may be used as the grinding aid, such as alkoxy silanes, trimethyl end blocked polydiorganosiloxane, siliconates, or polydiorganosiloxanolates. Both of the latter two types of compounds by definition contain
• Siliconates are defined as a salt of a silanol of the following structure: HOSiR(OZ) 2 .
• the cation, M of this salt may be either an alkaline metal cation or a quaternary ammonium or phosphonium cation.
• siliconates contain the following structure:
• SiOZ structure may be a disiloxane or a higher oligomer. If cross- condensation with a polydiorganosiloxane has occured, then the SiOZ structure links the siliconate salt to a polydiorganosiloxane.
• Preferred siliconates include potassium alkylsiliconates and sodium alkylsiliconates, most preferred being potassium methylsiliconate and sodium methylsiliconate.
• the polydiorganosiloxanolates are defined as salts of the terminal silanol or silanols of a polydiorganosiloxane, and include the same range of cations as do the siliconates.
• Preferred siloxanolates include dipotassium and disodium polydialkylsiloxanolates, the most preferred being dipotassium or disodium polydimethylsiloxanolate, K or
• silanes useful for this invention are represented by the general formula
• R is a methyl, ethyl, propyl or methoxyethyl radical
• R ⁇ is a monovalent hydrocarbon or halogen substituted hydrocarbon radical having from 1 to 4 carbon atoms
• ⁇ n has a value of 3 or 4.
• oligomeric products from partial hydrolysis and condensation of the alkoxy silanes can also be used in the compositions of this invention.
• mixtures and combinations of the materials can also be employed to achieve the results of the invention, such as mixtures of different cyclic siloxanes or different hydroxyl terminated polydiorganosiloxanes, etc., or combinations of a particular cyclic siloxanes and hydroxyl terminated polydiorganosiloxanes, or siliconates, etc.
• the grinding aids of the present invention may be added to the slag or slag/clinker mixture at any time during the grinding process but is preferably added just prior to the commencement of the grinding.
• the grinding aid will be added in the amount of 10 to 20,000 grams per metric ton of slag or slag/clinker mixture.
• the silicon containing grinding aid may be dispersed in appropriate solvents such as hydrocarbons derived products like xylene, toluene, mineral spirits, mineral oils, naphtha, isoparaffin and others that can dilute siloxane based products.
• the grinding aids may be emulsified and thereafter added to the clinker.
• the compositions of the present invention improve grinding efficiency of the slag during grinding, thus reducing the amount of energy consumed during the grinding process.
• concrete made from the slag/clinker containing the additive shows better short and long term compression strength over concrete made having no such grinding aid.
• the present compositions will produce cement having a reduced tendency for gravelling.
• the invention unexpectedly provides increased grinding efficiency and anti-graveling, other anticipated benefits include greater production throughput during and after grinding while handling powdered clinker or cement, and improved resistance to water damage of cured cement or concrete.
• DCC1 is 100% trimethyl silyl endblocked dimethyl siloxane, having a viscosity of 10 (mm)2/s.
• DCC 2 is a commercial grade of methyl trimethoxy silane.
• DCC 3 is a commercial grade of phenyl trimethoxy silane.
• DCC 4 is a commercially available solution of 32% by weight of a sodium methyl siliconate in 68% water.
• DCC 5 is a commercially available solution of 42% by weight of a potassium methyl siliconate in 58% water.
• DCC 6 is a commercially available mixture of cyclic siloxanes comprising 4% decamethyl cyclopentasiloxane and 96% octamethylcyclotetrasiloxane.
• DCC 7 is a commercially available mixture of cyclic and linear siloxanes comprising
• DCC 8 is a commercially available hydroxyl terminated polydimethylsiloxane having a viscosity of 55 to 90 (mm)2/s at 25°C and having a hydroxyl content of 1.0 to 2.5 wt%.
• DCC 9 is made from two components. The first component is used in an amount of 80% and has a viscosity of 2.2 to 3 (mm)2/s. It is a mixture of cyclic siloxanes, comprising about 22% by weight decamethylcyclopentasiloxane and 77% by weight octamethylcyclotetrasiloxane and trace amounts of other dimethylcyclosiloxanes.
• the second component is used in an amount of 20% and is 32% by weight of sodium methyl siliconate in water.
• the two immiscible liquids are mixed in a high shear mixer for 30 minutes, and allowed to separate overnight.
• the clear supernatent is recovered by decantation and the underlying aqueous layer is discarded.
• the slag was obtained from Belgo Mineira, and the slag had a composition of : SiO 2 , 36.04%; Al 2 O 3 , 13.28%; Fe 2 O 3 , 2.30%; CaO, 39.89%; MgO, 6.78%; CO 2 , 0.79%; SO 3 , 0.03%; Fire loss: 0.00.
• the grinding aids were added to the slag in an amount of 200 grams/metric ton of slag. Chrome alloy balls of the following sizes were used in the single chamber mill: 29.8 % were 20 mm in diameter, and the remainder were equally divided between diameters of 40, 50, 60 and 70 mm.
• the slag was then ground for 120 minutes in the ball mill with an average ball mill surface area of about 20 m 2 /ton and filling about 42% of the total void space of ball mill.
• the rotational speed of the ball mill was around 65% of its critical rotational speed.
• a sample of the milled product was analyzed.
• the specific surface area of milled slag designated as the Blaine in m2/Kg, was measured using NBR 7224. The average value of 3 different samples was taken and values with more than 5% variation from the average were discarded, following standards defined by Brazilian Portland Cement Association ABCP and also accepted by cement producers. Blaine is correlated directly with the strength of the resulting cement. The percent of retained material was measured for screen 200 mesh by using standard
• NBR 11579 and for screen 325 mesh by using standard NBR 9202.
• the average value of 3 different samples was taken and the values with more than 5% variation from the average were discarded, following standards defined by Brazilian Portland Cement Association ABCP. Larger mesh numbers correspond to finer mesh openings through which particles can pass.
• the primary purpose of grinding is to reduce the size of the particles being ground. Smaller particles have higher specific surface area and also pass more readily through finer mesh screens.
• the progress of grinding can be followed by periodically measuring the specific surface area or by measuring the percent of particles that pass through mesh screens. We quantitate the percent improvement in grinding efficiency by the following:
• the grinding aides of the present invention also improve the grinding efficiency of slag/clinker mixtures.
• the clinker commonly is produced with a mixture of 3 - 5 parts of limestone and 1 part of clay. This mixture is burned with iron ore and sand in a cement kiln with temperature around 1500 deg. Celsius generating the material named clinker.
• the clinker used in this work was produced by a Brazilian cement producer named Soeicom S.A. located at Vespasiano in Minas Gerais state.
• Compressive strength was measured using methods defined by ABNT (standard NBR
• the standard NBR 7215 is related to the measurement of compressive strength of cylindrical samples having diameter of 50 mm and height of 100 mm. These samples are prepared with a rendering mortar having the following composition (by weight): one part of cement, three parts of standard sand (defined by ABNT standard NBR 7214: 1982) and with a water/cement ratio of 0.48. This rendering mortar is blended with a mechanical mixer and is manually compacted inside a mold using a standard procedure. The molds with the samples are kept in a wet environment for the initial cure and after some time the samples are released from the molds and cured in hydrated lime saturated water until the date of the test.
• the compressive strength method and specification of the machine used to perform this test is defined by
• the additives of the present invention also improve the compression strength of the resulting cement made by grinding the slag/clinker mixtures.
• the improvement when compared to the values obtained with no grinding aid is up to 69% and 41% after 1 and 3 days of curing, respectively.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Ceramic Engineering (AREA)
• Materials Engineering (AREA)
• Structural Engineering (AREA)
• Organic Chemistry (AREA)
• Inorganic Chemistry (AREA)
• Food Science & Technology (AREA)
• Curing Cements, Concrete, And Artificial Stone (AREA)
• Disintegrating Or Milling (AREA)

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• 1998
  • 1998-12-29 BR BR9805843-6A patent/BR9805843A/pt not_active Application Discontinuation
• 1999
  • 1999-12-23 CA CA002358316A patent/CA2358316A1/en not_active Abandoned
  • 1999-12-23 AU AU23913/00A patent/AU2391300A/en not_active Abandoned
  • 1999-12-23 JP JP2000590960A patent/JP2002533297A/ja not_active Withdrawn
  • 1999-12-23 EP EP99967667A patent/EP1144331A1/en not_active Withdrawn
  • 1999-12-23 WO PCT/US1999/031012 patent/WO2000039046A1/en not_active Application Discontinuation
  • 1999-12-23 CN CN99815248A patent/CN1332705A/zh active Pending

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