Metal oxide activated cement

Abstract

A process for making a cement, the cement containing a naturally occurring silicate bound in an organic binder, and a metal oxide. An example process includes dissolving the organic binder at least in part, using an effective amount of a chemical activator. An example process also includes providing the silicate to react with other components of the cement. An example process also includes providing the silicate to participate in crystal growth. An example process also includes providing the silicate so that the cement is a structural load bearing cement.

Claims

1. A process for making a cement, the cement containing a naturally occurring silicate bound in an organic binder, and a metal oxide, the process comprising: dissolving the organic binder at least in part using an effective amount of a chemical activator in order to provide the silicate to react with other components of the cement; providing the silicate to participate in crystal growth; and providing the silicate so that the cement is a structural load bearing cement.

2. The process recited in claim 1, wherein the chemical activator is selected from a group comprising at least one of: a ligand, a chelate, a mineral acid, an organic acid, an amino acid derivative, an alkali, an amphoteric compound, a biochemical, a salt, and an etching agent.

3. The process recited in claim 1, wherein the chemical activator is pyridine N oxide.

4. The process recited in claim 1, wherein the chemical activator is a chelate selected from a group comprising at least one of: EDTA, PBTC, HEDTA, DTPA, oxyquinoline, and oxalic acid.

5. The process recited in claim 1, wherein the chemical activator is boric acid.

6. The process recited in claim 1, wherein the chemical activator is an organic acid selected from a group comprising at least one of: DL-malic acid, a carboxylic acid, citric acid, acetic acid, formic acid, lactic acid, DHBA, gallic acid, and acetylacetone.

7. The process recited in claim 1, wherein the chemical activator is an amino acid selected from a group comprising at least one of: L-histidine, and L-phenylalanine.

8. The process recited in claim 1, wherein the chemical activator is a biochemical selected from a group comprising at least one of: dopamine, and DOPAC.

9. The process recited in claim 1, wherein the chemical activator is monosodium glutamate.

10. The process recited in claim 1, wherein the chemical activator is an etching agent selected from a group comprising at least one of: ammonium difluoride, ammonium fluoride, potassium bifluoride, phosphoric acid, and phosphorous acid.

11. The process recited in claim 1, wherein the metal oxide is a primary metal oxide selected from a group comprising at least one of aluminum oxide, calcium oxide, magnesium oxide, and iron oxide.

12. The process recited in claim 1, wherein the metal oxide is a secondary metal oxide selected from a group comprising at least one of: titanium dioxide (titanium white), zinc oxide (neutral white), iron oxide (mars black), hydrated iron oxide (yellow ochre), and anhydrous iron oxide (red ochre).

13. A process for making a cement, containing a naturally occurring silicate bound in an organic binder, and a metal oxide, comprising: dissolving the binder, at least in part, using an effective amount of a chemical activator so that; dissolution of the binder enables the silicate to react with other components of the cement; dissolution of the binder enables the silicate to participate in crystal growth; dissolution of the binder configures the cement as a structural load bearing cement.

14. A process for making a cement, the cement containing a naturally occurring silicate bound in an organic binder, and a metal oxide, the process comprising: dissolving the organic binder at least in part using an effective amount of a chemical activator in order to provide the silicate to react with other components of the cement; providing the silicate to participate in crystal growth; and providing the silicate so that the cement is a structural load bearing cement; wherein the chemical activator is a chelate selected from a group comprising at least one of: EDTA, PBTC, HEDTA, DTPA, oxyquinoline, and oxalic acid.

Description

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Best Mode

Definitions and Terms

(1) The description in the body of the specification pertains to preferred modes of invention. Accordingly, features recited in the body should not be construed to be essential features of the invention unless explicitly indicated. Further, any reference in the body to the expression invention should be construed to imply a reference to preferred embodiments only.

(2) The recitation of problems recited in the Background Art section above, does not constitute an admission against interest that persons, other than the present inventor, identified the problems in the prior art.

(3) Gesser H D, Applied Chemistry, Springer, 2002, provides a reference source for basic technical terminology used in relation to cements.

(4) Reactants according to one mode of the present invention include: Primary metal oxides are most preferably Aluminum oxide Al.sub.2O.sub.3 and preferably: Calcium oxide CaO; Magnesium oxide MgO Iron oxide Fe.sub.2O.sub.3

(5) Secondary metal oxides are preferably Titanium dioxide TiO.sub.2 (Titanium White) due to its self-cleaning effect and due to its role in the creation of crystal nucleation sites.

(6) Transition metal oxides that form colored pigmentation are preferable, most notably: Zinc oxide ZnO (neutral white) Iron oxide Fe.sub.3O.sub.4 (Mars Black); Hydrated iron oxide Fe.sub.2O.sub.3.H.sub.2O (Yellow Ochre); Anhydrous iron oxide Fe.sub.2O.sub.3 (Red Ochre).

(7) Pozzolanic compounds that are a source of silica bearing minerals or metal silicates (containing SiO.sub.2, Al.sub.2O.sub.3, Fe.sub.2O.sub.3 and CaO). Synthetic compounds having properties similar to Pozzolanic silicates include (hereinafter referred to as synthetic Pozzolanic substitutes): Class F fly ash: Class C fly ash metakaolin kaolin clay zeolite Blast-furnace slag Silica fume; Rice hull ash;

(8) Alkaline silicates are preferably Potassium silicate K.sub.2SiO.sub.3 and preferably: Lithium silicate Li.sub.2SiO.sub.3 Sodium silicate Na.sub.2SiO.sub.3

(9) Preferred organic silica include: vegetable fiber reinforcement including untreated rice hulls; Hemp; Sisal; Bamboo fibers; Caesar-weed; Banana stems; Sugarcane; Date palm; Straw; Coir fibers from coconut husks Natural sponge fibers Wood waste

(10) Water-soluble activators, including in some cases chelates, include: Edetic Acid (EDTA) C.sub.10H.sub.16N.sub.2O.sub.8. (a strong colloidal silica dissolver and a chelate Ammonium Difluoride F.sub.2H.sub.5N Ammonium Fluoride FH.sub.4N Potassium Bifluoride F.sub.2HK Phosphoric Acid H.sub.3O.sub.4P Phosphorous Acid H.sub.3O.sub.3P PBTC Phosphonobutane-tricarboxylic acid C.sub.7H.sub.11O.sub.9P Sodium Glucoheptonate Dihydrate C.sub.7H.sub.13NaO.sub.8.2H.sub.2O HEDTA ethylenediamine-triacetic acid C.sub.10H.sub.18N.sub.2O.sub.7 DTPA Diethylene Triamine Penta Acetic acid C.sub.14H.sub.23N.sub.3O.sub.10 DTPA Pentetric Acid C.sub.14H.sub.23N.sub.3O.sub.10 DL-Malic Acid C.sub.4H.sub.6O.sub.5 Pyridine-N-Oxide C.sub.5H.sub.5NO L-Histidine C.sub.6H.sub.9N.sub.3O.sub.2 L-Phenylalanine C.sub.9H.sub.11NO.sub.2 Oxyquinoline C.sub.9H.sub.7NO Dopamine C.sub.8H.sub.11NO.sub.2 Carboxlic Acids Citric Acid C.sub.6H.sub.8O.sub.7 Acetic Acid C.sub.2H.sub.4O.sub.2 Oxalic Acid C.sub.2H.sub.2O.sub.4 Formic Acid, HCOOH EDTA Edetic Acid C.sub.10H.sub.16N.sub.2O.sub.8 Boric Acid BH.sub.3O.sub.3 Lactic Acid C.sub.3H.sub.6O.sub.3 Acetylacetone C.sub.5H.sub.8O.sub.2 DHBA Catechol C.sub.6H.sub.6O.sub.2 Gallic Acid C.sub.7H.sub.6O.sub.5 DHBA Pyrocatechuic Acid C.sub.7H.sub.6O.sub.4 DOPAC C.sub.8H.sub.8O.sub.4 Fluorone Black C.sub.19H.sub.12O.sub.5 Monosodium Glutamate C.sub.5H.sub.8NNaO.sub.4

Mode for Invention

Industrial Applicability

(11) One embodiment of the present invention uses an alternative aqueous-based solution-colloid processes for manufacturing of modern functional inorganic materials such as concrete, cements, mortars, concrete bricks, stoneware and trowel-able plasters, water-resistant plasterboards, silicate paints.

(12) In one embodiment, according to a hydraulic chelate-activated cement the following properties include (approximately in order of importance): Concrete production, as a substitute cementing material for Portland cement; Embankments and other structural fills (usually for road construction) Waste stabilization and solidification Mineral filler in asphaltic concrete Mine drilling fluid and bore cement Stabilization of soft soils and water harvesting Road sub-base construction As an aggregate substitute material (e.g. for brick production) Waterproof hard wall plasterboard, plaster setting compounds and stucco As a substitute for ceramic floor, wall and paving tiles; As a substitute for concrete and ceramic roofing tiles; Composite insulated panels for house siding and trim, As a binding agent in mineral silicate paints and undercoats; Grout and flow-able fill production Patching mortar for masonry repairs Carbon fiber reinforced auto bodies and boat hulls

(13) Other applications include kitchen counter tops, flotation devices, stucco, decking, fireplace mantles, cinder block, structural insulated panels, blasting grit, recycled plastic lumber, utility poles, railway sleepers, highway sound barriers, marine pilings, door and window frames, sign posts, paving stones, park benches, landscape timbers, planters, pallet blocks, bowling balls and artificial reefs.

(14) Tentative qualitative explanations of some of the processes in preferred embodiments, in use, follow. In the following embodiments, some activators can include chelates, some reactions can by catalytic in nature and some products of reactions can take on the appearance of a mineral polymer.

(15) Alternative aqueous-based solution processes for manufacturing of hard setting functional inorganic silica based materials can be formed from metal alkoxide solutions using embodiments of the present invention. The precursor used in a sol-gel process according to one embodiment of the present invention consists of a metaloid element, colloidal/amorphous silicate and any of a number of organic activators. Metal oxides, such as aluminates, calcium based reactants and titanates are preferred precursors because of their high reactivity towards water. The sol-gel process according to one embodiment of the present invention consists of a series of hydrolysis and condensation reactions of dissolved colloidal silicates.

(16) According to one embodiment, the process consist of: a) dissolution of metal oxide, silicate and metal-silicate precursors by an organic activator to provide the metal ion and all or part of the Si constituents needed, followed by; b) an hydrolysis reaction to generate metal and silicate species and finally; c) condensation of these species and or silicates from the activator to build up a structure having the appearance, under SEM (scanning electron microscopy) of a mineral polymer network structure.

Enhanced Durability

(17) Through the sol-gel process, homogenous, high durability inorganic metal silicates can be made at ambient temperature and at neutral or weakly alkaline PH rather than the high temperature and alkalinity required in conventional approaches for hydraulic cement materials. It is observed from SEM test results that a 3-dimensional gel is formed throughout the sample on curing that has the appearance of a mineral polymer. This pore filling process that incorporates metal silicate crystals provides additional beneficial effects such as higher strength; better wear resistance, greater durability, lower porosity and chemical stability.

Autogenous Heating

(18) Arguably, calcium complexes are not spent as they form cement crystals, but rather continue to work on their substrate. Complex molecules can be argued to diffuse naturally in solution through pores and voids of cement, masonry and plaster materials. Both water and space must be present for the crystals to form. The space is often provided by cracks that form due to damage to the substrate caused by weathering, drying shrinkage, or other mechanisms such as chloride or acid attack.

Pigment Binder

(19) Metal oxides in the form of mineral pigments are incorporated into the silica matrix rather than being present as an inert filler. Activators are also shown to form silica compounds with the most common pigments that are used as coloring oxides in cement. These pigment crystals are integral with the coating and less maintenance is required at the surface if there is chipping or cracking thus exposing the interior concrete. The pigments have been examined by SEM and reacted chemically to some extent in the cement crystal increasing process.

Self-Cleaning Capabilities

(20) When titanium dioxide (TiO.sub.2) absorbs ultraviolet light, it becomes and breaks down pollutants that come into contact with the concrete's surface. Several recent investigations have reported the ability of titanium dioxide and silica complexes (TiO2.SiO2), in combination with UV light, to kill various microbial and removed air pollution [J. S. Dalton, P. A. Janes, N. G. Jones, J. A. Nicholson, Hallam, G. C. Allen, Photocatalytic oxidation of NO.sub.x gases using TiO.sub.2: a surface spectroscopic approach, Environmental Pollution 120 (2002) pp. 415-422.]. Moreover, it was previously claimed by thermal analysis and SEM, that TiO.sub.2 cannot be reacted with Portland cement and water, instead forming a fine non-reactive filler to cement that modifies the hydration reaction primarily due to dilution [Thanongsak Nochaiya and Arnon Chaipanich, The effect of nano-TiO.sub.2 addition on Portland cement properties, Cement and Concrete Research Laboratory, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand, 50200]. The addition of an activator, which can include a chelate according to one embodiment of the present invention, has shown that titanium dioxide and silica complexes have been formed under the influence of the activator (which can have a catalytic effect in one embodiment).

(21) Scanning electron microscope (SEM) analysis of the coating confirms that in the case of a catalyst activator according to one embodiment, that a ligand, forms chelate complexes within the coating. Metal ions have formed insoluble precipitates with silica, a prominent example being calcium silicate hydrate, the primary product of the hydration of Portland cement that is primarily responsible for the strength in cement based materials. SEM images show that the secondary hydration products grow in the form of fibers on both C.sub.3S scaffold, Ca(OH).sub.2 and CaCO.sub.3 crystals. SEMQuant microanalysis of the fibrous particles indicates calcium metasilicate CaOSiO.sub.2 as wollastonite.

(22) In the influence of a Oxalic Acid C.sub.3H.sub.2O.sub.4 chelate the element spectra graph shows the presence of other metal silicates including: sodium metasilicate Na.sub.2SiO.sub.3.nH.sub.2O; Aluminium silicate Al.sub.2SiO.sub.3; Potassium Silicate K.sub.2SiO.sub.3; Titanium Silicate TiO.sub.2SiO.sub.2; and iron Silicate Fe.sub.2SiO.sub.4.